Hypoxic ventilatory response, carotid body cell division and
dopamine content during early hypoxic exposure in rats.
Bee, Denise, and D. J. Pallot.
Department of Medicine, University of Sheffield, Sheffield, UK and
Department of Human Anatomy, University of UAE, Al Ain, UAE
APStracts 2:0254A, 1995.
In a previous study we showed that the acute hypoxic ventilatory
response was blunted in anaesthetized chronically hypoxic rats and
restored by blockade of the dopamine D2 receptor with domperidone. We
now report observations made during 1 to 8 days exposure to 10% O2 on
the acute hypoxic ventilatory response and the effect of domperidone,
and relate this to dopamine content and cellular proliferation in the
carotid body. Hypoxic exosure caused a parallel shift in the hypoxic
response curve to higher levels of ventilation and arterial oxygen
saturation. The greatest response occurred at day 1 and was
unaffected by domperidone; dopamine content was diminished and
mitotic activity increased. By 8 days hypoxic ventilation approached
normal and was significantly augmented by domperidone; in the carotid
body dopamine levels had risen above control and mitoses had
diminished. Thus the increase in ventilation was inversely related to
carotid body dopamine content which was depressed. The possibility of
a causal relationship is discussed.
Received 26 September 1994; accepted in final form 6 June 1995.
APS Manuscript Number A1000-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 July 1995.