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

Botulinum toxin A (BTXA) has been used in several clinical trials to treat excessive glandular secretion; however, the precise mechanism of its action on the secretory function of salivary gland has not been fully elucidated. In this study, we aimed to investigate the effect of BTXA on secretion of submandibular gland in rabbits and to identify its mechanism of action on the secretory function of salivary gland. At 12 weeks after injection with 5 units of BTXA, we found a significant decrease in the saliva flow from submandibular glands, while the salivary amylase concentration increased. Morphological analysis revealed reduction in the size of acinar cells with intracellular accumulation of secretory granules that coalesced to form a large ovoid structure. Expression of M3-muscarinic acetylcholine receptor (M3 receptor) and aquaporin-5 (AQP5) mRNA decreased after BTXA treatment, and distribution of AQP5 in the apical membrane was reduced at 1, 2 and 4 weeks after BTXA injection. Furthermore, BTXA injection was found to induce apoptosis of acini. These results indicate that BTXA decreases the fluid secretion of submandibular glands and increases the concentration of amylase in saliva. Decreased expression of M3 receptor and AQP5, inhibition of AQP5 translocation, and cell apoptosis might involve in BTXA-reduced fluid secretion of submandibular glands.
Amylases ; drug effects ; Animals ; Apoptosis ; drug effects ; Aquaporin 5 ; antagonists & inhibitors ; Botulinum Toxins, Type A ; pharmacology ; Cell Membrane ; drug effects ; In Situ Nick-End Labeling ; Male ; Microscopy, Electron, Transmission ; Neuromuscular Agents ; pharmacology ; Organ Size ; Rabbits ; Random Allocation ; Receptor, Muscarinic M3 ; antagonists & inhibitors ; Saliva ; drug effects ; secretion ; Salivary Proteins and Peptides ; drug effects ; Salivation ; drug effects ; Secretory Rate ; drug effects ; Secretory Vesicles ; drug effects ; Submandibular Gland ; drug effects ; pathology ; secretion ; Time Factors

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

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

OBJECTIVETo determine the effect of exogenous GM3 on proliferation, apoptosis and VEGF expression in human lung adenocarcinoma cell line A549 cells.

METHODSA549 cells were treated with GM3 at different concentrations for 48 hours. MTT assay was used to detect the cell proliferation and flow cytometry was applied to analyze cell apoptosis. RT-PCR was used to detect the expression level of VEGF mRNA and confocal laser scanning microscopy was applied to observe the localization and fluorescence intensity of VEGF.

RESULTSComparing with the control, being treated with higher than 10 µmol/L GM3 significantly inhibited A549 cell proliferation (P < 0.05), and the suppressive effect could be enhanced following increasing doses. The IC(50) was 412 µmol/L. Comparing with the control, being treated with higher than 40 µmol/L GM3 significantly promoted the apoptotic rate of A549 cells (P < 0.05). Comparing with the control, being treated with higher than 40 µmol/L GM3 significantly decreased the VEGF mRNA level of A549 cells (P < 0.05), and the fluorescence intensity of VEGF distinctly weakened.

CONCLUSIONSExogenous ganglioside GM3 can inhibit the proliferation, promote apoptosis, and down-regulate the VEGF expression level in A549 cells. This may be considered as two mechanisms of GM3 for its anti-tumor effect by modulating cell apoptosis and angiogenesis.

Adenocarcinoma ; metabolism ; pathology ; Antineoplastic Agents ; administration & dosage ; pharmacology ; Apoptosis ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Dose-Response Relationship, Drug ; Down-Regulation ; G(M3) Ganglioside ; administration & dosage ; pharmacology ; Humans ; Inhibitory Concentration 50 ; Lung Neoplasms ; metabolism ; pathology ; RNA, Messenger ; metabolism ; Vascular Endothelial Growth Factor A ; genetics ; metabolism

