Xenbase Image ID: 84097

Fig. 4. Citral, an inhibitor of retinoic acid synthesis, inhibits the formation of primary neurons. (A) Functional assay of embryo movement at the tailbud stage in response to external stimulation. Embryos were grown from the late blastula stage to the early neurula stage in control (0.1× MBS), 10−7 M RA or 60μM citral and then in normal media to the tailbud stage (stage 28). Samples of 25 embryos were then analysed by lightly touching the embryo with a fine needle adjacent, but posterior, to the otic vesicle. The number of tailflips was then counted. Each batch of embryos was stimulated 50 times. Whereas control and RA treated embryos displayed a range of responses to stimulation, the citral treated embryos gave only the an occasional and short response. (B–D). NST expression in embryos treated with citral or citral plus RA. (B), embryos grown from the late blastula to early neurula stage in 40 μM citral show NST expression that is essentially normal (black arrow) in some, but decreased NST expression (open arrow) in other individuals. (C), The addition of 10−7 M RA at the late blastula stage to embryos grown in 40 μM citral results in the recovery of NST expression (black arrow). (D). Embryos grown in 60 μM citral have little or no NST expression (open arrow) though it is sometimes possible to distinguish weak NST expression (small black arrow). The addition of 10−7 M RA to these embryos results in the widespread rescue of NST expression (black arrow). Image published in: Sharpe C and Goldstone K (2000) Copyright © 2000. Image reproduced with permission of the Publisher, Elsevier B. V. Larger Image Printer Friendly View

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