Colocalisation and covariation of c-JUN transcription factor with galanin in primary afferent neurons and with CGRP in spinal motoneurons following transection of rat sciatic nerve.

The expression of galanin (GAL) in L5 dorsal root ganglia (DRG) and calcitonin gene-related peptide (CGRP) in motoneurons (MN) of lumbar spinal cord and their colocalisation with the nuclear c-JUN protein was investigated by immunocytochemistry following transection of rat sciatic nerve. Expression of c-JUN in L5 DRG neurons increased 10 h following transection. Between 24 h and 10 days 64%-72% of all neurons were labelled. After 50 and 150 days, the end of the observation period, 62% and 27%, respectively, of neurons were labelled by c-JUN. Expression of GAL started after 24 h, reached a maximum between 2 and 10 days in 40-50% of all neurons and persisted in 37% up to 50 days. After 150 days, GAL-IR had returned to basal levels. Between 24 h and 150 days, 75%-86% of all GAL positive neurons showed a nuclear c-JUN immunoreactivity, the maximal number was visible between 2 and 10 days. After 30 days, small diameter neurons showed a slightly increased colocalisation of GAL and c-JUN compared to large diameter neurons. In motoneurons (MN) of lumbar spinal cord of untreated rats, c-JUN was predominantly visible in small diameter MN. The number of c-JUN labelled MN raised 15 h following sciatic nerve transection in both small and large diameter MN. It reached its maximum after 2 days and declined after 40 days. CGRP showed basal expression exclusively in large MN. Its expression raised after 20 h, showed a maximum after 48 h and returned to control levels after 20 days.(ABSTRACT TRUNCATED AT 250 WORDS)