Category Archives: Brain Trauma

Using the endocannabinoid system as a neuroprotective strategy in perinatal hypoxic-ischemic brain injury.

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“One of the most important causes of brain injury in the neonatal period is a perinatal hypoxic-ischemic event. This devastating condition can lead to long-term neurological deficits or even death. After hypoxic-ischemic brain injury, a variety of specific cellular mechanisms are set in motion, triggering cell damage and finally producing cell death.

Effective therapeutic treatments against this phenomenon are still unavailable because of complex molecular mechanisms underlying hypoxic-ischemic brain injury. After a thorough understanding of the mechanism underlying neural plasticity following hypoxic-ischemic brain injury, various neuroprotective therapies have been developed for alleviating brain injury and improving long-term outcomes.

Among them, the endocannabinoid system emerges as a natural system of neuroprotection.

The endocannabinoid system modulates a wide range of physiological processes in mammals and has demonstrated neuroprotective effects in different paradigms of acute brain injury, acting as a natural neuroprotectant.

The aim of this review is to study the use of different therapies to induce long-term therapeutic effects after hypoxic-ischemic brain injury, and analyze the important role of the endocannabinoid system as a new neuroprotective strategy against perinatal hypoxic-ischemic brain injury.”

http://www.ncbi.nlm.nih.gov/pubmed/25206720

Mechanisms of control of neuron survival by the endocannabinoid system.

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“Endocannabinoids act as retrograde messengers that, by inhibiting neurotransmitter release via presynaptic CB(1) cannabinoid receptors, regulate the functionality of many synapses. In addition, the endocannabinoid system participates in the control of neuron survival.

Thus, CB(1) receptor activation has been shown to protect neurons from acute brain injury as well as in neuroinflammatory conditions and neurodegenerative diseases.

Cannabinoid neuroprotective activity relies on the inhibition of glutamatergic neurotransmission and on other various mechanisms, and is supported by the observation that the brain overproduces endocannabinoids upon damage.

Besides promoting neuroprotection, a role for the endocannabinoid system in the control of neurogenesis from neural progenitors has been put forward. In addition, activation of CB(2) cannabinoid receptors on glial cells may also participate in neuroprotection by limiting the extent of neuroinflammation.

Altogether, these findings support that endocannabinoids constitute a new family of lipid mediators that act as instructive signals in the control of neuron survival.”

http://www.ncbi.nlm.nih.gov/pubmed/18781978

Defective Adult Neurogenesis in CB1 Cannabinoid Receptor Knockout Mice

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Fig. 1.

“…endogenous cannabinoid signaling mechanisms may represent a key component of cell-survival programs mobilized in the injured brain.

In addition to their neuroprotective effects, cannabinergic systems may also have an important role in brain development…

…expression of endocannabinoids and cannabinoid receptors in brain…

Neurogenesis, or the birth of new neurons, continues to occur beyond development and into adulthood, and several lines of evidence suggest that cannabinoid signaling may be involved in this process as well…

In addition to the well known effects of growth factors, a variety of drugs has been shown to influence adult neurogenesis. These include excitatory amino acid receptor antagonists, antidepressants, lithium, nitric oxide donors, phosphodiesterase inhibitors, and statins.

Together with the finding that neurogenesis can be regulated by cannabinoids, these observations imply that a broad range of pharmacological approaches may exist through which to modify neurogenesis for therapeutic purposes.”

http://molpharm.aspetjournals.org/content/66/2/204.full

Marijuana May Grow Neurons in the Brain

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Medpage Today

“Advocates for medical marijuana can take heart over the findings of two Canadian research teams.

A synthetic cannabinoid — similar to the compounds found in marijuana, but substantially stronger — causes the growth of new neurons and reduces anxiety and depression, investigators at the University of Saskatchewan here reported.

And researchers at the University of Calgary said they’ve found evidence that the brain contains so-called CB2 cannabinoid receptors, previously seen in immune tissue but thought not to exist in brain tissue. The discovery, they added, could lead to new drugs to treat nausea associated with cancer or AIDS.

