Fig. 3. (A) Effects of endothelin (ET-1) on the diameter of the main artery to the head (normalized to the diameter under control conditions) in Xenopus laevis tadpoles (N-F stages 50–53). Values are means ± S.E.M. (N=6); the symbols and asterisks indicate significant differences from the control period. (B) Effect of endothelin (ET-1) on the diameter of the main vein from the head (normalized to the diameter under control conditions) in Xenopus laevis tadpoles. Values are means ± S.E.M. (N=6). Arrowheads indicate the point at which endothelin was applied.
