The role of Na+-K+ -ATPase in the vasorelaxant actions of synthetic atrial natriuretic factor.
The present study evaluated the role of Na+-K+ -ATPase stimulation in the relaxant response to synthetic atrial natriuretic factor (atriopeptin II; ANF) in norepinephrine (0.18 microM)-contracted rabbit aorta. ANF (10(-10)-10(-7) M) produced a concentration-related relaxation of NE-contracted aortic rings. The calculated concentration required to produce 50 per cent relaxation (EC50) was 5 +/- 3 X 10(-9) M. ANF-induced relaxation was significantly attenuated by ouabain (30 microM). Likewise, ANF (10(-7) and 5 X 10(-9) M) elicited significantly less relaxation of aortic rings contracted with norepinephrine in a physiological salt solution containing zero KCl. Nitroprusside-induced relaxation also was attenuated by ouabain and in zero KCl salt solution. The data suggest that synthetic ANF induces relaxation in rabbit aortic rings by a ouabain and KCl sensitive mechanism, presumably Na+-K+ -ATPase.
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D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D006152:Cyclic GMP / Q000494:pharmacology; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D009599:Nitroprusside / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D011817:Rabbits; D000254:Sodium-Potassium-Exchanging ATPase / Q000502:physiology*; D014665:Vasodilator Agents
D007473:Ion Channels; D014665:Vasodilator Agents; D009599:Nitroprusside; D010042:Ouabain; D011189:Potassium Chloride; D009320:Atrial Natriuretic Factor; D000254:Sodium-Potassium-Exchanging ATPase; D006152:Cyclic GMP; D009638:Norepinephrine