Expression Of Muscarinic Receptors Research Articles

Dynamic phenotypic shifts and M2 receptor downregulation in bladder smooth muscle cells induced by mirabegron.

Mirabegron is available for treatment of overactive bladder (OAB). However, mechanisms underlying symptom improvements and long-term effects on bladder smooth muscle cells are uncertain. Contractility and growth of bladder smooth muscle contribute to OAB, and depend on smooth muscle phenotypes, and on muscarinic receptor expression. Here, we examined prolonged exposure to mirabegron (20-48h) on phenotype markers, muscarinic receptor expression, and phenotype-dependent functions in human bladder smooth muscle cells (hBSMC). Expression of markers for contractile (calponin, MYH11) and proliferative (MYH10, vimentin) phenotypes, proliferation (Ki-67), and of muscarinic receptors were assessed by RT-PCR. Proliferation, viability, actin organization and contractions in cultured hBSMC were examined by EdU, CCK-8, phalloidin staining and matrix contraction assays. Calponin-1 mRNA decreased with 100nM and 150nM mirabegron applied for 20h (0.56-0.6 fold of controls). Decreases were resistant to the β3-AR antagonist L-748,337 (0.34-0.55 fold, 100-150nM, 20h). After 40h, decreases occured in the presence of L-748,337, but not without L-748,337. MYH11 mRNA increased with 150nM mirabegron (40h, 1.9 fold). This was partly preserved with L-748,337, but not observed after 20h mirabegron exposure. Vimentin mRNA reduced with 150nM mirabegron after 20h, but not after 40h, with and without L-748,337 (0.71-0.63 fold). MYH10 mRNA expression remained unaffected by mirabegron. Exposure to 150nM mirabegron increased Ki-67 mRNA after 20h in the presence of, but not without L-748,337, and after 40h without, but not with L-748,337. Proliferation rates and actin organization were stable with 50-150nM mirabegron (24h, 48h). Viability increased significantly after mirabegron exposure for 20h, and by trend after 40h, which was fully sensitive to L-748,337. M2 mRNA was reduced by 20h mirabegron, which was resistant to L-748,337. Carbachol (3µM) enhanced time-dependent contractions of hBSMC, which was inhibited by mirabegron (150nM) in late phases (24h), but not in early phases of contractions. Conclusion: Mirabegron induces dynamic phenotype alterations and M2 downregulation in hBSMC, which is paralleled by time-shifted anticontractile effects. Phenotype transitions may be involved in improvements of storage symptoms in OAB by mirabegron.

Neuroanatomical Substrates of Circuit-Specific Cholinergic Modulation across the Primate Anterior Cingulate Cortex.

Acetylcholine is a robust neuromodulator of the limbic system and a critical regulator of arousal and emotions. The anterior cingulate cortex (ACC) and the amygdala (AMY) are key limbic structures that are both densely innervated by cholinergic afferents and interact with each other for emotional regulation. The ACC is composed of functionally distinct dorsal (A24), rostral (A32), and ventral (A25) areas that differ in their connections with the AMY. The structural substrates of cholinergic modulation of distinct ACC microcircuits and outputs to AMY are thought to depend on the laminar and subcellular localization of cholinergic receptors. The present study examines the distribution of muscarinic acetylcholine receptors, m1 and m2, on distinct excitatory and inhibitory neurons and on AMY-targeting projection neurons within ACC areas, via immunohistochemistry and injections of neural tracers into the basolateral AMY in adult rhesus monkeys of both sexes. We found that laminar densities of m1+ and m2+ expressing excitatory and inhibitory neurons depended on area and cell type. Among the ACC areas, ventral subgenual ACC A25 exhibited greater m2+ localization on presynaptic inhibitory axon terminals and greater density of m1+ and m2+ expressing AMY-targeting (tracer+) pyramidal neurons. These patterns suggest robust cholinergic disinhibition and potentiation of amygdalar outputs from the limbic ventral ACC, which may be linked to the hyperexcitability of this subgenual ACC area in depression. These findings reveal the anatomical substrate of diverse cholinergic modulation of specific ACC microcircuits and amygdalar outputs that mediate cognitive-emotional integration and dysfunctions underlying stress and affective disorders.

A comprehensive assessment of the cholinergic-supporting and cognitive-enhancing effects of Rosa damascena Mill. (Damask rose) essential oil on scopolamine-induced amnestic rats.

