Influence of diet on the susceptibility of Xenopus laevis tadpoles to thiopentone and a membrane probe.

Xenopus laevis tadpoles were produced from wild-caught, laboratory-reared toads. Separate sets were fed on diets of (1) liver powder; (2) nettle powder; (3) aminosol and Intralipid. The tadpoles were reared for 3 weeks at 22 degrees C and then three groups of experiments performed. Group I experiments showed a significant difference in the response to thiopentone between tadpoles fed on liver powder and those fed on nettle powder. Group II experiments showed a difference in response to thiopentone which did not result from kinetic factors between sets 1, 2 and 3. The dose-response curves of the nettle-fed tadpoles when compared with the liver-fed tadpoles were shifted to the right. The Intralipid-fed tadpoles showed a flat dose-response curve, which tended to fall off. Group III experiments showed a very large difference in response to 1-iodo-4-azido benzene between tadpoles fed on liver powder and those fed on aminosol and Intralipid.