Textbook of Physiology

serotonin in platelets or other organs. Giarman and Schanberg (Biochem. Pharmacol. 1:301, 1959) showed that iproniazid does indeed hinder reserpine-induced release of serotonin from storage granules in rat's brain. Recently, the same has been found to be true about release of catecholamines from rabbit's atria. These objections and criticisms are raised here only to present one of the apparent weaknesses of such conferences. Often, leading investigators in these discussions make incompletely substantiated assertions which are accepted as well-established facts. Dr. K. Killam once again has presented in the second section of this volume his wife's and his work on an electrophysiological interpretation of the mode of action of the tranquilizers. They marshall strong evidence for establishing the reticular formation as a site of action of both reserpine and chlorpromazine. Especially attractive is their demonstration that both tranquilizers have the same action on this brain region: that of augmenting the effect of peripheral stimulation (input) upon it. Dr. W. P. Koella has made use of a technique similar in some respects to that of Dr. Marazzi and co-workers, to arrive at a similar conclusion-that serotonin is an inhibitory neurohumor. Dr. Koella used the cortical evoked potential from a light flash on the retina. The most valuable part of his presentation is the analysis of his data to show that three factors are involved in this neuro-inhibitory action of serotonin: (i) stimulation of the carotid sinus; (ii) subcortical inhibition which has a bilateral effect; (iii) cortical inhibition whch is ipsilateral. The last section of this book is devoted to another presentation of Dr. Brodie's hypothesis that Hess' central ergotropic system is adrenergic in characteristics of transmission, while his central trophotropic system is "serotonergic." This is, at best, a considerable over-simplification which challenges experimentation to refute it.