Cannabinoids

Glia. 2017 Jan;65(1):122-137. doi: 10.1002/glia.23080. Epub 2016 Oct 19.
Cannabinoids prevent the amyloid β-induced activation of astroglial hemichannels: A neuroprotective mechanism.
Gajardo-Gómez R1, Labra VC1, Maturana CJ1, Shoji KF2, Santibañez CA1, Sáez JC2, Giaume C3, Orellana JA1.
Author information
Abstract
The mechanisms involved in Alzheimer’s disease are not completely understood and how astrocytes and their gliotransmission contribute to this neurodegenerative disease remains to be fully elucidated. Previous studies have shown that amyloid-β peptide (Aβ) induces neuronal death by a mechanism that involves the excitotoxic release of ATP and glutamate associated to astroglial hemichannel opening. We have demonstrated that synthetic and endogenous cannabinoids (CBs) reduce the opening of astrocyte Cx43 hemichannels evoked by activated microglia or inflammatory mediators. Nevertheless, whether CBs could prevent the astroglial hemichannel-dependent death of neurons evoked by Aβ is unknown. Astrocytes as well as acute hippocampal slices were treated with the active fragment of Aβ alone or in combination with the following CBs: WIN, 2-AG, or methanandamide (Meth). Hemichannel activity was monitored by single channel recordings and by time-lapse ethidium uptake while neuronal death was assessed by Fluoro-Jade C staining. We report that CBs fully prevented the hemichannel activity and inflammatory profile evoked by Aβ in astrocytes. Moreover, CBs fully abolished the Aβ-induced release of excitotoxic glutamate and ATP associated to astrocyte Cx43 hemichannel activity, as well as neuronal damage in hippocampal slices exposed to Aβ. Consequently, this work opens novel avenues for alternative treatments that target astrocytes to maintain neuronal function and survival during AD. GLIA 2016 GLIA 2017;65:122-137.
© 2016 Wiley Periodicals, Inc.
KEYWORDS:
alzheimer; connexin43; glia; neuroinflammation; neuron
PMID: 27757991 DOI: 10.1002/glia.23080

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Phytother Res. 2016 Sep 22. doi: 10.1002/ptr.5712. [Epub ahead of print]
THC (Δ9-Tetrahydrocannabinol) Exerts Neuroprotective Effect in Glutamate-affected Murine Primary Mesencephalic Cultures Through Restoring Mitochondrial Membrane Potential and Anti-apoptosis Involving CB1 Receptor-dependent Mechanism.
Nguyen CH1, Krewenka C1, Radad K2, Kranner B1, Huber A1, Duvigneau JC1, Miller I1, Moldzio R3.
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Abstract
Aging-related neurodegenerative diseases, such as Parkinson’s disease (PD) or related disorders, are an increasing societal and economic burden worldwide. Δ9-Tetrahydrocannabinol (THC) is discussed as a neuroprotective agent in several in vitro and in vivo models of brain injury. However, the mechanisms by which THC exhibits neuroprotective properties are not completely understood. In the present study, we investigated neuroprotective mechanisms of THC in glutamate-induced neurotoxicity in primary murine mesencephalic cultures, as a culture model for PD. Glutamate was administered for 48 h with or without concomitant THC treatment. Immunocytochemistry staining and resazurin assay were used to evaluate cell viability. Furthermore, superoxide levels, caspase-3 activity, and mitochondrial membrane potential were determined to explore the mode of action of this compound. THC protected dopaminergic neurons and other cell types of primary dissociated cultures from glutamate-induced neurotoxicity. Moreover, THC significantly counteracted the glutamate-induced mitochondrial membrane depolarization and apoptosis. SR141716A, a CB1 receptor antagonist, concentration-dependently blocked the protective effect of THC in primary mesencephalic cultures. In conclusion, THC exerts anti-apoptotic and restores mitochondrial membrane potential via a mechanism dependent on CB1 receptor. It strengthens the fact that THC has a benefit on degenerative cellular processes occurring, among others, in PD and other neurodegenerative diseases by slowing down the progression of neuronal cell death. Copyright © 2016 John Wiley & Sons, Ltd.
Copyright © 2016 John Wiley & Sons, Ltd.
KEYWORDS:
THC; anti-apoptosis; glutamate; mesencephalic culture; neuroprotection; neurotoxicity
PMID: 27654887 DOI: 10.1002/ptr.5712

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