Physiological significance of Na+/K(+)-ATPase activity in the central nervous system and endogenous sodium-pump inhibitors in the neural regulation of arterial blood pressure.
In anesthetized Sprague-Dawley rats, cerebrolateral ventricular administration of potassium chloride solutions (KCl, 0.375-1.25 mumol, i.c.v.) produced concentration-dependent reductions in the arterial blood pressure and heart rate. These responses were significantly attenuated by prior i.c.v.-administration ouabain, a selective inhibitor of the Na+ pump, and by endothelin (ET-1), an endogenous peptide that is present in the CNS, suggesting that this peptide may participate in the neural regulation of arterial pressure via modulation of Na(+)-pump activity. Although both acute fluid volume expansion and/or osmotic stimulus have been shown to facilitate the release of the endogenous Na(+)-pump inhibitor(s) into the circulation, only volume expansion significantly attenuated the cardiovascular effects of i.c.v. potassium chloride. These observations collectively suggest that the Na+, K(+)-ATPase activity in CNS and Na(+)-pump inhibitors may play a significant role in the central regulation of arterial pressure under certain physiological conditions.
Shah
J
J
Department of Pharmacology, University of Houston, Texas 77204-5515.
Jandhyala
B S
BS
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002490:Central Nervous System / Q000201:enzymology*; D016232:Endothelins / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D007276:Injections, Intraventricular; D008297:Male; D010042:Ouabain / Q000378:metabolism* / Q000494:pharmacology*; D011189:Potassium Chloride / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism*
D016232:Endothelins; C083016:sodium-potassium ATPase inhibitory factor; D010042:Ouabain; D011189:Potassium Chloride; D000254:Sodium-Potassium-Exchanging ATPase