Abstract Exercise and addiction influence brain functions. The preventive effects of fixed and progressive forced exercises on both brain functions and body weight were investigated in morphine-addicted rats. Thirty-five rats were allocated to control, morphine, fixed exercise-morphine, and progressive exercise-morphine groups. Forced exercise was applied 1h/day for 21 days with morphine sulfate administered at doses of 10, 20, 30, 40, and 50 mg/kg for 5 consecutive days. The 50 mg/kg dose was repeated over the five subsequent days. Brain performance was evaluated using the passive avoidance test and EEG recordings. The passive avoidance test revealed no significant changes in brain functions (namely, latency, total dark stay time, and number of times entering the dark compartment). Compared to the control, the morphine group exhibited significantly lower alpha and beta waves but significantly higher delta and theta ones. Compared to the morphine group, the progressive and fixed exercise-morphine groups exhibited significant changes in their passive avoidance performance and only in the alpha wave of their EEG recordings. Progressive exercise improved learning, memory, and memory consolidation but reduced locomotor activity whereas fixed exercise affected EEG recordings in the addicted subjects. Clearly, different (fixed or progressive) exercise models produced different changes in brain functions.

RESUMO O presente estudo investigou os efeitos do carvacrol nos déficits motores e de memória, bem como na hiperalgesia, em um modelo da doença de Parkinson (DP) em ratos com lesões 6-OHDA. Os animais foram submetidos a microinjeção unilateral de 6-OHDA no feixe mediano do prosencéfalo e tratados com carvacrol (25, 50 e 100 mg / kg, ip) durante 6 semanas após a cirurgia. Os ratos com lesões 6-OHDA mostraram rotações contralaterais para o lado da lesão, que foram acompanhadas de déficits de aprendizagem e de memória em um teste de evitação passiva, e de uma diminuição da latência de retirada da cauda em um teste de cauda no final da semana 6. Os resultados também mostraram que o tratamento crônico com carvacrol a uma dose de 25 mg / kg aliviou os déficits de memória, sem efeito sobre rotações e hiperalgesia em ratos lesados. Em conclusão, o carvacrol melhora a deficiência de memória em ratos com DP e, portanto, pode servir como uma terapia complementar para aliviar os déficits de memória em pacientes com DP.

ABSTRACT The present study investigated the effects of carvacrol on motor and memory deficits as well as hyperalgesia in the 6-OHDA-lesioned rat model of Parkinson's disease. The animals were subjected to unilateral microinjection of 6-OHDA into the medial forebrain bundle and treated with carvacrol (25, 50 and 100 mg/kg, ip) for six weeks after surgery. The 6-OHDA-lesioned rats showed contralateral rotations towards the lesion side, which was accompanied by learning and memory deficits in a passive avoidance test and a decrease in tail withdrawal latency in a tail flick test at the end of week 6. The results also showed that treatment with carvacrol at a dose of 25 mg/kg ameliorated memory deficits, with no effect on rotations and hyperalgesia in lesioned rats. In conclusion, carvacrol improves memory impairments in rats with Parkinson's disease; therefore, it may serve as an adjunct therapy for the alleviation of memory deficits in Parkinson's disease patients.