Modification of Brain Vascular Eicosanoids After Pharmacological Treatment and Ischemia in the Rat: Drugs and Brain Vascular Eicosanoids

Abstract

Vascular eicosanoids (E) thromboxane (measured as T×B₂) and prostacyclin (measured as 6-keto-PGF_1α) may modulate hemodynamic parameters in brain circulation. We have studied (a) the effects of the administration of vasoactive drugs, in the rat, on T×B₂ and 6-keto-PGF_1α levels and release in brain cortex, and (b) changes of brain vascular E levels during hypoxia and recovery, in the same animal species. (a) Administration of vasoactive drugs (papaverine, dipyridamole, the carbochromene derivative AD₆ and nifedipine) to rats resulted in differential effects on endogenous levels and post-decapitation release of both compounds. Reduction of the T×B₂/6-keto-PGF_1α balance in brain cortex was obtained with papaverine and AD₆, whereas nifedipine reduced 6-keto-PGF_1α more than T×B₂. (b) During hypoxia there was no significant modification of brain vascular E, but during recovery both compounds were decreased. Thus pharmacological treatments during recovery from hypoxia may normalize brain vascular E levels.