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Neurochemical regulation of swallowing reflex in guinea pigs
Author(s) -
Jia Yu X,
Li Jian Q,
Matsui Toshifumi,
Yamaya Mutsuo,
Ohrui Takashi,
Sekizawa Kiyohisa,
Sasaki Hidetada
Publication year - 2001
Publication title -
geriatrics and gerontology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.823
H-Index - 57
eISSN - 1447-0594
pISSN - 1444-1586
DOI - 10.1046/j.1444-1586.2001.00012.x
Subject(s) - medicine , endocrinology , histamine , reflex , atropine , sch 23390 , receptor antagonist , pharmacology , chemistry , dopamine , antagonist , dopamine receptor d2 , receptor
Background: Most peripheral afferent fibers involved in swallowing travel through the glossopharyngeal and vagus nerves and terminate in the nucleus of the tractus solitarius (NTS) and nodose ganglion (NG). Sensory neurons within the NTS and NG contain several neurotransmitters, including acetylcholine, histamine, serotonin and dopamine. The roles of these four neurotransmitters were investigated. Methods: The effects of atropine (muscarinic cholinergic receptor antagonist); pyrilamine maleate (PM, histamine H 1 receptor antagonist); cimetidine (histamine H 2 receptor antagonist); 8‐hydroxy‐2‐(di‐ n ‐propylamino)‐tetralin (8‐OH‐DPAT, specific 5‐HT 1A receptor agonist); and selective dopamine D 1 receptor antagonist (Sch‐23390) on the number of swallows elicited by distilled water in anesthetized guinea pigs were investigated. Results: Atropine (0.2 mg/kg) inhibited swallowing by approximately 70%; PM (30 mg/kg) inhibited swallowing by approximately 60%; cimetidine (30 mg/kg) inhibited swallowing by approximately 52.9% and Sch‐23390 (chronic treatment) inhibited swallowing by approximately 40%. In contrast, 8‐OH‐DPAT did not alter the number of swallows. Chronic pretreatment of Sch‐23390 markedly decreased the substance P (SP) content in the pharyngeal mucosa and the esophagus. Conclusion: These findings indicate that acetylcholine, histamine and dopamine are involved in the regulation of the swallowing reflex, whereas it is unlikely that serotonin is involved.