Changes in cerebral blood flow and metabolism following intraarterial or local administration of nimodipine, before and after experimental subarachnoid hemorrhage in baboons.

Experimental subarachnoid hemorrhage (SAH) was induced in baboons by repeated injections of autologous blood into cisterna chiasmatis and cisterna magna, a total of 14-33 ml being injected over 3-4 days. Cerebral blood flow (CBF; 133xenon clearance) and cerebral metabolic rate of oxygen (CMRO2) were measured before, and 7 days after, the first blood injection. The effect of the calcium channel blocker, nimodipine, used in a commercially available form for clinical application, was studied following continuous i.a. infusion (0.1 microgram X kg-1 X min-1) for an interval of 45 min, and also 20 and 60 min after intrathecal administration of 1 microgram X kg-1. During the infusion experiments, CBF was increased by 25-30% both before and after the cisternal blood injection. CMRO2 was also enhanced, but much less. Nimodipine in doses given did not alter systemic blood pressure. Following intrathecal application, CBF and CMRO2 slightly increased at 20 min only before experimental SAH.