Effects of acetylcholine on cochlear nucleus neurons.
Iontophoretic application of acetylcholine (ACh) onto neurons in the dorsal cochlear nucleus (DCN) resulted in an inhibition of the tone-evoked responses of 85% of neurons which were affected. That effect in the DCN contrasts with the predominance of excitatory effects of ACh seen in ventral cochlear nucleus (VCN) neurons. The ACh-induced inhibition in the DCN had a considerably slower onset and time course of recovery than that seen with glycine-induced inhibition. The degree of ACh effects was constant with increasing intensity or attained a maximum effect at 20 to 30 dB above best-frequency threshold in contrast to glycine, which had effects that were relatively greater at low intensities. These findings suggested a modulatory role for ACh at DCN and VCN synapses.
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002682:Chinchilla; D003056:Cochlear Nerve / Q000166:cytology / Q000187:drug effects*; D003472:Curare / Q000494:pharmacology; D007478:Iontophoresis; D009433:Neural Inhibition / Q000187:drug effects; D009474:Neurons / Q000187:drug effects*
D001285:Atropine; D003472:Curare; D000109:Acetylcholine