title: Does the capsaicin-sensitive local neural circuit constitutively regulate vagally evoked esophageal striated muscle contraction in rats?
abstract: To determine whether a capsaicin-sensitive local neural circuit constitutively modulates vagal neuromuscular transmission in the esophageal striated muscle or whether the neural circuit operates in a stimulus-dependent manner, we compared the motility of esophageal preparations isolated from intact rats with those in which capsaicin-sensitive neurons had been destroyed. Electrical stimulation of the vagus nerve trunk evoked contractile responses in the esophagus isolated from a capsaicin-treated rat in a manner similar to those in the esophagus from a control rat. No obvious differences were observed in the inhibitory effects of D-tubocurarine on intact and capsaicin-treated rat esophageal motility. Destruction of the capsaicin-sensitive neurons did not significantly affect latency, time to peak and duration of a vagally evoked twitch-like contraction. These findings indicate that the capsaicin-sensitive neural circuit does not operate constitutively but rather is activated in response to an applied stimulus.
authors.affiliation: Laboratory of Physiology, Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Shima
authors.affiliation: Laboratory of Physiology, Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan. tshiina@gifu-u.ac.jp.
authors.forename: Takahiko
authors.initials: T
authors.lastname: Shiina
authors.affiliation: Laboratory of Physiology, Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan.
authors.forename: Kiyotada
authors.initials: K
authors.lastname: Naitou
authors.affiliation: Laboratory of Physiology, Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nakamori
authors.affiliation: Laboratory of Physiology, Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan.
authors.forename: Yuuki
authors.initials: Y
authors.lastname: Sano
authors.affiliation: Laboratory of Physiology, Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan.
authors.forename: Yasutake
authors.initials: Y
authors.lastname: Shimizu
mesh_terms: D000818:Animals; D002211:Capsaicin / Q000494:pharmacology*; D004558:Electric Stimulation / Q000379:methods; D004947:Esophagus / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D054792:Muscle, Striated / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014403:Tubocurarine / Q000494:pharmacology; D014630:Vagus Nerve / Q000187:drug effects / Q000502:physiology*
chemical_list: D002211:Capsaicin; D014403:Tubocurarine
keywords: Capsaicin-sensitive neuron; Enteric neuron; Esophagus; Striated muscle; Vagus