Expression of VGAT during amphioxus development. Whole mounts with anterior to the left. The cross-section in C is viewed from the caudal end of the animal. Whole mount and section scale bars are 50 μm and 25 μm, respectively. A: Side view of a 16-hour neurula showing five spots of VGAT expression in the neural tube. B: Cross-section of the embryo in A through level b. Two ventrolateral neurons are expressing VGAT. C: Enlarged dorsal view of the embryo in A showing five pairs of VGAT-positive neurons. D: Side view of a 30-hour larva. E: Magnification of the larva in D. N, notochord.