The Effect of Intracarotid Aminophylline Infusion on the Cerebral Circulation

The influence of aminophylline infusion into the internal carotid artery on cerebral blood flow (CBF) was studied in 12 patients. Six of them were studied using the N 2 O saturation technique of Kety and Schmidt, and the other six using the Xenon-133 intra-arterial injection method of Lassen and Ingvar. Intracarotid infusion of aminophylline resulted in a significant decrease of CBF. Previous studies have shown that aminophylline also reduced CBF when injected intravenously. Furthermore, in the present study it was demonstrated that a small dose of aminophylline which was without cerebral vasoconstricting effect when infused intravenously still reduced CBF when infused into the internal carotid artery. Thus aminophylline is a cerebral vasoconstrictor due to a local action on the cerebral vessels.