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FIGURE 5
Ethanol induces cranial nerve defects (A–D) Untreated isl1:RFP fish showing motor innervation in the ventral branchial muscles at 4dpf. (E–H) Ethanol-exposed isl1:RFP fish showing various motor innervation defects. (E) Arrow shows ectopic nerves along the medial axis. (F) Arrows show defasciculation at mylohyoid junction (MHJ). (G) Yellow arrow shows ectopic nerve along the lateral axis. Blue arrow shows asymmetrical extension of nerves innervating the left and right side of the hyohyoideus muscle. (H) Maximum intensity Z-projected image with motor nerves (in green) merged with a single Z-plane of brightfield channel showing boundary of the interhyoideus muscle. Arrow indicates motor axons located outside the muscle boundary. (I–M) Number of fish with various cranial nerve defects in untreated and ethanol-exposed groups (n = 30 in each group). Number of fish with total ectopic nerves, ectopic lateral nerves and nerves outside the muscle boundary significantly increase in the ethanol-exposed group in I, K, M. (N) Schematic showing different cranial nerve defects found in the ethanol-exposed fish. (O) Number of fish with total ectopic cranial nerves significantly increase in 0.75% ethanol-exposed isl1:RFP fish (n = 15 in each group). * = p < 0.05; ** = p < 0.01. Scale bar = 100 um.