Vascular responsiveness of isolated, perfused basilar arteries in dogs and monkeys

A new model of isolated basilar arterial preparation was developed in the dog and monkey. Isolated arteries were perfused at a constant flow rate with Krebs solution and suspended in a bath at 37 degrees C. By inserting the steel cannula into the artery, the space between the luminal wall of the artery and the cannula was narrowed enough to obtain a suitable perfusion pressure during the perfusion. The resting perfusion pressure was maintained at a constant level of 50-100 mmHg. The drug solution was intraluminally administered, and the response was obtained as changes in the perfusion pressure. Responses to 6 vasoactive substances (norepinephrine, 5-HT, PGF2 alpha, histamine, ATP and KCl) were compared between simian and canine basilar arteries. It was demonstrated that in simian arteries, PGF2 alpha was the strongest but 5-HT and norepinephrine induced slight vasoconstriction to the same degree, and in canine basilar arteries, 5-HT induced the strongest constriction but norepinephrine did not produce significant vasoconstriction, and KCl induced marked constriction to the same degree at extremely large doses in both species. It was demonstrated that the cannula inserting method is useful to observe the responses of isolated basilar arteries.