Pontine Micturition Center Research Articles

Effects of water avoidance stress on peripheral and central responses during bladder filling in the rat: A multidisciplinary approach to the study of urologic chronic pelvic pain syndrome (MAPP) research network study.

Stress plays a role in the exacerbation and possibly the development of functional lower urinary tract disorders. Chronic water avoidance stress (WAS) in rodents is a model with high construct and face validity to bladder hypersensitive syndromes, such as interstitial cystitis/bladder pain syndrome (IC/BPS), characterized by urinary frequency and bladder hyperalgesia and heightened stress responsiveness. Given the overlap of the brain circuits involved in stress, anxiety, and micturition, we evaluated the effects chronic stress has on bladder function, as well as its effects on regional brain activation during bladder filling. Female Wistar-Kyoto rats were exposed to WAS (10 days) or sham paradigms. One day thereafter, cystometrograms were obtained during titrated bladder dilation, with visceromotor responses (VMR) recorded simultaneously. Cerebral perfusion was assessed during passive bladder distension (20-cmH2O) following intravenous administration of [14C]-iodoantipyrine. Regional cerebral blood flow was quantified by autoradiography and analyzed in 3-dimensionally reconstructed brains with statistical parametric mapping. WAS animals compared to controls demonstrated a decreased pressure threshold and visceromotor threshold triggering the voiding phase. At 20-cmH2O, VMR was significantly greater in WAS animals compared to controls. WAS animals showed greater activation in cortical regions of the central micturition circuit, including the posterior cingulate, anterior retrosplenial, somatosensory, posterior insula, orbital, and anterior secondary (“supplementary”) motor cortices, as well as in the thalamus, anterior hypothalamus, parabrachial and Barrington nuclei, and striatum. Seed analysis showed increased functional connectivity of WAS compared to control animals of the posterior cingulate cortex to the pontine parabrachial nucleus; of the Barrington nucleus to the anterior dorsal midline and ventrobasilar thalamus and somatosensory and retrosplenial cortices; and of the posterior insula to anterior secondary motor cortex. Our findings show a visceral hypersensitivity during bladder filling in WAS animals, as well as increased engagement of portions of the micturition circuit responsive to urgency, viscerosensory perception and its relay to motor regions coordinating imminent bladder contraction. Results are consistent with recent findings in patients with interstitial cystitis, suggesting that WAS may serve as an animal model to elucidate the mechanisms leading to viscerosensitive brain phenotypes in humans with IC/BPS.

Effect of P. ginseng on the expression of c-Fos in the brain of Wistar rats with testosterone induced benign prostatic hyperplasia

The lower urinary tract symptoms (LUTS) show in benign prostatic hyperplasia (BPH). The three major micturition centers in brain are pontine micturition center (PMC), ventrolateral periaqueductal gray (vlPAG), and medial preopticnucleus (MPA) regions. Previous study showed that c-Fos expression change was associated with LUTS. In present study, the effect of P. ginseng on c-Fos expression in PMC, vlPAG, and MPA regions in rat brain was tested. P. ginseng is the four year-old Korean ginseng. It was collected at the department of medicinal crop research (Eumsunggun, Chungbuk, Korea) in September 2010. The four groups (n = 6) are control group, BPH-induced group, BPHinduced and P. ginseng-treated group, and BPH-induced and finasteride-treated group. BPH in rats was induced by testosterone. After 4 weeks, all animals were sacrificed to evaluate c-Fos expression in PMC, vlPAG, and MPA regions in rat brain. The c-Fos expression was evaluated in the regions of rat brain by immunohistochemistry (IHC). Present results showed that c-Fos expressions in PMC, vl-PAG, and MPA regions in brain of rats in the BPH-induced group were higher compared to c-fos expression of the control group. The increased c-Fos expression in three regions (PMC, vlPAG, and MPA) were decreased by treatment with P. ginseng (200 mg/kg). These results suggest that P. ginseng has an inhibitory effect on the symptoms of BPH and is associated with regulation of c-Fos expression in the brain in a testosterone induced BPH rat model.

A Quantitative Analysis of the Distribution of CRH Neurons in Whole Mouse Brain.

