[Linear, circadian and age-related differences in the burrowing reflex in mice and its alteration by ethanol]

The hole reflex (darkness preference) was stable in the C57BL/6 and CC57BR strains by day and in the evening, whereas its was only stable in the evening in the SHR. Intensity of locomotion was the highest in the evening in the C57BL/6 strain. The transition rate between dark and light chambers was the same by day and in the evening in all the strains. The C57BL/6 mice were much more resistant against ethanol-induced alterations of the hole reflex than the SHR.