Exposure to chronic hypoxia (CH) leads to ventilatory acclimatisation to hypoxia (VAH) which is a time-dependent increase in breathing. This study examined the role of the GABAA receptor in establishing VAH. Rats were exposed to CH or control (normoxic) conditions for 10 days during which the GABAA receptor antagonist, bicuculline, was infused systemically or directly into the nucleus of the solitary tract (NTS). Acute breathing trials were then performed to measure resting ventilation and ventilatory chemoreflexes. Systemic administration of bicuculline caused reductions in breathing during acute hypoxia and acute hypercapnia in the control but not the CH animals. Continuous infusion of bicuculline in to the NTS caused a reduction in the acute hypoxic ventilatory response in animals exposed to CH but not in the control animals. The results indicate that exposure to CH alters the GABAA-mediated regulation of acute ventilatory chemoreflexes both in the NTS and elsewhere in the brain.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/17212 |
| Date | 26 February 2009 |
| Creators | Phe, Balinda Siou Ing |
| Contributors | Reid, Stephen G. |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
| Format | 3836797 bytes, application/pdf |
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