Although single-channel and whole-cell patch-clamp
recordings have demonstrated the presence of Na+
currents in retinal ganglion cell somata, it has not previously
been reported that an anti-Na+-channel antiserum
stains both retinal ganglion cell somata and
proteins with molecular weights corresponding to complexes
of α and β subunits. We probed adult goldfish retinas
for Na+ channel-like immunoreactivity with a
polyclonal antibody directed against the EOIII segment
of vertebrate voltage-gated Na+ channels. In
vertical sections and whole mounts, this antibody consistently
stained the somata, axons, and proximal dendrites of retinal
ganglion cells. Some somata in the proximal third of the
inner nuclear layer were also stained. In Western blots,
this antibody specifically stained multiple protein bands
from retina and optic nerve, all with apparent molecular
weights between 200 and 315 kDa. The largest of these molecular
weights agrees with that reported previously for complexes
of α and β subunits in mammalian neurons, including
retinal ganglion cells. The intermediate and lowest molecular
weights are consistent with the presence of multiple Na+
channel α subunits, either in individual proximal retinal
neurons or in different morphological subtypes.
Acute Modulation of Voltage‐Gated Ca
2+
Channels in Retinal Ganglion Cells by Gabapentin
