Influence of central nervous system on arterial pressure during endotoxin shock

Some investigators have suggested that the hypotensive effects of endotoxin are exerted at the level of central nervous system (CNS). Others feel the effects are exerted peripherally and that the CNS is involved in the regulation of the cardiovascular system during the shock state. Still other data suggest that endotoxin shock is entirely a peripheral phenomenon. The present study used ventriculocisternal perfusion of endotoxin, a pretrigeminal brainstem transection, two midcollicular decerebrate preparations, and Cushing's reflex to investigate the involvement of the CNS during endotoxin shock. The results suggest the following: 1) endotoxin perfused centrally at a concentration equivalent to the maximum obtainable after peripheral injection will not alter mean arterial pressure (MAP); 2) either the forebrain is not involved in the MAP response or the remaining regions can compensate for its absence; and 3) Cushing's reflex will block the initial endotoxin-induced hypotension.