Starburst amacrine cells express parvalbumin but not calbindin and calretinin in rabbit retina

Calcium-binding proteins (CBPs) are important components in calcium-mediated cellular signal transduction. Among the many CBPs, at least three EF-hand CBPs, calbindin-D28K (CB), calretinin (CR), and parvalbumin (PV), have been extensively studied in the retina. In the present study, we investigated the expression patterns of these three CBPs in cholinergic starburst amacrine cells (SACs), which are the most important element for direction selectivity in the rabbit retina. Double-label immunocytochemical analysis of vibratome sections and single-cell injection after immunocytochemical analysis on whole mounts were carried out in rabbit retinas. We found that all SACs in the inner nuclear layer and the ganglion cell layer contained PV. However, none of the SACs in the inner nuclear layer or ganglion cell layer contained either CB or CR. These results suggest that PV, but not CR or CB, may act as a calcium-buffering protein in the SACs of the rabbit retina.