Search results for "acetylcholine receptor"
showing 10 items of 263 documents
Aged Mice Devoid of the M3 Muscarinic Acetylcholine Receptor Develop Mild Dry Eye Disease
2021
The parasympathetic nervous system is critically involved in the regulation of tear secretion by activating muscarinic acetylcholine receptors. Hence, various animal models targeting parasympathetic signaling have been developed to induce dry eye disease (DED). However, the muscarinic receptor subtype (M1–M5) mediating tear secretion remains to be determined. This study was conducted to test the hypothesis that the M3 receptor subtype regulates tear secretion and to evaluate the ocular surface phenotype of mice with targeted disruption of the M3 receptor (M3R−/−). The experimental techniques included quantification of tear production, fluorescein staining of the ocular surface, environmenta…
Non-neuronal cholinergic system contributes to corticosteroid resistance in chronic obstructive pulmonary disease patients
2016
Background: Inhaled corticosteroid (ICS) with long-acting beta-2 agonists is a well-documented combination therapy for chronic obstructive pulmonary disease (COPD) based on its additive anti-inflammatory properties. By contrast, the recommendation of ICS in combination with long-acting muscarinic antagonist (LAMA) is not evidence-based. In this study, neutrophils obtained from COPD patients were used to compare the anti-inflammatory effects of aclidinium bromide (a long-acting muscarinic antagonist) with corticosteroids and their potential additive effect. Methods: Human sputum and blood neutrophils were isolated from healthy individuals ( n = 37), patients with stable COPD ( n = 52) and th…
Association of Common Polymorphisms in the Nicotinic Acetylcholine Receptor Alpha4 Subunit Gene with an Electrophysiological Endophenotype in a Large…
2016
PLoS one 11(4), e0152984 (2016). doi:10.1371/journal.pone.0152984
Pancreatic polypeptide stimulates mouse gastric motor activity through peripheral neural mechanisms
2016
Background Pancreatic polypeptide (PP) is supposed to be one of the major endogenous agonists of the neuropeptide Y4 receptor. Pancreatic polypeptide can influence gastrointestinal motility, acting mainly through vagal mechanisms, but whether PP acts directly on the stomach has not been explored yet. The aims of this study were to investigate the effects of PP on mouse gastric emptying, on spontaneous tone of whole stomach in vitro and to examine the mechanism of action. Methods Gastric emptying was measured by red phenol method after i.p. PP administration (1–3 nmol per mouse). Responses induced by PP (1–300 mmol L−1) on gastric endoluminal pressure were analyzed in vitro in the presence o…
Characterization of the muscarinic receptor subtype(s) mediating contraction of the guinea-pig lung strip and inhibition of acetylcholine release in …
1997
1 The muscarinic receptor subtypes mediating contraction of the guinea-pig lung strip and inhibition of the release of acetylcholine from cholinergic vagus nerve endings in the guinea-pig trachea in vitro have previously been characterized as M-2-like, i.e. having antagonist affinity profiles that are qualitatively similar but quantitatively dissimilar compared to cardiac M-2 receptors. The present study sought to establish definitely the identity of these receptor subtypes by using the selective muscarinic receptor antagonist, tripitramine. Guinea-pig atria and guinea-pig trachea (postjunctional contractile response) were included for reference.2 It was found that tripitramine antagonized …
Endogenous noradrenaline release from guinea-pig isolated trachea is inhibited by activation of M2 receptors
1992
Overflow of endogenous noradrenaline (NA) from guinea-pig isolated tracheae was evoked by electrical field stimulation (3 Hz, 540 pulses). The muscarinic receptor agonist oxotremorine inhibited the evoked overflow of NA in a concentration-dependent manner (EC50 84 nM). Methoctramine, pirenzepine and p-fluoro-hexahydrosiladiphenidol (each 1 microM) shifted the concentration-response curves of oxotremorine to the right with apparent pA2 values of 7.60, 6.74 and 6.18, respectively. It is concluded that sympathetic nerve terminals in the guinea-pig trachea are endowed with inhibitory muscarinic M2 receptors.
The effects of several muscarinic antagonists on pre- and postsynaptic receptors in the isolated rabbit heart
1981
In order to reveal possible differences between pre- and postsynaptic muscarine receptors, seven antagonists were tested for their affinities on these receptor sites in the rabbit isolated perfused heart. Methacholine was used as an agonist to inhibit the noradrenaline overflow evoked by electrical stimulation (3 Hz, 3 min) of the sympathetic nerves (presynaptic parameter) and to decrease the systolic tension development of the right atrium (postsynaptic parameter). The affinity of an antagonist was expressed as pA2. A decreasing order of potency was obtained with ipratropium, scopolamine, atropine, trihexyphenidyl, amitriptyline, and gallamine, both for pre- and postsynaptic responses. The…
Expression of nicotinic acetylcholine receptor subunits in the cerebral cortex in Alzheimer's disease: histotopographical correlation with amyloid pl…
1999
Impairment of cholinergic transmission and decreased numbers of nicotinic binding sites are well-known features accompanying the cognitive dysfunction seen in Alzheimer's disease (AD). In order to elucidate the underlying cause of this cholinoceptive dysfunction, the expression of two pharmacologically different nicotinic acetylcholine receptor (nAChR) subunits (alpha4, alpha7) was studied in the cerebral cortex of Alzheimer patients as compared to controls. Patch-clamp recordings of 14 dissociated neurons of control cortices showed responses suggesting the existence of alpha4- and alpha7-containing functional nAChRs in the human cortex. In cortices of Alzheimer patients and controls, the p…
Effects of scopolamine on dopamine neurons in the substantia nigra : role of the pedunculopontine tegmental nucleus
2009
Previous neurochemical and behavioral studies suggest that muscarinic receptor antagonism has an excitatory effect on the nigrostriatal dopamine (DA) system. Using in vivo extracellular single unit recording, this study examined whether blockade of the muscarinic receptor by scopolamine alters the firing properties of DA neurons in the substantia nigra (SN). Scopolamine was administered either systemically or locally to DA neurons using microiontophoresis. Surprisingly, scopolamine did not cause any significant change in either the firing rate or pattern of the spontaneously active DA neurons. However, systemic injection of scopolamine significantly increased the number of active DA neurons…
Muscarinic Properties of Compounds Related to Arecaidine Propargyl Ester
2011
A series of new analogues of the arecaidine propargyl ester (CAS 35516-99-5, APE, 1a) with alcohols consisting of 4 or 5 carbon atoms were investigated at muscarinic receptor subtypes. The muscarinic activity of the quaternary and tertiary salts of the APE-related compounds were assayed on the isolated guinea-pig ileum (M 3 receptor subtype) and guinea-pig left atria (M 2 receptor subtype) as well as on rabbit isolated vas deferens (M 1 receptor subtype). The structural variations made in the APE molecule, replacing the triple bond in the ester side chain with structures such as double bond, an allene moiety, a single bond, a cyclopropyl group or two triple bonds should alter the selectivit…