title: Expression of voltage-gated calcium channel α(2)δ(4) subunits in the mouse and rat retina.
abstract: High-voltage activated Ca channels participate in multiple cellular functions, including transmitter release, excitation, and gene transcription. Ca channels are heteromeric proteins consisting of a pore-forming α(1) subunit and auxiliary α(2)δ and β subunits. Although there are reports of α(2)δ(4) subunit mRNA in the mouse retina and localization of the α(2)δ(4) subunit immunoreactivity to salamander photoreceptor terminals, there is a limited overall understanding of its expression and localization in the retina. α(2)δ(4) subunit expression and distribution in the mouse and rat retina were evaluated by using reverse transcriptase polymerase chain reaction, western blot, and immunohistochemistry with specific primers and a well-characterized antibody to the α(2)δ(4) subunit. α(2)δ(4) subunit mRNA and protein are present in mouse and rat retina, brain, and liver homogenates. Immunostaining for the α(2)δ(4) subunit is mainly localized to Müller cell processes and endfeet, photoreceptor terminals, and photoreceptor outer segments. This subunit is also expressed in a few displaced ganglion cells and bipolar cell dendrites. These findings suggest that the α(2)δ(4) subunit participates in the modulation of L-type Ca(2+) current regulating neurotransmitter release from photoreceptor terminals and Ca(2+)-dependent signaling pathways in bipolar and Müller cells.
authors.affiliation: Department of Neurobiology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, California 90095, USA. luisperez@mednet.ucla.edu
authors.forename: Luis Pérez
authors.initials: LP
authors.lastname: De Sevilla Müller
authors.forename: Janelle
authors.initials: J
authors.lastname: Liu
authors.forename: Alexander
authors.initials: A
authors.lastname: Solomon
authors.forename: Allen
authors.initials: A
authors.lastname: Rodriguez
authors.forename: Nicholas C
authors.initials: NC
authors.lastname: Brecha
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001923:Brain Chemistry / Q000502:physiology; D015220:Calcium Channels / Q000096:biosynthesis*; D003712:Dendrites / Q000378:metabolism; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D008099:Liver / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D020419:Photoreceptor Cells, Vertebrate / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D012160:Retina / Q000166:cytology / Q000378:metabolism*
chemical_list: C486058:Cacna2d2 protein, mouse; D015220:Calcium Channels