Corticotropin-releasing hormone (CRH), with widespread expression in the brain, plays a key role in modulating a series of behaviors, including anxiety, arousal, motor function, learning and memory. Previous studies have focused on some brain regions with densely distributed CRH neurons such as paraventricular hypothalamic nucleus (PVH) and bed nuclei of the stria terminalis (BST) and revealed some basic structural and functional knowledge of CRH neurons. However, there is no systematic analysis of brain-wide distribution of CRH neurons. Here, we performed a comprehensive study of CRH neurons in CRH-IRES-Cre;Ai3 mice via automatic imaging and stereoscopic cell counting in a whole mouse brain. We acquired four datasets of the CRH distributions with co-localized cytoarchitecture at a voxel resolution of 0.32 μm × 0.32 μm × 2 μm using brain-wide positioning system (BPS). Next, we precisely located and counted the EYFP-labeled neurons in different regions according to propidium iodide counterstained anatomical reference using Neuronal Global Position System. In particular, dense EYFP expression was found in piriform area, BST, central amygdalar nucleus, PVH, Barrington’s nucleus, and inferior olivary complex. Considerable CRH neurons were also found in main olfactory bulb, medial preoptic nucleus, pontine gray, tegmental reticular nucleus, external cuneate nucleus, and midline thalamus. We reconstructed and compared the soma morphology of CRH neurons in 11 brain regions. The results demonstrated that CRH neurons had regional diversities of both cell distribution and soma morphology. This anatomical knowledge enhances the current understanding of the functions of CRH neurons. These results also demonstrated the ability of our platform to accurately orient, reconstruct and count neuronal somas in three-dimension for type-specific neurons in the whole brain, making it feasible to answer the fundamental neuroscience question of exact numbers of various neurons in the whole brain.

Effects of pedunculopontine nucleus stimulation on human bladder function.

The pedunculopontine nucleus (PPN) is a deep brain stimulation target for Parkinson's disease (PD). Unilateral PPN stimulation has been described in a previous case report to provoke urinary frequency, urgency and detrusor overactivity, due to probable activation of the pontine micturition center. Our aim was to evaluate the effect of bilateral PPN DBS on urodynamic parameters and to investigate the likely mechanisms using probabilistic tractography. Six male PD subjects with bilateral PPN deep brain stimulators were recruited. Urodynamic bladder filling assessments were carried out with the stimulators ON and OFF. Two subjects also had diffusion-weighted and T1-weighted MRI scans performed and probabilistic tractography was carried out to describe white matter connections with the stimulated area. Five subjects completed urodynamic testing. PPN DBS did not give rise to detrusor overactivity or lower sensory thresholds during bladder filling. However, there was a significant increase in maximal bladder capacity with stimulation: mean bladder volume at maximal capacity was 199 mL (range 103-440) ON stimulation compared with 131 mL (range 39-230) OFF stimulation. Tractography demonstrated extensive connectivity to cortical and subcortical regions, some of which have been implicated in bladder control. Fiber pathways also passed close to the vicinity of the pontine micturition center. Bilateral PPN DBS did not have a detrimental effect on urodynamic filling parameters or produce detrusor overactivity, but did slightly increase maximal capacity. Possible mechanisms include long-range connectivity or local effects at the pontine micturition center.

Barrington's nucleus: Neuroanatomic landscape of the mouse “pontine micturition center”

AbstractBarrington's nucleus (Bar) is thought to contain neurons that trigger voiding and thereby function as the “pontine micturition center.” Lacking detailed information on this region in mice, we examined gene and protein markers to characterize Bar and the neurons surrounding it. Like rats and cats, mice have an ovoid core of medium‐sized Bar neurons located medial to the locus coeruleus (LC). Bar neurons express a GFP reporter for Vglut2, develop from a Math1/Atoh1 lineage, and exhibit immunoreactivity for NeuN. Many neurons in and around this core cluster express a reporter for corticotrophin‐releasing hormone (BarCRH). Axons from BarCRH neurons project to the lumbosacral spinal cord and ramify extensively in two regions: the dorsal gray commissural and intermediolateral nuclei. BarCRH neurons have unexpectedly long dendrites, which may receive synaptic input from the cerebral cortex and other brain regions beyond the core afferents identified previously. Finally, at least five populations of neurons surround Bar: rostral‐dorsomedial cholinergic neurons in the laterodorsal tegmental nucleus; lateral noradrenergic neurons in the LC; medial GABAergic neurons in the pontine central gray; ventromedial, small GABAergic neurons that express FoxP2; and dorsolateral glutamatergic neurons that express FoxP2 in the pLC and form a wedge dividing Bar from the dorsal LC. We discuss the implications of this new information for interpreting existing data and future experiments targeting BarCRH neurons and their synaptic afferents to study micturition and other pelvic functions.

Barrington's nucleus: Neuroanatomic landscape of the mouse "pontine micturition center".

Barrington's nucleus (Bar) is thought to contain neurons that trigger voiding and thereby function as the "pontine micturition center." Lacking detailed information on this region in mice, we examined gene and protein markers to characterize Bar and the neurons surrounding it. Like rats and cats, mice have an ovoid core of medium-sized Bar neurons located medial to the locus coeruleus (LC). Bar neurons express a GFP reporter for Vglut2, develop from a Math1/Atoh1 lineage, and exhibit immunoreactivity for NeuN. Many neurons in and around this core cluster express a reporter for corticotrophin-releasing hormone (BarCRH ). Axons from BarCRH neurons project to the lumbosacral spinal cord and ramify extensively in two regions: the dorsal gray commissural and intermediolateral nuclei. BarCRH neurons have unexpectedly long dendrites, which may receive synaptic input from the cerebral cortex and other brain regions beyond the core afferents identified previously. Finally, at least five populations of neurons surround Bar: rostral-dorsomedial cholinergic neurons in the laterodorsal tegmental nucleus; lateral noradrenergic neurons in the LC; medial GABAergic neurons in the pontine central gray; ventromedial, small GABAergic neurons that express FoxP2; and dorsolateral glutamatergic neurons that express FoxP2 in the pLC and form a wedge dividing Bar from the dorsal LC. We discuss the implications of this new information for interpreting existing data and future experiments targeting BarCRH neurons and their synaptic afferents to study micturition and other pelvic functions.

