Effects of intra-arterial papaverine on the chronic period of cerebral arterial vasospasm in rats.

Abstract

The effect of intra-arterial papaverine (IAP) on the basilar artery (BA) and cerebral perfusion pressure (CPP) during the chronic period of the cerebral arterial vasospasm in rats was investigated. The study was carried out on male, Swiss-Albino rats, the weight of each varied between 200-340 g. A large volume (0.3 cc) of nonheparinized, autolog blood was utilized in order to cause a subarachnoid haemorrhage. For the measurement of the changes in BA diameter, the angiograms were made prior to the subarachnoid haemorrhage, 48 h after the subarachnoid haemorrhage, and in 1, 15, 30, and 60 min after papaverine infusion into the vertebral artery. The BA vascular index was found separately for each angiogram. At each stage of the procedure mean arterial blood pressure (MAP) and intracranial pressure (ICP) were monitored. BA diameter measurements were found to be 226+/-32 microm in pre-haemorrhage angiograms and 145+/-44 microm in angiograms 48 h after the subarachnoid haemorrhage. In the angiograms immediately after IAP, it was found that the BA diameter reached about 92% (206+/-41 microm) of control values. But, in the angiograms 15 min after IAP, it was observed that BA underwent a spasm again. The dilatator effect of IAP on BA was temporary. Additionally, in the chronic vasospasm period when cerebral autoregulation mechanisms are impaired and CPP decreased significantly, IAP has adversely affected CPP decreasing MAP.