Differences in K+-induced relaxation of canine femoral and renal arteries.
The extent and initial rate of potassium-induced relaxation of canine femoral and renal arteries were measured as a function of potassium concentration [K+]. Both parameters were greater in the renal artery at low [K+]; the dissociation constant for potassium of the femoral artery was greater than that of the renal artery. If potassium-induced relaxation reflects sodium pump activity, then these data indicate that the sodium pumps of the two arteries are different. When we repeated the above experiments in a lowered sodium medium, the rate and extent of potassium-induced relaxation and the apparent affinity for potassium increased in the femoral artery as predicted by kinetic models based on both isolated Na+-K+-ATPase and intact tissue. The same parameters in the renal artery, however, were unaffected by lowered sodium. These results and those presented in the companion paper [Am. J. Physiol. 245 (Heart Circ. Physiol. 14): H604-H609, 1983] can be interpreted to mean that potassium-induced relaxation does not accurately reflect sodium pump function in canine renal arteries.
D000818:Animals; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D005263:Femoral Artery / Q000187:drug effects / Q000502:physiology*; D007700:Kinetics; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009126:Muscle Relaxation / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology*; D012077:Renal Artery / Q000187:drug effects / Q000502:physiology*; D012964:Sodium / Q000494:pharmacology
D011189:Potassium Chloride; D012964:Sodium; D009638:Norepinephrine