Muscarinc receptor-mediated signaling takes part in many physiological functions ranging from complex higher nervous activity to vegetative responses. Specificity of action of the natural muscarinic agonist acetylcholine is effected by action on five muscarinic receptor subtypes with particular tissue and cellular localization, and coupling preference with different G-proteins and their signali...

The selectivity profiles of the muscarinic receptor antagonists dicyclomine and trihexyphenidyl have been examined in binding and functional studies and compared with those of pirenzepine and atropine. Dicyclomine, trihexyphenidyl and pirenzepine demonstrated the highest affinity for the M1 muscarinic receptor subtype as revealed in competition experiments against [3H]-pirenzepine labelling of ...

The main purpose of this study was to determine whether one or both of the muscarinic receptor subtypes (M1 and M2) contributed to the total cholinergic receptor loss found in trimethyltin (TMT) treated rats and to assess the effect of TMT on phencyclidine (PCP) receptor density in several regions of the rat brain. The distribution and changes in muscarinic (M1 and M2) receptor and PCP receptor...

1. We have compared the binding properties of several hexocyclium and sila-hexocyclium derivatives to muscarinic M1 receptors (in rat brain, human neuroblastoma (NB-OK 1) cells and calf superior cervical ganglia), rat heart M2 receptors, rat pancreas M3 receptors and M4 receptors in rat striatum, with their functional antimuscarinic properties in rabbit vas deferens (M1/M4-like), guinea-pig atr...

Acetylcholine acting on muscarinic M(3) receptors on the detrusor muscle is the principal stimulus for inducing the contractile response for urinary bladder voiding. The urinary bladder expresses, however, all cloned muscarinic receptor subtypes (M(1)-M(5)). In terms of quantity, the M(2) subtype dominates over the M(3) subtype in the detrusor, and its role in contraction seems to be primarily ...

Within the basal ganglia, acetylcholine and dopamine play a central role in the extrapyramidal control of motor function. The physiologic effects of these neurotransmitters are mediated by a diversity of receptor subtypes, several of which have now been cloned. Muscarinic acetylcholine receptors are encoded by five genes (m1-m5), and of the two known dopamine receptor subtypes (D1 and D2) the D...

By means of the expression of two chimeric receptors, alpha(2)/M(3) and M(3)/alpha(2), in which the carboxy-terminal receptor portions, containing transmembrane domains VI and VII, were exchanged between the alpha(2C)-adrenergic and the M(3) muscarinic receptor, it has been shown that G protein-coupled receptors are able to interact functionally with each other at the molecular level to form (h...

There are five subtypes of muscarinic receptors that serve various important physiological functions in the central nervous system and the periphery. Mental functions like attention, learning, and memory are attributed to the muscarinic M1 subtype. These functions decline during natural aging and an early deficit is typical for Alzheimer s disease. In addition, stimulation of the M1 receptor in...

Based on the existence of choline acetyltransferase and acetylcholine in human placenta, we have investigated the presence of muscarinic acetylcholine receptors in brush-border and basal plasma membranes from human term placenta. Radioligand binding assay, using [3H]N-methyl-scopolamine as tracer, showed the existence of acetylcholine muscarinic receptors in brush-border (Kd 0.28 +/- 0.04 nM; B...