Effects of sodium nitroprusside on blood pressure responses to epinephrine

¹ Department of Pharmacology, University of Mississippi Medical Center, Jackson, Mississippi

The effects of decrease in tone produced by sodium nitroprusside on the blood pressure responses to epinephrine were studied in dogs anesthetized with sodium pentobarbital. A series of graded doses of l-epinephrine bitartrate was given before and during the infusion of sodium nitroprusside and the blood pressure responses to each dose of the administered epinephrine were recorded. Four different levels of sodium nitroprusside infusion were used; 2, 5, 8 and 10 µg/kg/min. Blood pressure records were analyzed in terms of maximum blood pressure attained, actual rise in blood pressure and duration of blood pressure rise before and during the infusion. The results showed that there is a significant reduction in the maximum attainable blood pressure, but no significant change in the actual rise in blood pressure or in the duration of blood pressure responses. The amount of change in maximum attainable blood pressure was directly related to the decrease in control blood pressure resulting from the sodium nitroprusside infusion. A three-dimensional dose response curve, including dose of sodium nitroprusside, dose of epinephrine and blood pressure, has been derived.

Note:
With the Technical Assistance of Dolores Cronin