DISTRIBUTION OF C-FOS EXPRESSING DORSAL HORN NEURONS AFTER ELECTRICAL-STIMULATION OF LOW-THRESHOLD SENSORY FIBERS IN THE CHRONICALLY INJURED SCIATIC-NERVE
C. Molander et al., DISTRIBUTION OF C-FOS EXPRESSING DORSAL HORN NEURONS AFTER ELECTRICAL-STIMULATION OF LOW-THRESHOLD SENSORY FIBERS IN THE CHRONICALLY INJURED SCIATIC-NERVE, Brain research, 644(1), 1994, pp. 74-82
The distribution of proto-oncogene c-Fos protein-immunoreactive cells
in the spinal cord dorsal horn was studied after electrical stimulatio
n at A alpha/A beta-fiber intensity of normal and previously injured s
ciatic nerves in urethane anesthetized rats. No or only occasional Fos
protein-like immunoreactive cells were seen after stimulation of the
normal uninjured nerve or after nerve transection without stimulation.
Electrical nerve stimulation at 3, 12, and 21 days after sciatic nerv
e transection resulted in substantial increases in the numbers of Fos
protein-like immunoreactive cell nuclei in each of Rexed's laminae I-V
. Combined demonstration of Fos protein-like immunoreactivity and of g
lial fibrillary acidic protein-like immunoreactivity (astroglia) or OX
-42 immunoreactivity (microglia), indicated that the observed Fos prot
ein-like response was confined to neurons and not to astroglia or micr
oglia. Combined demonstration in the spinal cord of Fos protein-like i
mmunoreactive neurons and neurons labeled retrogradely with Fluoro-Gol
d from the gracile nucleus showed that some of the Fos protein-like im
munoreactive neurons in Rexed's laminae III and IV contributed to the
postsynaptic dorsal column pathway. The results indicate that stimulat
ion at A alpha/A beta-fiber intensity of a previously injured nerve gi
ves rise to an abnormally increased activation pattern of postsynaptic
neurons in the dorsal horn, some of which contribute to the postsynap
tic dorsal column pathway.