Alzheimer's disease (AD) is a neurodegenerative condition characterized by gradual loss of cognitive abilities (dementia) and is a major public health problem. Here, we aimed at investigating the effects of Rosa damascena essential oil (RDEO) on learning and memory functions in a rat model of amnesia induced by scopolamine, as well as on changes in acetylcholinesterase (AChE) activity, M1 muscarinic acetylcholine receptor (mAChR) expression, and brain-derived neurotrophic factor (BDNF) levels in the extracted brain tissues. The control, amnesia (scopolamine, 1mg/kg/i.p.) and treatment (RDEO, 100μL/kg/p.o. or galantamine, 1.5mg/kg/i.p.) groups were subjected to Morris water maze and new object recognition tests. AChE activity was assayed by ELISA, and M1 mAChR and BDNF concentration changes were determined by western blotting. Also, using computational tools, human M1 mAChR was modeled in an active conformation, and the major components of RDEO were docked onto this receptor. According to our behavioral tests, RDEO was able to mitigate the learning and memory impairments caused by scopolamine in vivo. Our in vitro assays showed that the observed positive effects correlated well with a decrease in AChE activity and an increase in M1 mAChR and BDNF levels in amnestic rat brains. We also demonstrated in an in silico setting that the major components of RDEO, specifically -citronellol, geraniol, and nerol, could be accommodated favorably within the allosteric binding pocket of active-state human M1 mAChR and anchored here chiefly by hydrogen-bonding and alkyl-π interactions. Our findings offer a solid experimental foundation for future RDEO-based medicinal product development for patients suffering from AD.

Altered Sweat Composition Due to Changes in Tight Junction Expression of Sweat Glands in Cholinergic Urticaria Patients.

In cholinergic urticaria (CholU), small, itchy wheals are induced by exercise or passive warming and reduced sweating has been reported. Despite the described reduced muscarinic receptor expression, sweat duct obstruction, or sweat allergy, the underlying pathomechanisms are not well understood. To gain further insights, we collected skin biopsies before and after pulse-controlled ergometry and sweat after sauna provocation from CholU patients as well as healthy controls. CholU patients displayed partially severely reduced local sweating, yet total sweat volume was unaltered. However, sweat electrolyte composition was altered, with increased K+ concentration in CholU patients. Formalin-fixed, paraffin-embedded biopsies were stained to explore sweat leakage and tight junction protein expression. Dermcidin staining was not found outside the sweat glands. In the secretory coils of sweat glands, the distribution of claudin-3 and -10b as well as occludin was altered, but the zonula occludens-1 location was unchanged. In all, dermcidin and tight junction protein staining suggests an intact barrier with reduced sweat production capability in CholU patients. For future studies, an ex vivo skin model for quantification of sweat secretion was established, in which sweat secretion could be pharmacologically stimulated or blocked. This ex vivo model will be used to further investigate sweat gland function in CholU patients and decipher the underlying pathomechanism(s).

Effects of DDT and DDE on placental cholinergic receptors

The placental cholinergic system; known as an important factor in intracellular metabolic activities, regulation of placental vascular tone, placental development, and neurotransmission; can be affected by persistent organic pesticides, particularly organochlorine pesticides(OCPs), which can influence various epigenetic regulations and molecular pathways. Although OCPs are legally prohibited, trace amounts of the persistent dichlorodiphenyltrichloroethane(DDT) are still found in the environment, making prenatal exposure inevitable. In this study, the effects of 2,4’-DDT and 4,4’-DDT; and its breakdown product 4,4’-DDE in the environment on placental cholinergic system were evaluated with regards to cholinergic genes. 40 human placentas were screened, where 42,50% (17 samples) were found to be positive for the tested compounds. Average concentrations were 10.44 μg/kg; 15.07 μg/kg and 189,42 μg/kg for 4,4’-DDE; 2,4’-DDT and 4,4’-DDT respectively. RNA-Seq results revealed 2396 differentially expressed genes in positive samples; while an increase in CHRM1,CHRNA1,CHRNG and CHRNA2 genes at 1.28, 1.49, 1.59 and 0.4 fold change were found(p<0028). The increase for CHRM1 was also confirmed in tissue samples with immunohistochemistry. In vitro assays using HTR8/SVneo cells; revealed an increase in mRNA expression of CHRM1, CHRM3 and CHRN1 in DDT and DDE treated groups; which was also confirmed through western blot assays. An increase in the expression of CHRM1,CHRNA1, CHRNG(p<0001) and CHRNA2(p<0,05) were found from the OCPs exposed and non exposed groups.The present study reveals that intrauterine exposure to DDT affects the placental cholinergic system mainly through increased expression of muscarinic receptors. This increase in receptor expression is expected to enhance the sensitivity of the placental cholinergic system to acetylcholine.

