Category Archives: Brain Trauma

Endocannabinoid system in the brain…and elsewhere.

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“The endocannabinoid system is a complex system with endogenous ligands, synthesis and transport processes, specific receptors (CB1 and CB2) and intracellular degrading enzymes.

It is widely distributed in the central nervous system, but also in peripheral organs.

In the brain, endocannabinoids and CB1 receptors are almost ubiquitous and play a role in synaptic plasticity: they modulate, through an inhibitory retrograde action, the release of classical neurotransmitters such as amines, acetylcholine or amino acids.

They may exert a neuroprotective effect, but are also involved in appetite and alcohol/drug dependence.

At the periphery, they are present (and overexpressed in case of abdominal obesity) in various organs involved in energy control and metabolic regulation.

Furthermore, CB2 receptors are also present in the brain, although less numerous than CB1 receptors.

They could attenuate pain and also be neuroprotective.

Selective agonists, antagonists and inverse agonists of CB1 and CB2 receptors are currently developed and open new interesting therapeutic perspectives.”

http://www.ncbi.nlm.nih.gov/pubmed/18669206

Functions of the CB1 and CB 2 receptors in neuroprotection at the level of the blood-brain barrier.

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“The cannabinoid (CB) receptors are the main targets of the cannabinoids, which include plant cannabinoids, endocannabinoids and synthetic cannabinoids. Over the last few years, accumulated evidence has suggested a role of the CB receptors in neuroprotection.

The blood-brain barrier (BBB) is an important brain structure that is essential for neuroprotection. A link between the CB receptors and the BBB is thus likely, but this possible connection has only recently gained attention.

Cannabinoids and the BBB share the same mechanisms of neuroprotection and both protect against excitotoxicity (CB1), cell death (CB1), inflammation (CB2) and oxidative stress (possibly CB independent)-all processes that also damage the BBB.

Several examples of CB-mediated protection of the BBB have been found, such as inhibition of leukocyte influx and induction of amyloid beta efflux across the BBB.

Moreover, the CB receptors were shown to improve BBB integrity, particularly by restoring the tightness of the tight junctions. This review demonstrated that both CB receptors are able to restore the BBB and neuroprotection, but much uncertainty about the underlying signaling cascades still exists and further investigation is needed.”

http://www.ncbi.nlm.nih.gov/pubmed/24929655

Neuroprotective effects of the synthetic cannabinoid HU-210 in primary cortical neurons are mediated by phosphatidylinositol 3-kinase/AKT signaling.

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“Cannabinoids (CBs) are neuroprotective in vivo and in vitro.

…the PI 3-K/AKT signaling pathway mediates the neuroprotective effect of exogenous cannabinoids in primary CNS neurons.”

http://www.ncbi.nlm.nih.gov/pubmed/15607953

Cannabidiol, neuroprotection and neuropsychiatric disorders.

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“Cannabidiol (CBD) is a non-psychotomimetic phytocannabinoid derived from Cannabis sativa.

It has possible therapeutic effects over a broad range of neuropsychiatric disorders.

CBD attenuates brain damage associated with neurodegenerative and/or ischemic conditions.

It also has positive effects on attenuating psychotic-, anxiety- and depressive-like behaviors.

Moreover, CBD affects synaptic plasticity and facilitates neurogenesis.

The mechanisms of these effects are still not entirely clear but seem to involve multiple pharmacological targets.

In the present review, we summarized the main biochemical and molecular mechanisms that have been associated with the therapeutic effects of CBD, focusing on their relevance to brain function, neuroprotection and neuropsychiatric disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/26845349

Prior Cannabis Use Is Associated with Outcome after Intracerebral Hemorrhage.

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“The purpose of this study was to determine the implications of cannabis use in intracerebral hemorrhage (ICH) patients.

CONCLUSION:

In this multinational cohort, cannabis use was discovered in nearly 10% of patients with spontaneous ICH. Although there was no relationship between cannabis use and specific ICH characteristics, CB+ patients had milder ICH presentation and less disability at discharge.”

http://www.ncbi.nlm.nih.gov/pubmed/26820826

Cannabinoid receptors and their role in neuroprotection.

