Vasopressor effects of epinephrine, norepinephrine, ephedrine, phenylephrine, methoxamine and of mephentermine were compared in resrpinized dogs with or without nitrous oxide-oxygen-halothane anesthesia. The results are as follows: (1) Epinephrine and norepinephrine were shown to have the most potent pressor effect in reserpinized and nitrous oxide-oxygen-halothane-anesthetized dogs. Phenylephrine, methoxamine, mephen-termine and ephedrine were less potent in decreasing order. (2) Decrease in mean arterial pressure was less marked in dogs reserpinized and anesthetized with nitrous oxide-oxygen-halothane than in reserpinized but unanesthetized dogs. (3) It revealed that nitrous oxide-oxygen-halothane anesthesia potentiated the vasopressor effects of the sympathomimetic amines studied. Nitrous oxide-oxygen-halothane anesthesia is implicated to exert an sympathomimetic effect.
Anesthesia* ; Animals ; Arterial Pressure ; Dogs* ; Ephedrine ; Epinephrine ; Mephentermine ; Methoxamine ; Norepinephrine ; Phenylephrine ; Sympathomimetics*