Renal denervation improves cardiac function independently of afterload and restores myocardial norepinephrine levels in a rodent heart failure model.

Renal nerves play a critical role in cardiorenal interactions. Renal denervation (RDN) improved survival in some experimental heart failure (HF) models. It is not known whether these favorable effects are indirect, explainable by a decrease in vascular afterload, or diminished neurohumoral response in the kidneys, or whether RDN procedure per se has direct myocardial effects in the failing heart. To elucidate mechanisms how RDN affects failing heart, we studied load-independent indexes of ventricular function, gene markers of myocardial remodeling, and cardiac sympathetic signaling in HF, induced by chronic volume overload (aorto-caval fistula, ACF) of Ren2 transgenic rats. Volume overload by ACF led to left ventricular (LV) hypertrophy and dysfunction, myocardial remodeling (upregulated Nppa, MYH 7/6 genes), increased renal and circulating norepinephrine (NE), reduced myocardial NE content, increased monoaminoxidase A (MAO-A), ROS production and decreased tyrosine hydroxylase (+) nerve staining. RDN in HF animals decreased congestion in the lungs and the liver, improved load-independent cardiac function (Ees, PRSW, Ees/Ea ratio), without affecting arterial elastance or LV pressure, reduced adverse myocardial remodeling (Myh 7/6, collagen I/III ratio), decreased myocardial MAO-A and inhibited renal neprilysin activity. RDN increased myocardial expression of acetylcholinesterase (Ache) and muscarinic receptors (Chrm2), decreased circulating and renal NE, but increased myocardial NE content, restoring so autonomic control of the heart. These changes likely explain improvements in survival after RDN in this model. The results suggest that RDN has remote, load-independent and favorable intrinsic myocardial effects in the failing heart. RDN therefore could be a useful therapeutic strategy in HF.

Enhancement of muscarinic receptor-mediated excitation in spontaneously hypertensive rat adrenal medullary chromaffin cells.

One of the mechanisms for hypertension is an increase in blood catecholamines due to increased secretion from sympathetic nerve terminals and adrenal medullary chromaffin (AMC) cells. Spontaneously hypertensive rats (SHRs) are used as an animal model of hypertension. Catecholamine secretion in AMC cells occurs in response to humoral factors and neuronal inputs from the sympathetic nerve fibres. Acetylcholine (ACh) released from the nerve terminals activates nicotinic as well as muscarinic ACh receptors. The present experiment aimed to elucidate whether muscarinic receptor-mediated excitation is altered in SHR AMC cells and, if it is, how. Compared with normotensive rat AMC cells, muscarinic stimulation induced greater catecholamine secretion and larger depolarising inward currents in SHR AMC cells. In contrast to normotensive rat AMC cells, the muscarine-induced current consisted of quinine-sensitive and quinine-insensitive components. The former and the latter are possibly ascribed to nonselective cation channel activation and TWIK-related acid-sensitive K+ (TASK) channel inhibition, as noted in guinea pig AMC cells. In fact, immunoreactive material for TASK1 and several isoforms of transient receptor potential canonical (TRPC) channels was detected in SHR AMC cells. Stromal interaction molecule 1 (STIM1), which plays an essential role for heteromeric TRPC1-TRPC4 channel formation and is not expressed in normotensive rat AMC cells, was detected in the cytoplasm and co-localised with TRPC1. The expression of muscarinic M1 receptors was enhanced in SHR AMC cells compared with normotensive rats. The results indicate that muscarinic excitation is enhanced in SHR AMC cells, probably through facilitation of TRPC channel signalling.

