Author/Editor		Toplišek, Janez
Title		Uravnavanje acetilholinesteraze med ponovnim oživčevjem skeletne mišice
Type		monografija
Place		Ljubljana
Publisher		Medicinska fakulteta
Publication year		1993
Volume		str. 34
Language		slo
Abstract		Regulation of synthesis and distribution of macromolecules essential for transmission of impulses from nerve to muscle changes during ontogenetic development. Immature fetal and early postnatal muscles are able to syntesize the asymmetric forms of acetylcholinesterase (AChE) and the molecules of acetylcholine receptor (AChR) also in the endplate free regions. Segregation of AChR in the motor endplates of rat muscles is largely completed by the end of the first week of postnatal development, whereas the extrajunctional synthesis of the asymmetric forms of AChE is finally suppressed by the fourth week after birth. After denervation of mature muscle, synthesis of AChR, but not of the asymmetric forms of AChE, is restored in its endplate free regions. Therefore, we decided to test the hypothesis that, regarding regulation of AChE, a denervated muscle may need reinnervation in order to return transiently to immature, postnatal-like state. Molecular forms of AChE in the endplate free regions of slow soleus (SOL) and fast extensor digitorum longus (EDL) muscles of the rat were analysed by velocity sedimentation in linear sucrose gradients. Temporary denervation of these muscles followed by reinnervation was achieved by crush lesion of the sciatic nerve. Disuse of SOL muscle was produced by imobilisation of hind leg joints and transitory paralysis was achieved by a-bungara toxin blockade of AChR in the SOL muscle. We established that: - reinnervation after transient denervation of muscle temporarily reverted slow SOL muscle to immature postnatal-like state: the synthesis of the asymmetric AChE forms in the endplate regions of the muscle was transiently greatly increased again. On the other hand, the fast EDL muscle did not return to immature state after reinnervation: it seems that the syntesis of the extrajunctional asymmetric forms of AChE is irreversibly suppressed in this muscle; (Abstract truncated at 2000 charactes).
Descriptors		MUSCLE DENERVATION MUSCLE, SKELETAL ACETYLCHOLINESTERASE SCIATIC NERVE RATS, WISTAR RECEPTORS, CHOLINERGIC BUNGAROTOXINS