PT  - JOURNAL ARTICLE
AU  - Van der Zee, CE
AU  - Nielander, HB
AU  - Vos, JP
AU  - Lopes da Silva, S
AU  - Verhaagen, J
AU  - Oestreicher, AB
AU  - Schrama, LH
AU  - Schotman, P
AU  - Gispen, WH
TI  - Expression of growth-associated protein B-50 (GAP43) in dorsal root ganglia and sciatic nerve during regenerative sprouting
AID  - 10.1523/JNEUROSCI.09-10-03505.1989
DP  - 1989 Oct 01
TA  - The Journal of Neuroscience
PG  - 3505--3512
VI  - 9
IP  - 10
4099  - http://www.jneurosci.org/content/9/10/3505.short
4100  - http://www.jneurosci.org/content/9/10/3505.full
SO  - J. Neurosci.1989 Oct 01; 9
AB  - Recently it has been shown that B-50 is identical to the neuron- specific, growth-associated protein GAP43. The present study reports on the fate of B-50/GAP43 mRNA and B-50/GAP43 protein, determined by radioimmunoassay, in a rat model of peripheral nerve regeneration (sciatic nerve crush) over a period of 37 and 312 d, respectively. Moreover, the effects of repeated subcutaneous injection of the neurotrophic peptide Org.2766 (an ACTH4–9 analog) and of a conditioning lesion on B-50/GAP43 protein levels in the regenerating nerve and dorsal root ganglia (DRG) were investigated. Both treatments enhanced the functional recovery as evidenced by a foot-flick withdrawal test. Immunocytochemical analysis using antineurofilament antibodies revealed a peptide-induced increase in the number of outgrowing sprouts in the sciatic nerve. Both the peptide and the conditioning lesion amplified the crush lesion-induced increase in B-50 protein content in the nerve as determined by radioimmunoassay. B-50 protein levels seem to correlate proportionally with the number of sprouts. In the DRG of the crushed sciatic nerve, the time course of B-50 expression was studied. B-50 mRNA was quantified from Northern blots. A linear increase up to 10 times the basal level of B-50 mRNA was observed 2 d postsurgery, followed by a gradual decline to normal levels at day 37. The first significant rise in B-50 mRNA level became apparent between 8 and 16 hr after placement of the crush lesion. The first significant rise in B-50 protein level occurred 40 hr after the crush lesion, reaching a plateau of 3 times the basal level between day 6 and 20. B-50 protein levels in DRG cell bodies remained elevated up to 60 d after crush, a period much longer than that observed for B-50 mRNA. Thus, during a later phase of peripheral axonal regeneration, the presence of B-50 appears to be prolonged, probably by an increase in half-life and not so much by enhanced transcription. Treatment with Org.2766 did not affect the B- 50/GAP43 levels in DRG cell bodies during the first 6 d following crush. Conditioning lesion resulted in a DRG B-50/GAP43 protein amount at the same level as in rats 14 d after the test lesion. B-50/GAP43 levels in DRG are probably influenced by the rapid axonal transport of the protein, as has been reported by others.