Maternal diabetes decreases the expression of α2-adrenergic and M2 muscarinic receptors in the visual cortex of male rat neonates

AimsThis study investigates the impact of maternal diabetes on the expression of α2-adrenergic and M2 muscarinic receptors in the primary visual cortex of male offspring born to diabetic rats. Main methodsIn adult female rats, a single dose of intraperitoneal streptozotocin (STZ) was used to induce diabetes (Diabetic group). Diabetes was controlled with insulin in the Insulin-treated group. Female rats in the control group received normal saline instead of STZ. Male newborns were euthanized at P0, P7, and P14, and the expression of α2-adrenergic and M2 muscarinic receptors in the primary visual cortex was determined using immunohistochemistry (IHC). Key findingsThe study showed that α2-adrenergic and M2 muscarinic receptors were significantly suppressed in all layers of the primary visual cortex of male neonates born to diabetic rats at P0, P7, and P14 compared to the control group. The highest expression was for the Con group at P14 and the lowest one was in the Dia group at P0 for both receptors. The insulin treatment in diabetic mothers modulated the expression of these receptors to normal levels in their newborns. SignificanceThe results demonstrate maternal diabetes decreases the expression of α2-adrenergic and M2 muscarinic receptors in the primary visual cortex of male offspring born to diabetic rats. Insulin treatment can offset these effects of diabetes.

The Impact of Muscarinic Antagonism on Psychosis-Relevant Behaviors and Striatal [11C] Raclopride Binding in Tau Mouse Models of Alzheimer's Disease.

Psychosis that occurs over the course of Alzheimer's disease (AD) is associated with increased caregiver burden and a more rapid cognitive and functional decline. To find new treatment targets, studies modeling psychotic conditions traditionally employ agents known to induce psychosis, utilizing outcomes with cross-species relevance, such as locomotive activity and sensorimotor gating, in rodents. In AD, increased burdens of tau pathology (a diagnostic hallmark of the disease) and treatment with anticholinergic medications have, separately, been reported to increase the risk of psychosis. Recent evidence suggests that muscarinic antagonists may increase extracellular tau. Preclinical studies in AD models have not previously utilized muscarinic cholinergic antagonists as psychotomimetic agents. In this report, we utilize a human-mutant-tau model (P301L/COMTKO) and an over-expressed non-mutant human tau model (htau) in order to compare the impact of antimuscarinic (scopolamine 10 mg/kg/day) treatment with dopaminergic (reboxetine 20 mg/kg/day) treatment, for 7 days, on locomotion and sensorimotor gating. Scopolamine increased spontaneous locomotion, while reboxetine reduced it; neither treatment impacted sensorimotor gating. In the P301L/COMTKO, scopolamine treatment was associated with decreased muscarinic M4 receptor expression, as quantified with RNA-seq, as well as increased dopamine receptor D2 signaling, as estimated with Micro-PET [11C] raclopride binding. Scopolamine also increased soluble tau in the striatum, an effect that partially mediated the observed increases in locomotion. Studies of muscarinic agonists in preclinical tau models are warranted to determine the impact of treatment-on both tau and behavior-that may have relevance to AD and other tauopathies.

Specific dilation pattern in placental circulation and the NO/sGC role in preeclampsia placental vessels.

Endothelial functions in controlling blood flow in placental circulation are still unclear. The present study compares vascular dilations between placental circulation and other vessels, as well as between normal and preeclampsia placental vessels. Placental, umbilical, and other vessels (cerebral and mesenteric arteries) were collected from humans, sheep, and rats. Vasodilation was tested by JZ101 and DMT. Q-PCR, Western blot, and Elisa were used for molecular experiments. Endothelium-dependent/derived vasodilators, including acetylcholine, bradykinin, prostacyclin, and histamine, mediated no or minimal dilation in placental circulation, which was different from that in other vessels in sheep and rats. There were lower mRNA expressions of muscarinic receptors, histamine receptors, bradykinin receptor 2, endothelial nitric oxide synthesis (eNOS), and less nitric oxide (NO) in human umbilical vessels when compared with placental vessels. Exogenous NO donors (sodium nitroprusside, SNP) and soluble guanylate cyclase (sGC) activators (Bay41-2272) decreased the baseline of vessel tone in placental circulation in humans, sheep, and rats, but not in other arteries. The sGC inhibitor ODQ suppressed the reduced baseline caused by the SNP. The decreased baseline by SNP or Bay41-2272 was higher in placental vessels than in umbilical vessels, suggesting that the role of NO/sGC is more important in the placenta. NO concentrations in preeclampsia placental vessels were lower than those in control, while no significant change was found in umbilical plasma between the two groups. eNOS expression was similar between normal and preeclampsia placental vessels, but phosphorylated eNOS levels were significantly lower in preeclampsia. Following serotonin, SNP or Bay41-2272-mediated dilations were weaker in preeclampsia placental vessels. The decreased amplitude of SNP- or Bay41-2272 at baseline was smaller in preeclampsia. The decreased amplitudes of ODQ + SNP were comparable between the two groups. Despite higher beta sGC expression, sGC activity in the preeclampsia placenta was lower. This study demonstrated that receptor-mediated endothelium-dependent dilation in placental circulation was significantly weaker than other vessels in various species. The results, showed firstly, that exogenous NO played a role in regulating the baseline tone of placental circulation via sGC. Lower NO production and decreased NO/sGC could be one of the reasons for preeclampsia. The findings contribute to understanding specific features of placental circulation and provide information about preeclampsia in placental vessels.

