Influence of deaminated metabolites on the relaxing effect of dopamine on dog saphenous vein.
The relaxing effect of dopamine was studied on the dog isolated saphenous vein contracted by prostaglandin F2alpha after alpha-adrenoceptor blockade by phentolamine. This effect is partially inhibited by propranolol and haloperidol suggesting that dopamine has two types of receptors in this vessel: beta- and dopaminergic receptors. However, the results obtained after treatment with drugs that interfere with deamination of catecholamines or after denervating the venous tissue led us to conclude that the agonist substance is not dopamine, but probably one of its deaminated metabolites or a secondary condensation product, namely tetrahydropapaveroline. Adrenaline has also been used to compare the behaviour of the two amines when interference in the deamination process is produced. The dissimilar results obtained with adrenaline are in good agreement with the hypothesis.
D000818:Animals; D003641:Deamination; D004285:Dogs; D004298:Dopamine / Q000378:metabolism / Q000494:pharmacology*; D004347:Drug Interactions; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D009121:Muscle Denervation; D010646:Phentolamine / Q000494:pharmacology; D011460:Prostaglandins F / Q000494:pharmacology; D012501:Saphenous Vein / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects*
D011460:Prostaglandins F; D004298:Dopamine; D004837:Epinephrine; D010646:Phentolamine