TABLE 1.

Parameters of concentration-response curves

	% EC50 (95% C.I.)
Strain	Dark	Light	Slope constant (± SEM)
Canton-S	0.27 (0.26–0.28)	0.25 (0.24–0.26)	6.45 ± 0.34
inaF[P106×]	0.30 (0.28–0.31)	0.36 (0.34–0.38)	7.51 ± 0.62
trp[301]	0.30 (0.28–0.31)	0.35 (0.33–0.37)	8.31 ± 0.69
trpl [302];trp[301]	0.30 (0.28–0.32)	0.30 (0.28–0.32)	4.86 ± 0.38
w[1118]	0.35 (0.33–0.37)	0.21 (0.20–0.23)	4.47 ± 0.30
w[hd]	0.26 (0.25–0.28)	0.18 (0.17–0.19)	5.91 ± 0.40
w[1118];;trp[301]	0.27 (0.25–0.29)	0.24 (0.22–0.26)	4.15 ± 0.34

Curves were fit to a sigmoid function as before (Guan et al. 2000) with the aid of a commercial statistics package (SPSS, Chicago). To best assess the influence of illumination on a given strain, curves generated in dark and light were analyzed together to generate a single slope constant (± SEM) that defines their steepness. The analysis also yields EC50 values [each with its own 95% confidence interval (C.I.)] that define anesthetic potency in tests of each strain in the dark and in the light. A significant effect of illumination is ascertained when the 95% C.I. for the curve generated in ambient light fails to overlap the 95% C.I. for the curve generated in dim red light.