Most so-called drugs of abuse — such as alcohol or cocaine — inhibit the growth of new neurons, according to Xia Zhang, M.D., Ph.D., of the University of Saskatchewan.

“Only marijuana promotes neurogenesis,” Dr. Zhang said.”

http://www.medpagetoday.com/Psychiatry/AnxietyStress/1934

“Cannabinoids promote embryonic and adult hippocampus neurogenesis and produce anxiolytic- and antidepressant-like effects… In summary, since adult hippocampal neurogenesis is suppressed following chronic administration of opiates, alcohol, nicotine, and cocaine, the present study suggests that cannabinoids are the only illicit drug that can promote adult hippocampal neurogenesis following chronic administration.”  http://www.jci.org/articles/view/25509

University Of Saskatchewan Research Suggests Marijuana Analogue Stimulates Brain Cell Growth

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ScienceDaily: Your source for the latest research news

“A synthetic substance similar to ones found in marijuana stimulates cell growth in regions of the brain associated with anxiety and depression, pointing the way for new treatments for these diseases, according to University of Saskatchewan medical research published today in The Journal of Clinical Investigation.

Xia Zhang, an associate professor in the U of S neuropsychiatry research unit, led the team that tested the effects of HU-210, a potent synthetic cannabinoid similar to a group of compounds found in marijuana. The synthetic version is about 100 times as powerful as THC, the compound responsible for the high experienced by recreational users.

The team found that rats treated with HU-210 on a regular basis showed neurogenesis – the growth of new brain cells in the hippocampus. This region of the brain is associated with learning and memory, as well as anxiety and depression.

The effect is the opposite of most legal and illicit drugs such as alcohol, nicotine, heroin, and cocaine.

“Most ‘drugs of abuse’ suppress neurogenesis,” Zhang says. “Only marijuana promotes neurogenesis.””

http://www.sciencedaily.com/releases/2005/10/051016083817.htm

“Cannabinoids promote embryonic and adult hippocampus neurogenesis and produce anxiolytic- and antidepressant-like effects… In summary, since adult hippocampal neurogenesis is suppressed following chronic administration of opiates, alcohol, nicotine, and cocaine, the present study suggests that cannabinoids are the only illicit drug that can promote adult hippocampal neurogenesis following chronic administration.”  http://www.jci.org/articles/view/25509

Cannabinoid as a neuroprotective strategy in perinatal hypoxic-ischemic injury.

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“Perinatal hypoxia-ischemia remains the single most important cause of brain injury in the newborn, leading to death or lifelong sequelae.

Because of the fact that there is still no specific treatment for perinatal brain lesions due to the complexity of neonatal hypoxic-ischemic pathophysiology, the search of new neuroprotective therapies is of great interest.

In this regard, therapeutic possibilities of the endocannabinoid system have grown lately.

The endocannabinoid system modulates a wide range of physiological processes in mammals and has demonstrated neuroprotective effects in different paradigms of acute brain injury, acting as a natural neuroprotectant.

Concerning perinatal asphyxia, the neuroprotective role of this endogenous system is emerging these years.

The present review mainly focused on the current knowledge of the cannabinoids as a new neuroprotective strategy against perinatal hypoxic-ischemic brain injury.

http://www.ncbi.nlm.nih.gov/pubmed/21788999

[The cannabinoid system and its importance in the perinatal period].

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“The cannabinoid system has been recently described, including the endogenous ligands, mainly arachidonic acid derivatives, and their specific receptors. Endocannabinoids are involved in the modulation of synaptic transmission, through which they exert their psychoactive, motor and antinociceptive effects, among others; they also exert extraneural effects, mainly immunomodulation and vasodilation.

Recent data suggest that the cannabinoid system might play an important role in human ontogeny and could participate in the implantation and early development of the embryo, in fetal brain development, and in the beginning of breast feeding after birth.

In addition, the vasodilatory effect of cannabinoids, together with inhibition of the release of excitotoxic amino acids and cytokines, as well as modulation of oxidative stress and the toxic production of nitric oxide, justify the growing evidence pointing to a possible neuroprotective effect of cannabinoids in perinatal asphyxia.”

http://www.ncbi.nlm.nih.gov/pubmed/16266619

Cannabinoids: well-suited candidates for the treatment of perinatal brain injury.

