Abstract
Participation of various neurotransmitters in the canine inferior laryngeal nerve was studied by immunohistochemistry and NADPH-diaphorase (NADPH-d) histochemistry in combination with retrograde labelling using cholera toxin B subunit-gold (CTBG) as a tracer.
In the nucleus ambiguus, nearly all of cells labeled with CTBG had choline acetyltransferase (ChAT) -like immunoreactivity (ir) and many labeled cells had calcitonin gene-related peptide (CGRP) -like ir. In the dorsal nucleus of the vagus, many CTBG labeled cells had ChAT-like ir and some of CTBG labeled cells had CGRP-like ir. In the nodose ganglion, CTBG labeled cells were scattered in the ganglion. In these cells, CGRP-, substance P (SP) -and tyrosine hydroxylase (TH) -like immunoreactive cells were detected. NADPH-d positive cells were also observed. In the superior cervical ganglion, most CTBG labeled cells had TH-like ir and labeled cells with NPY-like ir were also found. Labeled cells with VIP-like ir were also detected, although the number was small.
These results indicate that many kinds of neurotransmitters participate in the sensory and autonomic innervation as well as motor innervation of the larynx through the inferior laryngeal nerve.
