EXPRESSION OF GLYCINE RECEPTOR SUBUNITS AND GEPHYRIN IN SINGLE BIPOLAR CELLS OF THE RAT RETINA

We studied the expression of glycine receptor (GlyR) subunits and geph yrin in the adult rat retina. Reverse transcribed RNA was amplified by polymerase chain reaction (RT-PCR) with primers designed to recognize GlyR alpha 1, alpha 2, alpha 3, beta subunits, and gephyrin. Using RN A isolated from the whole retina, signals for all four GlyR subunits a nd gephyrin could be observed. In rod bipolar cells, in contrast, we d etected a subset of GlyR subunits, alpha 1 and beta, and no gephyrin. Patch-clamp recording employing two subtype-specific blockers of the G lyR, picrotoxinin and cyanotriphenylborate (CTB), indicated that the G lyR in rod bipolar cells is a heteromeric protein composed of the alph a 1 and beta subunit. Moreover, the absence of detectable amounts of g ephyrin mRNA suggests that the anchor protein is not required for the function of GlyRs in rod bipolar cells.