The Rod Pathway of the Guinea Pig Retina: Identification of AII Amacrine Cells With Antibodies Against Disabled-1

Abstract

Abstract: : Purpose: To identify whether the rod pathway of the guinea pig retina follows the general mammalian scheme. Methods: Whole-mount preparations and vibratome sections were processed for Disabled-1 (Dab1) immunocytochemistry. Double labeling using anti-Dab1 and connexin 36 (Cx36), or protein kinase C (PKC), glycine transporter (glyT-1) antisera were applied. Results: Dab1 immunoreactivity was present in a class of amacrine cell bodies located in the distal row of the inner nuclear layer (INL) adjacent to the inner plexiform layer (IPL). Their processes ramified in whole depth of the IPL. Dab1 was co-localized with the high-affinity glycine transporter, indicating that these amacrine cells are glycinergic. Theses cells were further characterized by doubled-label immunofluorescence experiments with protein kinase C and connexin 36. PKC labeled rod bipolar cell axon terminals made contacts with Dab1 labeled processes, and Cx36 immunoreactivity was located at dendritic crossings between overlapping Dab1 amacrine cell processes. The density of Dab1-labeled AII amacrine cells decreased from approximately 3,750 cells/mm in the central retina to 1,725 cells/mm in the peripheral retina. Conclusions: These morphological, quantitative, and histochemical observations indicate that the rod pathway of the mammalian retina contains common synaptic circuitry.

Keywords: amacrine cells • retina: proximal(bipolar, amacrine, and gangli • retina