OBJECTIVE: To observe the expression of Muscarinic receptor M1, M3, M5 subunits in rat flocculus following left unilateral labyrinthectomy (UL). METHOD: The RT-PCR was used to observe the expression of Muscarinic receptor M1, M3, M5 subunits post-unilateral labyrinthectomy and investigate its effect on vestibular compensation. RESULT: Muscarinic receptor M1, M3, M5 subunits were induced decrease in both side flocculus after unilateral labyrinthectomy. The expression was the least in the 1 d flocculus of following UL. The expression is rising from the 3-7 d flocculus of following UL. No difference was observed in the 7 d and sham operation flocculus following UL. No difference was observed in the ipsilateral and contralateral flocculus at any group. CONCLUSION Muscarinic receptor M1, M3, M5 subunits were induced decrease in the flocculus after unilateral labyrinthectomy. But the significance of the change of Muscarinic receptor M1, M3, M5 subunits in the vestibular compensation is still unknown.
Animals ; Cerebellum ; metabolism ; Functional Laterality ; Gene Expression ; Male ; Postoperative Period ; Rats ; Receptor, Muscarinic M1 ; metabolism ; Receptor, Muscarinic M3 ; metabolism ; Receptor, Muscarinic M5 ; metabolism ; Vestibule, Labyrinth ; metabolism ; surgery

OBJECTIVE[corrected] To characterize the insulinotropic action of hippocampal cholinergic neurostimulating peptide (HCNP) and analyze the role of type 3 muscarinic receptor (M(3)R) pathway in the action of HCNP.

METHODSINS-1 cells were incubated in routine RPMI 1640 medium (control group), RPMI 1640 supplemented with 50 pg/ml synthetic HCNP (HCNP group), or HCNP-containing medium with the addition of PMA 18 h prior to insulin release assay. The insulin levels in the medium was measured using radioimmunoassay following stimulation with different concentrations of glucose. Real-time quantitative PCR was used for detecting the gene expression of HCNP-pp, choline acetyltransferase (ChAT) and M(3)R in HCNP group and control group.

RESULTSAfter stimulation with different concentrations of glucose (5.6 and 16.7 mmol/L), HCNP group showed significantly higher insulin levels than the control and HCNP+ PMA groups. Compared with those in the control group, the mRNA levels of HCNP-pp, ChAT, and M(3)R were all lowered in HCNP group.

CONCLUSIONHCNP can promote insulin release in INS-1 cells by increasing ChAT activity and activating M(3)R, and this effect is inhibited by PMA.

Animals ; Cell Line ; Insulin ; secretion ; Neuropeptides ; pharmacology ; Rats ; Receptor, Muscarinic M3 ; metabolism

Cardiovascular disease, with high morbidity and mortality, has been threatening the health of human beings. Therefore, expecting to find a more effective therapeutic method, a plenty of researchers devote themselves to the study of the cardiovascular disease all the time. Since discovered on the heart, M3 receptor of muscarinic acetylcholine receptor (mAchR, M receptor) became a new starting point of the research of the cardiovascular disease. With more and more investigation, many people found that M3 receptor could protect the heart from kinds of cardiovascular disease, which may make it a new hopeful therapeutic point. So, expecting to give support to the reference and encouragement for the study of disease related to M3 receptor in future, this review expounds M3 receptor on the heart from the main following aspects: the effect on the heart, the influence on the cardiovascular disease and the mechanism of M3 receptor involved.
Cardiovascular Diseases ; prevention & control ; Heart ; physiology ; physiopathology ; Humans ; Receptor, Muscarinic M3 ; physiology

PURPOSE: The location of acetylcholinesterase-containing nerve fibers suggests a role for acetylcholine in both contractility and secretion in the prostate gland. The colocalization of nitrergic nerves with cholinergic nerves, and the cotransmission of nitric oxide with acetylcholine in cholinergic nerves, has been demonstrated in the prostate glands of various species. Thus, we investigated the effects of acetylcholine on phenylephrine-induced contraction and the correlation between cholinergic transmission and nitric oxide synthase by using isolated prostate strips of rabbits. MATERIALS AND METHODS: Isolated prostate strips were contracted with phenylephrine and then treated with cumulative concentrations of acetylcholine. Changes in acetylcholine-induced relaxation after preincubation with NG-nitroarginine methyl ester, 7-nitroindazole, and aminoguanidine were measured. The effects of selective muscarinic receptor antagonists were also evaluated. RESULTS: In the longitudinal phenylephrine-contracted strip, the cumulative application of acetylcholine (10(-9) to 10(-4) M) elicited a concentration-dependent relaxation effect. Acetylcholine-induced relaxation was inhibited not only by nitric oxide synthase inhibitors (10 microM L-NAME or 10 microM 7-nitroindazole) but also by 10 microM atropine and some selective muscarinic receptor antagonists (10(-6) M 11-([2-[(diethylamino)methyl]-1-piperdinyl]acetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one and 10(-6) M 4-diphenylacetoxy-N-methyl-piperidine). In contrast, relaxation was significantly increased by pretreatment of the strips with 10 mM L-arginine. CONCLUSIONS: Acetylcholine relaxed phenylephrine-induced contractions of isolated rabbit prostate strips. This relaxation may be mediated via both cholinergic and constitutive nitric oxide synthase with both the M2 and M3 receptors possibly playing key roles.
Acetylcholine ; Atropine ; Contracts ; Guanidines ; Indazoles ; Nerve Fibers ; Neurons ; NG-Nitroarginine Methyl Ester ; Nitrergic Neurons ; Nitric Oxide ; Nitric Oxide Synthase ; Nitric Oxide Synthase Type I ; Phenylephrine ; Prostate ; Receptor, Muscarinic M2 ; Receptor, Muscarinic M3 ; Receptors, Muscarinic ; Relaxation

