It has been demonstrated that MK-801 potentiates the effects of the non-selective muscarinic antagonist scopolamine on memory in rats. In this study, we investigated the role of the M1-muscarinic receptor in this interaction, by administering different doses of dicyclomine (DIC) and MK-801 in combination to male Wistar rats before training on the inhibitory avoidance task. MK-801 and DIC in sub...

Muscarinic receptors play an important role in secretory and vasodilator responses in rat salivary glands. Nitric oxide synthase (NOS) activity was found coupled to muscarinic receptor activation as well as to nitric oxide-mediated amylase secretion elicited by carbachol. Parotid glands presented a predominant M(3) and a minor muscarinic M(1) acetylcholine receptor population, though carbachol ...

One component of muscarinic receptor inhibition of the function of cardiac ventricles is mediated by the inhibition of activated adenylate cyclase activity in sarcolemma. We have shown previously that muscarinic agonists inhibit GTP- but not Gpp(NH)p-activated adenylate cyclase activity, and various studies in other tissues indicate that nonhydrolyzable GTP analogues prevent inactivation of the...

Epibatidine, a neurotoxin isolated from the skin of Epipedobates tricolor, is an efficacious antinociceptive agent with a potency 200 times that of morphine. The toxicity of epibatidine, because of its nonspecificity for both peripheral and central nicotinic receptors, precludes its development as an analgesic. During the synthesis of epibatidine analogs we developed potent antinociceptive agen...

BACKGROUND Despite the major role attributed to myocardial vagal activity in left ventricular arrhythmogenesis in chronic myocardial infarction, the impact of infarction on left ventricular muscarinic receptor density remains unknown. METHODS AND RESULTS Left ventricular muscarinic receptor density was measured in vivo by positron emission tomography using the specific antagonist [(11)C]methy...

Muscarinic acetylcholine receptor (mAChR), a member of the G-protein-coupled receptors (GPCRs) gene superfamily, has been shown to mediate the effects of acetylcholine on differentiation and proliferation in the CNS. However, the mechanism or mechanisms whereby mAChRs regulate cell proliferation remain poorly understood. Here we show that in vitro bFGF-expanded neural progenitor cells dissociat...

Emerging evidence indicates that muscarinic receptors and ligands play key roles in regulating cellular proliferation and cancer progression. Both neuronal and nonneuronal acetylcholine production results in neurocrine, paracrine, and autocrine promotion of cell proliferation, apoptosis, migration, and other features critical for cancer cell survival and spread. The present review comprises a f...