Median Raphe Research Articles

Postnatal development of hippocampal CA2 structure and function during the emergence of social recognition of peers.

It is now well-established that the hippocampal CA2 region plays an important role in social recognition memory in adult mice. The CA2 is also important for the earliest social memories, including those that mice have for their mothers and littermates, which manifest themselves as a social preference for familiarity over novelty. The role of the CA2 in the development of social memory for recently encountered same-age conspecifics, that is, peers, has not been previously reported. Here, we used a direct social interaction test to characterize the emergence of novelty preference for peers during development and found that at the end of the second postnatal week, pups begin to significantly prefer novel over familiar peers. Using chemogenetic inhibition at this time, we showed that CA2 activity is necessary for the emergence of novelty preference and for the ability to distinguish never encountered fromrecently encountered peers. In adulthood, the CA2 region is known to integrate a large number of inputs from various sources, many of which participate in social recognition memory, but previous studies have not determined whether these afferents are present at adult levels by the end of the second postnatal week. To explore the development of CA2 inputs, we used immunolabeling and retrograde adenovirus circuit tracing and found that, by the end of the second postnatal week, the CA2 is innervated by many regions, including the dentate gyrus, supramammillary nucleus of the hypothalamus, the lateral entorhinal cortex, and the median raphe nucleus. Using retroviral labeling of postnatally generated granule cells in the dentate gyrus, we found that mossy fiber projections to the CA2 mature faster during development than those generated in adulthood. Together, our findings indicate that the CA2 is partially mature in afferent connectivity by the end of the second postnatal week, connections that likely facilitate the emergence of social recognition memory and preference for novel peers.

Smegma remains a diagnostic dilemma

A healthy, uncircumcised, two-year-old male presented with a six-month history of an asymptomatic, mobile, yellowish nodule near the base of the glans penis. An examination revealed a 1 × 0.5 cm, yellowish-white, soft, and mobile nodule between the glans and the foreskin of the penis (Fig. 1). No signs of infection or irritation were noted and the rest of the body was free of lesions. Ultrasound revealed soft tissue thickening, excluded a solid formation. The urine dipstick test was negative. Based on the clinical features, the diagnosis of a smegma cyst was reached. A smegma cyst is composed of epithelial debris, fat, and proteins and is covered by a well-formed, epithelial wall [1]. When there is no covering sac of lump, it is called the smegma pearl. Frequently located on the ventral surface of the glans, within the subpreputial space, the urethral meatus is not affected and the prepuce is partially retractable. It develops in uncircumcised patients. As phimosis resolves the inner foreskin, adhesions begin to undergo a gradual process of separation from the glans penis. Smegma may become entrapped during this process, forming smooth, palpable pearls [2]. It is neither damaging nor irritating. The differential diagnosis concerns either acquired or congenital penile cysts (e.g., trichilemmal cysts, preputial Epstein pearls, dermoid cysts, median raphe cysts, para meatal cysts, mucoid cysts, epidermoid cysts, pilosebaceous cysts, juvenile xanthogranuloma) [3]. Given the paucity of published reports, these collections are a diagnostic challenge for clinicians unfamiliar with this entity and a source of concern for parents. Smegma pearls are a benign entity. Bimanual retraction or gentle expression may be performed with a risk of paraphimosis, irritation, and recurrence [2,3]. Thus, these techniques must be discussed with the parents considering the spontaneous resolution. In the case of chronic evolution, smegma may evolve to preputial stones in adults and the elderly. No investigations or treatments are required. Only monitoring and parental reassurance are recommended.

Spatial organization of olfactory receptor gene choice in the complete V1R-related ORA family of zebrafish

The vertebrate sense of smell employs four main receptor families for detection of odors, among them the V1R/ORA family, which is unusually small and highly conserved in teleost fish. Zebrafish possess just seven ORA receptors, enabling a comprehensive analysis of the expression patterns of the entire family. The olfactory organ of zebrafish is representative for teleosts, cup-shaped, with lamella covered with sensory epithelium protruding into the cup from a median raphe. We have performed quantitative in situ hybridization on complete series of horizontal cryostat sections of adult zebrafish olfactory organ, and have analysed the location of ora-expressing cells in three dimensions, radial diameter, laminar height, and height-within-the-organ. We report broadly overlapping, but distinctly different distributions for all ora genes, even for ora3a and ora3b, the most recent gene duplication. Preferred positions in different dimensions are independent of each other. This spatial logic is very similar to previous reports for the much larger families of odorant receptor (or) and V2R-related olfC genes in zebrafish. Preferred positions for ora genes tend to be more central and more apical than those we observed for these other two families, consistent with expression in non-canonical sensory neuron types.