Role of aquaporin 5 and glandular blood flow in the acetylcholine-induced secretion of saliva in rats.

To clarify the role of the aquaporin 5 (AQP5) in salivary secretion, we evaluated acetylcholine (ACh)-induced secretion in Sprague-Dawley (SD) rats, rats expressing a low level of AQP5 protein (AQP5/low SD) which developed from SD rats, and Wistar/ST rats. The salivary secretion in AQP5/low SD rats in response to infusions of low-dose ACh (60-120 nmol/min) was 27-42% of that in SD rats. By contrast, Wistar/ST rats exhibited comparable secretion to that of SD rats in response to low-doses ACh, despite their low-level expression of AQP5. Experiments using spectrofluorometry and RT-PCR demonstrated no differences in the ACh-induced Ca2+ responses or the mRNA expression of muscarinic receptor, Cl- channel, or cotransporter between these strains. These findings imply that factors other than the function of salivary acinar cells regulates the secretion in response to weak stimuli. Monitoring of the hemodynamics in the submandibular gland revealed that low-doses ACh induced different patterns of the fluctuations in the blood flow in these strains. The blood flow decreased below the resting level in AQP5/low SD rats, but remained mostly above the resting level in Wistar/ST rats. The present study reveals that the contribution of AQP5-dependent transport of water is altered by stimulus intensity and blood flow.

Combined methods elucidate the multi-organ toxicity of cylindrospermopsin (CYN) on Daphnia magna

Global water bodies are now at risk from inevitable cyanobacterial blooms and their production of multiple cyanotoxins, in particular cylindrospermopsin (CYN). However, research on the CYN toxicity and its molecular mechanisms is still limited, whilst the responses of aquatic species against CYN are uncovered. By integrating behavioral observations, chemical detections and transcriptome analysis, this study demonstrated that CYN exerted multi-organ toxicity to model species, Daphnia magna. The present study confirmed that CYN could cause protein inhibition by undermining total protein contents, and altered the gene expression related to proteolysis. Meantime, CYN induced oxidative stress by increasing reactive oxygen species (ROS) level, decreasing the glutathione (GSH) concentration, and interfered with protoheme formation process molecularly. Neurotoxicity led by CYN was solidly determined by abnormal swimming patterns, reduced acetylcholinesterase (AChE), and downward expression of muscarinic acetylcholine receptor (CHRM). Importantly, for the first time, this research determined CYN directly interfered with energy metabolism in cladocerans. CYN distinctively reduced filtration and ingestion rate by targeting on heart and thoracic limbs, which declined the energy intake, and could be further displayed by the reduction of motional strength and the trypsin concentration. These phenotypic alterations were supported by transcriptomic profile, including the down-regulation of oxidative phosphorylation and ATP synthesis. Moreover, CYN was speculated to trigger the self-defense responses of D. magna, known as “abandon-ship” by moderating lipid metabolism and distribution. This study, overall, comprehensively demonstrated the CYN toxicity and the responses of D. magna against it, which is of great significance to the advancements of CYN toxicity knowledge.

Potential antiproliferative and apoptotic effects of pilocarpine combined with TNF alpha in chronic myeloid leukemia cells.

