Effects of pyridoxine neurotoxicity on a distribution of calcitonin gene-related peptide binding sites.

The possibility of changes in binding sites for calcitonin gene-related peptide (CGRP) in response to sensorial denervation was studied in rats after pyridoxine-induced neurotoxicity. Changes in CGRP binding sites were evaluated by an in vitro autoradiographic technique using [125I]-Tyr-rat-CGRP as a ligand. A bidirectional binding response was obtained: an increased binding, in comparison with the respective control, was observed in spinal cord and cerebellar regions whereas a decreased binding was noted in cerebrum. CGRP binding in selective areas comparising the pathways that are responsible for transmitting sensory impulses have shown significant changes. These results suggest that CGRP plays a modulatory role in the central nervous system. This study has also proposed and evaluated pyridoxine toxicity as a model for studying sensory denervation.