Absence of synaptic regulation by phosducin in retinal slices.

Published online

Journal Article

Phosducin is an abundant photoreceptor protein that binds G-protein βγ subunits and plays a role in modulating synaptic transmission at photoreceptor synapses under both dark-adapted and light-adapted conditions in vivo. To examine the role of phosducin at the rod-to-rod bipolar cell (RBC) synapse, we used whole-cell voltage clamp recordings to measure the light-evoked currents from both wild-type (WT) and phosducin knockout (Pd(-/-)) RBCs, in dark- and light-adapted retinal slices. Pd(-/-) RBCs showed smaller dim flash responses and steeper intensity-response relationships than WT RBCs, consistent with the smaller rod responses being selectively filtered out by the non-linear threshold at the rod-to-rod bipolar synapse. In addition, Pd(-/-) RBCs showed a marked delay in the onset of the light-evoked currents, similar to that of a WT response to an effectively dimmer flash. Comparison of the changes in flash sensitivity in the presence of steady adapting light revealed that Pd(-/-) RBCs desensitized less than WT RBCs to the same intensity. These results are quantitatively consistent with the smaller single photon responses of Pd(-/-) rods, owing to the known reduction in rod G-protein expression levels in this line. The absence of an additional synaptic phenotype in these experiments suggests that the function of phosducin at the photoreceptor synapse is abolished by the conditions of retinal slice recordings.

Full Text

Duke Authors

Cited Authors

  • Long, JH; Arshavsky, VY; Burns, ME

Published Date

  • 2013

Published In

Volume / Issue

  • 8 / 12

Start / End Page

  • e83970 -

PubMed ID

  • 24376776

Electronic International Standard Serial Number (EISSN)

  • 1932-6203

Digital Object Identifier (DOI)

  • 10.1371/journal.pone.0083970

Language

  • eng

Conference Location

  • United States