Comparison of the vascular effects of adenosine, AMP, ADP and ATP on isolated blood-perfused internal and external carotid arteries of dogs.

1. The effects of adenosine and adenine nucleotides were studied on arterial vasculature in blood-perfused arterial preparations of dogs which were isolated from the internal and external carotid arteries. Each compound was administered directly into the cannulated artery over a period of 4 s. 2. In both arterial preparations, adenosine produced a dose-related vasodilatation and was more potent than AMP. On the other hand, ATP produced a dose-related vasoconstriction and was more potent than ADP.