Selective enhancement of intratumoural blood flow in malignant gliomas: experimental study in rats by intracarotid administration of adenosine or adenosine triphosphate.

We studied the effect of intravenous and intracarotid infusion of adenosine and adenosine triphosphate (ATP) on the regional blood flow of intracerebrally transplanted RG-C6 tumours in rats, using the hydrogen clearance method. The intracarotid administration of adenosine or ATP selectively increased blood flow in the tumour, but did not produce any significant change either in the regional cerebral blood flow of the extratumoural ipsilateral hemisphere or in the ipsilateral hemisphere without tumour. The intracarotid administration of ATP at a dose of 10 micrograms/kg/min produced the most effective increase in the tumour blood flow (+51.5 +/- 16.8%). In contrast, both the intravenous administration of adenosine and that of ATP failed to increase tumour blood flow. These results may possibly indicate that intracarotid administration of the adenosine or ATP might contribute in selectively enhancing the delivery of anti-cancer agents to malignant brain tumours.