The time-course of Aβ-evoked c-fos expression in neurons of the dorsal horn and gracile nucleus after peripheral nerve injury

We have examined the mechanisms underlying Aβ-evoked c-fos expression in the dorsal horn and gracile nucleus following either sciatic nerve section or crush injury. The results indicate that in the spinal cord Aβ-evoked c- fos does not depend on primary afferent sprouting but is associated with the disconnection from the peripheral target since its expression in the dorsal horn reverts to normal after crush injury when regeneration occurs but persists after cut and ligation where regeneration is prevented. In contrast, however, Aβ-evoked c-fos expression in the gracile nucleus may be under some other control since its expression appears independent of peripheral nerve regeneration.