Abstract:OBJECTIVE: To study the effects of nimodipin and ketamine on cerebral blood flow and metabolism in rabbits with global ischemic reperfusion. METHODS: The model of global cerebral ischemic reperfusion was established in rabbits. The ischemic rabbits were randomly assigned into an ischemic group, a nimodipin treatment group and a ketamine treatment group (n=8 each). Eight sham operated rabbits were served as the non ischemic controls. RESULTS: ①The mean flow velocities (Vm) [( 14.50 ± 3.25 ), ( 14.13 ± 2.96 ) and ( 14.31 ± 2.96 ) cm/s] of right middle cerebral artery (MCA) in the ischemic group at 2 h, 6 h and 24 h of reperfusion were significantly decreased compared with that of pre ischemia [( 23.44 ± 3.13 ) cm/s] and those of the control group, nimodipin treatment group and ketamine treatment group (P< 0.05 ). There was no significant difference in the Vm between before and after operation in the control group, nimodipin treatment group and ketamine treatment group; no significant difference was noted among the three groups. ②Compared with the indexes before operation, the plasma lactic acids in all four groups at 2 h, 6 h and 24 h after ischemic reperfusion were significantly increased (P< 0.05 ). The plasma lactic acid level and arteriovenous oxygen differences (AVDO 2) were higher in both the ischemic and nimodipin treatment groups than those in the non ischemic control and ketamine treatment groups after reperfusion (P< 0.05 ). ③ The mean blood pressure and heart rate decreased in the nimodipin group at 2 h and 6 h after reperfusion compared with those of before administrating nimodipin and those of the other three groups (P< 0.05 ). CONCLUSIONS: Both nimodipin and ketamine could improve cerebral blood flow velocity of rabbits. Ketamine could decrease plasma lactic acid level and AVDO 2, indicating ketamine may have protective effects on brain of rabbits with ischemic reperfusion. Nimodipin failed to improve the cerebral metabolism might be the consquence of its effects of restraining the function of cardiovascular system.
