DIFFERENTIAL REGULATION OF FIBROBLAST GROWTH-FACTOR (FGF)-2 AND FGF RECEPTOR-1 MESSENGER-RNAS AND FGF-2 ISOFORMS IN SPINAL GANGLIA AND SCIATIC-NERVE AFTER PERIPHERAL-NERVE LESION

To study the functional role of endogenous basic fibroblast growth fac tor-2 (FGF-2) during degeneration and regeneration of the sensory syst em, we have determined the expression and regulation of FGF-2 and FGF receptor (FGFR)-1 mRNAs in spinal ganglia and sciatic nerve during exp erimental transection and crush injury of the sciatic nerve. In contra st to levels of the FGFR-1 transcript, which is not altered, the level of FGF-2 mRNA is dramatically up-regulated in spinal ganglia after in jury. In the proximal and distal nerve stumps both transcript levels a re significantly elevated, albeit at different time points. The FGF-2 isoforms are differently up-regulated in spinal ganglia and sciatic ne rve following peripheral nerve lesion. The differential response of FG F-2 mRNA and protein and of FGFR-1 mRNA in spinal ganglia and sciatic nerve after lesion is suggestive of different physiological functions: a local reaction at the lesion site where axonal regrowth occurs and a trophic reaction for the degenerating/regenerating sensory neurons.