Bromocriptine induces climbing behaviour: possible D-1 or D-2 dopamine receptor involvement.
The ability of bromocriptine (BRC), a dopamine D-2 receptor agonist, to induce climbing behaviour was studied in mice. BRC (2-32 mg/kg IP) evoked climbing behaviour. The maximum effect was obtained with 8 mg/kg, while higher doses of BRC (16 and 32 mg/kg) were less effective. Climbing began about 2 h after injection and was most marked 5 h after bromocriptine administration. Pretreatment of animals with the dopamine antagonist pimozide (0.5 mg/kg IP) decreased BRC-induced climbing. Sulpiride (0.25-1.25 mg/kg IP), a potent D-2 antagonist and/or SCH 23390 (0.025 and 0.05 mg/kg SC), a D-1 receptor antagonist, also decreased the response. Furthermore, the climbing behaviour induced by BRC was abolished by pretreatment with reserpine plus alpha-methyl-p-tyrosine (AMPT). Concomitant administration of apomorphine (APO) and BRC potentiated the effect of APO on climbing. Concomitant injection of BRC and SKF 38393 (SKF, D-1 agonist) reduced the effect of SKF on climbing, while administration of BRC 4 h before SKF potentiated the effect of both drugs. It is suggested that BRC induces climbing through D-1 and/or D-2 dopamine receptors.
Zarrindast
M R
MR
Department of Pharmacology, Medical Faculty, University of Tehran, Iran.
Shahed-Dirin
K
K
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000494:pharmacology; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001522:Behavior, Animal / Q000187:drug effects*; D001971:Bromocriptine / Q000494:pharmacology*; D018492:Dopamine Antagonists; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D008297:Male; D008781:Methyltyrosines / Q000494:pharmacology; D051379:Mice; D010868:Pimozide / Q000494:pharmacology; D011954:Receptors, Dopamine / Q000187:drug effects*; D012110:Reserpine / Q000494:pharmacology; D013469:Sulpiride / Q000494:pharmacology; D019805:alpha-Methyltyrosine
D018492:Dopamine Antagonists; D008781:Methyltyrosines; D011954:Receptors, Dopamine; D010868:Pimozide; D001971:Bromocriptine; D019805:alpha-Methyltyrosine; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D013469:Sulpiride; D012110:Reserpine; D001058:Apomorphine