Effects of Hypoxia on the Vasopressin Response to Hemorrhage and its Role inMaintenance of Blood Pressure

摘要

The research, conducted in conscious female goats, demonstrates for the firsttime that maintenance of blood pressure during hemorrhage is greatly compromised during conditions of hypoxia. This earlier reduction in blood pressure leads to an earlier increase in plasma levels of vasopressin but not plasma renin activity. Although these data would suggest a decrease in the baroreceptor-mediated renin release, subsequent experiments employing acute reductions in blood pressure by administration of sodium nitroprusside, did not confirm this. Thus, increases in renin were identical in response to 20% reductions in blood pressure whether or not 10% O2 was administered. On the other hand, the sodium nitroprusside experiments demonstrated that baroreceptor-mediated vasopressin release was enhanced by hypoxia. The apparent reduced renin sensitivity to blood volume reduction in the hemorrhage experiments is presently theorized to be due to a decrease in sympathetic tone resulting from hypotension.... Vasopressin, Hemorrhage, Blood pressure, Blood, RA II, MIPR.