Effect of intracarotid bradykinin infusion on cerebral blood flow in dogs

We examined whether intracarotid infusion of bradykinin altered circulation in the normal canine brain. Twenty-four anesthetized dogs were divided int o four groups receiving different doses of bradykinin (1, 2.5, 5, and 10 mu g kg(-1) min(-1)). Regional cerebral blood flow (rCBF) was measured contin uously using laser Doppler flowmetry through a burr hole in the frontal bon e. Systemic blood pressure (SBP) and heart rate (HR) were monitored simulta neously. Higher doses of bradykinin significantly but temporarily decreased rCBF and SEP immediately after the start of infusion; these parameters rap idly recovered and then were stable through the rest of the infusion. Durin g this period, percent change in rCBF and SEP was small, and differences be tween groups were not significant. On the other hand, HR increased during i nfusion and remained high. SEP, rCBF, and HR returned to pre-infusion level s after bradykinin was stopped. The results suggest that intracarotid infus ion of bradykinin for treatment of brain tumors would be safe in terms of c irculation to the uninvolved brain.