[Dependence of angiotensin II induced drinking on local cerebral vasomotor function in rats].

In the Rat, injection of vasoplegics such as papaverine, NaNO2, sodium nitroprusside or prostaglandin E 2 into the subfornical organ, the antero-inferior part of the 3rd ventricle or the lateral ventricle blocks the dipsogenic action of angiotensin II (A II) injected through the same cannula practically completely without diminishing that of carbachol. This antagonism of A II by substances known to relax vascular smooth muscle supports our hypothesis that the mechanism of action of this dipsogenic substance, in contrast to that of carbachol, involves mechanoreceptors situated in special cavernous structures.