Top-down projections of the prefrontal cortex to the ventral tegmental area, laterodorsal tegmental nucleus, and median raphe nucleus.

Anatomical and functional evidence suggests that the PFC is fairly unique among all cortical regions, as it not only receives input from, but also robustly projects back to mesopontine monoaminergic and cholinergic cell groups. Thus, the PFC is in position to exert a powerful top-down control over several state-setting modulatory transmitter systems that are critically involved in the domains of arousal, motivation, reward/aversion, working memory, mood regulation, and stress processing. Regarding this scenario, the origin of cortical afferents to the ventral tegmental area (VTA), laterodorsal tegmental nucleus (LDTg), and median raphe nucleus (MnR) was here compared in rats, using the retrograde tracer cholera toxin subunit b (CTb). CTb injections into VTA, LDTg, or MnR produced retrograde labeling in the cortical mantle, which was mostly confined to frontal polar, medial, orbital, and lateral PFC subdivisions, along with anterior- and mid-cingulate areas. Remarkably, in all of the three groups, retrograde labeling was densest in layer V pyramidal neurons of the infralimbic, prelimbic, medial/ventral orbital and frontal polar cortex. Moreover, a lambda-shaped region around the apex of the rostral pole of the nucleus accumbens stood out as heavily labeled, mainly after injections into the lateral VTA and LDTg. In general, retrograde PFC labeling was strongest following injections into MnR and weakest following injections into VTA. Altogether, our findings reveal a fairly similar set of prefrontal afferents to VTA, LDTg, and MnR, further supporting an eminent functional role of the PFC as a controller of major state-setting mesopontine modulatory transmitter systems.

Raphe and ventrolateral medulla proteomics in epilepsy and sudden unexpected death in epilepsy.

Brainstem nuclei dysfunction is implicated in sudden unexpected death in epilepsy. In animal models, deficient serotonergic activity is associated with seizure-induced respiratory arrest. In humans, glia are decreased in the ventrolateral medullary pre-Botzinger complex that modulate respiratory rhythm, as well as in the medial medullary raphe that modulate respiration and arousal. Finally, sudden unexpected death in epilepsy cases have decreased midbrain volume. To understand the potential role of brainstem nuclei in sudden unexpected death in epilepsy, we evaluated molecular signalling pathways using localized proteomics in microdissected midbrain dorsal raphe and medial medullary raphe serotonergic nuclei, as well as the ventrolateral medulla in brain tissue from epilepsy patients who died of sudden unexpected death in epilepsy and other causes in diverse epilepsy syndromes and non-epilepsy control cases (n = 15–16 cases per group/region). Compared with the dorsal raphe of non-epilepsy controls, we identified 89 proteins in non-sudden unexpected death in epilepsy and 219 proteins in sudden unexpected death in epilepsy that were differentially expressed. These proteins were associated with inhibition of EIF2 signalling (P-value of overlap = 1.29 × 10−8, z = −2.00) in non-sudden unexpected death in epilepsy. In sudden unexpected death in epilepsy, there were 10 activated pathways (top pathway: gluconeogenesis I, P-value of overlap = 3.02 × 10−6, z = 2.24) and 1 inhibited pathway (fatty acid beta-oxidation, P-value of overlap = 2.69 × 10−4, z = −2.00). Comparing sudden unexpected death in epilepsy and non-sudden unexpected death in epilepsy, 10 proteins were differentially expressed, but there were no associated signalling pathways. In both medullary regions, few proteins showed significant differences in pairwise comparisons. We identified altered proteins in the raphe and ventrolateral medulla of epilepsy patients, including some differentially expressed in sudden unexpected death in epilepsy cases. Altered signalling pathways in the dorsal raphe of sudden unexpected death in epilepsy indicate a shift in cellular energy production and activation of G-protein signalling, inflammatory response, stress response and neuronal migration/outgrowth. Future studies should assess the brain proteome in relation to additional clinical variables (e.g. recent tonic–clonic seizures) and in more of the reciprocally connected cortical and subcortical regions to better understand the pathophysiology of epilepsy and sudden unexpected death in epilepsy.

