[Effect of tropane on the cholinoreceptors of the cerebral cortex]

Spontaneous electric activity of single neurons of the sensorimotor cortex was recorded extracellularly in experiments on unanesthetized rabbits. During microiontophoretic application of tropane and acetylcholine to the neurons, the response to both the agents was the same. The cells excitable by acetylcholine are also excitable by tropane, while those inhibited by acetylcholine are also inhibited by tropane. The cells that do not respond to acetylcholine are also irresponsive to tropane. The excitatory response pattern to tropane is similar to that of acetylcholine. Under the same conditions of microiontophoretic application, tropane causes less excitation as compared with acetylcholine. Tropane preliminarily applied to the neuron reduces the excitatory effect of acetylcholine. The possible role of agonist-antagonist relations between tropane and acetylcholine in the mechanism of the pharmacological effects of tropane and its derivatives is discussed.