A QUANTITATIVE STUDY OF THE EFFECT OF COCAINE ON THE RESPONSE OF THE CAT NICTITATING MEMBRANE TO NERVE STIMULATION AND TO INJECTED NORADRENALINE.

Results are reported of a quantitative study of the potentiating effect of cocaine on the responses of the cat nictitating membrane to intravenously and intra-arterially injected noradrenaline, as well as to different types of sympathetic nerve stimulation. Responses of the membrane to noradrenaline were potentiated more with intravenous than with close-arterial injections. From studies of the responses of the nictitating membrane to various forms of sympathetic nerve stimulation before and after injection of cocaine, conclusions are drawn as to the extent to which the transmitter amine liberated by nerve activity is normally removed and its effect thereby limited in duration and extent. This uptake was greatest at low stimulus frequencies. The mechanism by which cocaine potentiates sympathetic responses is discussed.