Fig. 2. Effects of TRH, CG3703, and TA0910 on sleep stages in narcoleptic dogs. Vehicle, TRH (400 or 1600 μg/kg, i.v.), CG3703 (100 or 400 μg/kg, i.v.), or TA0910 (100 or 400 μg/kg, i.v.) was injected in four narcoleptic Doberman pinschers, and polygraph data were recorded for 6 hr. Sleep stage effects are shown for every 2 hr period and for the total 6 hr recording session. TRH had no significant effects on any sleep parameters. In contrast, CG3703 and TA0910, two biologically stabilized TRH analogs, significantly decreased sleep (for the first 2 hr) and increased wakefulness in a dose-dependent manner (*p < 0.05, by nonparametric Friedman’s ANOVA). The effect of CG3703 on sleep was also assessed in control animals in which it was found to increase wakefulness significantly and dose-dependently (data given in Results).CAT, Cataplexy; REM, REM sleep;LS, light sleep; DS, deep sleep.