[Brain monoamines and circadian rhythm of spontaneous motor activity of rats]

The effect of three drugs, parachlorophenylalanine, nialamide and disulfiram, drugs known by their action on the two sleep phases, slow wave sleep and I-REM-sleep, have been studied and tested by their effect on the motor circadian rhythm : PCPA and disulfiram reduce the amplitude of the rhythm by two opposed mechanisms : PCPA increases the motor activity, especially the day-time activity, disulfiram reduces the motor activity, especially the night-time activity. The former reduces the serotonine content, the latter the noradrenaline content of the central nervous system. Nialamide (5 or 10 mg/1000 g) is without any action of the rhythm. Both doses increase very much the motor activity ; but the central excitatory state undergoes the normal circadian rhythm. This monoaminoxydase inhibitor is without any action on the circadian rhythm.