Hiroki Takekata, S. Goto, A. Satoh
Mar 4, 2014
Biological Rhythm Research
Apteronemobius asahinai shows two rhythms in its locomotor activity. One is the circatidal rhythm, which produces active and inactive phases, and the other is the circadian rhythm, which suppresses the intensity of the activity of the circatidal active phase during the subjective day. In the present study, to reveal whether light suppresses locomotor activity by masking the circatidal rhythm without interfering with the circadian rhythm, we observed the activity under 23-h light–dark cycles before and after RNA interference (RNAi) of the circadian clock gene period (per RNAi), which disrupts the circadian rhythm but not the circatidal rhythm. Hyperactivity just after lights-on and lights-off was observed both before and after per RNAi. However, the activity levels were suppressed in the photophase as compared to the scotophase before per RNAi, but not suppressed in the photophase after per RNAi. Thus, the activity of A. asahinai is not directly suppressed by light.