THE EFFECT OF NIMODIPINE ON AUTOREGULATION OF CEREBRAL BLOOD-FLOW AFTER SUBARACHNOID HEMORRHAGE IN RAT

Disturbance of the autoregulation of the cerebral blood flow (CBF) is frequently seen following subarachnoid haemorrhage (SAH) and is possib ly partly caused by cerebral ischaemia. It is well-known, that the cal cium channel blocker nimodipine reduces the incidence of cerebral infa rction and ischaemic dysfunction after SAH. The aim of the present stu dy was to investigate the effect of nimodipine on autoregulation of CB F in an experimental model of SAH. The autoregulation was investigated in 10 control rats with SAH and in 10 nimodipine treated rats with SA H by serial measurements of CBF using a (133)Xenon intracarotid inject ion method during controlled blood pressure manipulations. In the cont rol rats the autoregulation was severely disturbed, no plateau was fou nd where CBF was independent of changes in the arterial blood pressure (MABP). In rats treated with intravenous nimodipine (0.03 mg/kg bodyw eight/h), CBF was 33.0% higher and MABP 5.3% higher compared with the controls. CBF was found constant in the MABP interval between 60 and 1 00 mmHg which indicates, that nimodipine improves the autoregulation o f CBF after SAH.