Category Archives: Cerebral Ischemia

Delayed treatment with cannabidiol has a cerebroprotective action via a cannabinoid receptor-independent myeloperoxidase-inhibiting mechanism.

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“We examined the neuroprotective mechanism of cannabidiol, non-psychoactive component of marijuana, on the infarction in a 4 h mouse middle cerebral artery (MCA) occlusion model in comparison with Delta(9)-tetrahydrocannabinol (Delta(9)-THC).

Both pre- and post-ischemic treatment with cannabidiol resulted in potent and long-lasting neuroprotection, whereas only pre-ischemic treatment with Delta(9)-THC reduced the infarction.

Unlike Delta(9)-THC, cannabidiol did not affect the excess release of glutamate in the cortex after occlusion.

Cannabidiol suppressed the decrease in cerebral blood flow by the failure of cerebral microcirculation after reperfusion and inhibited MPO activity in neutrophils.

Furthermore, the number of MPO-immunopositive cells was reduced in the ipsilateral hemisphere in cannabidiol-treated group.

Cannabidiol provides potent and long-lasting neuroprotection through an anti-inflammatory CB(1) receptor-independent mechanism, suggesting that cannabidiol will have a palliative action and open new therapeutic possibilities for treating cerebrovascular disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/17437545

Cannabidiol prevents a post-ischemic injury progressively induced by cerebral ischemia via a high-mobility group box1-inhibiting mechanism.

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“We examined the cerebroprotective mechanism of cannabidiol, the non-psychoactive component of marijuana, against infarction in a 4-h mouse middle cerebral artery (MCA) occlusion model.

Cannabidiol was intraperitoneally administrated immediately before and 3h after cerebral ischemia.

Cannabidiol significantly prevented infarction and MPO activity at 20h after reperfusion.

Cannabidiol inhibited the MPO-positive cells expressing HMGB1 and also decreased the expression level of HMGB1 in plasma.

In addition, cannabidiol decreased the number of Iba1- and GFAP-positive cells at 3 days after cerebral ischemia.

Moreover, cannabidiol improved neurological score and motor coordination on the rota-rod test.

Our results suggest that cannabidiol inhibits monocyte/macropharge expressing HMGB1 followed by preventing glial activation and neurological impairment induced by cerebral ischemia.

Cannabidiol will open new therapeutic possibilities for post-ischemic injury via HMGB1-inhibiting mechanism.”

http://www.ncbi.nlm.nih.gov/pubmed/18634812

The CB1 Antagonist, SR141716A, Is Protective in Permanent Photothrombotic Cerebral Ischemia.

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“Modulation of the endocannabinoid system has been shown to have a significant impact on outcomes in animal models of stroke.

We have previously reported a protective effect of the CB1 antagonist, SR141716A, in a transient reperfusion mouse model of cerebral ischemia. This protective effect was in part mediated by activation of the 5HT1A receptor.

Here we have examined its effect in a mouse model of permanent ischemia induced by photoinjury.

The CB1 antagonist was found to be protective in this model.

As was the case following transient ischemia reperfusion, SR141716A (5mg/kg) resulted in smaller infarct fractions and stroke volumes when utilized both as a pretreatment and as a post-treatment. In contrast to the effect in a transient ischemia model, the pretreatment effect did not depend on the 5HT1A receptor.

Neurological function correlated favorably to the reduction in stroke size when SR141716A was given as a pretreatment.

With the incidence of stroke predicted to rise in parallel with an ever aging population, understanding mechanisms underlying ischemia and therapeutics remains a paramount goal of research.”

http://www.ncbi.nlm.nih.gov/pubmed/27453059

Stimulated CB1 Cannabinoid Receptor Inducing Ischemic Tolerance and Protecting Neuron from Cerebral Ischemia.

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“Anandamide system is mainly made up of cannabinoid receptors, their endogenous ligands and some related enzymes. Activation of the system mediates various molecular events, thereafter leading to vasodilation, bradycardia and anti-inflammation.

The stimulated cannabinoid receptors may take part in protection of endothelial cells from injury and therefore can be potential targets in therapy for some diseases, especially cardio or cerebral vascular disturbances.

Cerebral ischemia is a deadly disease that modern people have to face and will probably face for a long period of time. Ischemic tolerance has the protective effect of brain as an endogenous event in cerebral ischemia, in which variety of inducers such as transient cerebral ischemia, hypoxia, hypothermia and drug agents are involved.

Most of cannabinoid 1 receptors (CB1Rs), a member in G protein-coupled receptor family, exist in central nervous systems.

