Localization of voltage-sensitive L-type calcium channels in the chicken retina

L-type calcium channels have been associated with synaptic transmission in the retina, and are a potential site for modulation of the release of neurotransmitters. The present study documents the immunohistochemical localization of neuronal alpha1 subunits of L-type calcium channels in chicken retina, using antibodies to the alpha 1c, alpha 1d and alpha 1f subunits of L-type calcium channels. The alpha 1c-like subunits were localized to Muller cells, with predominantly radial processes, and a prominent band of horizontal processes in the outer plexiform layer. The antibody to alpha 1d subunits labelled most, if not all, cell bodies. The antibody to a human alpha 1f subunit strongly labelled photoreceptor terminals. Fainter immunoreactivity was detected in the inner segments of the photoreceptors, a subset of amacrine cells, two bands of labelling in the inner plexiform layer and many ganglion cells. The differential cellular distributions of these alpha1-subunits suggests subtle functional differences in their roles at different cellular locations.