Kf. Schmidt et al., FIBROBLAST GROWTH-FACTORS ALTER LIGHT RESPONSES AND DARK VOLTAGE IN RETINAL RODS OF THE FROG (RANA-TEMPORARIA), Neuroscience letters, 191(3), 1995, pp. 177-180
Fibroblast growth factors (FGF-1 and FGF-2) were applied intracellular
ly via whole-cell patch-clamp electrodes while the membrane voltage wa
s recorded simultaneously. During recording the exchange of substances
by diffusion between cytosol and pipette medium affects the cell's fu
nction. Under control conditions, the loss of nucleotides is reflected
by a slow hyperpolarization of the dark voltage and prolongated light
responses. Addition of FGF-1 and FGF-2 to the pipette medium accelera
ted the time course of the hyperpolarization and intensified the prolo
ngation of the light responses. The depolarization of photoreceptor ce
lls after intracellular application of the nitric oxide (NO)-synthase
cofactor nicotinamide adenine dinucleotide phosphate (NADPH) and the s
tabilization of light response recovery by L-arginine is abolished by
FGF-2. FGF-2 was ineffective when it was applied together with the cal
cium chelator ethylene glycol-bis(2-aminoethylether)tetraacetate (EGTA
). The results indicate a possible role of FGF in the regulation of NO
and calcium in photoreceptor cells and may explain protective effects
of FGF in degenerative processes of photoreceptor cells.