B-HT 920 activates dopamine D2 receptors coupled to inhibition of adenylate cyclase activity.
In homogenates of female rat anterior pituitary, the azepine derivative B-HT 920 inhibited the forskolin-stimulated adenylate cyclase activity with an EC50 value of 0.35 microM. In male rat anterior pituitary, B-HT 920 curtailed the stimulation of adenylate cyclase activity by vasoactive intestinal peptide with an EC50 of 0.20 microM. In synaptic plasma membranes of rat striatum, B-HT 920 significantly reduced basal adenylate cyclase activity with an EC50 of 0.68 microM. Both in pituitary and striatum, the B-HT 920 inhibition was counteracted by the dopamine (DA) D2 receptor antagonist 1-sulpiride, but not by the alpha 2-adrenergic antagonist yohimbine. These results indicate that B-HT 920 is capable of activating DA D2 receptors negatively coupled to adenylate cyclase activity.
Department of Neurosciences, University of Cagliari, Italy.
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D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D001381:Azepines / Q000494:pharmacology*; D003342:Corpus Striatum / Q000166:cytology / Q000201:enzymology / Q000378:metabolism; D015259:Dopamine Agents / Q000494:pharmacology*; D005260:Female; D008297:Male; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000201:enzymology / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects*; D017448:Receptors, Dopamine D2; D013469:Sulpiride / Q000494:pharmacology; D015016:Yohimbine / Q000494:pharmacology
D001381:Azepines; D015259:Dopamine Agents; D011954:Receptors, Dopamine; D017448:Receptors, Dopamine D2; D015016:Yohimbine; C024763:talipexole; D013469:Sulpiride; D000262:Adenylyl Cyclases