Pilocarpine is a selective M1/M3 agonist of muscarinic acetylcholine receptor subtypes. Muscarinic acetylcholine receptors are G protein-coupled receptors. These receptors are different drug targets. The aim of the present work was to investigate the effect of pilocarpine on the expression of M3 muscarinic acetylcholine receptor, the AChE activity, IL-8 release response, and proliferation in K562 cells, via muscarinic receptor activation.Human chronic myeloid leukemic cell cultures were incubated with drugs. Proliferation assays were performed by BrdU assay. Expression of M3 muscarinic acetylcholine receptor and apoptosis proteins such as bcl, bax, cyt C, and caspases was assessed with the semiquantitative Western blotting method.Pilocarpine inhibits chronic myeloid cell proliferation and M3 muscarinic acetylcholine receptor protein expression. Pilocarpine increases caspase-8 and -9 expression levels, upregulating the proapoptotic protein Bax and downregulating the expression levels of the antiapoptotic protein Bcl-2. The apoptotic activity of pilocarpine is associated with an increase in AChE activity. M3 muscarinic acetylcholine receptors can activate multiple signal transduction systems and mediate inhibitory effects on chronic myeloid K562 cell proliferation depending on the presence of 1% FBS conditions. This apoptotic effect of pilocarpine may be due to the concentration of pilocarpine and the increase in AChE level.Our results suggest that inhibition of cell proliferation by inducing apoptosis of pilocarpine in K562 cells may be one of the targets. M3 selective agonist may have therapeutic potential in chronic myeloid leukemia.

The effect of combination pretreatment of donepezil and environmental enrichment on memory deficits in amyloid-beta-induced Alzheimer-like rat model

Alzheimer's disease (AD) is progressive neurodegeneration known as the most common cause of dementia, and it is the sixth leading cause of death in older people. Given the promising data on the additive effect of combination therapy with donepezil (Aricept), an acetylcholinesterase inhibitor (AChEI), and regarding the similar neuronal mechanisms through which donepezil (DON) and environmental enrichment (EE) exert their enhancing effects on cognition; we asked whether simultaneous treatment with two paradigms in amyloid-beta-induced AD rats may lead to greater protection against the cognitive impairments than either treatment individually. The experimental groups consisted of Alz, sham-operated, Alz + DON, Alz + EE, and Alz + DON + EE. AD was induced by intrahippocampal injection of amyloid-beta (1–42, 6 μg), and DON was orally administrated (4 mg/kg) for 21 days. Environmental enrichment consisted of housing animals in large cages (50 × 50 × 50 cm) containing a running wheel and differently shaped objects for 21 days. Spatial learning and memory were assessed in the Morris water maze (MWM) and Real-time PCR was performed to assess the expression of brain-derived neurotrophic factor (BDNF) and M1 muscarinic acetylcholine receptor (AchM1R) within the hippocampus. Spatial memory was impaired in Alz animals, and while neither pretreatment with DON nor EE alone could significantly restore spatial memory scores in Alz rats, combination therapy was effective. BDNF expression was suppressed in Alz rats and pretreatment with DON plus EE could increase it to the saline levels. The data suggest that a cholinesterase inhibitor and cognitive stimulation can be used effectively in combination to protect cognitive loss in an AD rat model. This additive protective effect may be in part due to the augmented influence of this combination on BDNF levels and cholinergic neuronal system within the hippocampus.

Treatment with the soluble guanylate cyclase activator BAY 60-2770 restores in vitro bladder contractile responses in a rat model of chronic prostatitis

Aim:Examine how innate bladder contractility and corresponding receptor expression was affected by chronic prostatitis (CP) and how treatment with the soluble guanylate cyclase (sGC) activator BAY 60-2770 influenced this. Methods:To create a functional model for CP, 24 male Sprague-Dawley rats were intraprostatically injected with either zymosan or saline, serving as control. After a recovery period, the rats were treated with either BAY 60-2770 or dimethyl sulfoxide (DMSO; vehicle) on days 8–20. Urine samples were collected for measurement of ATP. On day 21, the bladder was excised and contractile responses to electrical field stimulation (EFS), methacholine, ATP and nitric oxide (NO) were examined in an in vitro organ bath. Subsequently, the expression of purinergic (P2X1 & P2X3) and muscarinic (M3) receptors as well as sGC was examined immunohistochemically. Results:Induction of CP led to significantly attenuated purinergic bladder contractions, which were normalized by treatment with BAY 60-2770. Induction of CP did not alter the contractile bladder responses to EFS, methacholine or NO. However, treatment with BAY 60-2770 led to significantly increased contractile bladder responses to EFS and MeCh and significantly enhanced relaxatory nitrergic responses. There were no significant differences between the groups regarding purinergic or cholinergic receptor expression, however treatment with BAY 60-2770 led to attenuated expression of sGC in the urothelium. Conclusion:Taken together, these findings indicate that drugs targeting the nitric oxide/cyclic guanosine monophosphate (NO/cGMP) pathway may be a promising option to restore alterations in bladder contractility that arise due to CP.

