Centrally acting endogenous hypotensive substances in rats subjected to endotoxic shock.

Cerebroventricular perfusate (CVP) from rats subjected to endotoxic shock was infused into the lateral ventricle of the naive rat. This procedure produced a hypotensive response in the recipient rat which could be reversed by the intravenous injection of the opioid antagonist naltrexone. The degree of endotoxemic hypotension in the donor rat was attenuated by perfusing the cerebroventricular system with mock CSF. The results suggest the existence of endogenous hypotensive substances in rat central nervous system, possibly opioid in nature, which may play a critical role in the pathogenesis of endotoxic shock.