Effects of inhalation anesthetics on parasympathetic reflex vasodilatation

1998 Fiscal Year Final Research Report Summary

• Project/Area Number: 09671886
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Functional basic dentistry
• Research Institution: Tohoku University
• Principal Investigator: IZUMI Hiroshi School of Dentistry, Tohoku University Assistant, 歯学部, 助手 (20108541)
• Project Period (FY): 1997 – 1998
• Keywords: Inhalation / GABA / Parasympathetic / Vasodilatation / Autonomic

Research Abstract

The present experiments were designed to examine the effects of inhalation anesthetics (isoflurane, halothane, and sevoflurane) on the parasympathetic reflex vasodilation in the lower lip and palate elicited by electrical stimulation of the central cut end of the lingual nerve in vago-sympathectomized cats. Isoflurane (1.5%), halothane (1.0 %), sevoflurane (2.5%), each at a concentration of 1.0 MAC (minimum alveolar concentra-tion), markedly suppressed the evoked blood flow increases in the lower lip, whereas nitrous oxide (70 % in 30% oxygen) and morphine (2 mg/kg, iv) did not. Prior administra-tion of picrotoxin, a GABA antagonist, (2 mg/kg, iv) reversed the inhibitory effect of isoflurane on the parasympathetic reflex response. Decerebration had no significant effect on the isoflurane-induced inhibition. These findings suggest that there is a GABA-mediated suppressive mechanism acting on this parasympathetic reflex response ; the sites at which inhalation anesthetics exert such an inhibitory action could be in the mid-brain, pons, or medulla, but not in the hypothalamus or higher structures.

Research Products

• [Publications] Izumi, H.and Ito, Y.: "Correlation of MAC value for various inhalation anesthetics from the ID_<50> obtained for their effect on parasympathetic reflex response" Gen.Pharmacol.in press. (1999)
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] Izumi, H.: "Review : Nervous control of blood flow in the orofacial region" Pharmac.Therap.,. 81. 141-161 (1999)
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] Izumi, H.and Ito, Y.: "Sympathetic attenuation of reflex parasympathetic vasodilatation in the cat orofacial areas" J.Physiol.(Lond.). 510. 915-921 (1998)
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] Ito, Y., Izumi, H., et al.: "Suppression of parasympathetic reflex vasodilatation in the lower lip of the cat by isoflurane, propofol, ketamine and pentobarbital : implications for mechanisms underlying the production of anaesthesia" Br.J.Anaesthesia. 81. 563-568 (1998)
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] Izumi, H.and Ito.Y.: "Correlation of MAC value for various inhalation anesthetics from the ID_<50> obtained for their effect on parasympathetic reflex response" Gen.Pharmacol.(in press). (1999)
  • Description: 「研究成果報告書概要(欧文)」より
• [Publications] Izumi, H.: "Review : Nervous control of blood flow in the orofacial region" Pharmac.Therap.81. 141-161 (1999)
  • Description: 「研究成果報告書概要(欧文)」より
• [Publications] Izumi, H.and Ito, Y.: "Sympathetic attenuation of reflex parasympa-thetic vasodilatation in the cat orofacial areas" J.Physiol. (Lond.). 510. 915-921 (1998)
  • Description: 「研究成果報告書概要(欧文)」より
• [Publications] Ito, Y., Izumi, H., Sato, M., Karita, K.and Iwatsuki, N.: "Suppression of parasympathetic reflex vasodilatation in the lower lip of the cat by Isoflurane, propofol, ketamine and pentobarbital : implications for mechanisms underlying the production of anaesthesia" Br.J.Anaesthesia. 81. 563-568 (1998)
  • Description: 「研究成果報告書概要(欧文)」より