|Budget Amount *help
¥4,800,000 (Direct Cost : ¥4,800,000)
Fiscal Year 1994 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1993 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1992 : ¥3,700,000 (Direct Cost : ¥3,700,000)
Presuming that adverse influences of different chemical substances may primarily appear as deterioration of behavioral functions or behavioral disorders, it is of importance to detect behavioral abnormality associated with a given chemical agent. The purpose of the project was to develop behavioral assessment system sensitive to behavioral ch-ges induced by a very small quantity of putative toxic substance which do not produce any abnormal pathological changes in nervous systems in themselves.
The system developed was mainly composed of three subsystems. First is an operant chamber for behavioral experiment using small animals. It was equipped with manipulanda, such as response lever, and other sources of discriminative stimuli, and animals were ordinarily housed in the chamber. Second was a experiment-controlling system for stimulus presentation and recording of responses. Thereby, collection, storing and analysis of behavioral data were also automatized. Third was a system to expose subjects to toxic substance, which consisted of a constant-temperature water bath, glass tube, Teflon bulbs and solenoid bulbs. Amount and duration of exposure were precisely controlled with them.
To demonstrate reliability and usefulness of the system, the effects of acute/chronic exposure to nitrogen dioxide, methanol gas and ethanol gas upon acquisition of conditioned responses (lever pressing) on the spatial memory task and their temporal distributions under free operant situation were compared with those of clean air. All of the results obtained from these experiments indicated that the system was a superior one for measurement of operant behavior under long term exposure to toxic substance. Finally, it was suggested that brain microdialysis was among possible physiological methods to be incorporated into the present system in the future.