Milk Formula Enriched with Sodium Butyrate Influences Small Intestine Contractility in Neonatal Pigs.

Butyrate, a by-product of gut bacteria fermentation as well as the digestion of fat in mother’s milk, exerts a wide spectrum of beneficial effects in the gastrointestinal tissues. The present study aimed to determine the effects of sodium butyrate on small intestine contractility in neonatal piglets. Piglets were fed milk formula alone (group C) or milk formula supplemented with sodium butyrate (group B). After a 7-day treatment period, isometric recordings of whole-thickness segments of the duodenum and middle jejunum were obtained by electric field stimulation under the influence of increasing doses of Ach (acetylocholine) in the presence of TTX (tetrodotoxin) and atropine. Moreover, structural properties of the intestinal wall were assessed, together with the expression of cholinergic and muscarinic receptors (M1 and M2). In both intestinal segments (duodenum and middle jejunum), EFS (electric field stimulation) impulses resulted in increased contractility and amplitude of contractions in group B compared to group C. Additionally, exposure to dietary butyrate led to a significant increase in tunica muscularis thickness in the duodenum, while mitotic and apoptotic indices were increased in the middle jejunum. The expression of M1 and M2 receptors in the middle jejunum was significantly higher after butyrate treatment. The results indicate increased cholinergic signaling and small intestinal growth and renewal in response to feeding with milk formula enriched with sodium butyrate in neonatal piglets.

A Potential Role of Cholinergic Dysfunction on Impaired Colon Motility in Experimental Intestinal Chagas Disease.

Background/AimsChagasic megacolon is caused by Trypanosoma cruzi, which promotes in several cases, irreversible segmental colonic dilation. This alteration is the major anatomic-clinical disorder, characterized by the enteric nervous system and muscle wall structural damage. Herein, we investigate how T. cruzi-induced progressive colonic structural changes modulate the colonic contractile pattern activity.MethodsWe developed a murine model of T. cruzi-infection that reproduced long-term modifications of the enlarged colon. We evaluated colonic and total intestinal transit time in animals. The patterns of motor response at several time intervals between the acute and chronic phases were evaluated using the organ bath assays. Enteric motor neurons were stimulated by electric field stimulation. The responses were analyzed in the presence of the nicotinic and muscarinic acetylcholine receptor antagonists. Western blot was performed to evaluate the expression of nicotinic and muscarinic receptors. The neurotransmitter expression was analyzed by real-time polymerase chain reaction.ResultsIn the chronic phase of infection, there was decreased intestinal motility associated with decreased amplitude and rhythmicity of intestinal contractility. Pharmacological tests suggested a defective response mediated by acetylcholine receptors. The contractile response induced by acetylcholine was decreased by atropine in the acute phase while the lack of its action in the chronic phase was associated with tissue damage, and decreased expression of choline acetyltransferase, nicotinic subunits of acetylcholine receptors, and neurotransmitters.ConclusionsT. cruzi-induced damage of smooth muscles was accompanied by motility disorders such as decreased intestinal peristalsis and cholinergic system response impairment. This study allows integration of the natural history of Chagasic megacolon motility disorders and opens new perspectives for the design of effective therapeutic.

Cholinergic Senescence in the Ts65Dn Mouse Model for Down Syndrome

Down syndrome (DS) induces a variable phenotype including intellectual disabilities and early development of Alzheimer’s disease (AD). Moreover, individuals with DS display accelerated aging that affects diverse organs, among them the brain. The Ts65Dn mouse is the most widely used model to study DS. Progressive loss of cholinergic neurons is one of the hallmarks of AD present in DS and in the Ts65Dn model. In this study, we quantify the number of cholinergic neurons in control and Ts65Dn mice, observing a general reduction in their number with age but in particular, a greater loss in old Ts65Dn mice. Increased expression of the m1 muscarinic receptor in the hippocampus counteracts this loss. Cholinergic neurons in the Ts65Dn mice display overexpression of the early expression gene c-fos and an increase in the expression of β-galactosidase, a marker of senescence. A possible mechanism for senescence induction could be phosphorylation of the transcription factor FOXO1 and its retention in the cytoplasm, which we are able to confirm in the Ts65Dn model. In our study, using Ts65Dn mice, we observe increased cholinergic activity, which induces a process of early senescence that culminates in the loss of these neurons.

