@article {Shen6088, author = {Yin Shen and J. Alexander Heimel and Maarten Kamermans and Neal S. Peachey and Ronald G. Gregg and Scott Nawy}, title = {A Transient Receptor Potential-Like Channel Mediates Synaptic Transmission in Rod Bipolar Cells}, volume = {29}, number = {19}, pages = {6088--6093}, year = {2009}, doi = {10.1523/JNEUROSCI.0132-09.2009}, publisher = {Society for Neuroscience}, abstract = {On bipolar cells are connected to photoreceptors via a sign-inverting synapse. At this synapse, glutamate binds to a metabotropic receptor which couples to the closure of a cation-selective transduction channel. The molecular identity of both the receptor and the G protein are known, but the identity of the transduction channel has remained elusive. Here, we show that the transduction channel in mouse rod bipolar cells, a subtype of On bipolar cell, is likely to be a member of the TRP family of channels. To evoke a transduction current, the metabotropic receptor antagonist LY341495 was applied to the dendrites of cells that were bathed in a solution containing the mGluR6 agonists l-AP4 or glutamate. The transduction current was suppressed by ruthenium red and the TRPV1 antagonists capsazepine and SB-366791. Furthermore, focal application of the TRPV1 agonists capsaicin and anandamide evoked a transduction-like current. The capsaicin-evoked and endogenous transduction current displayed prominent outward rectification, a property of the TRPV1 channel. To test the possibility that the transduction channel is TRPV1, we measured rod bipolar cell function in the TRPV1-/- mouse. The ERG b-wave, a measure of On bipolar cell function, as well as the transduction current and the response to TRPV1 agonists were normal, arguing against a role for TRPV1. However, ERG measurements from mice lacking TRPM1 receptors, another TRP channel implicated in retinal function, revealed the absence of a b-wave. Our results suggest that a TRP-like channel, possibly TRPM1, is essential for synaptic function in On bipolar cells.}, issn = {0270-6474}, URL = {https://www.jneurosci.org/content/29/19/6088}, eprint = {https://www.jneurosci.org/content/29/19/6088.full.pdf}, journal = {Journal of Neuroscience} }