P2Y6-deficiency increases micturition frequency and attenuates sustained contractility of the urinary bladder in mice

The role of the P2Y6 receptor in bladder function has recently attracted a great deal of attention in lower urinary tract research. We conducted this study to determine contributions of the P2Y6 receptor in lower urinary tract function of normal phenotypes by comparing P2Y6-deficient mice and wild-type mice. In in vivo experiments, P2Y6-deficient mice had more frequent micturition with smaller bladder capacity compared to wild-type mice; however, there was no difference between these groups in bladder-filling pressure/volume relationships during cystometry under decerebrate, unanaesthetized conditions. Analysis of in vivo bladder contraction revealed significant difference between the 2 groups, with P2Y6-deficient mice presenting markedly shorter bladder contraction duration but no difference in peak contraction pressure. However, analysis of in vitro experiments showed no P2Y6 involvements in contraction and relaxation of bladder muscle strips and in ATP release by mechanical stimulation of primary-cultured urothelial cells. These results suggest that the P2Y6 receptor in the central nervous system, dorsal root ganglion, or both is involved in inhibition of bladder afferent signalling or sensitivity in the pontine micturition centre and that the receptor in the detrusor may be implicated in facilitation to sustain bladder contraction force.

MP82-11 THE MOLECULAR BIOLOGIC STUDY ABOUT THE CIRCADIAN RHYTHMIC CONTROL OF MICTURITION FUNCTION

You have accessJournal of UrologyUrodynamics/Lower Urinary Tract Dysfunction/Female Pelvic Medicine: Basic Research & Pathophysiology II1 Apr 2017MP82-11 THE MOLECULAR BIOLOGIC STUDY ABOUT THE CIRCADIAN RHYTHMIC CONTROL OF MICTURITION FUNCTION Su Jin Kim, Young Sam Cho, and Khae Hawn Kim Su Jin KimSu Jin Kim More articles by this author , Young Sam ChoYoung Sam Cho More articles by this author , and Khae Hawn KimKhae Hawn Kim More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2017.02.2558AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES We investigate the relationship between circadian rhythm and water metabolism and expression of circadian clock gene in peripheral bladder and central micturition centers. METHODS Normal mouse (C57BL/6J male; WT) and circadian gene knock-out mouse (per1-/-per2-/-; PDK) was used. Water intake and urine output according to the circadian rhythm was checked using metabolic cage in 12:12 LD photoperiodic cycle (LD cycle) and constant dark cycle (DD cycle) in both WT and PDK. Circadian clock gene expression rhythm in bladder was evaluated with the activation of Per2 promotor. Circadian expression of representative clock gene was analysed; Bmal1 and Rev-erba and rhythmic expression of circadian clock gene was analysed according to time in three main functional tissue related with micturition (detrusor smooth muscle, sphincter smooth muscle and urothelium) in both WT and PDK. Expression of clock gene in central micturition center was analysed; lumbar spinal cord, pontine micturition center (PMC) and ventrolateral periaqueductal gray (vlPAG), real-time RT-PCR was used in every 3 hours for 24 hours in DD cycle in both WT and PDK. RESULTS Water intake and urine output was increased in night-time of WT in LD and DD cycle. However this tendency was disappeared to PDK. Water intake and urine output was increased in night-time of WT in LD cycle and DD cycle was disappeared in PDK and this means that circadian rhythm is due to endogenous circadian rhythm not outside environment. We can observe the activation of Per2 promotor approximately 24 hours of rhythm. And this finding represents that bladder peripheral clock was well functioned. In case of WT, characteristic circadian expression pattern of clock gene in all three tissues. On the contrary, 24 hours of promoter activated rhythm was not observed in PDK. In spinal level, unlike PDK, clock gene expression rhythm was observed in WT. But, there was no definite rhythmicity of circadian expression pattern of clock gene in the upper region of central micturition center like PMC and vlPAG. CONCLUSIONS Endogenous circadian rhythm in water intake and urine output is exist approximately 24 hours. Bladder peripheral clock gene is existed in main functional tissue related with micturition. But in terms of central micturition center, we can find circadian clock gene expression only in lumbar spinal cord. Further study about the reason why absence of circadian clock in upper central micturition center and finding other circadian control mechanism in upper micturition center is needed. © 2017FiguresReferencesRelatedDetails Volume 197Issue 4SApril 2017Page: e1101 Advertisement Copyright & Permissions© 2017MetricsAuthor Information Su Jin Kim More articles by this author Young Sam Cho More articles by this author Khae Hawn Kim More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

