Lc. Anderson et al., NGF DEPLETION REDUCES IPSILATERAL AND CONTRALATERAL TRIGEMINAL SATELLITE CELL REACTIONS AFTER INFERIOR ALVEOLAR NERVE INJURY IN ADULT RATS, Experimental neurology, 150(2), 1998, pp. 312-320
Following peripheral nerve injury, neuronal cell functions in sensory
ganglia shift from normal maintenance and neurotransmission toward sur
vival and regeneration, A rapid modulation of glial cell activity, whi
ch is related to changes in neuronal-support cell interaction, also oc
curs after nerve injury. Nerve ,growth factor (NGF) is required for th
e survival and maintenance of specific populations of sensory and symp
athetic neurons, and changes in neuronal gene expression after axonal
injury are due in part to a loss of NGF retrograde transport from the
periphery to the cell body. ii similar role for NGF in modulating supp
ort cell responses to peripheral nerve injury, however; has mot been d
emonstrated. Using an autoimmune model, we assessed the effects of NGF
depletion in adult rats on the injury-induced expression of glial fib
rillary acid protein immunoreactivity (GFAP-IR) in the ipsilateral and
contralateral trigeminal ganglia (TG). Unilateral inferior alveolar n
erve crush resulted in a bilateral, NGF-dependent trigeminal satellite
cell response. In control rats there was a widespread induction of GF
AP-IR in the: ipsilateral al as well as the contralateral TG. In contr
ast, GFAP-IR mas reduced to the mandibular division of the ipsilateral
TG; in NGF-depleted rats, and the contralateral up-regulation of GFAP
-IR Nas entirely abolished. Bilateral sympathectomy failed to mimic th
e effects of autoimmunization. Our results provide evidence that NGF d
epletion inhibits injury-induced satellite cell responses, independent
of its effects on sympathetic nerve function. (C) 1998 Academic Press
.