Jy. Li et al., GAP-43 AND ITS RELATION TO AUTONOMIC AND SENSORY NEURONS IN SCIATIC-NERVE AND GASTROCNEMIUS-MUSCLE IN THE RAT, Journal of the autonomic nervous system, 50(3), 1995, pp. 299-309
The presence of the growth-associated protein, GAP-43, in rat sciatic
nerve and gastrocnemius muscle was studied, using indirect immunofluor
escence, in lumbar sympathectomized and sham-sympathectomized rats. To
study fast axonal transport and accumulation of immunogenic GAP-43, t
he sciatic nerves were crush operated, 6 h before perfusion fixation.
In sections of normal, crushed sciatic nerve GAP-43-like immunoreactiv
ity (LI) rapidly accumulated, on both sides of the crushes, in medium
and thin sized axons. In double immunostaining experiments, GAP-43-LI
was mainly colocalized with tyrosine hydroxylase (TH)-LI, or neuropept
ide Y (NPY)-LI, markers of sympathetic nerves. In some axons, GAP-43-L
I was colocalized with Substance P (SP)-LI. In perivascular nerve term
inals in the gastrocnemic muscle, strong GAP-43-immunofluorescence was
observed, in most cases colocalized with TH-LI, but in some terminals
with SP-LI. Three days after lumbar sympathectomy (removal of the L1-
L4 sympathetic ganglia bilaterally), TH-LI and NPY-LI positive axons i
n the sciatic nerve were reduced in number by more than 90%. GAP-43-LI
positive axons were reduced by about 50%. In the gastrocnemic muscle,
some GAP-43-LI positive terminals, but very few TH-LI positive nerve
fibres, were found around blood vessels. No further changes were seen
8 days after sympathectomy. SP-LI in axons in the sciatic nerve and in
perivascular nerve terminals of the gastrocnemic muscle, did not chan
ge after sympathectomy; most of these axons also contained GAP-43-LI.
S-100-LI was present periaxonally in the sciatic nerves, but it did no
t colocalize with GAP-43, indicating that Schwann cells contained no G
AP-43-LI in these experiments. The results show that, in normal adult
rats, GAP-43-LI is mainly present in sympathetic and sensory nerve fib
ers in sciatic nerve and in perivascular nerve terminals. The peptide
is axonally transported, mainly in sensory and adrenergic axons.