TY - JOUR
T1 - Role of GABA within the nucleus tractus solitarii in the hypoxic ventilatory decline of awake rats
AU - Tabata, M.
AU - Kurosawa, H.
AU - Kikuchi, Y.
AU - Hida, W.
AU - Ogawa, H.
AU - Okabe, S.
AU - Tun, Y.
AU - Hattori, Toshio
AU - Shirato, K.
PY - 2001
Y1 - 2001
N2 - 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.
AB - 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.
KW - Carotid body denervation
KW - Control of breathing
KW - Hypoxia
KW - Microdialysis
KW - γ-aminobutyric acid receptor
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U2 - 10.1152/ajpregu.2001.281.5.r1411
DO - 10.1152/ajpregu.2001.281.5.r1411
M3 - Article
C2 - 11641110
AN - SCOPUS:0035199702
VL - 281
SP - R1411-R1419
JO - American Journal of Physiology
JF - American Journal of Physiology
SN - 0363-6119
IS - 5 50-5
ER -