Calcitonin gene-related peptide, a peptide present in spinal cord motoneurons, increases the number of acetylcholine receptors in primary cultures of chick embryo myotubes.

Using immunohistochemical methods we show that calcitonin gene-related peptide (CGRP, a peptide encoded by the calcitonin gene) is present in chick spinal cord motoneurons. When added to cultured chicken myotubes, CGRP caused an average 1.5-fold increase in levels of surface acetylcholine receptors. Moreover, the effect of CGRP was independent of the one produced by tetrodotoxin, a blocker of membrane electrical activity but not of that caused by cholera toxin, an activator of adenylate cyclase.