TABLE 3

Ethanol and steroid effects on tadpole righting reflexes

The loss of righting reflex in tadpoles is affected in a manner consistent with the hypothesis of synergistic effects of potentiating steroids and ethanol. Thirty nanomolar 3α5αP alone did not produce LRR in tadpoles (estimated from four experiments using a total of 40 tadpoles). The values are best-fit parameters ± S.D. estimated from a fit of the Hill equation (Y = ([ethanol]^nH)/([ethanol]^nH + EC₅₀^nH), where EC₅₀ is the concentration causing half-maximal effect and ⁿH is the Hill coefficient. A total of 20 tadpoles were exposed to each condition, in two replicates of 10 tadpoles each. The difference in the concentration-effect relationships was assessed using a two-tailed Kolmogorov-Smirnov two-sample test, with n = 20 observations. The concentration-effect relationship for ethanol + 30 nM 3α5αP differed from that for ethanol alone (P < 0.05); no other comparisons showed a significant difference (P > 0.05).