Responses of cortical neurons to microiontophoretic application of acetylcholine to their dendrites.

Spike responses of neurons to the microiontophoretic application of acetylcholine to the soma and the dendrites were studied. The somatic and dendritic membranes had virtually equal sensitivity to acetylcholine. Only activatory responses were seen, which were most typical of spontaneously active neurons. Muscarinic activation induced spike responses with equal latent periods and equal intensities on application of acetylcholine to dendrites and the soma. It is suggested that intracellular chemical signaling is involved in the propagation of cholinergic excitation via dendrites.