Role of Na+,K(+)-ATPase in the centrally mediated hypotensive effects of potassium in anaesthetized rats.
Several investigators have demonstrated the antihypertensive properties of potassium in various models of hypertension. The present studies were conducted to determine whether central mechanisms contribute to these salutary effects of potassium. In Inactin-anaesthetized rats, intracerebroventricular administration of KCl solutions (0.375, 0.75 and 1.25 mumol/5 microliters) produced concentration-dependent reductions in arterial pressure and heart rate. These effects were significantly attenuated by prior central administration of ouabain, a selective inhibitor of the sodium pump. In a separate series of experiments, prior central administration of alpha 1- and alpha 2-antagonist phentolamine, or the dopamine receptor (DA1 and DA2) antagonist RS-sulpiride, was also effective in inhibiting the hypotensive and bradycardiac effects of intracerebroventricular administration of potassium. Thus, these data suggest that activation of Na+,K(+)-ATPase and central noradrenergic and dopaminergic mechanisms are involved in the central actions of potassium and these central mechanisms may contribute to the salutary effects of a potassium-rich diet in hypertensive subjects. The present studies demonstrate a potentially important relationship between Na+,K(+)-ATPase activity in the central nervous system and neural regulation of arterial blood pressure.
Shah
J
J
Department of Pharmacology, University of Houston, TX 77204-5515.
Jandhyala
B S
BS
D000768:Anesthesia, General; D000818:Animals; D001693:Biological Transport, Active / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects*; D001921:Brain / Q000187:drug effects*; D010042:Ouabain / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D011189:Potassium Chloride / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000502:physiology*; D013469:Sulpiride / Q000494:pharmacology
D010042:Ouabain; D011189:Potassium Chloride; D013469:Sulpiride; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D010646:Phentolamine