Figure 4.
Ethanol treatment of zebrafish embryos during gastrulation and somitogenesis stages reduces neural axis patterning (particularly forebrain) and reduces hatching gland formation (a prechordal plate derivative), which was improved by including retinoic acid during ethanol treatment. Lateral views (anterior is left) of 30 hpf living embryos were imaged using DIC microscopy. Embryos were untreated in control embryos (top panel), and treated with 100 mM ethanol (second and third panels from top, note reduced forebrain, white asterisks, and reduced hatching gland, white arrows, which was variable), 100 mM ethanol and 10−9 M retinoic acid (fourth panels from top), and 10−9 M retinoic acid alone (bottom panel) from 3 hpf until 24 hpf (see Materials and Methods). At 24 hpf, ethanol and/or retinoic acid treatments were discontinued, and embryos were incubated with normal embryo medium until 30 dpf, anesthetized and imaged. Abbreviations: ey, eye; fb, forebrain; hb, hindbrain; hg, hatching gland; mid, midbrain; and ov, otic vesicle. In the four lower panels, asterisks indicate forebrains, and the hatching glands are indicated by arrows.