抄録
The plasmodium of the myxomycete Physarum polycephalum shows rhythmic contraction. The effect of mitochondrial inhibitors on this activity was examined. The separate inhibition of respiration or of H-F--ATPase activity or of ATP/ADP translocation failed to stop rhythmic contraction although the period of oscillation was affected. The concurrent inhibition of respiration and ATPase activity or the concurrent inhibition of respiration and ATP/ADP translocation, however, almost wholly suppressed contraction. Removal of respiratory inhibition in either case restored rhythmic contraction. The resumption of rhythmic activity occurred even though the ATP concentra-tion in the plasmodium remained at half the control level. Our results suggest that a particular mitochondrial state is indispensable for rhythmic contraction in Physarum polycephalum, and that this state influences rhythmic activities by means other than the control of the ATP level.