Therapeutic Effects of Quetiapine and 5-HT1A Receptor Agonism on Hyperactivity in Dopamine-Deficient Mice

Some diseases that are associated with dopamine deficiency are accompanied by psychiatric symptoms, including Parkinson’s disease. However, the mechanism by which this occurs has not been clarified. Previous studies found that dopamine-deficient (DD) mice exhibited hyperactivity in a novel environment. This hyperactivity is improved by clozapine and donepezil, which are used to treat psychiatric symptoms associated with dopamine deficiency (PSDD). We considered that DD mice could be used to study PSDD. In the present study, we sought to identify the pharmacological mechanism of PSDD. We conducted locomotor activity tests by administering quetiapine and drugs that have specific actions on serotonin (5-hydroxytryptamine [5-HT]) receptors and muscarinic receptors. Changes in neuronal activity that were induced by drug administration in DD mice were evaluated by examining Fos immunoreactivity. Quetiapine suppressed hyperactivity in DD mice while the 5-HT1A receptor antagonist WAY100635 inhibited this effect. The number of Fos-positive neurons in the median raphe nucleus increased in DD mice that exhibited hyperactivity and was decreased by treatment with quetiapine and 5-HT1A receptor agonists. In conclusion, hyperactivity in DD mice was ameliorated by quetiapine, likely through 5-HT1A receptor activation. These findings suggest that 5-HT1A receptors may play a role in PSDD, and 5-HT1A receptor-targeting drugs may help improve PSDD.

Structural and metabolic activity differences in serotonergic cell groups in a rat model of individual differences of emotionality and stress reactivity

Serotonin regulates a diverse set of functions, including emotional behavior, cognition, sociability, appetite, and sleep. Serotonin is also a key trophic factor that shapes neurodevelopmental processes. Genetic and environmental factors that drive individual differences in the serotonergic system have the capacity to impact brain structure and behavior, and likely contribute to pathophysiological processes involved in neuropsychiatric disorders. Using adult rats selectively bred for low novelty exploration (Low Responders, LR), we previously demonstrated pronounced increases in the levels of their anxiety- and depression- relevant behaviors as compared to the selectively bred High Novelty Responder (HR) rats. These behavioral differences were accompanied by alterations in the expression of genes that regulate serotonin synthesis in the brainstem, and its signaling in the forebrain. The present study extends these observations with a focus on the organization and the metabolism of brainstem serotonin cell groups that provide serotonergic innervation of the hippocampus and other limbic regions of male HR/LR rats. Using design-based stereology, we found the median raphe (MnR) in adult male LR rats contains increased number of serotonergic neurons as compared to the HRs. This is preceded by an increase in the metabolic activity of the caudal dorsal raphe (DRC) and the intrafascicular DR (DRI) during early postnatal development. These findings suggest that structural and functional differences in the raphe-limbic projections shape behavioral inhibition throughout the lifespan.

1314-P: Activating GABAergic Neurons in the Caudal Preoptic Area Promote Energy Expenditure in Diet-Induced Obesity

