ABNORMALITIES IN BEHAVIOR, LEARNING-ABILITY, AND THE CHOLINERGIC SYSTEM INDUCED BY LONG-TERM ULTRAVIOLET-A IRRADIATION OF MICE

Behavioral abnormalities, jumping reaction, increase in spontaneous ac tivity, abnormal violence, and lethargy were observed in long-term ult raviolet A (UVA)-irradiated hairy male Crj:CD-1 mice, The learning abi lity of 6- and 12-months UVA-irradiated mice was significantly reduced compared to unirradiated age-matched mice. Acetylcholine levels, acet ylcholinesterase and choline acetyltransferase activities in the whole brains were decreased in both of 6- and 12-month irradiated mice. Onl y 1 of 6 mice irradiated for 12 months was histologically observed to have a drastic loss of bilateral hippocampal pyramidal cells in the CA 1 field of Ammon's horn.