Dysregulation of the Enteric Nervous System in the Mid Colon of Complement Component 3 Knockout Mice with Constipation Phenotypes.

Complement component 3 (C3) contributes to neurogenesis, neural migration, and synaptic elimination under normal and disease conditions of the brain, even though it has not been studied in the enteric nervous system (ENS). To determine the role of C3 in the regulatory mechanism of ENS during C3 deficiency-induced constipation, the changes in the markers of neuronal and interstitial cells of Cajal (ICCs), the markers for excitatory and inhibitory transmission of ENS, and expression of C3 receptors were analyzed in the mid colon of C3 knockout (KO) mice at 16 weeks of age. Prominent constipation phenotypes, including the decrease in stool parameters, changes in the histological structure, and suppression of mucin secretion, were detected in C3 KO mice compared to wildtype (WT) mice. The expression levels of the neuron specific enolase (NSE), protein gene product 9.5 (PGP9.5), and C-kit markers for myenteric neurons and ICCs were lower in the mid colon of C3 KO mice than WT mice. Excitatory transmission analysis revealed similar suppression of the 5-hydroxytryptamine (5-HT) concentration, expression of 5-HT receptors, acetylcholine (ACh) concentration, ACh esterase (AChE) activity, and expression of muscarinic ACh receptors (mAChRs), despite the mAChRs downstream signaling pathway being activated in the mid colon of C3 KO mice. In inhibitory transmission analysis, C3 KO mice showed an increase in the nitric oxide (NO) concentration and inducible nitric oxide synthase (iNOS) expression, while neuronal NOS (nNOS) expression, cholecystokinin (CCK), and gastrin concentration were decreased in the same mice. Furthermore, the levels of C3a receptor (C3aR) and C3bR expression were enhanced in the mid colon of C3 KO mice compared to the WT mice during C3 deficiency-induced constipation. Overall, these results indicate that a dysregulation of the ENS may play an important role in C3 deficiency-induced constipation in the mid colon of C3 KO mice.

Autophagy Induced by Muscarinic Acetylcholine Receptor 1 Mediates Migration and Invasion Targeting Atg5 via AMPK/mTOR Pathway in Prostate Cancer.

Increasing numbers of researchers discovered the expression of muscarinic acetylcholine receptor 1 in human cancers, while its function in human prostate cancer is still unclear. Our present study focused on CHRM1 to clarify its role in mediating autophagy in prostate cancer. We used immunohistochemistry, western blotting, and immunofluorescence experiments to observe the expression of muscarinic acetylcholine receptor 1 both in nude mice with subcutaneous tumors and in prostate cancer cells. The autophagy was observed through transmission electron microscopy, western blotting, quantitative real-time PCR, and immunofluorescence. After that, we used lentivirus to establish CHRM1 and Atg5 knockdown models. Then, the migration and invasion abilities after knocking down muscarinic acetylcholine receptor 1 and Atg5 were detected by transwell assays. In addition, the AMPK/mTOR pathway-related targets were detected by western blotting. We found that muscarinic acetylcholine receptor 1 was abundantly expressed both in vitro and in vivo in prostate cancer. The overexpression of muscarinic acetylcholine receptor 1 positively regulated migration and invasion in tumor cells as well as the activation of autophagy. Muscarinic acetylcholine receptor 1 was highly correlated with Atg5 and activated the AMPK/mTOR signaling pathway. Downregulation of Atg5 inhibited cell autophagy in prostate cancer cells and the migration and invasion of prostate cancer cells. Meanwhile, abnormal expressions of AMPK/mTOR pathway-related proteins were found. In conclusion, the present findings indicated that muscarinic acetylcholine receptor 1 is highly expressed in prostate cancer cells and promotes cell invasion and migration of prostate cancer. Autophagy is activated in prostate cancer cells and the activation of muscarinic acetylcholine receptor 1 positively regulates autophagy in prostate cancer cells. Moreover, muscarinic acetylcholine receptor 1 induces autophagy-mediated cell migration and invasion by targeting Atg5 in prostate cancer cells via AMPK/mTOR pathway, which uncovered that regulating muscarinic acetylcholine receptor 1, identified in this study, can be a promising solution for treating prostate cancer.