Peroxisome proliferator-activated receptor-γ (PPARγ) has been reported to be involved in the etiology of pathological features of Alzheimer's disease (AD). Cannabidiol (CBD), a Cannabis derivative devoid of psychomimetic effects, has attracted much attention because of its promising neuroprotective properties in rat AD models, even though the mechanism responsible for such actions remains unknown. This study was aimed at exploring whether CBD effects could be subordinate to its activity at PPARγ, which has been recently indicated as its putative binding site. CBD actions on β-amyloid-induced neurotoxicity in rat AD models, either in presence or absence of PPAR antagonists were investigated. Results showed that the blockade of PPARγ was able to significantly blunt CBD effects on reactive gliosis and subsequently on neuronal damage. Moreover, due to its interaction at PPARγ, CBD was observed to stimulate hippocampal neurogenesis. All these findings report the inescapable role of this receptor in mediating CBD actions, here reported.

1 We have studied the eect of cannabinoid agonists (CP 55,940 and cannabinol) on intestinal motility in a model of intestinal in¯ammation (induced by oral croton oil in mice) and measured cannabinoid receptor expression, endocannabinoids (anandamide and 2-arachidonylglycerol) and anandamide amidohydrolase activity both in physiological and pathophysiological states. 2 CP 55,940 (0.03 ± 10 nmol mouse 71) and cannabinol (10 ± 3000 nmol mouse 71 ) were more active in delaying intestinal motility in croton oil-treated mice than in control mice. These inhibitory eects were counteracted by the selective cannabinoid CB 1 receptor antagonist SR141716A (16 nmol mouse 71). SR141716A (1 ± 300 nmol mouse 71 ), administered alone, increased intestinal motility to the same extent in both control and croton oil-treated mice 3 Croton oil-induced intestinal in¯ammation was associated with an increased expression of CB 1 receptor, an unprecedented example of up-regulation of cannabinoid receptors during in¯ammation. 4 High levels of anandamide and 2-arachidonylglycerol were detected in the small intestine, although no dierences were observed between control and croton oil-treated mice; by contrast anandamide amidohydrolase activity increased 2 fold in the in¯amed small intestine. 5 It is concluded that in¯ammation of the gut increases the potency of cannabinoid agonists possibly by`up-regulating' CB 1 receptor expression; in addition, endocannabinoids, whose turnover is increased in in¯amed gut, might tonically inhibit intestinal motility.

Alzheimer's disease is widely held to be associated with oxidative stress due, in part, to the membrane action of b-amyloid peptide aggregates. Here, we studied the effect of cannabidiol, a major non-psychoactive component of the marijuana plant (Cannabis sativa) on b-amyloid peptide-induced toxicity in cultured rat pheocromocytoma PC12 cells. Following exposure of cells to b-amyloid peptide (1 lg/mL), a marked reduction in cell survival was observed. This effect was associated with increased reactive oxygen species (ROS) production and lipid peroxidation, as well as caspase 3 (a key enzyme in the apoptosis cell-signalling cascade) appearance, DNA fragmentation and increased intracellular calcium.Treatment of the cells with cannabidiol (10 )7 )10 )4 M) prior to b-amyloid peptide exposure significantly elevated cell survival while it decreased ROS production, lipid peroxidation, caspase 3 levels, DNA fragmentation and intracellular calcium. Our results indicate that cannabidiol exerts a combination of neuroprotective, anti-oxidative and anti-apoptotic effects against b-amyloid peptide toxicity, and that inhibition of caspase 3 appearance from its inactive precursor, pro-caspase 3, by cannabidiol is involved in the signalling pathway for this neuroprotection.

Background and purpose: Pharmacological inhibition of beta-amyloid (Ab) induced reactive gliosis may represent a novel rationale to develop drugs able to blunt neuronal damage and slow the course of Alzheimer's disease (AD). Cannabidiol (CBD), the main non-psychotropic natural cannabinoid, exerts in vitro a combination of neuroprotective effects in different models of Ab neurotoxicity. The present study, performed in a mouse model of AD-related neuroinflammation, was aimed at confirming in vivo the previously reported antiinflammatory properties of CBD. Experimental approach: Mice were inoculated with human Ab (1-42) peptide into the right dorsal hippocampus, and treated daily with vehicle or CBD (2.5 or 10 mg kg À1 , i.p.) for 7 days. mRNA for glial fibrillary acidic protein (GFAP) was assessed by in situ hybridization. Protein expression of GFAP, inducible nitric oxide synthase (iNOS) and IL-1b was determined by immunofluorescence analysis. In addition, ELISA assay of IL-1b level and the measurement of NO were performed in dissected and homogenized ipsilateral hippocampi, derived from vehicle and Ab inoculated mice, in the absence or presence of CBD. Key results: In contrast to vehicle, CBD dose-dependently and significantly inhibited GFAP mRNA and protein expression in Ab injected animals. Moreover, under the same experimental conditions, CBD impaired iNOS and IL-1b protein expression, and the related NO and IL-1b release. Conclusion and implications:The results of the present study confirm in vivo anti-inflammatory actions of CBD, emphasizing the importance of this compound as a novel promising pharmacological tool capable of attenuating Ab evoked neuroinflammatory responses.

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