Figure 8.

Triplet images showing stereoscopic (left two of three images) and reverse stereoscopic images (right two images) of medium-size gap junction in adult female Mosquitofish. (A) Classical gap junction plaque (red overlays) labeled by 14 6-nm gold beads (six indicated by white arrowheads) and six 18-nm gold beads representing Cx36 (39–4200 and 37–4600). A single 12-nm gold nanoparticle (black arrow), ostensibly for anti-pannexin 1 (see Section Materials and Methods), represents non-specific labeling because it is on the non-biological side (upper surface) of the replica where labeling is not possible. Note the narrowing of the extracellular space (blue overlay) at the point of closest membrane approach within the gap junction. (B) E-face image of gap junction plaque (red overlay) labeled for Cx36 (36–4600) by eight 12-nm gold beads and six 30-nm gold beads. Because of greatly different amino acid sequences in fish vs. mammalian glutamate receptors (see text), the immediately adjacent cluster of glutamate receptor-like E-face IMPs (yellow overlay) does not exhibit labeling for GluR2 (6-nm and 18-nm gold beads, none present). Calibration bars are 0.25 µm.