Cannabidiol reduces lipopolysaccharide-induced nociception via endocannabinoid system activation.

Bacterial infections are often accompanied by fever and generalized muscle pain. However, the treatment of pain with an infectious aetiology has been overlooked. Thus, we investigated the impact of cannabidiol (CBD) in bacterial lipopolysaccharide (LPS)-induced nociception. Male Swiss mice received intrathecal (i.t.) LPS injection, and the nociceptive threshold was measured by the von Frey filaments test. Spinal involvement of the cannabinoid CB2 receptor, toll-like receptor 4 (TLR4), microglia and astrocytes were evaluated by i.t. administration of their respectively antagonists or inhibitors. Western blot, immunofluorescence, ELISA and liquid chromatography-mass spectrometry were used to assess Cannabinoid CB2 receptors and TLR4 spinal expression, proinflammatory cytokines and endocannabinoid levels. CBD was administered intraperitoneally at 10 mg/kg. The pharmacological assay demonstrated TLR4 participation in LPS-induced nociception. In addition, spinal TLR4 expression and proinflammatory cytokine levels were increased in this process. CBD treatment prevented LPS-induced nociception and TLR4 expression. AM630 reversed antinociception and reduced CBD-induced endocannabinoids up-regulation. Increased spinal expression of the cannabinoid CB2 receptor was also found in animals receiving LPS, which was accompanied by reduced TLR4 expression in CBD-treated mice. Taken together, our findings indicated that CBD is a potential treatment strategy to control LPS-induced pain by attenuating TLR4 activation via the endocannabinoid system.

Cannabidiol anticonvulsant effect is mediated by the PI3Kγ pathway.

The phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB/Akt)/mechanistic target of rapamycin (mTOR) signaling pathway has been associated with several pathologies in the central nervous system (CNS), including epilepsy. There is evidence supporting the hypothesis that the PI3Kγ signaling pathway may mediate the powerful anticonvulsant properties associated with the cannabinoidergic system. This work aims to investigate if the anticonvulsant and neuroprotective effects of cannabidiol (CBD) are mediated by PI3Kγ. In vitro and in vivo experiments were performed on C57Bl/6 wild-type (WT) and PI3Kγ-/- mice. Behavioral seizures were induced by bilateral intra-hippocampal pilocarpine microinjection. Twenty-four hours after the first behavioral seizure, animals were perfused and their brains removed and processed, for histological analysis of neurodegeneration, microgliosis and astrocytosis. Primary cultures of hippocampal neurons were used for glutamate-induced cell death assay. CDB increased latency and reduced the severity of pilocarpine-induced behavioral seizures, as well as prevented postictal changes, such as neurodegeneration, microgliosis and astrocytosis, in WT animals, but not in PI3Kγ-/-. CBD in vivo effects were abolished by pharmacological inhibition of cannabinoid receptor or mTOR. In vitro, PI3Kγ inhibition or deficiency also changed CBD protection observed in glutamate-induced cell death assay. Thus, we suggest that the modulation of PI3K/mTOR signaling pathway is involved in the anticonvulsant and neuroprotective effects of CBD. These findings are important not only for the elucidation of the mechanisms of action of CBD, which are currently poorly understood, but also to allow the prediction of therapeutic and side effects, ensuring efficacy and safety in the treatment of patients with epilepsy.

Cannabidiol rescues acute hepatic toxicity and seizure induced by cocaine.

Cocaine is a commonly abused illicit drug that causes significant morbidity and mortality. The most severe and common complications are seizures, ischemic strokes, myocardial infarction, and acute liver injury. Here, we demonstrated that acute cocaine intoxication promoted seizure along with acute liver damage in mice, with intense inflammatory infiltrate. Considering the protective role of the endocannabinoid system against cell toxicity, we hypothesized that treatment with an anandamide hydrolysis inhibitor, URB597, or with a phytocannabinoid, cannabidiol (CBD), protects against cocaine toxicity. URB597 (1.0 mg/kg) abolished cocaine-induced seizure, yet it did not protect against acute liver injury. Using confocal liver intravital microscopy, we observed that CBD (30 mg/kg) reduced acute liver inflammation and damage induced by cocaine and prevented associated seizure. Additionally, we showed that previous liver damage induced by another hepatotoxic drug (acetaminophen) increased seizure and lethality induced by cocaine intoxication, linking hepatotoxicity to seizure dynamics. These findings suggest that activation of cannabinoid system may have protective actions on both liver and brain induced by cocaine, minimizing inflammatory injury promoted by cocaine, supporting its further clinical application in the treatment of cocaine abuse.