Mechanism of neuroprotection mediated by the receptor is considered through facilitating neurotransmitter release and regulating other molecular events. In this review, advance of the neuroprotection against cerebral ischemia and the mechanism of the action are overviewed.”

http://www.ncbi.nlm.nih.gov/pubmed/27142423

“Cerebral ischemia or brain ischemia, is a condition that occurs when there isn’t enough blood flow to the brain to meet metabolic demand. This leads to limited oxygen supply or cerebral hypoxia and leads to the death of brain tissue, cerebral infarction, or ischemic stroke. It is a sub-type of stroke along with subarachnoid hemorrhage and intracerebral hemorrhage. There are two kinds of ischemia: focal ischemia: confined to a specific region of the brain; global ischemia: encompasses wide areas of brain tissue.”  http://www.columbianeurosurgery.org/conditions/cerebral-ischemia/

ENDOCANNABINOID SYSTEM: A multi-facet therapeutic target.

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Image result for Curr Clin Pharmacol.

“Cannabis sativa is also popularly known as marijuana. It is being cultivated and used by man for recreational and medicinal purposes from many centuries.

Study of cannabinoids was at bay for very long time and its therapeutic value could not be adequately harnessed due to its legal status as proscribed drug in most of the countries.

The research of drugs acting on endocannabinoid system has seen many ups and down in recent past. Presently, it is known that endocannabinoids has role in pathology of many disorders and they also serve “protective role” in many medical conditions.

Several diseases like emesis, pain, inflammation, multiple sclerosis, anorexia, epilepsy, glaucoma, schizophrenia, cardiovascular disorders, cancer, obesity, metabolic syndrome related diseases, Parkinson’s disease, Huntington’s disease, Alzheimer’s disease and Tourette’s syndrome could possibly be treated by drugs modulating endocannabinoid system.

Presently, cannabinoid receptor agonists like nabilone and dronabinol are used for reducing the chemotherapy induced vomiting. Sativex (cannabidiol and THC combination) is approved in the UK, Spain and New Zealand to treat spasticity due to multiple sclerosis. In US it is under investigation for cancer pain, another drug Epidiolex (cannabidiol) is also under investigation in US for childhood seizures. Rimonabant, CB1 receptor antagonist appeared as a promising anti-obesity drug during clinical trials but it also exhibited remarkable psychiatric side effect profile. Due to which the US Food and Drug Administration did not approve Rimonabant in US. It sale was also suspended across the EU in 2008.

Recent discontinuation of clinical trial related to FAAH inhibitor due to occurrence of serious adverse events in the participating subjects could be discouraging for the research fraternity. Despite of some mishaps in clinical trials related to drugs acting on endocannabinoid system, still lot of research is being carried out to explore and establish the therapeutic targets for both cannabinoid receptor agonists and antagonists.

One challenge is to develop drugs that target only cannabinoid receptors in a particular tissue and another is to invent drugs that acts selectively on cannabinoid receptors located outside the blood brain barrier. Besides this, development of the suitable dosage forms with maximum efficacy and minimum adverse effects is also warranted.

Another angle to be introspected for therapeutic abilities of this group of drugs is non-CB1 and non-CB2 receptor targets for cannabinoids.

In order to successfully exploit the therapeutic potential of endocannabinoid system, it is imperative to further characterize the endocannabinoid system in terms of identification of the exact cellular location of cannabinoid receptors and their role as “protective” and “disease inducing substance”, time-dependent changes in the expression of cannabinoid receptors.”

http://www.ncbi.nlm.nih.gov/pubmed/27086601

The multiplicity of action of cannabinoids: implications for treating neurodegeneration.

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“The cannabinoid (CB) system is widespread in the central nervous system and is crucial for controlling a range of neurophysiological processes such as pain, appetite, and cognition. The endogenous CB molecules, anandamide, and 2-arachidonoyl glycerol, interact with the G-protein coupled CB receptors, CB(1) and CB(2).

These receptors are also targets for the phytocannabinoids isolated from the cannabis plant and synthetic CB receptor ligands.

The CB system is emerging as a key regulator of neuronal cell fate and is capable of conferring neuroprotection by the direct engagement of prosurvival pathways and the control of neurogenesis.

Many neurological conditions feature a neurodegenerative component that is associated with excitotoxicity, oxidative stress, and neuroinflammation, and certain CB molecules have been demonstrated to inhibit these events to halt the progression of neurodegeneration.

Such properties are attractive in the development of new strategies to treat neurodegenerative conditions of diverse etiology, such as Alzheimer’s disease, multiple sclerosis, and cerebral ischemia.

