Muscarinic blocking drugs are compounds that selectively antagonize the responses to acetylcholine (ACh) and other parasympathomimetics that are mediated by activation of muscarinic receptors. These agents are also referred to as muscarinic antagonists, antimuscarinic drugs, and anticholinergics. The belladonna alkaloids, such as atropine, are the oldest known muscarinic blocking compounds, and...

Members of the muscarinic acetylcholine receptor family (M1-M5) are known to be involved in a great number of important central and peripheral physiological and pathophysiological processes. Because of the overlapping expression patterns of the M1-M5 muscarinic receptor subtypes and the lack of ligands endowed with sufficient subtype selectivity, the precise physiological functions of the indiv...

Analysis of muscarinic cholinergic receptors in pancreatic acinar carcinoma of rat by measurement of N-[methyl-3H]scopolamine binding has revealed a single homogenous population of muscarinic receptors in the tumor. The plasmalemma density (approximately 25 receptors/micron 2 of cell membrane surface) and dissociation constant (approximately 0.4 nM) of muscarinic receptors in acinar carcinoma c...

Advances in understanding the phosphoinositide cycle have helped unravel the chain of events initiated by muscarinic receptor stimulation. Hydrolysis of membrane phosphoinositides generates both diacylglycerol, an activator of protein kinase C, and inositol phosphates. In the nervous system, muscarinic receptors elicit a wide range of electrophysiological responses. Recent studies have made pro...

Previous studies have indicated that denervation of adult rodent sweat glands results in the loss of secretory responsiveness to muscarinic agonists. To elucidate the molecular basis of this loss, we have characterized the muscarinic cholinergic receptor present in adult rat sweat glands and examined the effects of cholinergic denervation on its properties and expression. When homogenates of gl...

The main objective of the present work was to determine whether the regulation of ACh release by nicotinic and muscarinic autoreceptors is compromised in the aged rat brain. For this, the effects of the nicotinic agonist N-methylcarbamylcholine (MCC) and the muscarinic-M2 antagonist AF-DX 116 on ACh release from brain slices of young (3-month-old), adult (9-month-old), and aged (27-month-old) r...

Introduction: Learning and memory processes result from interaction of neurotransmitter systems in various brain regions such as amygdala and hippocampus. Considering that morphine induces memory impairment, in the current study, we examined the possible role of cholinergic muscarinic receptors of the central amygdala (CeA) on the morphine-induced amnesia in adult male Wistar rats. Methods...

Although the heart is considered a relatively pure source of m2 muscarinic receptors, the possible expression of other muscarinic receptor genes at discrete sites within the myocardium or by intrinsic cardiac ganglia had not been evaluated. Accordingly, the present study used in situ hybridization histochemistry with 35S-labeled oligonucleotide probes to address this issue. Initial experiments ...