Chronic enhancement of neuromuscular activity increases
acetylcholinesterase gene expression in rat skeletal muscle.
Sveistrup, Heidi, Roxanne Y. Y. Chan, and Bernard J. Jasmin.
Department of Physiology, Faculty of Medicine, University of
Ottawa, Ottawa, Ontario, Canada K1H 8M5
APStracts 2:0165C, 1995.
We determined levels of mRNA encoding acetylcholinesterase (AChE) in
muscles of rats subjected to chronic enhancement of neuromuscular
activation. Following eight weeks of voluntary wheel running, EDL
muscles displayed a 72% increase in total AChE activity as a result
of a selective 3-fold increase in the G4 content. Soleus muscles on
the other hand, exhibited a 30% decrease in A12 while displaying a
small (33%) increase in total AChE activity. These enzymatic
adaptations were paralleled by increases in the levels of AChE mRNAs
in both EDL (32%; P < 0.03) and soleus (42%; P < 0.02) muscles. In
addition, compensatory hypertrophy of the plantaris muscle increased
total AChE activity by 75%. This change was reflected by an elevation
in all AChE molecular forms with A12 (89%) and A8 (179%) showing the
most prominent increases. Similar to exercise-trained muscles,
hypertrophied plantaris displayed an increase in AChE transcripts
(25%; P < 0.04). These results indicate that increases in
neuromuscular activity modulate expression of the AChE gene in vivo,
and suggest the involvement of pretranslational regulatory mechanisms
in the adaptive response of AChE to enhanced neuromuscular
activation.
Received 18 January 1995; accepted in final form 28 March 1995.
APS Manuscript Number C37-5.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 25 April 1995.