Tag Archives: neuroprotection

Activation of Cannabinoid CB2 Receptor-Mediated AMPK/CREB Pathway Reduces Cerebral Ischemic Injury.

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“The type 2 cannabinoid receptor (CB2R) was recently shown to mediate neuroprotection in ischemic injury. However, the role of CB2Rs in the central nervous system, especially neuronal and glial CB2Rs in the cortex, remains unclear. We, therefore, investigated anti-ischemic mechanisms of cortical CB2R activation in various ischemic models….

  Collectively, these data demonstrate that cortical CB2R activation by TC (trans-caryophyllene, a CB2R agonist,), ameliorates ischemic injury, potentially through modulation of AMPK/CREB signaling, and suggest that cortical CB2Rs might serve as a putative therapeutic target for cerebral ischemia.”

http://www.ncbi.nlm.nih.gov/pubmed/23414569

Modulation of Cannabinoid Receptor Activation as a Neuroprotective Strategy for EAE and Stroke

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“These results provide evidence that alteration of the activation patterns of the various cannabinoid receptors warrant consideration for future therapeutic strategies.

Interest in the medicinal use of Cannabis sativa (marijuana) has a long historical record, extending back thousands of years. In comparison to the extensive history for medicinal applications of marijuana, the existence of an “endocannabinoid system”, with important homeostatic and pathologic functions, has only recently gained appreciation. The endocannabinoid system consists of endogenously produced cannabinoids, their receptors, and the enzymes responsible for their synthesis and degradation…

Although used in ancient Greece, Rome, and China for therapeutic purposes, concern about the use of cannabinoids as a drug of abuse has dampened interest in developing the potential therapeutic benefits of these compounds. However, a better understanding of the biologic effects has led recently to an upsurge in interest for the development of therapeutic drugs through modification of the endocannabinoid system. An additional incentive was provided by the development of synthetic cannabinoid analogs and specific inhibitors of cannabinoid receptors. Several excellent reviews cover the therapeutic potential of cannabinoids….

The present review is focused on the effects of CB2 receptor activation in models of multiple sclerosis (experimental autoimmune encephalomyelitis) and stroke (middle cerebral occlusion/reperfusion).

In summary, selective CB2 receptor agonists and CB1 receptor antagonists have significant potential for neuroprotection in animal models of two devastating diseases that currently lack effective treatment options.”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2855650/

A molecular link between the active component of marijuana and Alzheimer’s disease pathology.

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“A link between the endocannabinoid system and Alzheimer’s disease has been discovered which has provided a new therapeutic target for the treatment of patients suffering from Alzheimer’s disease. These studies have demonstrated the ability of cannabinoids to provide neuroprotection against β-amyloid peptide (Aβ) toxicity.

Here, we demonstrate that the active component of marijuana, Δ9-tetrahydrocannabinol (THC), competitively inhibits the enzyme acetylcholinesterase (AChE) as well as prevents AChE-induced amyloid β-peptide (Aβ) aggregation, the key pathological marker of Alzheimer’s disease. 

 Compared to currently approved drugs prescribed for the treatment of Alzheimer’s disease, THC is a considerably superior inhibitor of Aβ aggregation, and this study provides a previously unrecognized molecular mechanism through which cannabinoid molecules may directly impact the progression of this debilitating disease.

Since the characterization of the Cannabis sativa-produced cannabinoid, Δ9-tetrahydrocannabinol (THC), in the 1960’s,1 this natural product has been widely explored as an anti-emetic, anti-convulsive, anti-inflammatory, and analgesic.”

Read more: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2562334/

 

Differential transcriptional profiles mediated by exposure to the cannabinoids cannabidiol and Δ9-tetrahydrocannabinol in BV-2 microglial cells.

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“Apart from their effects on mood and reward, cannabinoids exert beneficial actions such as neuroprotection and attenuation of inflammation. The immunosuppressive activity of cannabinoids has been well established. We previously showed that the psychoactive cannabinoid Δ(9) -tetrahydrocannabinol (THC) and the non-psychoactive cannabidiol (CBD) differ in their anti-inflammatory signalling pathways.

CONCLUSIONS AND IMPLICATIONS:

These observations indicated that CBD, but much less than THC, induced a cellular stress response in microglial cells and suggested that this effect could underlie its anti-inflammatory activity.”

http://www.ncbi.nlm.nih.gov/pubmed/21542829

Cannabinoid CB1 receptor stimulation affords neuroprotection in MPTP-induced neurotoxicity by attenuating S100B up-regulation in vitro.

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 “…the involvement of the endocannabinoid system was investigated by using selective inhibitors of endocannabinoid inactivation (cellular re-uptake or enzymatic hydrolysis) and selective cannabinoid CB1 and CB2 receptor antagonists and by silencing the CB1 receptor…

 Our data suggest that selective activation of CB1 receptors by either exogenous or endogenous cannabinoids might afford neuroprotection…”

http://www.ncbi.nlm.nih.gov/pubmed/17639288

CB1 cannabinoid receptor activation rescues amyloid β-induced alterations in behaviour and intrinsic electrophysiological properties of rat hippocampal CA1 pyramidal neurones.

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“Amyloid beta (Aβ) is believed to be responsible for the synaptic failure that occurs in Alzheimer’s disease (AD), but there is little known about the functional impact of Aβ on intrinsic neuronal properties. Here, the cellular effect of Aβ-induced neurotoxicity on the electrophysiological properties of CA1 pyramidal neurons and the mechanism(s) of neuroprotection by CB1 cannabinoid receptor activation was explored.