MP85-06 BRAIN NETWORKS CONTROLLING BLADDER FILLING AND VOIDING

You have accessJournal of UrologyUrodynamics/Lower Urinary Tract Dysfunction/Female Pelvic Medicine: Neurogenic Voiding Dysfunction I1 Apr 2017MP85-06 BRAIN NETWORKS CONTROLLING BLADDER FILLING AND VOIDING Hanneke Verstegen, John Mathai, Mark Zeidel, and Joel Geerling Hanneke VerstegenHanneke Verstegen More articles by this author , John MathaiJohn Mathai More articles by this author , Mark ZeidelMark Zeidel More articles by this author , and Joel GeerlingJoel Geerling More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2017.02.2668AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Lower urinary tract symptoms (LUTS) are common and poorly understood; treatment is often ineffective. Failure of neural control of bladder function likely contributes to LUTS symptoms in many patients. Prior studies have shown that the pontine micturition center (PMC) directly controls voiding. Within the PMC corticotropin releasing hormone neurons (PMCCRH) project axons directly to spinal sacral cord nuclei that control bladder contraction. Here we show that PMCCRH neurons are critical for voiding, and identify neurons, particularly in the ventrolateral periaqueductal gray (PAGVL) which directly modulate PMCCRH and alter voiding. METHODS We inject adeno-associated viruses expressing proteins in a Cre-dependent fashion into anatomically defined regions of mice expressing Cre recombinase in specific neural types, to cause highly selective expression of these probes in target neuron populations. We monitor conscious voiding with micturition video thermography (MVT), and CMG under anesthesia while monitoring/stimulating specific neuron groups. RESULTS Stimulating PMCCRH neurons using designer receptors exclusively activated by designer drugs (DREADDs) produces urinary frequency in awake mice and on anesthetized CMG. Also, ablating PMCCRH neurons by selective expression of diphtheria toxin A disrupts normal voiding and the normal CMG voiding reflex. To identify neurons which provide input to PMCCRH, we used modified rabies virus and cholera toxin B labeling of PMCCRH and confirmed our results with viral anterograde tracing. Afferents to PMCCRH are located in PAGVL, the preoptic area, the lateral hypothalamic area, and other sites. Because sacral afferents sensing bladder filling project to PAGVL we determined the impact of stimulating Glutamatergic or GABA-ergic neurons (PAGVLGLUT or PAGVLGABA) in this region. Chemogenetic or optogenetic stimulation of PAGVLGLUT neurons leads to voiding and detrusor contraction. By contrast, chemogenetic or optogenetic activation of PAGVLGABAinhibits voiding and delays detrusor contraction on CMG. CONCLUSIONS 1. PMCCRH are driver neurons for detrusor contraction/voiding. 2. PAGVLGLUT project to PMCCRH, and when fired drive voiding/detrusor contraction. 3. PAGVLGABA project to PMCCRH and inhibit voiding/detrusor contraction. PAGVL, which receives bladder-based sacral afferents, likely controls bladder filling, and is a potential target in efforts to control urge incontinence and urgency symptoms of LUTS. © 2017FiguresReferencesRelatedDetails Volume 197Issue 4SApril 2017Page: e1150 Advertisement Copyright & Permissions© 2017MetricsAuthor Information Hanneke Verstegen More articles by this author John Mathai More articles by this author Mark Zeidel More articles by this author Joel Geerling More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

