Increased sodium permeability and transport as primary events in the hypertensive response to deoxycorticosterone acetate (DOCA) in the rat.
We report here that 18-24 h after subcutaneous administration of DOCA to the rat, plasma [Na] was significantly increased and [K] reduced without change in cell Na concentration, [Na]i, or cell K concentration, [K]i, as measured in rapidly excised tail arteries. The large increase in the transmembrane K gradient, operationally [K]i/[K]o, was associated with a significant decline of about 7 mV in the transmembrane membrane potential (Em) measured in small mesenteric arteries in situ, and a small but significant rise in blood pressure. We conclude that the permeability of the membrane to Na relative to K was increased at this time but enhanced transport of both ions was sufficient to maintain near-normal cell concentrations. These were primary events in relation to the hypertension induced by DOCA, as the rise in plasma [Na] and fall in [K] were already apparent at 6 h.
D000818:Animals; D001158:Arteries / Q000187:drug effects / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects*; D003900:Desoxycorticosterone / Q000494:pharmacology*; D006973:Hypertension / Q000097:blood / Q000139:chemically induced*; D066298:In Vitro Techniques; D008297:Male; D011188:Potassium / Q000097:blood; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000097:blood*
D003900:Desoxycorticosterone; D012964:Sodium; D011188:Potassium