A ROLE FOR CALCITONIN-GENE-RELATED PEPTIDE IN THE REGULATION OF RAT SKELETAL-MUSCLE G(4) ACETYLCHOLINESTERASE

Calcitonin gene-related peptide (CGRP) acts as an anterograde trophic agent which regulates skeletal muscle acetylcholine receptor function. We examined whether CGRP also influences other synaptic transmission- related molecules, i.e. acetylcholinesterase (AChE) forms. Results sho w that: (a) CGRP associated with rat anterior gracilis muscle endplate s declines following obturator nerve transection; (b) exogenous CGRP t reatment has a selective, innervation-like effect on the globular tetr amer (G(4)) of AChE in gracilis motor endplates; and (c) this effect i s reversed by the CGRP receptor antagonist hCGRP(8-37). We conclude th at exogenous CGRP, and/or a biologically active CGRP fragment(s), infl uences G(4) AChE levels through specific CGRP-CGRP receptor interactio ns. This conclusion is consistent with the notion that motor nerve-der ived CGRP participates in the trophic control of G(4) AChE at the neur omuscular junction.