Cocaine alters myosin isoform expression in the rat soleus.
Prevost, Michael C., Arnold G. Nelson, K. Patrick Kelly, Dong H. Han,
and Robert K. Conlee.
Dept. of Kinesiology, Louisiana State Univ., Baton Rouge, La.,
70803, Dept. of Physical Education, Brigham Young Univ., Provo, Ut.
84602
APStracts 2:0143A, 1995.
The purpose of this study was to determine if chronic cocaine
administration alters the expression of myosin isoforms in the rat
soleus. Forty-five adult Sprague Dawley rats were divided into three
groups: CC (chronic cocaine) (N=15), 12.5 mg/kg cocaine-HCl injected
interperitoneally (ip) twice daily for 14 days, and one injection of
cocaine (12.5 mg/kg, ip) on day 15: AC (acute cocaine) (N=15), saline
injections twice daily for 14 days and one injection of cocaine (12.5
mg/kg, ip) on day 15: CS (chronic saline) (N=15), saline injections
twice daily for 14 days, and one saline injection on day 15. Myosin
isoform content of the soleus (native and heavy chains) was
identified by electrophoresis. The solei samples from the CS and AC
animals contained slow myosin only. However, solei samples from the
CC group contained slow myosin and 2-3 other myosin isoforms and the
associated heavy chains IIa and IIx. Therefore, chronic cocaine
administration causes in the rat soleus a shift in myosin expression
from slow isoforms to fast isoforms.
Received 12 September 1994; accepted in final form 21 March 1995.
APS Manuscript Number A953-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 10 April 1995.