Author/Editor		Pregelj, Peter; Sketelj, Janez
Title		Phasic muscle activation pattern and calcineurin inhibition increase acetylcholinesterase expression in the slow soleus muscle of the rat
Type		članek
Source		In: Inestrosa NC, Campos EO, editors. Cholinesterases in the second millenium: biomolecular and pathological aspects. 7th international meeting on cholinesterases; 2004; Pucon, Chile. Pucon: P. universidad catolica de Chile,
Publication year		2004
Volume		str. 309-13
Language		eng
Abstract		In the rat, motor units in the slow soleus muscle are activated tonically with low-frequency nerve impulses, whereas those in the fast extensor digitorum longus (EDL) muscle are excited phasically with high-frequency bursts of nerve activity. Fast and slow mammalian muscles differ also in regard to acetylcholinesterase (AChE) expression. The AChE mRNA levels in the normal soleus muscles are only about 20-30% of those in the EDL. The aim of the present study was to investigate the role of muscle activation pattern in regulation of the expression of AChE in the slow soleus muscle and examine the possible involvement of the calcineurin signaling pathway in this regulation. AChE mRNA, analysed by Northern blot, in the denervated and phasically stimulated soleus muscles increased to the levels in the normal fast EDL muscles. If the rats were treated for 5 days by a high dose of cyclosporin A, a calcineurin inhibitor, AChE mRNA levels in the soleus muscles increased to reach about 50% of the levels in the control EDL muscles. The results of this study provide additional proof that the AChE expression in the skeletal muscle fibers is largely regulated by muscle activity. Calcineurin signaling seems to be a part of the complex mechanism controlling AChE expression in mature muscles.
Descriptors		MUSCLE, SKELETAL MUSCLE FIBERS, SLOW-TWITCH ACETYLCHOLINESTERASE RNA, MESSENGER MUSCLE DENERVATION CYCLOSPORINE PHOSPHOPROTEIN PHOSPHATASE ELECTRIC STIMULATION RATS, WISTAR