MP85-07 FUNCTIONAL NEUROIMAGING OF URINE STORAGE AND VOIDING IN MICE

You have accessJournal of UrologyUrodynamics/Lower Urinary Tract Dysfunction/Female Pelvic Medicine: Neurogenic Voiding Dysfunction I1 Apr 2017MP85-07 FUNCTIONAL NEUROIMAGING OF URINE STORAGE AND VOIDING IN MICE Bryce MacIver, Aaron Grant, Timothy Pagliaro, David Alsop, John Mathai, and Mark Zeidel Bryce MacIverBryce MacIver More articles by this author , Aaron GrantAaron Grant More articles by this author , Timothy PagliaroTimothy Pagliaro More articles by this author , David AlsopDavid Alsop More articles by this author , John MathaiJohn Mathai More articles by this author , and Mark ZeidelMark Zeidel More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2017.02.2669AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Lower urinary tract symptoms (LUTS) are common and poorly understood; treatment is often ineffective. Failure of neural control of bladder function likely contributes to LUTS symptoms in many patients. Mice are continent and serve as excellent models of LUTS, in part because they can be manipulated genetically. To relate what is learned in mice to humans, we have developed functional MRI methods for mice which mirror those in humans. Such methods will allow us to compare directly the activation patterns of mouse and human brains during bladder filling and voiding, in normal and disease states. METHODS Mice are anesthetized with urethane and a catheter is implanted in the bladder dome. Blood Oxygen Level Detection Magnetic Resonance Imaging (BOLD-MRI) is carried out in a Bruker 9.4T magnet with a 4 element mouse brain phased array coil. A series of 2D multislice gradient echo-planar images are acquired every 2s, while the mouse undergoes cystometry. 25 slices are acquired with slices of 500µm, interslice distance 600µm and in-plane resolution of 250µm. Imaging occurs over a 45 minute time frame during which the mouse undergoes 10-15 voiding cycles (CMG). Data are analyzed with Statistical Parameter Mapping (SPM12) software using mouse brain adaptations. Linear modeling proceeds in 2 stages; first by providing a statistical map of the brain of individual animals and second by combining results across all animals in a group. RESULTS Preliminary results on female C57BL6/J (n =5) with a fixed effects analysis identified candidate regions across the brain with clear activation in the right Pontine Micturition Center (PMC) observed, which was confirmed by a region based random effects analysis. Negative contrast identified more extensive regions such as the periaqueductal gray and inferior colliculus with an indication that these regions are ″switched off″ during the transition to voiding. CONCLUSIONS Although technically challenging due to the small size, BOLD-MRI on mice is feasible and reveals regions of brain activation related to voiding cycles. Development of this technique along with fine mapping of brain circuits related to voiding will help define mechanisms of LUTS in mouse models that should be translatable to human disease. © 2017FiguresReferencesRelatedDetails Volume 197Issue 4SApril 2017Page: e1150 Advertisement Copyright & Permissions© 2017MetricsAuthor Information Bryce MacIver More articles by this author Aaron Grant More articles by this author Timothy Pagliaro More articles by this author David Alsop More articles by this author John Mathai More articles by this author Mark Zeidel More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

MP82-04 TRANSCRIPTIONAL REGULATION OF CORTICOTROPIN RELEASING FACTOR

You have accessJournal of UrologyUrodynamics/Lower Urinary Tract Dysfunction/Female Pelvic Medicine: Basic Research & Pathophysiology II1 Apr 2017MP82-04 TRANSCRIPTIONAL REGULATION OF CORTICOTROPIN RELEASING FACTOR Lizath Aguiniga, Anthony Schaeffer, and David Klumpp Lizath AguinigaLizath Aguiniga More articles by this author , Anthony SchaefferAnthony Schaeffer More articles by this author , and David KlumppDavid Klumpp More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2017.02.2551AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Interstitial cystitis (IC) patients suffer from chronic pelvic pain and bladder dysfunction. IC patients have altered cortisol levels suggesting dysregulation of the hypothalamic-pituitary adrenal (HPA) axis and suffer from exacerbated symptoms in response to high stress. Corticotropin-releasing factor (CRF) is the initiator of the HPA axis and mediates stress responses and voiding control, where increased CRF levels in Barrington's nucleus induce bladder dysfunction. Arachidonic acid (AA) metabolites have been shown to induce CRF expression, however the transcriptional mediators of this modulation are unknown. Here we identify transcription factors that mediate AA-induced CRF gene expression. METHODS We used MIRAGE software to identify candidate transcription factor binding sites in a 1kb region of the human CRF gene promoter. We identified a peroxisome proliferator activated hormone response element (PPRE) and two Xenobiotic Responsive Element (XRE) sites as candidate mediators of AA-dependent CRF induction. Site-directed mutations of the PPRE and XRE sites were generated in a CRF-luciferase reporter plasmid to evaluate responses to AA and the impact of AhR and PPAR gamma expressed in HEK 293T cells. The hypothalamic neuronal cell line N42 was used to evaluate the role of AhR and PPAR gamma in native promoter regulation by RT PCR. We also generated mice that have PPAR gamma and AhR knocked-out in CRF-expressing cells and characterized voiding activity. RESULTS AA induction in the PPRE mutant resulted in increased CRF promoter activity compared to WT, whereas XRE1 had decreased activity. The mutation of both XRE1 and XRE2 resulted in decreased responsiveness to AA. Over-expression of PPAR gamma alone showed no change, while over-expression of AhR alone showed a significant increase in AA-induced CRF expression; this was inhibited by over-expression of both AhR and PPAR gamma in HEK 293T cells. Over-expression of AhR in N42 cells resulted in increased CRF mRNA in response to AA induction. AhR conditional knockout mice showed increased voiding frequency. CONCLUSIONS These results suggest AhR binding to the XRE sites modulates AA-dependent CRF gene expression. PPAR gamma inhibits AA-dependent CRF gene expression. Continued studies will use mouse models to examine the in vivo role of AhR and PPAR gamma inhibitors to modulate voiding activity. © 2017FiguresReferencesRelatedDetails Volume 197Issue 4SApril 2017Page: e1098 Advertisement Copyright & Permissions© 2017MetricsAuthor Information Lizath Aguiniga More articles by this author Anthony Schaeffer More articles by this author David Klumpp More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Assessment of serum level of corticotropin-releasing factor in primary nocturnal enuresis