BACKGROUND: Non-depolarizing muscle relaxants have their muscle relaxing effect by competing with acetylcholine (ACh) at the nicotinic receptor level. What are the effects of such muscle relaxants on the tracheal smooth muscle? This present study was set up to address the question as to how vecuronium and pancuronium influence the tracheal smooth muscle. METHODS: Sixty male Sprague-Dawley rat tracheal smooth muscles were isolated at optimal length for isometric force. The preparations were set up in an organ bath containing Tyrode's solution. And isometric force displacement transducer and physiograph were used to record the change in force. After the equilibration period the preparations were contracted with ACh 10(-5) M and carbachol 3x10(-7)M seperately. The preparations were washed with fresh tyrode's solution and allowed to return passively to resting tone. Then the cumulartive effect of ACh (from 3 10(-7) M through 10(-5) M) and carbachol (CCh, from 10(-8) M through 3 10(-6) M) were produced before and after pretreating the preparation with vecuronium (10(-5) M and 10(-6) M) and pancuronium (10(-5) M and 10(-6) M) respectively. Also, we studied the changes of contraction produced by neostigmine before and after pretreatment with vecuronium (10(-5) M and 3 10(-5) M) and pancuronium (3 10(-6) M and 3 10(-5) M). RESULTS: Vecuronium shifted the ACh dose-response curve of the tracheal contraction to the left (p<0.0001) and pancuronium shifted the curve to the right side (p<0.0001). However vecuronium shifted the carbachol dose-response curve to the right side as did pancuronium. Also the contraction effects of neostigmine after pretreatment with muscle relaxants decreased in the group pretreated with vecuronium (p<0.05) and a higher concentration of pancuronium (p<0.01), but with a low concentration of pancuronium the effect increased (p>0.05). CONCLUSIONS: Vecuronium inhibits the ACh hydrolyzing enzyme, especially acetylcholinesterase. Therefore it potentiates ACh contraction in the tracheal smooth muscle, but not the CCh contraction, while pancuronium has a different effect in comparison with vecuronium. That is, at a low concentration it reveals an antagonistic effect on the muscarinic M2 receptor and at a higher concentration it has an antagonistic effect on the muscarinic M3 receptor in the tracheal smooth muscle.
Acetylcholine ; Acetylcholinesterase ; Animals ; Baths ; Carbachol ; Humans ; Male ; Muscle, Smooth* ; Neostigmine ; Neuromuscular Nondepolarizing Agents ; Pancuronium* ; Rats* ; Rats, Sprague-Dawley ; Receptor, Muscarinic M2 ; Receptor, Muscarinic M3 ; Receptors, Nicotinic ; Transducers ; Vecuronium Bromide*

OBJECTIVETo investigate the effect of diabetic autonomic neuropathy on the seminal vesicle and search for the theoretical evidence for the prevention and treatment of diabetic infertility by observing changes in the contents of the nerve growth factor (NGF) and muscarinic M3 receptor in the seminal vesicle of diabetic rats.

METHODSDiabetic models were established in 10 of the 15 male adult SD rats by intraperitoneal injection of streptozotocin (STZ), and the other 5 were included in a normal control group. Eight weeks after modeling, seminal vesicles were collected from the rats for HE and immunohistochemical staining.

RESULTSCompared with the normal controls, the diabetic models showed a decreased number of smooth muscle cells, thinner cytoplasm of glandular epithelial cells and disordered structure in the seminal vesicle. The intensity of NGF-positive staining was significantly enhanced, but that of M3 markedly reduced in the diabetic group. There were statistically significant differences in the mean integrated optical density (IA) of muscarinic M3 receptors and NGF between the control and diabetic groups (0.0187 +/- 0.0024 vs 0.0100 +/- 0.0015 and 0.0209 +/- 0.0085 vs 0.0412 +/- 0.0117, P<0.01).

CONCLUSIONThe changes in the expressions of NGF and M3 receptors in the seminal vesicle of diabetic rats suggest that diabetes mellitus may induce autonomic neuropathy of the seminal vesicle.

