Participation of cholinergic mechanisms in the origination of the dendritic potential of the cerebral cortex.

The influence of a series of muscarinic (M) and nicotinic (N) substances on the dendritic potentials of the cerebral cortex was studied in acute experiments on adult cats under deep nembutal anesthesia. M-Antagonists in large doses and M-agonists, N-agonists and acetylcholine elicited a decrease in the amplitude of dendritic potentials. M-Antagonists in small doses and N-antagonists elicited an increase in the amplitude of the dendritic potentials. The application of an anticholinesterase substance, proserine, to the cortex elicited an increase in the amplitude and duration of the dendritic potentials. It is hypothesized that there are postsynaptic M-cholinoreceptors of the M1 type, presynaptic M-cholinoreceptors of the M2 type, and presynaptic N-cholinoreceptors in the neuropil of layer I of the cortex.