title: Hydralazine-relaxing effect on rat aorta is not mediated through changes in ATPase activity.
abstract: Hydralazine, a hypotensive agent, induces relaxation on smooth musculature. Several mechanisms related to membrane processes have been proposed to explain its relaxing action. In the present paper, the effects of hydralazine on ATPase activity in rat aorta have been studied. Hydralazine (10(-4)-5 X 10(-3) M concentration-dependently relaxed the isolated rat aortic arterial strips under norepinephrine-, serotonin- and K+-contractures. 5-Hydroxytryptamine contractures were more sensitive to the effects of hydralazine than noradrenaline- and potassium-contractures. We found that hydralazine does not modify ATPase activity on rat aorta homogenates. On the other hand, ATPase activity of rat aorta homogenates is dependent on divalent cations Ca2+ and Mg2+, and a little Na, K-ATPase activity was found.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D006830:Hydralazine / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000201:enzymology; D009638:Norepinephrine / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000494:pharmacology
chemical_list: D006830:Hydralazine; D012701:Serotonin; D000251:Adenosine Triphosphatases; D011188:Potassium; D009638:Norepinephrine