Obesity results from the imbalance between energy intake and energy expenditure, which are tightly regulated by dynamic hypothalamic circuits. Our goal is to identify and leverage hypothalamic components that promote energy expenditure for successful weight loss. Vesicular communication by ventromedial hypothalamic nucleus (VMN) steroidogenic factor 1 (Sf1) neurons is required for maintaining body weight, due at least in part to stimulating metabolic activity in adipose tissue, but the mechanistic details are unclear. VMNSf1 neurons efferently communicate with relatively few places in the brain but the most prominent projections are in the most caudal regions of the preoptic area (cPOA) (+0.1 to -0.3mm bregma, lateral to the suprachiasmatic nucleus) . We tested the hypothesis that GABAergic cPOA neurons promote energy expenditure and weight loss by activating either GABAergic or glutamatergic neurons via hM3dq, using vGATCre (vesicular GABAergic transporter) or vGLUT2Cre (vesicular glutamatergic transporter 2) in diet-induced obese male mice. Activating vGATcPOA neurons reduced body weight and adiposity without altering food intake. Activating vGLUT2cPOA neurons reduced body weight and food intake but did not reduce adiposity. Activating vGLUT2cPOA neurons reduced core body temperature, but not vGATcPOA neurons. We are currently investigating the mechanisms for how vGATcPOA neurons reduce adiposity. Weight loss is not likely mediated by direct inhibition of vGLUT2cPOA neurons because diet induced obese male mice with CNO-initiated signaling of hM4di in vglut2cPOA neurons does not reduce adiposity or body weight. Alternatively, vGATcPOA neurons may communicate with a distinct efferent system. Indeed, vGATcPOA, but not vGLUT2cPOA, neurons project to the lateral hypothalamus and medial raphe. Future studies will reveal the functional connection between VMNSf1 neurons and vGATcPOA neurons, and the descending circuitry that promotes energy expenditure. Disclosure R.Basu: None. A.J.Elmendorf: Research Support; Eli Lilly and Company. C.A.Mahler: Stock/Shareholder; AstraZeneca, Pfizer Inc. J.Flak: Research Support; Eli Lilly and Company. Funding American Diabetes Association (17-INI-15) ; IU CDMD NIH/NIDDK (P30 DK097512)

Effects of prenatal exposure to fluoxetine on circadian rhythmicity in the locomotor activity and neuropeptide Y and 5-HT expression in male and female adult Wistar rats.

Serotonin (5-HT) reuptake inhibitors, such as fluoxetine, are the most prescribed antidepressant for maternal depression. In this sense, it exposes mothers and the brains of infants to increased modulatory and trophic effects of serotonergic neurotransmission. 5-HT promotes essential brain changes throughout its development, which include neuron migration, differentiation and organisation of neural circuitries related to emotional, cognitive and circadian behavior. Early exposure to the SSRIs induces long-term effects on behavioral and neural serotonergic signalisation. We have aimed to evaluate the circadian rhythm of locomotor activity and the neurochemical content, neuropeptide Y (NPY) and 5-HT in three brain areas: intergeniculate leaflet (IGL), suprachiasmatic nuclei (SCN) and raphe nuclei (RN), at two zeitgebers (ZT6 and ZT18), in male and female rat's offspring early exposed (developmental period GD13-GD21) to fluoxetine (20 mg/kg). First, we have conducted daily records of the locomotor activity rhythm using activity sensors coupled to individual cages over 4 weeks. We have lastly evaluated the immunoreactivity of NPY in both SCN and IGL, as well the 5-HT expression in the dorsal and medial RN. In summary, our results showed that (1) prenatal fluoxetine affects phase entrainment of the rest/activity rhythm at ZT6 and ZT18, more in male than female specimens, and (2) modulates the NPY and 5-HT expression. Here, we show male rats are more susceptible to phase entrainment and the NPY and 5-HT misexpression compared to female ones. The sex differences induced by early exposure to fluoxetine in both the circadian rhythm of locomotor activity and the neurochemical expression into SCN, IGL and midbrain raphe are an important highlight in the present work. Thus, our results may help to improve the knowledge on neurobiological mechanisms of circadian rhythms and are relevant to understanding the "broken brains" and behavioral abnormalities of offspring early exposed to antidepressants.