Primary nocturnal enuresis is one of the sleep related phenomena characterized by disruption in the relationship between arousal and urination. Corticotropin-releasing factor (CRF) is a neurohormone released from the paraventricular nucleus of the hypothalamus into the median eminence to elicit release of adrenocorticotrophin from the anterior pituitary. It may act to modulate autonomic function and behavior in concert with the endocrine effects. Conflicting animal studies about the role of CRF in micturition, either facilitating or inhibiting, have been raised. It was suggested to be a novel target for treatment of urinary disorders based on the finding that manipulation of CRF in the pontine micturition circuit could affect urodynamic function. The aim was to throw light on the possible role of CRF in primary monosymptomatic nocturnal enuresis by assessing its serum level. Twenty-nine children aged 8-14 years complaining of primary monosymptomatic nocturnal enuresis and 16 age- and sex-matched healthy children with good toilet control day and night were recruited to the study. History taking, clinical examination, and assessment of serum CRF levels in the morning and evening (9 a.m. and 9 p.m.) were carried out for all patients and controls. A positive family history of enuresis was detected in 82.8% of enuretic patients. Serum levels of CRF (both morning and evening) were significantly lower in patients than in controls. Several animal studies suggested that CRF in descending projections from Barrington's nucleus to the lumbosacral parasympathetic neurons is inhibitory to micturition, which supports our results and the assumption that reduction of the evening serum CRF level could have a role in the occurrence of primary monosymptomatic nocturnal enuresis. No significant difference was found between morning and evening CRF serum levels in either cases or controls, which negates our assumption of having a rhythmic pattern of release (figure). No correlations with age were found. According to their history, all our enuretic patients were deep sleepers. Deep sleep and difficult arousal were found to have a major role in primary monosymptomatic nocturnal enuresis. It was proposed that CRF function may allow arousal to occur before micturition to facilitate preparative behaviors. A lower CRF level may explain deep-sleep pattern in children with enuresis. CRF was deficient in our enuretic children, which may draw attention to the possible pathophysiological implications in primary nocturnal enuresis (either at the level of loss of inhibitory effect on micturition or lack of arousal in response to bladder distension). Further proof studies are recommended.

Distribution of corticotropin-releasing factor neurons in the mouse brain: a study using corticotropin-releasing factor-modified yellow fluorescent protein knock-in mouse.

We examined the morphological features of corticotropin-releasing factor (CRF) neurons in a mouse line in which modified yellow fluorescent protein (Venus) was expressed under the CRF promoter. We previously generated the CRF-Venus knock-in mouse, in which Venus is inserted into the CRF gene locus by homologous recombination. In the present study, the neomycin phosphotransferase gene (Neo), driven by the pgk-1 promoter, was deleted from the CRF-Venus mouse genome, and a CRF-Venus∆Neo mouse was generated. Venus expression is much more prominent in the CRF-Venus∆Neo mouse when compared to the CRF-Venus mouse. In addition, most Venus-expressing neurons co-express CRF mRNA. Venus-expressing neurons constitute a discrete population of neuroendocrine neurons in the paraventricular nucleus of the hypothalamus (PVH) that project to the median eminence. Venus-expressing neurons were also found in brain regions outside the neuroendocrine PVH, including the olfactory bulb, the piriform cortex (Pir), the extended amygdala, the hippocampus, the neocortices, Barrington's nucleus, the midbrain/pontine dorsal tegmentum, the periaqueductal gray, and the inferior olivary nucleus (IO). Venus-expressing perikarya co-expressing CRF mRNA could be observed clearly even in regions where CRF-immunoreactive perikarya could hardly be identified. We demonstrated that the CRF neurons contain glutamate in the Pir and IO, while they contain gamma-aminobutyric acid in the neocortex, the bed nucleus of the stria terminalis, the hippocampus, and the amygdala. A population of CRF neurons was demonstrated to be cholinergic in the midbrain tegmentum. The CRF-Venus∆Neo mouse may be useful for studying the structural and functional properties of CRF neurons in the mouse brain.

Central Control Circuit for Context-Dependent Micturition

Urine release (micturition) serves an essential physiological function as well as a critical role in social communication in many animals. Here, we show a combined effect of olfaction and social hierarchy on micturition patterns in adult male mice, confirming the existence of a micturition control center that integrates pro- and anti-micturition cues. Furthermore, we demonstrate that a cluster of neurons expressing corticotropin-releasing hormone (Crh) in the pontine micturition center (PMC) is electrophysiologically distinct from their Crh-negative neighbors and sends glutamatergic projections to the spinal cord. The activity of PMC Crh-expressing neurons correlates with and is sufficient to drive bladder contraction, and when silenced impairs micturition behavior. These neurons receive convergent input from widespread higher brain areas that are capable of carrying diverse pro- and anti-micturition signals, and whose activity modulates hierarchy-dependent micturition. Taken together, our results indicate that PMC Crh-expressing neurons are likely the integration center for context-dependent micturition behavior.

