title: Antagonism by cholinomimetic drugs of the turning induced by intrastriatal pirenzepine in mice.
abstract: In order to investigate the behavioural effect of selective blockade of M1 muscarinic receptors in the forebrain, and to characterize a new model for the evaluation of muscarinic agonistic activity, the effect of intrastriatally injected pirenzepine was studied in mice. The direct injection of pirenzepine (0.01-1 microgram/mouse) into the right striatum of conscious mice resulted in contralateral turning behaviour. When injected intraperitoneally (IP) 15 min before pirenzepine (1 microgram), the muscarinic receptor agonists arecoline and pilocarpine (0.3-3 mg/kg), oxotremorine (0.003-0.03 mg/kg) and RS 86 (0.03-1 mg/kg) antagonized pirenzepine-induced turning, as did the choline-esterase inhibitor physostigmine (0.01-0.1 mg/kg) and the nootropic drug aniracetam (10-30 mg/kg). Haloperidol (0.03-0.3 mg/kg IP) weakly, but significantly, decreased the effect of pirenzepine, whereas (+/-) sulpiride (3-100 mg/kg) failed to affect it. Finally, (+/-)-amphetamine (0.1-3 mg/kg IP), citalopram (1-30 mg/kg IP) and muscimol (0.03-0.3 mg/kg IP) failed to modify pirenzepine-induced turning when administered prior to intrastriatal pirenzepine. These results suggest an involvement of M1 muscarinic receptors in rotational behaviour, and indicate that pirenzepine-induced turning may represent a new model for studying the central activity of cholinomimetic drugs.
mesh_terms: D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology; D001522:Behavior, Animal / Q000187:drug effects*; D015283:Citalopram; D003342:Corpus Striatum; D003913:Dextroamphetamine / Q000494:pharmacology; D004347:Drug Interactions; D005260:Female; D007267:Injections; D051379:Mice; D009118:Muscimol / Q000494:pharmacology; D010277:Parasympathomimetics / Q000494:pharmacology*; D010890:Pirenzepine / Q000008:administration & dosage / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D011437:Propylamines / Q000494:pharmacology
chemical_list: D014150:Antipsychotic Agents; D010277:Parasympathomimetics; D011437:Propylamines; D015283:Citalopram; D009118:Muscimol; D010890:Pirenzepine; D003913:Dextroamphetamine