This article will discuss the experimental and clinical evidence supporting a potential role for CB-based therapies in the treatment of certain neurological diseases that feature a neurodegenerative component.”

http://www.ncbi.nlm.nih.gov/pubmed/20875047

[Protective effect of paeoniflorin on the hippocampus in rats with cerebral ischemia-reperfusion through activating cannabinoid receptor 2].

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Objective:

To investigate the protective effect of paeoniflorin on hippocampal neurons in rats subjected to cerebral ischemia and reperfusion through activating cannabinoid receptor 2 (CBR2).

Conclusion:

CBR2 may participate in the protective effect of paeoniflorin on hippocampal neurons of cerebral ischemia-reperfusion rat models.”

http://www.ncbi.nlm.nih.gov/pubmed/25854559

http://www.ncbi.nlm.nih.gov/pubmed/?term=Paeoniflorin

http://www.ncbi.nlm.nih.gov/pubmed/?term=Paeonia+lactiflora

http://en.wikipedia.org/wiki/Paeonia_lactiflora

 

 

Therapeutic potential of cannabinoid medicines.

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Drug Testing and Analysis

“Cannabis was extensively used as a medicine throughout the developed world in the nineteenth century but went into decline early in the twentieth century ahead of its emergence as the most widely used illicit recreational drug later that century. Recent advances in cannabinoid pharmacology alongside the discovery of the endocannabinoid system (ECS) have re-ignited interest in cannabis-based medicines.

The ECS has emerged as an important physiological system and plausible target for new medicines. Its receptors and endogenous ligands play a vital modulatory role in diverse functions including immune response, food intake, cognition, emotion, perception, behavioural reinforcement, motor co-ordination, body temperature, wake/sleep cycle, bone formation and resorption, and various aspects of hormonal control. In disease it may act as part of the physiological response or as a component of the underlying pathology.

In the forefront of clinical research are the cannabinoids delta-9-tetrahydrocannabinol and cannabidiol, and their contrasting pharmacology will be briefly outlined. The therapeutic potential and possible risks of drugs that inhibit the ECS will also be considered. This paper will then go on to review clinical research exploring the potential of cannabinoid medicines in the following indications: symptomatic relief in multiple sclerosis, chronic neuropathic pain, intractable nausea and vomiting, loss of appetite and weight in the context of cancer or AIDS, psychosis, epilepsy, addiction, and metabolic disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/24006213

http://onlinelibrary.wiley.com/doi/10.1002/dta.1529/abstract

Activation of Cortical Type 2 Cannabinoid Receptors Ameliorates Ischemic Brain Injury, Study Suggests

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“A new study published in the March issue of The American Journal of Pathology suggests that cortical type 2 cannabinoid (CB2) receptors might serve as potential therapeutic targets for cerebral ischemia.

Researchers found that the cannabinoid trans-caryophyllene (TC) protected brain cells from the effects of ischemia in both in vivo and in vitro animal models. In rats, post-ischemic treatment with TC decreased cerebral infarct size and edema. In cell cultures composed of rat cortical neurons and glia exposed to oxygen-glucose deprivation and reoxygenation (OGD/R), TC decreased neuronal injury and mitochondrial depolarization, specifically through type 2 cannabinoid receptor (CB2R) pathways.

“To our knowledge, novel data presented in this study provide evidence for the first time supporting a previously unappreciated role of cortical CB2R, especially neuronal CB2Rs, in ischemia,” says lead investigator Won-Ki Kim, PhD, of the Department of Neuroscience, College of Medicine, Korea University in Seoul. “This study suggests that further investigation is warranted to establish the clinical usefulness of TC as a preventative and therapeutic agent for treatment of stroke.””

More: http://www.sciencedaily.com/releases/2013/02/130221141140.htm

The endocannabinoid system and its therapeutic exploitation.

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Image result for Nat Rev Drug Discov.

“The term ‘endocannabinoid’ – originally coined in the mid-1990s after the discovery of membrane receptors for the psychoactive principle in Cannabis, Delta9-tetrahydrocannabinol and their endogenous ligands – now indicates a whole signalling system that comprises cannabinoid receptors, endogenous ligands and enzymes for ligand biosynthesis and inactivation. This system seems to be involved in an ever-increasing number of pathological conditions. With novel products already being aimed at the pharmaceutical market little more than a decade since the discovery of cannabinoid receptors, the endocannabinoid system seems to hold even more promise for the future development of therapeutic drugs. We explore the conditions under which the potential of targeting the endocannabinoid system might be realized in the years to come.”  http://www.ncbi.nlm.nih.gov/pubmed/15340387

http://www.nature.com/nrd/journal/v3/n9/full/nrd1495.html