Effects of Panax ginseng on the nerve growth factor expression in testosterone induced benign prostatic hyperplasia

The prostatic hyperplasia in benign prostatic hyperplasia (BPH) leads to obstructive micturition symptoms. Previous studies showed that pontine micturition center (PMC), ventrolateral periaqueductal gray (vlPAG), and medial preopticnucleus (MPA) regions in the brain have been known to regulate the urinary bladder function. The present study shows the influences of Panax ginseng on nerve growth factor (NGF) expressions in PMC, vlPAG, and MPA regions in the brain. Wistar rats were used for the present study. The rats split into four groups; 4 groups (n = 6) in control group, BPH-induced group, BPH-induced and P. ginseng-treated group, and BPH-induced and finasteride-treated group. BPH in rats was induced by testosterone and the animals were evaluated for NGF expression in PMC, vlPAG, and MPA regions in the brain. The NGF expression was identified using immunohistochemistry (IHC). The NGF expression by IHC showed spots with dark brown color. In our results, NGF expressions in PMC, vlPAG, and MPA regions in the brainstem of the BPH-induced group showed increase than the control animal. These increased NGF expressions in three regions were decreased using treatment with P. ginseng (200 mg/kg). These results suggest that P. ginseng has therapeutic effects on the symptoms of BPH and is associated with the regulation of NGF expression in the brain. In conclusion, the administration of P. ginseng helps nerve growth factor activation.

The Foxb1‐expressing neurons of the ventrolateral hypothalamic parvafox nucleus project to defensive circuits

ABSTRACTThe parvafox nucleus is an elongated structure that is lodged within the ventrolateral hypothalamus and lies along the optic tract. It comprises axially located parvalbumin (Parv)‐positive neurons and a peripheral cuff of Foxb1‐expressing ones. In the present study, injections of Cre‐dependent adenoviral constructs were targeted to the ventrolateral hypothalamus of Foxb1/Cre mice to label specifically and map the efferent connections of the Foxb1‐expressing subpopulation of neurons of the parvafox nucleus. These neurons project more widely than do the Parv‐positive ones and implicate a part of the axons known to emanate from the lateral hypothalamus. High labeling densities were found in the dorsolateral and the upper lateral portion of the periaqueductal gray (PAG), the Su3 and PV2 nuclei of the ventrolateral PAG, the cuneiform nucleus, the mesencephalic reticular formation, and the superior colliculus. Intermediate densities of terminals were encountered in the septum, bed nucleus of the stria terminalis, substantia innominata, various thalamic and hypothalamic nuclei, pedunculopontine nucleus, Barrington's nucleus, retrofacial nucleus, and retroambigual nucleus. Scattered terminals were observed in the olfactory bulbs, the prefrontal cortex and the lamina X of the cervical spinal cord. Because the terminals were demonstrated to express the glutamate transporter VGlut2, the projections are presumed to be excitatory. A common denominator of the main target sites of the Foxb1‐positive axons of the parvafox nucleus appears to be an involvement in the defensive reactions to life‐threatening situations. The hypothalamic parvafox nucleus may contribute to the autonomic manifestations that accompany the expression of emotions. J. Comp. Neurol. 524:2955–2981, 2016. © 2016 Wiley Periodicals, Inc.

The Foxb1-expressing neurons of the ventrolateral hypothalamic parvafox nucleus project to defensive circuits.

The parvafox nucleus is an elongated structure that is lodged within the ventrolateral hypothalamus and lies along the optic tract. It comprises axially located parvalbumin (Parv)-positive neurons and a peripheral cuff of Foxb1-expressing ones. In the present study, injections of Cre-dependent adenoviral constructs were targeted to the ventrolateral hypothalamus of Foxb1/Cre mice to label specifically and map the efferent connections of the Foxb1-expressing subpopulation of neurons of the parvafox nucleus. These neurons project more widely than do the Parv-positive ones and implicate a part of the axons known to emanate from the lateral hypothalamus. High labeling densities were found in the dorsolateral and the upper lateral portion of the periaqueductal gray (PAG), the Su3 and PV2 nuclei of the ventrolateral PAG, the cuneiform nucleus, the mesencephalic reticular formation, and the superior colliculus. Intermediate densities of terminals were encountered in the septum, bed nucleus of the stria terminalis, substantia innominata, various thalamic and hypothalamic nuclei, pedunculopontine nucleus, Barrington's nucleus, retrofacial nucleus, and retroambigual nucleus. Scattered terminals were observed in the olfactory bulbs, the prefrontal cortex and the lamina X of the cervical spinal cord. Because the terminals were demonstrated to express the glutamate transporter VGlut2, the projections are presumed to be excitatory. A common denominator of the main target sites of the Foxb1-positive axons of the parvafox nucleus appears to be an involvement in the defensive reactions to life-threatening situations. The hypothalamic parvafox nucleus may contribute to the autonomic manifestations that accompany the expression of emotions. J. Comp. Neurol. 524:2955-2981, 2016. © 2016 Wiley Periodicals, Inc.

