%0 Journal Article
%T Morphine has latent deleterious effects on the ventilatory responses to a hypoxic challenge*
%A Walter J. May
%A Ryan B. Gruber
%A Joseph F. Discala
%A Veljko Puskovic
%A Fraser Henderson Jr.
%A Lisa A. Palmer
%A Stephen J. Lewis
%J Open Journal of Molecular and Integrative Physiology
%P 166-180
%@ 2162-2167
%D 2013
%I Scientific Research Publishing
%R 10.4236/ojmip.2013.34022
%X <p>
	<span style=\"font-size:10.0pt;\">The aim of this study was to determine whether
morphine depresses the ventilatory responses elicited by a hypoxic challenge
(10% O<sub>2</sub>, 90% N<sub>2</sub>) in conscious rats at a time when the
effects of morphine on arterial blood gas (ABG) chemistry, Alveolar-arterial
(A-a) gradient and minute ventilation (Vm) had completely subsided. In
vehicle-treated rats, each episode of hypoxia stimulated ventilatory function
and the responses generally subsided during each normoxic period. Morphine (5
mg/kg, i.v.) induced an array of depressant effects on ABG chemistry, A-a
gradient and Vm (via decreases in tidal volume). Despite resolution of these
morphine-induced effects, the first episode of hypoxia elicited substantially
smaller increases in Vm than in vehicle-treated rats, due mainly to smaller
increases in frequency of breathing. The pattern of ventilatory responses
during subsequent episodes of hypoxia and normoxia changed substantially in
morphine-treated rats. It is evident that morphine haslatent deleterious
effects on ventilatory responses elicited by hypoxic challenge.</span> 
</p>
%K Morphine
%K Hypoxia
%K Minute Ventilation
%K Arterial Blood Gas Chemistry
%K Conscious Rats
%U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=39563