Axonal Flow Blockade Induces Alpha-CGRP MRNA Expression in Rat Motoneurons

Axonal flow of motoneurons was blocked in the sciatic nerve by the application of vinblastine at a low concentration (100 microM) not considered likely to cause axonal degeneration. The number of motoneurons expressing alpha-calcitonin gene-related peptide (CGRP) mRNA was significantly increased by vinblastine application, while the expression of beta-CGRP mRNA was not influenced. These findings suggest that the synthesis of these two peptides is differentially regulated and that alpha-CGRP mRNA is possibly down-regulated by unknown factor(s) which normally undergo retrograde transport from the periphery.