Central control of visceral pain and urinary tract function.

Afferent input from Aδ and C-fibres innervating the urinary bladder are processed differently by the brain, and have different roles in signaling bladder sensation. Aδ fibres that signal bladder filling activate a spino-bulbo-spinal loop, which relays in the midbrain periaqueductal grey (PAG) and pontine micturition centre (PMC). The excitability of this circuitry is regulated by tonic GABAergic inhibitory processes. In humans and socialised animals micturition is normally under volitional control and influenced by a host of psychosocial factors. Higher nervous decision-making in a social context to 'go now' or 'do not go' probably resides in frontal cortical areas, which act as a central control switch for micturition. Exposure to psychosocial stress can have profoundly disruptive influence on the process and lead to maladaptive changes in the bladder. During sleeping the voiding reflex threshold appears to be reset to a higher level to promote urinary continence. Under physiological conditions C-fibre bladder afferents are normally silent but are activated in inflammatory bladder states and by intense distending pressure. Following prolonged stimulation visceral nociceptors sensitise, leading to a lowered threshold and heightened sensitivity. In addition, sensitization may occur within the central pain processing circuitry, which outlasts the original nociceptive insult. Visceral nociception may also be influenced by genetic and environmental influences. A period of chronic stress can produce increased sensitivity to visceral pain that lasts for months. Adverse early life events can produce even longer lasting epigenetic changes, which increase the individual's susceptibility to developing visceral pain states in adulthood.

Pudendal but not tibial nerve stimulation inhibits bladder contractions induced by stimulation of pontine micturition center in cats.

This study examined the possibility that pudendal nerve stimulation (PNS) or tibial nerve stimulation (TNS) inhibits the excitatory pathway from the pontine micturition center (PMC) to the urinary bladder. In decerebrate cats under α-chloralose anesthesia, electrical stimulation of the PMC (40 Hz frequency, 0.2-ms pulse width, 10-25 s duration) using a microelectrode induced bladder contractions >20 cmH2O amplitude when the bladder was filled to 60-70% capacity. PNS or TNS (5 Hz, 0.2 ms) at two and four times the threshold (2T and 4T) to induce anal or toe twitch was applied to inhibit the PMC stimulation-induced bladder contractions. Propranolol, a nonselective β-adrenergic receptor antagonist, was administered intravenously (1 mg/kg i.v.) to determine the role of sympathetic pathways in PNS/TNS inhibition. PNS at both 2T and 4T significantly (P < 0.05) reduced the amplitude and area under the curve of the bladder contractions induced by PMC stimulation, while TNS at 4T facilitated the bladder contractions. Propranolol completely eliminated PNS inhibition and TNS facilitation. This study indicates that PNS, but not TNS, inhibits PMC stimulation-induced bladder contractions via a β-adrenergic mechanism that may occur in the detrusor muscle as a result of reflex activity in lumbar sympathetic nerves. Neither PNS nor TNS activated a central inhibitory pathway with synaptic connections to the sacral parasympathetic neurons that innervate the bladder. Understanding the site of action involved in bladder neuromodulation is important for developing new therapies for bladder disorders.

Dopamine is produced in the rat spinal cord and regulates micturition reflex after spinal cord injury

Dopamine (DA) neurons in the mammalian central nervous system are thought to be restricted to the brain. DA-mediated regulation of urinary activity is considered to occur through an interaction between midbrain DA neurons and the pontine micturition center. Here we show that DA is produced in the rat spinal cord and modulates the bladder reflex. We observed numerous tyrosine hydroxylase (TH)+ neurons in the autonomic nuclei and superficial dorsal horn in L6–S3 spinal segments. These neurons are dopamine-β-hydroxylase (DBH)− and some contain detectable dopamine decarboxylase (DDC), suggesting their capacity to produce DA. Interestingly, following a complete thoracic spinal cord injury (SCI) to interrupt supraspinal projections, more TH+ neurons emerged in the lumbosacral spinal cord, coincident with a sustained, low level of DA expression there and a partially recovered micturition reflex. Non-selective blockade of spinal DA receptors reduced bladder activity whereas activation of spinal D2-like receptors increased bladder activity and facilitated voiding. Additionally, depletion of lumbosacral TH+ neurons with 6-hydroxydopamine (6-OHDA) decreased bladder non-voiding contractions and voiding efficiency. Furthermore, injecting the transsynaptic neuronal tracer pseudorabies virus (PRV) into the bladder detrusor labeled TH+ cells in the lumbosacral cord, confirming their involvement in spinal micturition reflex circuits. These results illustrate that DA is synthesized in the rat spinal cord; plasticity of lumbosacral TH+ neurons following SCI may contribute to DA expression and modulate the spinal bladder reflex. Thus, spinally-derived DA and receptors could be a novel therapeutic target to improve micturition recovery after SCI.