FIBROBLAST GROWTH FACTOR-II DEPRESSES THE IMPULSE ACTIVITY OF RAT DORSAL HORN NEURONS IN-VIVO

The neurotrophic and neuroprotective actions of fibroblast growth fact or-2 (FGF-2) are well known. Almost no information is available, howev er, about possible FGF-2 effects on neuronal electrical activity in vi vo. In the present study, the effects of spinal application of FGF-2 o n the discharges of lumbar dorsal horn neurones were studied in anaest hetized rats. FGF-2 depressed the background activity and reduced the proportion of cells dominated by low-threshold mechanosensitive input. In contrast, the proportion of units with C-fibre input was increased . Nitric oxide appears not to be involved in the depression of backgro und activity. The results suggest that elevated levels of intrathecal FGF-2 affect sensory processing by depressing low-threshold mechanorec eption.