Cocaine and exercise: temporal changes in the plasma concentrations
of catecholamines, lactate, glucose, and cocaine.
Han, Dong H., K. Patrick Kelly, Gilbert W. Fellingham, and Robert K.
Conlee.
Departments of Physical Education and Statistics, Brigham Young
University, Provo, Utah 84602
APStracts 2:0224E, 1995.
To determine the combined sympathoadrenal effects of cocaine and
exercise in awake animals, rats were assigned to one of four
treatment groups: saline-rest (SR), saline-exercise (SE), cocaine
-rest (CR), and cocaine-exercise (CE). Venous blood samples from
jugular catheters were obtained at -40, 0, 1, 2, 3, 4, 7, 10, 13, 16,
19, 26, and 36 min after intravenous injection of cocaine (5 mg/kg)
or saline and the simultaneous onset of a 16-min treadmill run (26
m/min, 10% grade). Cocaine-exercise increased plasma epinephrine
(24.2 nM at 16 min), norepinephrine (28.0 nM at 10 min), and lactate
(11.2 mM at 4 min) to levels 2-5 times greater than either treatment
(SE and CR) alone (P<0.05), and 11-35 times higher than SR.
Blood glucose values were significantly depressed in CE (-33% vs SE)
but increased in CR (+26% vs SR). Plasma cocaine peaked less than 2
min after injection in both CR and CE, and the peak was 69% higher in
CE (P<0.05); however, the plasma elimination half-life (12 - 14
min) was not different. These results indicate that the combined
effect of the two sympathoadrenal stimulants, exercise and cocaine,
amplify the catecholamine responses to levels far greater than when
each stimulant is used alone.
Received 10 March 1994; accepted in final form 1 November 1995.
APS Manuscript Number E97-4.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 30 November 95