The Effects of Mild Traumatic Brain Injury (mTBI) on Serotonergic Gene Expression

Traumatic brain injury (TBI) is a risk factor for suicide. Approximately 1.7 million TBIs occur each year and new TBI cases in the U.S. military have more than doubled in the last 5 years. The majority of military TBIs are mild in severity and can lead to chronic symptoms including, impulsivity, emotional instability, and impaired inhibition. Impulsivity is one of the most frequent behavioral changes seen following mTBI and involves poor response inhibition and/or poor decision making. Also, impulsivity is a key risk factor for suicide. The serotonergic system is an important modulator of impulsivity and, thus, a molecular target for understanding the behavioral changes in impulsivity that occur following mTBI. One major source of serotonin in the brain is the raphe nuclei in the pons. The serotonergic neurons in the raphe nuclei project to the prefrontal cortex, frontal cortex and hippocampus and are involved in many cognitive processes related to impulsivity and suicidality. In addition, both animal and human research indicates that the brainstem is affected in mTBI, particularly, in the lateral fluid percussion model utilized in this study. This provides additional support for the notion that mTBI may lead to dysfunction of the serotonin producing raphe nuclei located in the brain stem. In this study, changes in serotonergic gene expression in the raphe nuclei and target regions including the prefrontal cortex, frontal cortex and hippocampus were assessed using qRT‐PCR. Rats sustained a single mTBI induced using the lateral fluid percussion model and were sacrificed three months following injury. Brains were extracted, flash frozen, sectioned at 300um and tissue for the raphe nuclei and target regions was collected using a 1.5 mm tissue punch. RNA was extracted from the tissue punches, reverse transcribed into cDNA and qRT‐PCR was performed. The hypothesis states that mTBI leads to altered expression of serotonin related genes in the raphe nuclei and/or raphe nuclei target regions including the prefrontal cortex, frontal cortex, and hippocampus. Results show altered expression levels of tryptophan hydroxylase and serotonin transporter genes in both the medial raphe and dorsal raphe nuclei in mTBI rats compared to SHAM control rats. Changes in expression levels of the 5HT1A and 5HT2A receptor genes were also seen in the frontal cortex, prefrontal cortex, and ventral hippocampus. The current study serves to provide evidence for a link between TBI and altered serotonin levels to better understand the molecular mechanisms underlying impulsivity and suicidality in humans following TBI.

Serotonin facilitates late-associative plasticity via synaptic tagging/cross-tagging and capture at hippocampal CA2 synapses in male rats.

Synaptic plasticity in the hippocampal Cornu Ammonis (CA) subfield, CA2, is tightly regulated. However, CA2 receives projections from several extra-hippocampal modulatory nuclei that release modulators that could serve to fine-tune plasticity at CA2 synapses. Considering that there are afferent projections from the serotonergic median raphe to hippocampal CA2, we hypothesized that the neuromodulator serotonin (5-hydroxytryptamine; 5-HT) could modulate CA2 synaptic plasticity. Here, we show that bath-application of serotonin facilitates the persistence of long-term depression (LTD) at the CA3 Schaffer collateral inputs to CA2 neurons (SC-CA2) when coupled to a weak low frequency electrical stimulation, in acute rat hippocampal slices. The observed late-LTD at SC-CA2 synapses was protein synthesis- and N-methyl-D-aspartate receptor (NMDAR)-dependent. Moreover, this late-LTD at SC-CA2 synapses paves way for the associative persistence of transient forms of LTD as well as long-term potentiation to long-lasting late forms of plasticity through synaptic tagging and cross-tagging respectively, at the entorhinal cortical synapses of CA2. We further observe that the 5-HT-mediated persistence of activity-dependent LTD at SC-CA2 synapses is blocked in the presence of the brain-derived neurotrophic factor scavenger, TrkB/Fc.

Architectural pattern of different cells lining the olfactory epithelium of long-whiskered catfish, Sperata aor (Hamilton)

The structural organization of the olfactory epithelium in Sperata aor was studied by light as well as scanning electron microscopy. The elongated olfactory organ comprised of 52-54 primary lamellae assorted on both sides of narrow median raphe. The middle dorsal part of the olfactory lamellae was characterised with linguiform processes. Sensory and non-sensory areas were distributed separately on each olfactory lamella. The sensory epithelium occupied in the middle linguiform process, whereas the basal part of lamellae was covered with non-sensory epithelium. The sensory epithelium was composed of morphologically distinct two types of receptor neurons either ciliated or microvillous. The non-sensory epithelium contained mucous cells and supporting cells with inconspicuous microridges. The orientation of different cells lining the olfactory epithelium was discussed in light of their functional significance.

