Nocturnal sleep structure and temperature slope in MPTP treated monkeys

The nocturnal sleep of three 1-Methyl, 4-phenyl, 1,2,3,6-tetrahydropyridine (MPTP) treated monkeys (one non-motor disabled and two severely motor disabled), while held in a primate chair was registered using a reversible system for head fixation and chronic recordings. Two electroencephalogram (EEG) channels, one electrooculogram (EOG) and one electromyogram (EMG) channel were monitored constantly and tape recorded during eight nights for posterior analyses. Subcutaneous temperature was registered each minute using a radio telemetry system. An analysis of sleep patterns and temperature parameters revealed lighter sleep, decreased amounts of slow wave and rapid eye movement (REM) sleep and lower temperature values in the two motor disabled MPTP-treated monkeys than in the non-motor disabled monkey. The temperature linear slope was negative in the case of one disabled monkey for just one night. Although the motor disability of the two monkeys was similar, their sleep organization patterns and temperatures slopes differed. The present study confirmed the differential vulnerability of the nigrostriatal system of monkeys to MPTP, suggesting that if a high cumulative dose was needed to reach stable motor alterations, the cumulative dose-effect of the toxin independent of the nigrostriatal system might be responsible for non-motor symptoms that also appear in Parkinson's disease besides the classic tetrad.