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“Evidence has accumulated over the last few years suggesting that endocannabinoid-based drugs may potentially be useful to reduce the effects of neurodegeneration. In fact, exogenous and endogenous cannabinoids were shown to exert neuroprotection in a variety of in vitro and in vivo models of neuronal injury via different mechanisms,”

http://www.ncbi.nlm.nih.gov/pubmed/16052037

Daily Marijuana Use Is Not Associated with Brain Morphometric Measures in Adolescents or Adults

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“No statistically significant differences were found between daily users and nonusers on volume or shape in the regions of interest.

Effect sizes suggest that the failure to find differences was not due to a lack of statistical power, but rather was due to the lack of even a modest effect.

In sum, the results indicate that, when carefully controlling for alcohol use, gender, age, and other variables, there is no association between marijuana use and standard volumetric or shape measurements of subcortical structures.

The press may not cite studies that do not find sensational effects, but these studies are still extremely important. While the literature clearly supports a deleterious short-term effect of marijuana on learning and memory, it seems unlikely that marijuana use has the same level of long-term deleterious effects on brain morphology as other drugs like alcohol.”

http://www.jneurosci.org/content/35/4/1505.full

Cannabinoids produce neuroprotection by reducing intracellular calcium release from ryanodine-sensitive stores.

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“Exogenously administered cannabinoids are neuroprotective in several different cellular and animal models.

In the current study, two cannabinoid CB1 receptor ligands (WIN 55,212-2, CP 55,940) markedly reduced hippocampal cell death, in a time-dependent manner, in cultured neurons subjected to high levels of NMDA…

The results suggest that cannabinoids prevent cell death by initiating a time and dose dependent inhibition of adenylyl cyclase, that outlasts direct action at the CB1 receptor and is capable of reducing [Ca2+](i) via a cAMP/PKA-dependent process during the neurotoxic event.”

http://www.ncbi.nlm.nih.gov/pubmed/15910885

[Neuroprotective mechanisms of cannabinoids in brain ischemia and neurodegenerative disorders].

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“One of the most important causes of morbidity and mortality is neurologic dysfunction; its high incidence has led to an intense research of the mechanisms that protect the central nervous system from hypoxia and ischemia. The mayor challenge is to block the biochemical events leading to neuronal death.

This may be achieved by neuroprotective mechanisms that avoid the metabolic and immunologic cascades that follow a neurological damage. When it occurs, several pathophysiological events develop including cytokine release, oxidative stress and excitotoxicity.

Neuroprotective effects of cannabinoids to all those mechanisms have been reported in animal models of brain ischemia, excitotoxicity, brain trauma and neurodegenerative disorders.

Some endocannabinoid analogs are being tested in clinical studies (I-III phase) for acute disorders involving neuronal death (brain trauma and ischemia).

The study of the cannabinoid system may allow the discovery of effective neuroprotective drugs for the treatment of neurological disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/26299059

Cannabinoids in Neurodegenerative Disorders and Stroke/Brain Trauma: From Preclinical Models to Clinical Applications.

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“Cannabinoids form a singular family of plant-derived compounds (phytocannabinoids), endogenous signaling lipids (endocannabinoids), and synthetic derivatives with multiple biological effects and therapeutic applications in the central and peripheral nervous systems.

One of these properties is the regulation of neuronal homeostasis and survival, which is the result of the combination of a myriad of effects addressed to preserve, rescue, repair, and/or replace neurons, and also glial cells against multiple insults that may potentially damage these cells.

These effects are facilitated by the location of specific targets for the action of these compounds (e.g., cannabinoid type 1 and 2 receptors, endocannabinoid inactivating enzymes, and nonendocannabinoid targets) in key cellular substrates (e.g., neurons, glial cells, and neural progenitor cells).

This potential is promising for acute and chronic neurodegenerative pathological conditions. In this review, we will collect all experimental evidence, mainly obtained at the preclinical level, supporting that different cannabinoid compounds may be neuroprotective in adult and neonatal ischemia, brain trauma, Alzheimer’s disease, Parkinson’s disease, Huntington’s chorea, and amyotrophic lateral sclerosis.

This increasing experimental evidence demands a prompt clinical validation of cannabinoid-based medicines for the treatment of all these disorders, which, at present, lack efficacious treatments for delaying/arresting disease progression…”

http://www.ncbi.nlm.nih.gov/pubmed/26260390