Abstract

We have developed a technique which can measure directly and simultaneously changes in both nasal vascular and airway resistances in the dog. Nasal vascular resistance was measured by either direct monitoring of the arterial inflow or a change in the perfusion pressure of the nasal vascular bed with blood flow maintained constant. Nasal airway resistance was measured by a rhinomanometric method. Intra-arterial infusion of prostaglandin (PG) E1 at the rate of 1 ml/min in doses of 0.001 to 10 micrograms/min caused a dose-dependent decrease in both nasal vascular and airway resistances. When compared with the control, the average maximal effect of PGE1 on vascular resistance was -38.4%, whereas on airway resistance it was -16.4%. The present studies demonstrate that PGE1 has significant vasodilatatory activity in the canine nasal vascular bed and suggest that the vascular and airway responses to PGE1 may be due to a decrease in inflow and outflow vascular resistance and/or opening of arteriovenous anastomoses.