Immunoelectron microscopic studies of synaptic organization in the intralaryngeal ganglia of the cat.
The synaptic organization of nerve terminals containing calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP), substance P (SP) and enkephalin (ENK) in the intralaryngeal local ganglia of the cat was investigated by immunoelectron microscopy. CGRP-immunoreactive (IR) and VIP-IR varicose fibers formed mainly axo-dendritic synapses, whereas SP-IR and ENK-IR varicose fibers made axo-somatic synapses to the principal neurons of the local ganglion. The synaptic specializations of the CGRP-IR varicosities were asymmetrical, or Gray's type I, whereas the other peptide-IR varicosities showed symmetrical, or Gray's type II, synaptic specializations. After denervation of the extrinsic nerves, CGRP-IR varicose fibers disappeared from the ganglion, but VIP-IR, SP-IR and ENK-IR varicose fibers and synapses remained. These results suggest that local ganglia act as an integration center of laryngeal function rather than as a unidirectional parasympathetic relay center.
Tsuda
K
K
Department of Otolaryngology, Saga Medical School, Japan.
Shin
T
T
Masuko
S
S
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis; D002415:Cats; D004745:Enkephalins / Q000032:analysis; D005260:Female; D005724:Ganglia / Q000648:ultrastructure*; D007823:Laryngeal Nerves / Q000648:ultrastructure*; D008297:Male; D016253:Microscopy, Immunoelectron; D009411:Nerve Endings / Q000737:chemistry; D009474:Neurons / Q000648:ultrastructure; D013373:Substance P / Q000032:analysis; D013569:Synapses / Q000648:ultrastructure*; D014660:Vasoactive Intestinal Peptide / Q000032:analysis
D004745:Enkephalins; D013373:Substance P; D014660:Vasoactive Intestinal Peptide; D015740:Calcitonin Gene-Related Peptide