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The canine coronary artery possesses a smooth muscle relaxant serotonin (5-HT) receptor distinct from previously characterized 5-HT receptors. On the basis of the ability of LY53857 to block weakly coronary smooth muscle relaxation to 5-HT, we examined several structurally related ergolines in endothelium denuded rings of canine coronary artery(More)
The rat gastric fundus is known to possess an "atypical" beta-adrenergic receptor that mediates relaxation to isoproterenol. The purpose of this study was to characterize the relationship between this "atypical" beta receptor in the rat stomach and the cloned rat beta 3 receptor by taking advantage of highly selective pharmacological and molecular(More)
Serotonin-induced contraction in porcine coronary artery was studied in ring segments of coronary artery without endothelium. 5-hydroxytryptamine (5-HT), 5-methoxytryptamine (5-MeOT) and alpha-methyl-5-HT (alpha Me-5-HT) concentration-dependently contracted vessels with similar maximal force. The agonist rank order potency was 5-HT > alpha Me-5-HT > 5-MeOT.(More)
The involvement of a guanine-nucleotide-binding regulatory protein (G protein) in the relaxing responses to adenosine receptor agonists was investigated in bovine coronary vessels. Ring segments of left anterior descending artery branches were suspended in organ baths for measurement of isometric tension. The adenosine analogs,(More)
We investigated the involvement of adenosine 3',5'-cyclic monophosphate (cAMP) and guanosine 3',5'-cyclic monophosphate (cGMP) in adenosine (ADO) receptor-mediated coronary artery relaxation. Rings from left anterior descending coronary artery, with the endothelium mechanically removed, contracted with prostaglandin F2 alpha and relaxed in a(More)
The identity of the serotonin (5-HT) receptor(s) that mediate(s) contraction in canine coronary artery and saphenous vein remains controversial. Ring segments of endothelium-denuded coronary artery and helical strips of saphenous vein were suspended in organ chambers for measurement of isometric force. 5-HT, alpha Me-5-HT and sumatriptan contracted both(More)
The existence of specific adenosine binding sites in bovine testicular tissue was evaluated using the novel antagonist radioligand 8-cyclopentyl-1,3-[3H]dipropylxanthine ([3H]DPCPX). Saturation analysis revealed specific binding that was saturable at approximately 1 nM. Scatchard analysis indicated a single class of binding sites with a KD = 0.26 nM and a(More)
The coupling of the human coronary adenosine receptor to a G protein was investigated in vitro. Hearts were obtained from accidental death victims and the left anterior descending coronary artery (LAD) was taken for experimentation. Cholera toxin (CT) and pertussis toxin (PT) ADP-ribosylated proteins with Mr of 45, 49 (CT), and 41 (PT) kDa. Both processes(More)
The effect of adenosine, 2-chloroadenosine (CAD), and 5'-(N-ethylcarboxamido)-adenosine (NECA) on the contraction produced by phorbol 12,13-dibutyrate (PDB) was investigated in porcine coronary artery in vitro to determine whether adenosine receptor-mediated relaxation was linked to protein kinase C. Also, the coronary relaxation produced by adenosine and(More)
Serotonin (5-HT) is one important mediator of the coronary vasospasm and occlusion associated with thrombosis and atherosclerosis. 5-HT concentration-dependently contracted both canine and porcine coronary artery rings in vitro. In the dog, 5-HT-induced contraction was not blocked by either LY53857 (1 microM) or ketanserin (1 microM), but was blocked by the(More)