Accumulation of Prostacyclin in Rat Brain during Haemorrhagic Hypotension—Possible Role of PGI2in Autoregulation

Abstract

The effect of haemorrhagic hypotension on the levels of prostaglandin E₂(PGE₂), thromboxane B₂(TXB₂), and 6-keto prostaglandin F_1α(6-keto-PGF_1α) in cortical tissue of rats was studied. Lightly anesthetized rats were subjected to steady-state hypotension for 15 min, with a mean arterial blood pressure of 80, 60, and 40 mm Hg, and compared to a control group of normotensive rats. No significant change was found in the levels of PGE₂and TXB₂. The level of 6-keto-PGF_1αincreased from 7.8 ± 0.9 to 14.1 ± 1.9 pg/mg protein (p < 0.02) at 80 mm Hg. Our findings suggest that prostacyclin, which is a potent vasodilator, might play a role in setting the lower limit of the autoregulation range.