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

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

OBJECTIVE: To investigate the expression of M3 subtype of muscarinic receptors (M3R) during the incised wound healing of the skin in mice and the characteristics of its time-dependent. METHODS: The change of M3R in skin incised wound was detected by immunohistochemical staining and Western blot. RESULTS: M3R-positive cells were detected in epidermis, hair follicle, sebaceous glands, sweat glands, dermomuscular layer in normal mouse skin. Expression of M3R was mainly detectable in polymorphonuclear cells (PMNs) in the wound specimens aged from 6h to 12h after injury. Afterwards, the M3R-positive cells were mostly mononuclear cells (MNCs) and fibroblastic cells (FBCs) at 1 d to 3d post-injury, whereas the M3R-positive cells were mostly FBCs aged from 5 d to 14d. Morphometrically, the ratio of the M3R-positive cells increased aged from 6h to 12h after injury, with a peak at 12h. The ratios kept a high relatively level aged from 1 d to 5 d, but significantly that lowered as compared with aged 12h after injury. The ratio reached the peak at 7 d again after injury, and then decreased gradually. The M3R protein also revealed a time-dependent tendency with double peaks at 12h and 7 d after injury as detected by Western blotting. CONCLUSION M3R is time-dependently expression in PMNs, MNCs and FBCs suggesting that it may play roles during the skin incised wound healing, and M3R may be used as a marker for wound age determination.
Animals ; Blotting, Western ; Fibroblasts/metabolism* ; Immunohistochemistry ; Male ; Mice ; Monocytes/metabolism* ; Neutrophils/metabolism* ; Receptor, Muscarinic M3/metabolism* ; Skin/metabolism* ; Time Factors ; Wound Healing ; Wounds and Injuries/metabolism*

AIMAcetylcholine(ACh) is a neurotransmitter and a potent vasodilator in many vascular beds. ACh hyperpolarizes the smooth muscle cells(SMCs) of arteries including the cochlear spiral modiolar artery(SMA) via an endothelium-dependent mechanism, but the biochemical and biophysical basis of the hyperpolarization and vasodilation remain unclear and controversial.

METHODSUsing intracellular recording techniques and an in vitro preparation of the SMA, the ionic mechanism of the hyperpolarization and a possible role of nitric oxide(NO) were investigated.

RESULTSWith 5 mmol/L K(+) in the bathing solution and a minimum longitudinal tension, ACh (0.1-10 micromol/L) induced a robust hyperpolarization in low RP cells but caused a depolarization in the high RP cells. The ACh hyperpolarization was fast in onset and offset and the amplitude was concentration-dependent(22 and 30 mV by 1 micromol/L and 10 micromol/L ACh, respectively, n = 7 ). ACh also hyperpolarized the cells that initially had a high resting potential (RP) but were pre-depolarized by Ba(2+) (50-100 micromol/L). The onset time courses of the hyperpolarization were often slower in these cases than those without the presence of Ba(2+) . The ACh-induced hyperpolarization was blocked by atropine (0.1- 1 micromol/L, n = 6) or DAMP (50 -100 nmol/L, n = 6, a selective M3 antagonist) and also by BAPTA-AM (10 micromol/L, n = 7, a membrane-permeable Ca(2+)-chelator), or charybdotoxin plus apamin (50-100 nmol/L, n= 4, Ca(2+) -activated K(+) -channel blockers), but not by Nomega-nitro-L-arginine methyl ester (L-NAME, 300 micromol/L, n = 8, an inhibitor of NO-synthase), glipizide (10 micromol/L, n = 4, ATP-sensitive K(+) -channel blocker) and indomethacin (10 micromol/L, n = 4, cyclo-oxygenase inhibitor).

CONCLUSIONIt is concluded that ACh-induced hyperpolarization in the arterial SMCs is primarily due to an activation of calcium-activated potassium channels via M3 receptors of endothelial cell and is independent of NO-release in the spiral modiolar artery.

Acetylcholine ; physiology ; Animals ; Arteries ; Cell Polarity ; physiology ; Cochlea ; blood supply ; physiology ; Guinea Pigs ; Membrane Potentials ; physiology ; Muscle, Smooth, Vascular ; metabolism ; physiology ; Nitric Oxide ; metabolism ; Potassium Channels, Calcium-Activated ; metabolism ; Receptor, Muscarinic M3 ; metabolism