Microdialyzed adenosine in nucleus tractus solitarii and
ventilatory response to hypoxia in piglets.
Yan, Sheng, Andr[acute]e Laferri[grave]ere, Cunxian Zhang, and
Immanuela R. Moss.
Developmental Respiratory Laboratory, Department of Pediatrics,
McGill University and Montreal Children's Hospital Research
Institute, Montreal, Quebec, Canada H3H 1P3
APStracts 2:0123A, 1995.
Levels of adenosine, inosine and hypoxanthine from the interstitial
space at the nucleus tractus solitarii were measured by microdialysis
in 8, 20 to 25 day-old anesthetized, spontaneously breathing piglets.
Microdialysed samples were collected every 30 min for 2 h after the
insertion of the probe to ensure stability of purine levels, then
during 30 min each of normoxia, hypoxia (10% O2 in 90% N2) and
normoxia. The purines were separated by high pressure liquid
chromatography with UV detection and quantified at 254 nm wave
length. Tidal volume, breathing frequency, minute ventilation as well
as mean arterial blood pressure, pH and gas tensions were measured.
As compared to control, adenosine levels during hypoxia increased by
40.7 +/- 5.5%, then tended to decline during the recovery from
hypoxia, but remained higher than control. Ventilatory measures
exhibited a modest biphasic pattern during hypoxia and resumed
control values by 10 min after the removal of the hypoxia. The
increased adenosine release during hypoxia provides additional
evidence for the possible participation of adenosine in the central
suppression of breathing during hypoxia.
Received 15 August 1994; accepted in final form 15 March 1995.
APS Manuscript Number A862-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 28 March 1995.