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

Objectives - The effect of intra-arterial papaverine (IAP) on the basilar a rtery (BA) and cerebral perfusion pressure (CPP) during the chronic period of the cerebral arterial vasospasm in rats was investigated. Material and m ethods - The study was carried out on male, Swiss-Albino rats, the weight o f 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. F or the measurement of the changes in BA diameter, the angiograms were made prior to the subarachnoid haemorrhage, 48 h after the subarachnoid haemorrh age, and in 1, 15, 30, and 60 min after papaverine infusion into the verteb ral artery. The BA vascular index was found separately for each angiogram. At each stage of the procedure mean arterial blood pressure (MAP) and intra cranial pressure (ICP) were monitored. Results - BA diameter measurements w ere found to be 226+/-32 mu m in pre-haemorrhage angiograms and 145+/-44 mu m 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 mu m) of control values. But, in the angiograms 15 min after IAP , it was observed that BA underwent a spasm again. Conclusion - The dilatat or effect of IAP on BA was temporary. Additionally, in the chronic vasospas m period when cerebral autoregulation mechanisms are impaired and CPP decre ased significantly, IAP has adversely affected CPP decreasing MAP.