Immunohistochemical Study of Neuropeptides in Feline Vagal Afferent Neurons / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Nodose ganglion (NG) of the vagus nerve is well known as a sensory ganglion mediated by many neurotransmitters. These neurotransmitters are substance P (SP), calcitonin gene-related peptide (CGRP), cholecystokinin (CCK), neurokinin A (NKA) etc. Controversy exists about other neurotransmitters of NG such as vasoactive intestinal polypeptide (VIP), cholineacetyl transferase (ChAT), and tyrosine hydroxylase (TH). SP is considered to be mainly a sensory neurotransmitter, and ChAT is an enzyme that stimulates acetylcholine synthesis, and is considered to be motor specific. VIP is considered to be a neurotransmitter mainly acting on the parasympathetic system. TH is a rate-limiting enzyme of catecholamine synthesis in the sympathetic system. In this study, we demonstrated the presence of these neurotransmitters in NG. MATERIALS AND METHODS:Seven NG was obtained from five wild cats after ketamine intramuscular anesthesia. Immunohistichemical staining was performed on anti-SP, anti-ChAT, anti-TH, and anti-VIP antibody using Avidin-Biotin-Peroxidae Complex and DAB (diamino benzidine) reaction. RESULTS: 1) Many SP-immunoreactve cells were present in NG, especially in the rostral portion. 2) A few VIP-immunoreactive cells were present, accounting for about 2-5% of all the cells. 3) A few ChAT-immunoreactive cells present. These cells are wide spread in NG, accounting for about 1-3% of all. 4) Many TH-immunoreactive cells present. These cells stained very strongly and were smaller than any other immunoreactive cells. CONCLUSION: We concluded that NG have many neurotransmitters and that their role may be sensory mediation. But we could not exclude the possibility that NG might have other functions other than sensory, so further study should follow.