Figure 6.

Localization of neurexin 1, neuroligin-2 (NL-2), and SynCAM in rat pancreas. To determine the localization of neurexin, neuroligin, and SynCAM in rat pancreas sections, immunohistochemical localization was performed using antibodies to neurexin-1 (Nrxn), neuroligin-2, and SynCAM. Tissues were costained for insulin (Ins), glucagon (Glu), or syntaxin-1. Images were captured under either a confocal or deconvolution microscope equipped with a ×60 lens. Both neuroligin (row 1) and neurexin (row 3) were exclusively detected in cells that expressed insulin and absent in cells that expressed glucagon (row 2 and supplemental Fig. 4), indicating a β-cell specific pattern of expression. Neuroligin-2 displayed some intracellular colocalization with insulin (row 1, yellow in merged image). Neurexin was primarily expressed on the cell surface and colocalized in β-cells with the plasma-membrane associated SNARE protein syntaxin-1 (row 4). SynCAM was detected both in the islet mantle (the periphery, which primarily consists of non-β-endocrine cells: mostly α-cells) and in the insulin positive β-cells (row 5). Staining for SynCAM was consistently stronger in the islet mantle region.