Studies on the morphology of the olfactory organ in the freshwater teleost, Labeo bata (Hamilton

The structural components of the olfactory apparatus of Labeo bata (Hamilton, 1822) were studied morphologically as well as histologically. The oval shaped olfactory rosette was comprised of 24-26 lamellae of different sizes on each side of the median raphe. Histologically each lamella was composed of two layers of olfactory epithelium separated by narrow central core which made up of loose connective tissues, nerve fibres and blood vessels. The sensory olfactory epithelium contained principally three types of receptor cells: primary, secondary and microvillous cells. The non-sensory epithelium was typified with a series of mucous cells, stratified epithelial cells and mast cells. Basal cells were situated at the base of the epithelium, adjacent to the central core. Various cells on the olfactory epithelium were correlated with their functional consequence of fish concerned.

Rare case cystic scrotal lymphangioma presented as a hydrocele.

Introduction and importanceCystic scrotal lymphangiomas are very uncommon lesions caused by congenital lymphatic malformation. These tumors are usually located in the neck and axilla, occasionally in the mediastinum, retroperitoneum, and thigh. The scrotum and perineum are the least frequented sites. They present as painless scrotal swelling and are easily misdiagnosed as hydrocele. We present here a case of cystic scrotal lymphangioma in a school-aged child who presented to us with a massive scrotal swelling.Case presentationWe present here a case of a 6-year-old child who presented with scrotal swelling, which was sonographically identified as chronic hydrocele. The right testis could be felt separately from the mass, and the left scrotum was normal. Scrotal ultrasound reveals multiple cystic lesions with septa in the right hemiscrotum extending to the proximal inguinal canal. Median raphe incision and excision of the lobulated mass Cyst testicular lymphangioma was confirmed histopathologically.Clinical discussionCystic lymphangiomas are benign congenital tumors with no identifiable cause. The majority of lymphangiomas (90%) appear during the first two years of life, and half of them are present at birth. Lymphangiomas are categorized into three types: capillary, cavernous lymphangiomas, and cystic hygromas. A scrotal lymphangioma is frequently misdiagnosed as a hydrocele, inguinal hernia, hematocele, varicocele, or even testis torsion. In our case, the diagnosis was made by ultrasonography with Doppler and confirmed by a biopsy of an excised mass lesion. The scrotum is a very uncommon site for cystic lymphangioma.ConclusionA cystic or septate cystic mass discovered intra-operatively should not be dismissed as a complex hydrocele, since cystic lymphangiomas predictably recur if incompletely resected. A proper diagnosis of the scrotal lymphangioma and its extent using the US is essential for planning an appropriate surgical approach.

Congenital perineal defect with rectal duplication and extreme hypospadias\u2014a rare association

BackgroundCongenital perineal hernia is an extremely rare entity with only 10 cases having been reported in literature. We report a newborn with exposed bowel loops coming out through a defect in the perineum to the right of the median raphe and propose the term perineoschisis for this abnormality. The exposed bowel loops were a sequestered segment of colon. The baby also had extreme perineal hypospadias and left undescended testis.Case presentationA term neonate, born of caesarean section, was noted at birth to have exposed bowel loops visible in the perineum. The bowel loops were not covered by any membrane. To avoid injury to the exposed bowel loops and setting in of infection, the baby was taken up for emergency surgery. At laparotomy, the bowel loops were traced from duodeno–jejunal junction to ileocecal junction and sigmoid colon and rectum. No loops were seen herniating outside from the abdomen through the perineum opening. The extruded bowel loops were sequestered and ending blindly close to the rectum. The sequestered bowel loops were excised completely and perineum reconstruction was done.ConclusionThe extruded bowel loops would appear to be a form of colonic duplication with the duplicated colonic loops herniating outside through an opening in the perineum. Since the bowel loops were lying to the right of median raphe and were not covered by hernia sac or any other membrane we propose the term perineoschisis for this abnormality. The baby also had extreme hypospadias with a perineal meatus, bifid scrotum and penoscrotal transposition. This association of herniated duplicated colon with extreme hypospadias is hitherto unreported to the best of our knowledge.

