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Regulation of the Expression of Acetylcholinesterase by Muscular Activity in Avian Primary Cultures
Author(s) -
Vallett FrançoisMarie,
Massoulié Jean
Publication year - 1991
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1991.tb02046.x
Subject(s) - veratridine , acetylcholinesterase , depolarization , myogenesis , tetrodotoxin , electrophorus , aché , quail , biology , secretion , sodium channel , medicine , chemistry , endocrinology , myocyte , biochemistry , microbiology and biotechnology , sodium , enzyme , receptor , acetylcholine receptor , torpedo , organic chemistry
Primary cultures of avian muscle cells express both globular and asymmetric molecular forms of acetylchoiinesterase (AChE) when grown in a simple defined culture medium. Under these conditions, we analyzed the role of various agents interfering with muscular activity: tetrodotoxin (TTX) and veratridine, as well as a depolarizing concentration of KC1. These treatments caused the complete cessation of contractions in mature myotubes. We observed no influence on cellular AChE activity. The paralyzing treatments induced different effects on AChE secretion: TTX increased the secretion by ∼25%, whereas KC1 and veratridine reduced it by ∼30%. The proportions of secreted molecular forms (mostly hydrophilic G 4 and G 2 ) were not modified significantly. TTX did not affect the pattern of molecular forms of cellular AChE (in particular, the proportion of A forms was not changed). Depolarization by veratridine or KC1 induced an increase in the proportion of A forms in mature myotubes by a factor of 2–3. Similar results were obtained with quail myotubes cultured under the same conditions. This study shows that, in avian muscle cultures, the ionic balance across myotube membranes, rather than muscular activity per se, can regulate the level of A forms and the rate of AChE secretion. These results do not exclude the possible involvement of other factors, such as Ca 2+ and/or peptidic factors. In addition, taking together our results and data from the literature, we conclude that the expression of AChE molecular forms depends both on the species and on the culture conditions used.