Ataxia-ameliorating effects of YM-14673, a potent analog of thyrotropin releasing hormone, in ataxic mutant mice.

The effects of YM-14673 (N alpha-[[(S)-4-oxo-2-azetidinyl]carbonyl]- L-histidyl-L-prolinamide dihydrate), a potent analog of thyrotropin releasing hormone (TRH), on the behavior of ataxic mutant mice (staggerer, realer, Purkinje cell degeneration and weaver mice) were investigated in comparison with those of TRH in an open-field apparatus. The fall index, the ratio of the number of falls to the distance moved, was defined as an index for ataxia. YM-14673 reduced the fall index in all types of ataxic mice examined and was more potent than TRH in reeler, staggerer and Purkinje cell degereration mice. YM-14673 may have a beneficial effect on patients with spinocerebellar degeneration.