Potentiation of dopamine receptor-mediated responses by B-HT 920 in mice.
The effect of B-HT 920, an alpha 2-agonist, on postsynaptic dopamine receptor-mediated stereotypic behaviour, was studied in mice. Apomorphine produced typical stereotypic responses in mice such as sniffing, rearing, biting, licking and grooming. B-HT 920, when given alone, produced mild stereotypy. Pretreatment with B-HT 920 significantly potentiated the stereotypic behaviour of apomorphine. The specific alpha 2-blockers, idazoxan and yohimbine, failed to block the potentiating effect of B-HT 920. The specific D2-receptor blockers haloperidol and molindone, completely blocked the stereotypic responses due to B-HT 920 and apomorphine. On reserpinization of animals there was a 5-fold increase in stereotypy induced by the combination of apomorphine and B-HT 920. B-HT 920 also potentiated amphetamine-induced locomotor responses in mice in a haloperidol-sensitive way. These data imply an interaction of B-HT 920 with postsynaptic dopamine receptors.
Chopra
K
K
Department of Pharmaceutical Sciences, Panjab University, Chandigarh, India.
Kulkarni
S K
SK
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001381:Azepines / Q000494:pharmacology*; D005260:Female; D006220:Haloperidol / Q000494:pharmacology; D008297:Male; D051379:Mice; D008972:Molindone / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects; D011954:Receptors, Dopamine / Q000502:physiology*; D013239:Stereotyped Behavior / Q000187:drug effects; D015016:Yohimbine / Q000494:pharmacology
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D001381:Azepines; D011954:Receptors, Dopamine; D015016:Yohimbine; C024763:talipexole; D006220:Haloperidol; D001058:Apomorphine; D008972:Molindone