Animals ; Diabetes Mellitus, Experimental ; metabolism ; Male ; Nerve Growth Factor ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptor, Muscarinic M3 ; metabolism ; Seminal Vesicles ; metabolism

Our previous studies document the expression of adrenoceptors and purinoceptors in the rat prostate neuroendocrine cells (RPNECs). However, a direct investigation of the receptors for acetylcholine (ACh) is still lacking in the prostate neuroendocrine cells. RPNECs were freshly isolated from the ventral lobes of rat prostate by using collagenase. Effects of ACh and various muscarinic antagonists on the intracellular Ca2+ concentration ([Ca2+]c ) were investigated by using the fura-2 spectrofluorimetry. Single-cell RT-PCR analysis was applied to identify the transcripts for the muscarinic receptor subtypes. ACh (5 micrometer) induced a sharp transient increase in the [Ca2+]c of RPNECs, which was independent of the extracellular Ca2+. In the same RPNECs, high KCl (60 mM), phenylephrine (5micrometer), UTP (P2Y1/2 agonist, 50, micrometer), and alpha, beta-meATP (P2X1/3 agonist, 0.5micrometer) also increased the [Ca2+]c. The ACh-induced [Ca2+]c change (delta[Ca2+]c ) was blocked by atropine or by para-fluorohexahydrosiladifenidol (M3 antagonist, 0.3micrometer), but not by telenzepine (M1 antagonist, 1 micrometer) and himbacine (M2 and M4 antagonist, 1 mircoM). The single-cell RT-PCR demonstrated the selective expression of mRNAs for M3 in RPNECs. In summary, RPNECs express M3 muscarinic receptors that are linked to the release of Ca2+ from intracellular stores. The Ca2+ signals of RPNECs might mediate the parasympathetic regulation of prostate gland.
Acetylcholine/pharmacology ; Animals ; Calcium/*metabolism ; Calcium Signaling ; Male ; Neurosecretory Systems/*metabolism ; Prostate/*metabolism ; Rats ; Rats, Sprague-Dawley ; Receptor, Muscarinic M3/*physiology ; Research Support, Non-U.S. Gov't

The relationship between M3 cholinergic receptor agonist (carbachol) hyperstimulation-induced pancreatic acinar cellular injury and trypsinogen activation or NF-kappaB activation in rats was studied in vitro. Rat pancreatic acinar cells were isolated, cultured and treated with carbachol, the active protease inhibitor (pefabloc), and NF-kappaB inhibitor (PDTC) in vitro. Intracellular trypsin activity was measured by using a fluorogenic substrate. The cellular injury was evaluated by measuring the leakage of LDH from pancreatic acinar cells. The results showed that as compared with control group, 10(-3) mol/L carbachol induced a significant increase of the intracellular trypsin activity and the leakage of LDH from pancreatic acinar cells. Pretreatment with 2 mmol/L pefabloc could significantly decrease the activity of trypsin and the leakage of LDH from pancreatic acinar cells (P < 0.01) following the treatment with a high concentration of carbachol (10(-3) mol/L) in vitro. The addition of 10(-2) mol/L PDTC didn't result in a significant decrease in the activity of trypsin and the leakage of LDH from pancreatic acinar cells treated with a high concentration of carbachol (10(-3) mol/L) in vitro (P > 0.05). It was concluded that intracellular trypsinogen activation is likely involved in pancreatic acinar cellular injury induced by carbachol hyperstimulation in vitro. NF-kappaB activation may not be involved in pancreatic acinar cellular injury induced by carbachol hyperstimulation in vitro.
Carbachol/*pharmacology ; Cholinergic Agonists/pharmacology ; NF-kappa B/*metabolism ; Pancreas/metabolism ; Pancreas/*pathology ; Rats, Wistar ; Receptor, Muscarinic M3/agonists ; Trypsinogen/*metabolism

Animals ; Arecoline ; pharmacology ; Cholinergic Agonists ; pharmacology ; Female ; Guinea Pigs ; In Vitro Techniques ; Male ; Muscle Contraction ; drug effects ; Muscle, Smooth ; physiology ; Pyloric Antrum ; physiology ; Receptor, Muscarinic M3 ; metabolism

OBJECTIVETo observe the therapeutic effect of tiotropium bromide powder inhalation on stable bronchiectasis.

METHODSTwenty-two patients with stable bronchiectasis received inhalation of totropium bromide powder at the daily dose of 18 microg, and on days 1 and 28, the patients were examined for forced expiratory volume in one second (FEVl), predicted value [FEVl(%)], forced expiratory volume (FEV), and FEVl/FVC. The symptom score and BODE index were also recorded.

RESULTSAfter 1 month of inhalation therapy, the FEV1% of the patients showed a moderate increase but the increment was not statistically significant (t=-1.875, P>0.05); the symptom score and BODE index decreased significantly after the therapy (t=7.091, P<0.001; t=2.982, P<0.05).

CONCLUSIONLong-term inhalation of tiotropium bromide powder can improve the clinical symptoms and BODE index and enhance the exercise tolerance and quality of life of the patients with bronchiectasis.

Administration, Inhalation ; Adult ; Aged ; Bronchiectasis ; drug therapy ; Female ; Forced Expiratory Volume ; Humans ; Male ; Middle Aged ; Powders ; Receptor, Muscarinic M3 ; antagonists & inhibitors ; Scopolamine Derivatives ; administration & dosage ; Tiotropium Bromide