Fig. 5.

Colocalization of FM1-43Fx-labeled puncta, GnRH-1, and the marker for the active zone, Bassoon (BSN), indicates GnRH-1 secretory vesicles in the soma and neuroprocess located at the active sites of exocytosis. Representative cases of a GnRH-1 soma (top and middle panels) and one neuroprocess with three varicosities (bottom panel) are shown. All cultures were fixed immediately after the second 5-min infusion of 56 mm K⁺ (see Materials and Methods) and subjected to double immunocytochemical staining with GnRH-1 and Bassoon antibodies. A single plane confocal microscope picture indicates that puncta (arrowheads) labeled with FM dye (green) were also immunopositive with GnRH-1 (red) and Bassoon (blue). White spots in the merged pictures of the three signals indicate colocalization of FM1-43Fx, GnRH-1, and Bassoon. Scale bar, 10 μm.