Role of GABA within the nucleus tractus solitarii in the hypoxic ventilatory decline of awake rats

M. Tabata, H. Kurosawa, Y. Kikuchi, W. Hida, H. Ogawa, S. Okabe, Y. Tun, T. Hattori, K. Shirato

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48 Citations (Scopus)

Abstract

The purpose of this study was to examine our hypothesis that γ-aminobutyric acid (GABA) in the nucleus tractus solitarii (NTS) may be related to the hypoxic ventilatory decline (HVD) and that chemoreceptor stimulation was essential to activate this mechanism. We used unanesthetized, freely moving rats in this study. An in vivo microdialysis technique was used to measure the extracellular GABA concentration ([GABA]o), and an in vivo microinjection technique was used to examine the effects of the GABA agonists and antagonists on the ventilation during hypoxia. The GABA agonists injected into the NTS attenuated the ventilation during hypoxia. By hypoxic exposure, [GABA]o was increased during the HVD. However, by carotid body denervation (CBD), this GABA increase was abolished. Although GABA antagonists microinjected into the NTS during the HVD phase significantly increased the depressed ventilation, this effect on the ventilation was abolished by CBD. These results suggest that the GABA in the NTS has a pivotal role in the HVD and that this mechanism is not activated without chemoreceptor stimulation.

Original languageEnglish
Pages (from-to)R1411-R1419
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume281
Issue number5 50-5
DOIs
Publication statusPublished - 2001

Keywords

  • Carotid body denervation
  • Control of breathing
  • Hypoxia
  • Microdialysis
  • γ-aminobutyric acid receptor

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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