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Hypoxia attenuates the respiratory response to injection of substance P into the nucleus of the solitary tract of the rat

Citation

Mazzone, SB and Hinrichsen, CFL and Geraghty, DP, Hypoxia attenuates the respiratory response to injection of substance P into the nucleus of the solitary tract of the rat, Neuroscience Letters, 256, (1) pp. 9-12. ISSN 0304-3940 (1998) [Refereed Article]

DOI: doi:10.1016/S0304-3940(98)00743-5

Abstract

Prolonged or repetitive bouts of hypoxia may desensitize the brain stem respiratory centres leading to reduced stimulation of ventilation. We investigated the possible involvement of changes in the sensitivity of the commissural nucleus of the solitary tract (cNTS) to the tachykinin peptide, substance P (SP). Urethane-anaesthetised rats were allowed to breath room air (normoxic) or subjected to four, 30 s bouts of hypoxia (10% O2/90% N2) prior to the injection of SP (750 pmol) into the cNTS. In normoxic rats (n = 5), SP produced a fall in frequency (f, 88 ± 4% control) after 4 min and a maximum rise in tidal volume (V(T)) after 6 min (138 ± 10% control) leading to an overall increase in minute ventilation (V(E), maximum, 127 ± 12% control after 2 min). In rats (n = 5) exposed to four bouts of hypoxia and allowed to recover for 10 min, injection of SP produced a similar fall in f but a delayed and significantly (P < 0.001) reduced V(T) (maximum after 10 min, 110 ± 1% control) and hence, V(E) response (104 ± 3% control). Sixty min after hypoxia, the f, V(T) and VE responses to SP were identical to those of normoxic rats. These data suggest that hypoxia desensitizes SP receptors in the cNTS and this may partly explain why the respiratory response to hypoxia declines over time.

Item Details

Item Type:Refereed Article
Research Division:Medical and Health Sciences
Research Group:Pharmacology and Pharmaceutical Sciences
Research Field:Basic Pharmacology
Objective Division:Health
Objective Group:Other Health
Objective Field:Health not elsewhere classified
Author:Mazzone, SB (Mr Stuart Brett Mazzone)
Author:Hinrichsen, CFL (Dr Colin Hinrichsen)
Author:Geraghty, DP (Professor Dominic Geraghty)
ID Code:12940
Year Published:1998
Web of Science® Times Cited:16
Deposited By:Health Sciences A
Deposited On:1998-08-01
Last Modified:2011-08-05
Downloads:0

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