INTRAMUSCULAR NERVE SPROUTING INDUCED BY CNTF IS ASSOCIATED WITH INCREASES IN CGRP CONTENT IN MOUSE MOTOR-NERVE TERMINALS

It is known that motor nerve terminal sprouting induced by either nerv e injury or muscle paralysis is associated with an increase in calcito nin gene-related peptide (CGRP) content in the soma of motoneurons and in motor endplates. In the present study, CGRP-like immunoreactivity (CGRP-LI) was determined in motor endplates of animals in which nerve terminal sprouting hud been induced by exogenous application of ciliar y neurotrophic factor (CNTF). After 18 days of CNTF treatment we obser ved 3 significant increase in CGRP-LI in motor endplates. The results indicate that CGRP is upregulated when motor nerve outgrowth is induce d. even in the absence of muscle paralysis or nerve lesion.