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“Perinatal brain injury can be induced by a number of different damaging events occurring during or shortly after birth… the number of clinical interventions available for the treatment of the affected newborn babies is extremely limited. Hence, there is a dramatic need to develop new effective therapies aimed to prevent acute brain damage and enhance the endogenous mechanisms of long-term brain repair.

The endocannabinoid system is an endogenous neuromodulatory system involved in the control of multiple central and peripheral functions. An early responder to neuronal injury, the endocannabinoid system has been described as an endogenous neuroprotective system that once activated can prevent glutamate excitotoxicity, intracellular calcium accumulation, activation of cell death pathways, microglia activation, neurovascular reactivity and infiltration of circulating leukocytes across the blood-brain barrier.

The modulation of the endocannabinoid system has proven to be an effective neuroprotective strategy to prevent and reduce neonatal brain injury in different animal models and species.

Also, the beneficial role of the endocannabinoid system on the control of the endogenous repairing responses (neurogenesis and white matter restoration) to neonatal brain injury has been described in independent studies.”

http://www.ncbi.nlm.nih.gov/pubmed/24961520

Marijuana & Stroke: Pot Compounds Protect Brain, New Meta-Study Shows

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“Cannabinoids, chemicals related to those found in cannabis could be effective in restoring neurological function by shrinking the area of the brain affected by stroke, according to a new study led by Dr. Tim England, Honorary Consultant Stroke Physician at the University of Nottingham and Royal Derby Hospital.

Stroke, a leading cause of adult disability in the UK leaves over half of all survivors dependent on others for life. Over one million people are living with the effects of stroke and it is reported that in the UK alone, over 150,000 people have a stroke every year. Finding new treatments to help survivors recover quickly has never been more important.

The authors examined 94 studies evaluating the effects of cannabinoids on 1022 mice, monkeys, and male rats. Cannabinoids can be classified into endocannabinoids that occur naturally in the body, phytocannabinoids that are obtained from plant extracts, and synthetic cannabinoids.

A meta-analysis of experimental studies conducted by the researchers at the University of Nottingham identifies the potential of all three categories of these compounds potential to reduce brain damage caused by stroke and help improve brain function after an attack.

The U.S. government sought a patent in 2001 for the naturally occuring marijuana molecule, cannabidiol, for use as a brain protector during stroke. ”

http://blog.sfgate.com/smellthetruth/2013/12/11/marijuana-stroke-pot-compounds-protect-brain-new-meta-study-shows/

The Cannabinoid WIN55212-2 Promotes Neural Repair After Neonatal Hypoxia–Ischemia

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Figure 1.

“In the last years, cannabinoids have emerged as promising neuroprotective agents in several animal paradigms of acute and degenerative brain damage. Most neuroprotective effects of cannabinoids result from the activation of cannabinoid Type 1 (CB1R) and Type 2 (CB2R) receptors in neural and immune cells.

Besides, the stimulating effect of cannabinoids on proliferation, survival, and differentiation of neural progenitor cells provides interesting prospects for long-term neural repair after acute brain damage.

The endocannabinoid system has been involved in the modulation of neural stem cells proliferation, survival and differentiation as well as in the generation of new oligodendrocyte progenitors in the postnatal brain. The present work aims to test the effect of the synthetic Type 1 and Type 2 cannabinoid receptor agonist WIN55212-2 on these processes in the context of neonatal rat brain hypoxia–ischemia (HI)…

Our results suggest that the activation of the endocannabinoid system promotes white and gray matter recovery after neonatal HI injury…

In conclusion, we have demonstrated that the synthetic cannabinoid WIN55212-2 enhances SVZ cell proliferation, oligodendrogenesis, white matter remyelination, and neuroblast generation after neonatal HI.

These findings, summed to the previously described neuroprotective properties of cannabinoids after acute brain damage, may possess therapeutic repercussions in the long-term management of neonatal HI encephalopathy, a prevalent and devastating condition for which no pharmacological treatments are yet available.”

http://stroke.ahajournals.org/content/41/12/2956.full