Mechanism of potentiating action of epinephrine on thiopental anesthesia.

A number of papers have been presented in support of the concept that epinephrine potentiates barbiturate anesthesia in experimental animals (1-3). Recently, Mazel et al. (4) reported that epinephrine increased the brain level of barbital above controls and suggested that epinephrine may affect the permeability of the blood-brain barrier as well as other barriers. However, mechanism of the potentiating action of epinephrine on barbiturate anesthesia still remained to be elucidated. Meanwhile, Ohshika in our laboratory has reported that thiopental bound to plasma albumin can be displaced in vitro by a series of fatty acids (5) and further that anesthetic effect of thiopental was potentiated in rats or mice pretreated with sodium oleate. From a consideration of the results, he suggested the implication of plasma free fatty acids