Effects on fluid balance induced by non-febrile intracerebroventricular infusions of PGE2, PGF2alpha, and arachidonic acid in the goat

Abstract

Prostaglandins (PG) E2, F2 alpha (30 ng/kg . min-1) and arachidonic acid (150 and 300 ng/kg . min-1) were infused for 30 min into the lateral cerebral ventricle of conscious hydrated and non-hydrated goats. Like previously shown as concerns PGE1 PGE2 was found to inhibit the water diuresis and cause some increase in the renal sodium excretion in the hydrated animal, and to elicit thirst in the non-hydrated goat. The effects of PGE2 were enhanced when hypertonic (0.25 M) NaCl was simultaneously infused into the ventricle. The antidiuretic effect of PGF2 alpha was less pronounced, and drinking only occasionally occurred when this PG was infused into the non-hydrated animal. Only a weak, post-infusion reduction of the water diuresis was observed when arachidonic acid was administered into the hydrated goat. Neither the PG:s, nor arachidonic acid affected the temperature regulation of the animals. The possibility is discussed that the lack of febrile response was due to the choice of platinum-iridium as material for the cerebral implantations. It is suggested that PGE2 might have interacted with CSF Na+ in stimulating juxtaventricular receptors involved in the control of fluid balance. The experiments do not support the concept that PG:s of the E series constitute a cerebral humoral link in pyrogen-induced fever.