RESUMO
Deltamethrin (DM) is widely used in agriculture, veterinary medicine and control of domestic pests. Epidemiological studies suggest that DM exposure is a risk factor for neurodegenerative disorders such as Parkinson's (PD) and Alzheimer diseases; however the mechanisms are elusive. In the present study we evaluated the effects of intracerebroventricular (i.c.v.) administration of DM on locomotion activity, spatial working memory and dopaminergic pathway in the rat. Middle-aged male Wistar rats received three i.c.v. injections of DM 0.5 µg, DM 5 µg or vehicle, every other day. Across the treatment, the animals were submitted to behavioral evaluation in the catalepsy test, open field test, and spontaneous alternation task. Following completion of behavioral tests, rats were perfused and their brains were processed to tyrosine hydroxylase (TH) immunohistochemistry. We observed that i.c.v. administration of DM 5 µg increased locomotion activity (open field) and caused spatial working memory impairment (spontaneous alternation task). These alterations were accompanied by reduction TH immunoreactivity in the substantia nigra pars compacta (SNpc), ventral tegmental area (VTA) and dorsal striatum. Conversely, no motor change was observed in the catalepsy test. These results indicate that i.c.v. administration of DM can cause hyperactivity and cognitive alteration which may be related to disruption of the dopaminergic pathway.
Assuntos
Atividade Motora/efeitos dos fármacos , Nitrilas/farmacologia , Piretrinas/farmacologia , Memória Espacial/efeitos dos fármacos , Animais , Encéfalo/efeitos dos fármacos , Cognição/efeitos dos fármacos , Corpo Estriado/efeitos dos fármacos , Dopamina/metabolismo , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/metabolismo , Infusões Intraventriculares , Locomoção/efeitos dos fármacos , Masculino , Memória de Curto Prazo/efeitos dos fármacos , Nitrilas/efeitos adversos , Nitrilas/metabolismo , Parte Compacta da Substância Negra/efeitos dos fármacos , Piretrinas/efeitos adversos , Piretrinas/metabolismo , Ratos , Ratos Wistar , Tirosina 3-Mono-Oxigenase/metabolismo , Área Tegmentar Ventral/efeitos dos fármacosRESUMO
Geraniol is a monoterpene alcohol that is derived from the essential oils of aromatic plants, with anti-inflammatory, antimicrobial, antioxidant and neuroprotective properties. This study characterized the effect of geraniol on behavior and brainwave patterns in rats. Male rats were submitted to administration of geraniol (25, 50 and 100 mg/kg). The hole board (HB) and open field (OF) tests were performed to evaluate anxiety and motor behavior, respectively. In addition, barbiturate-induced sleeping time (BIST) was used to analyze sedative effect. Finally, electrocorticogram (ECoG) recordings were used to characterize brain-wave patterns. The results showed that geraniol treatment in rats decreased the distance traveled, rearing numbers and lead to increase in immobility time in HB and OF tests. In BIST test, geraniol treatment increased sleep duration but not sleep latency in the animals. Furthermore, geraniol-treated animals demonstrated an increase in the percentage of delta waves in the total spectrum power. Taken together, our results suggested that geraniol exerted a depressant effect on the central nervous system of rats.