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Fig. 5
Anatomy of swimbladders from larvae at the ESC stage of swimbladder development. Panels a, c, e, g show images taken from swimbladders of control group (n = 38); panels b, d, f, h show images from swimbladders of experimental group (n = 60). b, c (insets show higher magnification views): Phalloidin labeling showed that no swimbladder muscular development was present in either group. c, d: Tie-2-like immunoreactivity showed blood vessels extending along the walls and ending in anastomotic loops (arrows) in swimbladders from both groups. Erythrocytes are visible within some vessels (arrowheads). e, f: In both groups, zn-12 immunoreactivity showed paired lateral nerves coursing to the cranial end of the swimbladder, then along the walls bilaterally before converging caudally at the apex (arrowhead). g, h: Details of regions shown within boxes in panels e and f. Numerous fine ramifications arose from lateral nerves in specimens from both groups; a putative cell body (arrow) was associated with a lateral nerve in the sample from the control group, although these cells were also observed in tissue from the experimental group (data not shown). In tissue from both groups, intensely stained structures resembling varicosities (arrowheads) occurred along many fibers. Scale bars represent: a, b, 50 μm (inset, 20 μm); c?f, 50 μm; g, h, 10 μm.