title: On the mode of action of six putative dopamine receptor agonists on suppression of exploratory behaviour in rats.
abstract: The effects of six putative dopamine receptor agonists on exploratory behaviour in rats were assessed: pergolide, (+)- and (-)-3-PPP, bromocriptine, mesulergine and CQ 32-084. Behaviour was automatically recorded in a holeboard apparatus and the data were analysed by the novel multivariate statistical method of partial least squares. All six substances suppressed exploratory behaviour at low doses. Pergolide and (+)-3-PPP-induced stereo-typed behaviour at higher doses. The suppression of exploration induced by pergolide was completely antagonised by sulpiride, partly antagonised by metoclopramide and weakly affected by haloperidol pretreatment. The effects of a low dose of (+)-3-PPP, bromocriptine or CQ 32-084, but not (-)-3-PPP or mesulergine, were antagonised by sulpiride. These findings support the hypotheses that pergolide, (+)-3-PPP, bromocriptine and CQ 32-084 inhibit exploration via stimulation of dopamine receptors. The present data do not substantiate the hypothesis that the suppression of exploration induced by (-)-3-PPP is mediated by stimulation of dopamine autoreceptors. A detailed analysis of the dose curves for pergolide and (+)-3-PPP indicates that the latter compound may have effects in addition to those of a dopamine receptor agonist.
authors: L
authors: L
authors: Ståhle
authors: U
authors: U
authors: Ungerstedt
mesh_terms: D000818:Animals; D001971:Bromocriptine / Q000494:pharmacology; D004873:Ergolines / Q000494:pharmacology; D005106:Exploratory Behavior / Q000187:drug effects*; D006185:Habituation, Psychophysiologic / Q000187:drug effects; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D010880:Piperidines / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects*
chemical_list: D004873:Ergolines; D010880:Piperidines; D011954:Receptors, Dopamine; C031648:etisulergine; D001971:Bromocriptine; C026539:preclamol; C031649:mesulergine