Effects of intracerebroventricular administration of prostaglandin D2 and angiotensin II on blood pressure in conscious rats.

To evaluate the role of brain prostaglandins in the regulation of blood pressure, we examined the effects of intracerebroventricular injections of prostaglandin D2, angiotensin II and indomethacin on blood pressure in conscious rats. Intraventricular administration of prostaglandin D2, the major prostaglandin synthesized in the rat brain, did not elicit a significant change in blood pressure. On the other hand, intraventricular injection of angiotensin II resulted in an increase in blood pressure in a dose-related manner. However, this central pressor effect of angiotensin II was not affected by intraventricular pretreatment with indomethacin. Indomethacin per se did not induce any change in blood pressure. These results suggest that prostaglandin D2 in the brain does not play an important role in the regulation of blood pressure in conscious rats. It is also suggested that the central pressor effect of angiotensin II is not mediated by prostaglandin biosynthesis in the central nervous system.