CONCLUSIONS:

In vivo Aβ treatment altered significantly the intrinsic electrophysiological properties of CA1 pyramidal neurons and the activation of CB1 cannabinoid receptors exerted a strong neuroprotective action against Aβ toxicity.”

http://www.ncbi.nlm.nih.gov/pubmed/22508047

Increasing cannabinoid levels by pharmacological and genetic manipulation delay disease progression in SOD1 mice.

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“Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by the selective loss of motoneurons in the spinal cord, brain stem, and motor cortex. However, despite intensive research, an effective treatment for this disease remains elusive. In this study we show that treatment of postsymptomatic, 90-day-old SOD1G93A mice with a synthetic cannabinoid, WIN55,212-2, significantly delays disease progression…

Increasing evidence suggests that cannabinoids might have therapeutic potential in neurodegenerative conditions. In a variety of in vivo and in vitro models, cannabinoids exert neuroprotective effects under excitotoxic, ischemic, and inflammatory conditions. This combination of neuroprotective actions might be particularly relevant to ALS and suggests that cannabinoids might have a greater impact on disease progression than the established therapy that targets excitotoxicity alone.

… the neuroprotective effects observed following pharmacological and genetic augmentation of cannabinoid levels are not necessarily mediated by the CB1 receptor, and indeed inhibition of the CB1 receptor might actually be neuroprotective. Therefore, in contrast to previous studies that have suggested that cannabinoids exert neuroprotection via the CB1 receptor, the present results suggest that activation of CB2 receptors might underlie the beneficial effects of cannabinoids at least in SOD1G93A mice .”

Together these results show that cannabinoids have significant neuroprotective effects in this model of ALS and suggest that these beneficial effects may be mediated by non-CB1 receptor mechanisms.”

http://www.fasebj.org/content/20/7/1003.long

Identification of receptors and enzymes for endocannabinoids in NSC-34 cells: relevance for in vitro studies with cannabinoids in motor neuron diseases.

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“NSC-34 cells, a hybridoma cell line derived from the fusion of neuroblastoma cells with mice spinal cord cells, have been widely used as an in vitro model for the study of motor neuron diseases [i.e. amyotrophic lateral sclerosis (ALS)]. In the present study, they were used to characterize different elements of the cannabinoid signaling system, which have been reported to serve as targets for the neuroprotective action of different natural and synthetic cannabinoid compounds…

Assuming that glutamate toxicity is one of the major causes of neuronal damage in ALS and other motor neurons diseases, the differentiated NSC-34 cells might serve as a useful model for studying neuroprotection with cannabinoids in conditions of excitotoxic injury, mitochondrial malfunctioning and oxidative stress.”

http://www.ncbi.nlm.nih.gov/pubmed/22206832

Δ⁹-tetrahydrocannabinol (Δ⁹-THC) exerts a direct neuroprotective effect in a human cell culture model of Parkinson’s disease.

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Neuropathology and Applied Neurobiology

“Δ⁹-tetrahydrocannabinol (Δ⁹-THC) is neuroprotective in models of Parkinson’s disease (PD).

Although CB1 receptors are increased within the basal ganglia of PD patients and animal models, current evidence suggests a role for CB1 receptor-independent mechanisms.

Here, we utilized a human neuronal cell culture PD model to further investigate the protective properties of Δ⁹-THC.

We found CB1 receptor up-regulation in response to MPP+, lactacystin and paraquat and a protective effect of Δ⁹-THC against all three toxins. This neuroprotective effect was not reproduced by the CB1 receptor agonist WIN55,212-2 or blocked by the CB1 antagonist AM251. Furthermore, the antioxidants α-tocopherol and butylhydroxytoluene as well as the antioxidant cannabinoids, nabilone and cannabidiol were unable to elicit the same neuroprotection as Δ⁹-THC.

 

We have demonstrated up-regulation of the CB1 receptor in direct response to neuronal injury in a human PD cell culture model, and a direct neuronal protective effect of Δ⁹-THC that may be mediated through PPARγ activation.”

https://www.ncbi.nlm.nih.gov/pubmed/22236282

“In conclusion, we have demonstrated up-regulation of the CB1 receptor in a human cell culture model of PD, as well as a direct neuroprotective effect of the phytocannabinoid, Δ9-THC, not mediated by the CB2 receptor. Although a CB1 receptor-mediated effect cannot totally be excluded, we propose that activation of PPARγ leading to antioxidant effects is highly relevant in mediating the neuroprotection afforded by Δ9-THC in our model.”

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2990.2011.01248.x/full

The neuroprotective effect of cannabidiol in an in vitro model of newborn hypoxic-ischemic brain damage in mice is mediated by CB(2) and adenosine receptors.

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Abstract

“To investigate the mechanisms involved in cannabidiol (CBD)-induced neuroprotection in hypoxic-ischemic (HI) immature brain, forebrain slices from newborn mice underwent oxygen and glucose deprivation in the presence of vehicle, or CBD alone or with selective antagonists of cannabinoid CB(1) and CB(2), and adenosine A(1) and A(2) receptors. CBD reduced acute (LDH efflux to the incubation medium) and apoptotic (caspase-9 concentration in tissue) HI brain damage by reducing glutamate and IL-6 concentration, and TNFalpha, COX-2, and iNOS expression. CBD effects were reversed by the CB(2) antagonist AM630 and by the A(2A) antagonist SCH58261. The A(1A) antagonist DPCPX only counteracted the CBD reduction of glutamate release, while the CB(1) antagonist SR141716 did not modify any effect of CBD. In conclusion, CBD induces robust neuroprotection in immature brain, by acting on some of the major mechanisms underlying HI cell death; these effects are mediated by CB(2) and adenosine, mainly A(2A), receptors.”

http://www.ncbi.nlm.nih.gov/pubmed/19900555