Acetylcholine Receptor Regulation in L5 Muscle Cells is Independent of Increasesin Collagen Secretion Induced by Ascorbic Acid

摘要

Ascorbic acid is the active component of fetal brain extract that inducesincreased acetylcholine receptor (AChR) expression in L5 rat clonal muscle cell cultures. The induction of AChR expression, as determined by I-a-bun-garotoxin binding, occurs with a delay of 20-25 h. We report that the delayed increase in AChR can be triggered by a 5-h exposure to ascorbic acid. These studies suggest that intermediary processes may be involved. Ascorbic acid treatment also causes a threefold increase in collagen secretion in L5 cultures by 3 h. The rapid increase in collagen secretion and the delayed induction of surface AChR suggested that there may be a link between these two responses. However, although bacterial collagenase eliminated secreted collagen, it had no effect on the increase in surface AChR.