Search results for "Muscarinic acetylcholine receptor M1"

Modulation by Scopolamine, Acetylcholine and Choline of the Evoked Release of Acetylcholine from the Guinea Pig Myenteric Plexus: Evidence for a Musc…

1981

There is evidence that the release of acetylcholine (ACh) from the guinea pig myenteric plexus is controlled via presynaptic muscarine receptors. Muscarinic antagonists such as atropine enhance the release evoked by either electrical field stimulation, by nicotinic drugs or by high K+ concentrations (4,7,10). On the other hand, the muscarinic agonist oxotremorine inhibits the evoked release of ACh (7). A comparable feedback inhibition has been described for the release of ACh from central cholinergic nerves (for review, see Ref. 12). However, it has so far not been shown whether the physiological transmitter itself is able to depress the release of neuronal ACh. We have, therefore, studied …

Glycopyrronium bromide blocks differentially responses mediated by muscarinic receptor subtypes.

1993

To analyse the potency of glycopyrronium bromide in blocking responses mediated via subtypes of muscarinic receptors in vitro, we tried to determine its equilibrium dissociation constants at prejunctional muscarinic receptors inhibiting the twitch response of rabbit vas deferens (presumed M1 type), at M2 (paced at left atria), M3 (guinea pig ileum) muscarinic receptor subtypes and at the muscarinic receptor of the rabbit iris sphincter (not M1-M4, not m5). Glycopyrronium bromide shifted to the right the curve for inhibition of the twitch response induced by the agonist McN-A-343, and the methacholine-induced curves for inhibition of rat atrial contraction, and for tonic contraction of guine…

Different muscarinic receptor subtypes modulate proliferation of primary human detrusor smooth muscle cells via Akt/PI3K and map kinases.

2013

While acetylcholine (ACh) and muscarinic receptors in the bladder are mainly known for their role in the regulation of smooth muscle contractility, in other tissues they are involved in tissue remodelling and promote cell growth and proliferation. In the present study we have used primary cultures of human detrusor smooth muscle cells (HDSMCs), in order to investigate the role of muscarinic receptors in HDSMC proliferation. Samples were obtained as discarded tissue from men >65 years undergoing radical cystectomy for bladder cancer and cut in pieces that were either immediately frozen or placed in culture medium for the cell culture establishment. HDSMCs were isolated from samples, propagat…

Receptor phosphorylation does not mediate cross talk between muscarinic M(3) and bradykinin B(2) receptors.

1999

This study examined cross talk between phospholipase C-coupled muscarinic M3and bradykinin B2receptors coexpressed in Chinese hamster ovary (CHO) cells. Agonists of either receptor enhanced phosphoinositide signaling (which rapidly desensitized) and caused protein kinase C (PKC)-independent, homologous receptor phosphorylation. Muscarinic M3but not bradykinin B2receptors were also phosphorylated after phorbol ester activation of PKC. Consistent with this, muscarinic M3receptors were phosphorylated in a PKC-dependent fashion after bradykinin B2receptor activation, but muscarinic M3receptor activation did not influence bradykinin B2receptor phosphorylation. Despite heterologous phosphorylatio…

The non-neuronal cholinergic system in peripheral blood cells: Effects of nicotinic and muscarinic receptor antagonists on phagocytosis, respiratory …

2007

Peripheral blood cells express the complete non-neuronal cholinergic system. For example synthesis of acetylcholine and nicotinic as well muscarinic receptors have been demonstrated in leucocytes isolated from human peripheral blood. In the present experiments mononuclear cells and granulocytes were isolated from the peripheral blood to investigate content and synthesis of acetylcholine as well as phenotypic functions like respiratory burst, phagocytosis and migration. Mononuclear cells (T-cells and monocytes) contained 0.36 pmol/10(6) cells acetylcholine, whereas acetylcholine content in granulocytes was 100-fold lower. Acetylcholine synthesis amounted to 23.2+/-4.7 nmol/mg protein/h and 2…

PRESYNAPTIC MUSCARINIC CONTROL OF NORADRENALINE RELEASE

1980

Chapter 17 Muscarinic receptors and cell signalling

1996

Publisher Summary Cells have developed signal transduction mechanisms in order to communicate with the cell exterior. Acetylcholine as an external signal is recognized by nicotinic and muscarinic receptors. This chapter presents various muscarinic receptors belonging to the superfamily of G protein-coupled receptors consisting of seven transmembrane (TM) helices tightly packed in a ring-like structure and arranged in a counter-clockwise fashion. Agonist binding leads to a conformational change of the receptor, thereby activating associated G proteins. Muscarinic stimulation of G proteins leads to the activation or inhibition of ion channels, such as K + and Ca 2+ channels, the activation of…

Prejunctional M1 and postjunctional M3 muscarinic receptors in the circular muscle of the guinea-pig ileum.

1995

The effects of subtype-selective muscarinic receptor antagonists on electrically evoked release of acetylcholine and muscle contraction were compared in circular muscle preparations of the guinea-pig ileum. Incubation of the preparation with [3H]choline resulted in the formation of [3H]acetylcholine. Electrical stimulation caused the release of [3H]acetylcholine which was abolished by tetrodotoxin and omission of calcium from the medium. 5-Hydroxytryptamine (10 microM) and the nicotinic agonist 1,1-dimethyl-4-phenyl-piperazinium (300 microM) did not change acetylcholine release. The muscarinic antagonists pirenzepine (M1 selective), AF-DX 116 (M2 selective) and hexahydrosiladifenidol (M3 se…

Cholinergic Responses of Ophthalmic Arteries in M3and M5Muscarinic Acetylcholine Receptor Knockout Mice

2009

PURPOSE. To determine the functional role of M 3 and M 5 muscarinic acetylcholine receptor subtypes in ophthalmic arteries using gene-targeted mice. METHODS. Muscarinic receptor gene expression was quantified in murine ophthalmic arteries using real-time PCR. To test the functional relevance of M 3 and M 5 receptors, ophthalmic arteries from mice deficient in either subtype (M3R -/- , M5R -/- , respectively) and wild-type controls were isolated, cannulated with micropipettes, and pressurized. Changes in luminal vessel diameter in response to muscarinic and nonmuscarinic receptor agonists were measured by video microscopy. RESULTS. With the use of real-time PCR, all five muscarinic receptor …

Identification of the Muscarinic Acetylcholine Receptor Subtype Mediating Cholinergic Vasodilation in Murine Retinal Arterioles

2011

To identify the muscarinic acetylcholine receptor subtype that mediates cholinergic vasodilation in murine retinal arterioles.Muscarinic receptor gene expression was determined in murine retinal arterioles using real-time PCR. To assess the functional relevance of muscarinic receptors for mediating vascular responses, retinal vascular preparations from muscarinic receptor-deficient mice were studied in vitro. Changes in luminal arteriole diameter in response to muscarinic and nonmuscarinic vasoactive substances were measured by video microscopy.Only mRNA for the M(3) receptor was detected in retinal arterioles. Thus, M(3) receptor-deficient mice (M3R(-/-)) and respective wild-type controls …