The pharmacological characterisation of pilocarpine-induced purposeless chewing behaviour in the rat.
Purposeless chewing in rats was induced by the acute administration of the cholinergic agonist pilocarpine or by physostigmine. Pilocarpine-induced chewing was antagonised by the centrally acting anticholinergic drugs scopolamine, benzhexol and secoverine, but not by the peripherally acting anticholinergic drug methylscopolamine. Both benzhexol and secoverine caused dose-dependent inhibition of pilocarpine-induced chewing. The D-2 antagonist sulpiride and the D-1 antagonist SCH 23390 did not inhibit pilocarpine-induced chewing. The non-selective neuroleptics pimozide, trifluoperazine and thioridazine also were inactive. In contrast, clozapine caused a dose-related inhibition of pilocarpine-induced chewing. The alpha-1 antagonist prazosin, the alpha-2 antagonist idazoxan, the beta-antagonists propranolol and metoprolol and the H-1 antagonist mepyramine did not reduce pilocarpine-induced chewing. Purposeless chewing behaviour induced by pilocarpine was reduced in a dose-related manner by the administration of the 5-HT antagonists methiothepin and mianserin, but not by spiperone or ketanserin. These data confirm that pilocarpine-induced chewing behaviour in the rat is a model of central cholinergic activity, but suggest that a serotonergic component may be involved in the mediation of this behaviour.
Stewart
B R
BR
University Department of Neurology, King's College Hospital Medical School, London, UK.
Jenner
P
P
Marsden
C D
CD
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology; D001058:Apomorphine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005473:Fluoxetine / Q000494:pharmacology; D008297:Male; D010276:Parasympatholytics / Q000494:pharmacology; D010862:Pilocarpine / Q000494:pharmacology*; D011738:Pyrilamine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012702:Serotonin Antagonists / Q000494:pharmacology; D013239:Stereotyped Behavior / Q000187:drug effects*
D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D014150:Antipsychotic Agents; D010276:Parasympatholytics; D012702:Serotonin Antagonists; D005473:Fluoxetine; D010862:Pilocarpine; D011738:Pyrilamine; D001058:Apomorphine