Clozapine prevented social interaction deficits and reduced c-Fos immunoreactivity expression in several brain areas of rats exposed to acute restraint stress.

In the present study, we evaluate the effect of acute restraint stress (15 min) of male Wistar rats on social interaction measurements and c-Fos immunoreactivity (c-Fos-ir) expression, a marker of neuronal activity, in areas involved with the modulation of acute physical restraint in rats, i.e., the paraventricular nucleus of the hypothalamus (PVN), median raphe nucleus (MnR), medial prefrontal cortex (mPFC), cingulate prefrontal cortex (cPFC), nucleus accumbens (NaC), hippocampus (CA3), lateral septum (LS) and medial amygdala (MeA). We considered the hypothesis that restraint stress exposure could promote social withdrawal induced by the activation of the hypothalamic-pituitary-adrenocortical (HPA) axis, and increase c-Fos expression in these limbic forebrain areas investigated. In addition, we investigated whether pretreatment with the atypical antipsychotic clozapine (5 mg/kg; I.P.) could attenuate or block the effects of restraint on these responses. We found that restraint stress induced social withdrawal, and increased c-Fos-ir in these areas, demonstrating that a single 15 min session of physical restraint of rats effectively activated the HPA axis, representing an effective tool for the investigation of neuronal activity in brain regions sensitive to stress. Conversely, pretreatment with clozapine, prevented social withdrawal and reduced c-Fos expression. We suggest that treatment with clozapine exerted a preventive effect in the social interaction deficit, at least in part, by blocking the effect of restraint stress in brain regions that are known to regulate the HPA-axis, including the cerebral cortex, hippocampus, hypothalamus, septum and amygdala. Further experiments will be done to confirm this hypothesis.

A serpiginous lesion of scrotum

BackgroundMedian raphe cyst is usually benign and asymptomatic male genitalia lesions. Although uncommon, infection may be a complication.Case presentationWe report the case of a 4-year-old child presented to the emergency department for a serpiginous and redness lesion extended from the basis of the penis until the perineum. An infected median raphe cyst was suspected, and the patient underwent surgical treatment and antibiotic therapy with complete resolution of symptoms. Liquid culture resulted positive for Serratia Marcescens.ConclusionInfection is a rare complication, especially in childhood. To prevent relapses and clinical symptoms, the majority of authors recommend surgical excision followed by primary closure. In case of infections caused by Serratia Marcescens, chronic granulomatous disease should always be rule out.

Neurodegeneration in the centrally-projecting Edinger\u2013Westphal nucleus contributes to the non-motor symptoms of Parkinson\u2019s disease in the rat

BackgroundThe neuropathological background of major depression and anxiety as non-motor symptoms of Parkinson’s disease is much less understood than classical motor symptoms. Although, neurodegeneration of the Edinger–Westphal nucleus in human Parkinson’s disease is a known phenomenon, its possible significance in mood status has never been elucidated. In this work we aimed at investigating whether neuron loss and alpha-synuclein accumulation in the urocortin 1 containing (UCN1) cells of the centrally-projecting Edinger–Westphal (EWcp) nucleus is associated with anxiety and depression-like state in the rat.MethodsSystemic chronic rotenone administration as well as targeted leptin–saporin-induced lesions of EWcp/UCN1 neurons were conducted. Rotarod, open field and sucrose preference tests were performed to assess motor performance and mood status. Multiple immunofluorescence combined with RNAscope were used to reveal the functional–morphological changes. Two-sample Student’s t test, Spearman’s rank correlation analysis and Mann–Whitney U tests were used for statistics.ResultsIn the rotenone model, besides motor deficit, an anxious and depression-like phenotype was detected. Well-comparable neuron loss, cytoplasmic alpha-synuclein accumulation as well as astro- and microglial activation were observed both in the substantia nigra pars compacta and EWcp. Occasionally, UCN1-immunoreactive neuronal debris was observed in phagocytotic microglia. UCN1 peptide content of viable EWcp cells correlated with dopaminergic substantia nigra cell count. Importantly, other mood status-related dopaminergic (ventral tegmental area), serotonergic (dorsal and median raphe) and noradrenergic (locus ceruleus and A5 area) brainstem centers did not show remarkable morphological changes. Targeted partial selective EWcp/UCN1 neuron ablation induced similar mood status without motor symptoms.ConclusionsOur findings collectively suggest that neurodegeneration of urocortinergic EWcp contributes to the mood-related non-motor symptoms in toxic models of Parkinson’s disease in the rat.

