Abnormalities in behavior, learning ability, and the cholinergic system induced by long-term ultraviolet A...

Behavioral abnormalities, jumping reaction, increase in spontaneous activity abnormal violence, and lethargy were observed in long-term ultraviolet A (UVA)-irradiated hairy male Crj:CD-1 mice. The learning ability of 6- and 12-months UVA-irradiated mice was significantly reduced compared to un-irradiated age-matched mice. Acetylcholine levels, acetylcholinesterase and choline acetyltransferase activities in the whole brains were decreased in both of 6- and 12-month irradiated mice. Only 1 of 6 mice irradiated for 12 months was histologically observed to have a drastic loss of bilateral hippocampal pyramidal cells in the CA1 field of Ammon's horn.