Cannabidiol prevents LPS-induced microglial inflammation by inhibiting ROS/NF-κB-dependent signaling and glucose consumption.

We used mouse microglial cells in culture activated by lipopolysaccharide (LPS, 10 ng/ml) to study the anti-inflammatory potential of cannabidiol (CBD), the major nonpsychoactive component of cannabis. Under LPS stimulation, CBD (1-10 µM) potently inhibited the release of prototypical proinflammatory cytokines (TNF-α and IL-1ß) and that of glutamate, a noncytokine mediator of inflammation. The effects of CBD were predominantly receptor-independent and only marginally blunted by blockade of CB2 receptors. We established that CBD inhibited a mechanism involving, sequentially, NADPH oxidase-mediated ROS production and NF-κB-dependent signaling events. In line with these observations, active concentrations of CBD demonstrated an intrinsic free-radical scavenging capacity in the cell-free DPPH assay. Of interest, CBD also prevented the rise in glucose uptake observed in microglial cells challenged with LPS, as did the inhibitor of NADPH oxidase apocynin and the inhibitor of IκB kinase-2, TPCA-1. This indicated that the capacity of CBD to prevent glucose uptake also contributed to its anti-inflammatory activity. Supporting this view, the glycolytic inhibitor 2-deoxy-d-glucose (2-DG) mimicked the antioxidant/immunosuppressive effects of CBD. Interestingly, CBD and 2-DG, as well as apocynin and TPCA-1 caused a reduction in glucose-derived NADPH, a cofactor required for NADPH oxidase activation and ROS generation. These different observations suggest that CBD exerts its anti-inflammatory effects towards microglia through an intrinsic antioxidant effect, which is amplified through inhibition of glucose-dependent NADPH synthesis. These results also further confirm that CBD may have therapeutic utility in conditions where neuroinflammatory processes are prominent.

Chronic fluoxetine treatment alters cardiovascular functions in unanesthetized rats.

In the present study, we investigated the effects induced by fluoxetine treatment (10 mg/kg) for either 1 or 21 consecutive days on arterial pressure and heart rate basal levels, baroreflex activity, hemodynamic responses to vasoactive agents and cardiovascular responses to acute restraint stress. Mild hypertension was observed after 21 days of treatment, but not after administration for 1 day. Moreover, chronic treatment affected the baroreflex control of heart rate, which was characterized by a reduced reflex tachycardia and an enhanced bradycardiac baroreflex response. The pressor responses to systemic administration of the selective α(1)-adrenoceptor agonist phenylephrine, as well as the depressor responses to systemic infusion of the nitric oxide donor sodium nitroprusside, were reduced after chronic fluoxetine treatment. Fluoxetine treatment for 21 days reduced both the pressor and tachycardiac responses evoked by acute restraint stress. In conclusion, the results indicate the development of mild hypertension after chronic fluoxetine treatment. This effect was followed by changes in the baroreflex control of heart rate and altered vascular responsiveness to pressor and depressor agents, which may explain, at least in part, the increase in arterial pressure. Chronic fluoxetine treatment also affected cardiovascular responses to restraint stress, thus indicating that fluoxetine may affect cardiovascular adaptation under conditions of stress.