ABSTRACT
Aim: Disruption in cerebellar inputs, as well as dysfunction of Purkinje cells (PCs), causes a change in the timing of electrical signaling in the cerebellum resulting in disorders such as cerebellar ataxia. Although much clinical and molecular genetics research has been conducted to understand this disorder, there is no specific treatment for cerebellar ataxia. As cannabinoid type 1 receptors (CB1Rs) are highly expressed in the cerebellum and have been suggested as a therapeutic strategy, we determined whether AM251, a cannabinoid receptor antagonist, was neuroprotective of PCs in a rat cerebellar ataxic model.Materials and methods: To this end, we conducted behavioral and histological tests in the 3-acetylpyridine (3AP) rat cerebellar ataxia model, to explore whether AM251 was protective against induction of ataxia and cell death.Results: Rats with chemical degeneration of the inferior olive induced by 3AP (55 mg/kg, i.p.) clearly showed cerebellar ataxic symptoms. The locomotor activity and motor coordination of the ataxic animals were clearly disrupted compared to the control group. Further, histological analysis showed cell death and PCs degenerated with loss of cell membrane integrity associated with 3AP. Pre-treatment by AM251 improved the locomotor activity of the ataxic animals, and AM251 almost prevented PCs neuronal degeneration.Conclusion: Our data which show protection of cerebellar PCs and motor improvement in the ataxic rat model by treatment with AM251 suggests that targeting cannabinoid receptors should be considered for therapeutic intervention in cerebellar ataxia. HIGHLIGHTS:AM251 was protective against induction of ataxia and cell death.CBR antagonist typically ameliorated 3AP induced Ataxia.AM251 affected explorative and gait disturbances induced by 3AP.CBR antagonist improved impairments of anxiety-like behaviors following 3AP.
ABSTRACT
Parkinson's disease (PD) is a destroying and prevalent neurodegenerative disease that is characterized by a progressive death of midbrain dopaminergic neurons. It is important to understand the possible neuroprotective effects of reagents that rescue the neurons from death and apoptosis. In this study, we investigated the effects of abscisic acid (ABA) on 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in human dopaminergic neuroblastoma SH-SY5Y cell line as an in vitro model of PD. Cell damage was induced by 150 µM 6-OHDA and the cell viability was examined by 2-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl-2-tetrazolium bromide (MTT) assay. Reactive oxygen species (ROS) and mitochondrial membrane potential were assessed by fluorescence probe methods. Biochemical markers of apoptosis were also determined by immunoblotting. The data showed that 6-OHDA caused a significant loss of cell viability and mitochondrial membrane potential. In addition, intracellular ROS, cleaved caspase-3, Bax:Bcl-2 ratio, and cytochrome c release were significantly increased in 6-OHDA-incubated cells. ABA (100 µM) elicited a significant protective effect and reduced biochemical markers of cell damage and death. Blockage of peroxisome proliferator-activated receptor (PPAR)γ completely prevented the effect of ABA on 6-OHDA-induced cell toxicity. The results suggest that ABA has neuroprotective property against 6-OHDA-induced neurotoxicity, which is performed through PPARγ signaling. However, ABA antioxidant and antiapoptotic properties are involved, at least in part, in such protection.
