Avaliação do perfil de sono/vigilia em um modelo crônico de parkinsonismo em ratos

Abstract

Parkinson’s disease (PD) is a neurodegenerative and progressive disorder with varied clinical spectrum. In addition to the classic motor symptoms may also emerge non-motor complications, highlighting cognitive, psychiatric and autonomic problems. Evidence shows that such non-motor symptoms often precede the onset of motor signs and are extremely relevant given the negative impact they have on the quality of life of the individuals. Non-motor symptoms may present multiple causes, among which a possible dysfunction of the circadian system. Therefore, many physiological processes influenced by the circadian timing system (CTS) as the sleep / wake cycle can show alterations in PD patients. In this study we sought to evaluate the profile of sleep/wake behavior in a chronic model of PD in rats compared with possible neurochemical changes in the suprachiasmatic nucleus(SCN), the main pacemaker of the CTS. To this end, young (6 months) and middle-age (10 months) wistar rats were subjected to a treatment with repeated administration of reserpine (0.1 mg / kg) for 20 days. During treatment sleep behavioral analysis were performed as well as the motor assessment of the individuals. After the end of treatment, immunohistochemical analyzes were performed in the SCN of the animals. Our results showed that chronic treatment with reserpine promoted progressive motor impairment both in young as in middle-age animals. It is noticed significant losses from the 12th day of treatment. Furthermore, the behavioral analyzes revealed disturbances in sleep / wake cycle of the treated animals compared to control subjects, including advanced sleep phase and increased sleep fragmentation. Such changes were observed from the 6th day of treatment, prior to the onset of motor symptoms. The immunohistochemical analysis not allowed to observe significant effects of treatment with reserpine on the neurochemical composition of the SCN. Thus, our data support the observation that non-motor symptoms precede the onset of motor symptoms in PD and are extremely important for early clinical diagnosis of the disease.