Serotonin-1A receptor activation in the median raphe nucleus improves response learning-based strategy in 192IgG saporin-induced cognitive impairments

Deficits in the translation between egocentric-allocentric strategies may become another diagnostic mark for neurodegenerative disorders, especially Alzheimer's disease. Regarding the specific regional distribution of serotonin-1A receptor in brain areas mediating allocentric (externally-centered) spatial navigation to the escape location, here we studied the effects of median raphe nucleus serotonin-1A autoreceptors stimulation, [8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT); 4 μg/0.5 μl saline], of a selective cholinergic denervation by intracerebroventricular administration of the 192IgG saporin (1μl/each ventricle), on male Wistar rats search strategies in a Morris maze during acquisition, and before probe sessions. Despite some evidence of spatial hippocampal dependent knowledge to those PBS/Saline animals, their performance dropped to chance levels on probe trial. Therefore, we considered two probabilities and first analyzed the ability of the rats to make better use of one or more strategies. We showed statistically significant increases in the distances associated with egocentric (body-centered) non-spatial strategies, random searching in particular, in 192IgG/8OH rats, which led to their improved performance. Second, considering to what extent a shift in search strategy use improves performance indicated that 8-OH-DPAT alone did not affect learning since it appeared the related performance was impaired over days. However, the strategy choices made by 192IgG/8OH rats increased performance by more than 12% compared to 192IgG/Saline rats, an effect reversed with pre-treatment by serotonin-1A receptor antagonist, N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl) cyclohexane-carboxamide (WAY 100635). The results strongly suggest the potential role of serotonergic system, via the serotonin-1A receptors, in spatial navigation. We argue that the receptors are of interest as therapeutic targets that can be used against age-related cognitive decline.

Median Raphe Nonserotonergic Neurons Modulate Hippocampal Theta Oscillations

Hippocampal theta oscillations (HTOs) during rapid eye movement (REM) sleep play an important role in mnemonic processes by coordinating hippocampal and cortical activities. However, it is not fully understood how HTOs are modulated by subcortical regions, including the median raphe nucleus (MnR). The MnR is thought to suppress HTO through its serotonergic outputs. Here, our study on male mice revealed a more complex framework indicating roles of nonserotonergic MnR outputs in regulating HTO. We found that nonselective optogenetic activation of MnR neurons at theta frequency increased HTO amplitude. Granger causality analysis indicated that MnR theta oscillations during REM sleep influence HTO. By using three transgenic mouse lines, we found that MnR serotonergic neurons exhibited little or no theta-correlated activity during HTO. Instead, most MnR GABAergic neurons and Vglut3 neurons respectively increased and decreased activities during HTO and exhibited hippocampal theta phase-locked activities. Although MnR GABAergic neurons do not directly project to the hippocampus, they could modulate HTO through local Vglut3 and serotonergic neurons as we found that MnR GABAergic neurons monosynaptically targeted Vglut3 and serotonergic neurons. Additionally, pontine wave recorded from the MnR during REM sleep accompanied nonserotonergic activity increase and HTO acceleration. These results suggest that MnR nonserotonergic neurons modulate hippocampal theta activity during REM sleep, which regulates memory processes.SIGNIFICANCE STATEMENT The MnR is the major source of serotonergic inputs to multiple brain regions including the hippocampus and medial septal area. It has long been thought that those serotonergic outputs suppress HTOs. However, our results revealed that MnR serotoninergic neurons displayed little firing changes during HTO. Instead, MnR Vglut3 neurons were largely silent during HTO associated with REM sleep. Additionally, many MnR GABAergic neurons fired rhythmically phase-locked to HTO. These results indicate an important role of MnR nonserotonergic neurons in modulating HTO.