Relative activity of psychotoxic drugs on the avian optic lobe

Because of restrictions in the use of psychotoxic drugs in the human, a subhuman experimental tool suitable for the study of these drugs and their antagonist would be useful. Using standard electrophysiological techniques, the action of psychotoxic drugs on the electrical activity of the optic tectum of the young chick has been studied. The intravenous administration of lysergic acid diethylamide L(SD) to this animal produces a well defined and consistent change in tectal activity. A comparable change occurs following administration of other psychotoxic agents (psilocybin, mescaline and amphetamine). The relative potency of these agents on tectal activity compares favorably with their relative psychotoxic potency in man. These results favor the view that the mechanism of action of these psychotoxic agents on the chick tectum resembles, to some degree, their psychotoxic properties in man. It is suggested that the avian preparation may be useful for the study of the pharmacology of psychotoxic drugs and antagonists.