Gaba-mediated Neurotransmission in the Nucleus of the Solitary Tract Alters Resting Ventilation Following Exposure to Chronic Hypoxia in Conscious Rats.
From: Centre for the Neurobiology of Stress, Dept. of Life Sciences, Univ. of Toronto at Scarborough, 1265 Military Trail, Toronto, ON, Canada M1C 1A4.
American journal of physiology. Regulatory, integrative and comparative physiology
- Publish Date: Nov 2006
- ISSN: 0363-6119
- Volume: 291
- Issue: 5
- Pages: R1449-56
- Medium: Print
- Language: English
- Citation (JAMA): Chung Sean, Ivy Gwen O, Reid Stephen G, et al. Gaba-mediated Neurotransmission in the Nucleus of the Solitary Tract Alters Resting Ventilation Following Exposure to Chronic Hypoxia in Conscious Rats.. Am. J. Physiol. Regul. Integr. Comp. Physiol. Nov 2006;291:R1449-56
Abstract
This study investigated whether changes in GABA-mediated neurotransmission within the nucleus of the solitary tract (NTS) contribute to the changes in breathing (resting ventilation and the acute HVR) that occur following exposure to chronic hypoxia (CH). Rats were exposed to 9 days of hypobaric hypoxia (0.5 atm) and then subjected to acute hypoxic breathing trials before and after bilateral microinjections of GABA, bicuculline (a GABAA-receptor antagonist), or bicuculline plus CGP-35348 (a GABAB receptor antagonist) into the caudal regions of the NTS. Breathing was measured using whole body plethysmography. CH caused an increase in resting ventilation when the animals were breathing 30% O2 but did not alter ventilation during acute hypoxia (10% O2). GABA alone had no effect on breathing in either the control or chronically hypoxic rats. Bicuculline and bicuculline/CGP had no effect on breathing in control rats. Following CH, bicuculline and bicuculline/CGP reduced minute ventilation (VI) during acute exposure to 30% O2 but had no effect during acute exposure to 10% O2. The bicuculline-induced reduction in VI resulted from a decrease in breathing frequency (fR) and tidal volume (VT). The bicuculline/CGP-induced reduction in VI was due to a decrease in fR with no change in VT. The results suggest that changes in GABA receptor-mediated neurotransmission, within the NTS, are involved in the increase in resting ventilation that occurs following CH.
Mesh Headings (Keywords): Animals, Anoxia, Bicuculline, GABA Antagonists, Male, Organophosphorus Compounds, Pulmonary Ventilation, Rats, Rats, Sprague-Dawley, Receptors, GABA, Respiratory Mechanics, Rest, Solitary Nucleus, Synaptic Transmission, gamma-Aminobutyric Acid
Check for Full Text / PubMed Unique Identifier (PMID): 16778062
This abstract is part of PubMed, a service of the U.S. National Library of Medicine. PubMed includes more than 17 million citations from MEDLINE and other life science journals for biomedical articles. See Copyright and Disclaimers.
Linked medical terms appearing on this page are added by Healia to help readers find more information and are not part of the original PubMed document.
The data herein was last updated on July 8th, 2008 and may not reflect the most current and accurate data available from NLM.