AN ADJUSTABLE-CURRENT SWIMMING POOL FOR THE EVALUATION OF ENDURANCE CAPACITY OF MICE

A new forced-swimming apparatus for determining maximum swimming time in mice was devised for use in the evaluation of the endurance capacit y of Std ddY and CDF1 mice after various diet and drug treatments. Wit h the apparatus, a water current is generated by circulating water wit h a pump in a swimming pool. A spout and suction slit were contrived t o generate a constant current while the strength of the current is reg ulated by a valve. The decrease in the leg-kicking intervals of mice a ccompanying the increase in the current speed confirmed that the workl oad is adjustable by regulation of the current speed. Compared with th e number of forelimb strokes, that of the hindlimb kicks was greater. The swimming time until fatigue was observed to decrease with increasi ng current speed in the two strains of mice. As biochemical indexes, t he blood lactate and muscle glycogen levels corroborated the correlati on between current speed and increase in workload. These results indic ate that the apparatus employed in the present study is suitable for t he evaluation of the endurance capacity of mice and that it is useful for detecting the effects of dietary differences and drug pretreatment s on this capacity.