HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 287/5/C1445    most recent 00518.2003v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Radzyukevich, T. L. Articles by Heiny, J. A. Search for Related Content PubMed PubMed Citation Articles by Radzyukevich, T. L. Articles by Heiny, J. A.

MUSCLE CELL BIOLOGY AND CELL MOTILITY

Regulation of dihydropyridine receptor gene expression in mouse skeletal muscles by stretch and disuse

Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio 45267-0576

Submitted 19 November 2003 ; accepted in final form 30 July 2004

This study examined dihydropyridine receptor (DHPR) gene expression in mouse skeletal muscles during physiological adaptations to disuse. Disuse was produced by three in vivo models—denervation, tenotomy, and immobilization—and DHPR _1s mRNA was measured by quantitative Northern blot. After 14-day simultaneous denervation of the soleus (Sol), tibialis anterior (TA), extensor digitorum longus (EDL), and gastrocnemius (Gastr) muscles by sciatic nerve section, DHPR mRNA increased preferentially in the Sol and TA (+1.6-fold), whereas it increased in the EDL (+1.6-fold) and TA (+1.8-fold) after selective denervation of these muscles by peroneal nerve section. It declined in all muscles (–1.3- to –2.6-fold) after 14-day tenotomy, which preserves nerve input but removes mechanical tension. Atrophy was comparable in denervated and tenotomized muscles. These results suggest that factor(s) in addition to inactivity per se, muscle phenotype, or associated atrophy can regulate DHPR gene expression. To test the contribution of passive tension to this regulation, we subjected the same muscles to disuse by limb immobilization in a maximally dorsiflexed position. DHPR _1s mRNA increased in the stretched muscles (Sol, +2.3-fold; Gastr, +1.5-fold) and decreased in the shortened muscles (TA, –1.4-fold; EDL, –1.3-fold). The effect of stretch was confirmed in vitro. DHPR protein did not change significantly after 4-day immobilization, suggesting that additional levels of regulation may exist. These results demonstrate that DHPR _1s gene expression is regulated as an integral part of the adaptive response of skeletal muscles to disuse in both slow- and fast-twitch muscles and identify passive tension as an important signal for its regulation in vivo.

dihydropyridine receptor mRNA; decreased use; passive tension; denervation; tenotomy; hindlimb immobilization

This article has been cited by other articles:

				A. Raffaello, P. Laveder, C. Romualdi, C. Bean, L. Toniolo, E. Germinario, A. Megighian, D. Danieli-Betto, C. Reggiani, and G. Lanfranchi Denervation in murine fast-twitch muscle: short-term physiological changes and temporal expression profiling Physiol Genomics, March 13, 2006; 25(1): 60 - 74. [Abstract] [Full Text] [PDF]