Tag Archives: Cannabinoids

Cannabinoid Type 2 Receptors Mediate a Cell Type-Specific Plasticity in the Hippocampus

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“Endocannabinoids (eCBs) exert major control over neuronal activity by activating cannabinoid receptors (CBRs).

The functionality of the eCB system is primarily ascribed to the well-documented retrograde activation of presynaptic CB1Rs.

We find that action potential-driven eCB release leads to a long-lasting membrane potential hyperpolarization in hippocampal principal cells that is independent of CB1Rs.

The hyperpolarization, which is specific to CA3 and CA2 pyramidal cells (PCs), depends on the activation of neuronal CB2Rs, as shown by a combined pharmacogenetic and immunohistochemical approach.

Upon activation, they modulate the activity of the sodium-bicarbonate co-transporter, leading to a hyperpolarization of the neuron.

CB2R activation occurred in a purely self-regulatory manner, robustly altered the input/output function of CA3 PCs, and modulated gamma oscillations in vivo.

To conclude, we describe a cell type-specific plasticity mechanism in the hippocampus that provides evidence for the neuronal expression of CB2Rs and emphasizes their importance in basic neuronal transmission.”

http://www.cell.com/neuron/abstract/S0896-6273(16)30025-3

A Multiple-Dose, Randomized, Double-Blind, Placebo-Controlled, Parallel-Group QT/QTc Study to Evaluate the Electrophysiologic Effects of THC/CBD Spray.

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“Delta-9-tetrahydrocannabinol (THC)/cannabidiol (CBD) oromucosal spray has proved efficacious in the treatment of spasticity in multiple sclerosis and chronic pain.

A thorough QT/QTc study was performed to investigate the effects of THC/CBD spray on electrocardiogram (ECG) parameters in compliance with regulatory requirements, evaluating the effect of a recommended daily dose (8 sprays/day) and supratherapeutic doses (24 or 36 sprays/day) of THC/CBD spray on the QT/QTc interval in 258 healthy volunteers.

The safety, tolerability, and pharmacokinetic profile of THC/CBD spray were also evaluated. Therapeutic and supratherapeutic doses of THC/CBD spray had no effect on cardiac repolarization with primary and secondary endpoints of QTcI and QTcF/QTcB, respectively, showing similar results. There was no indication of any effect on heart rate, atrioventricular conduction, or cardiac depolarization and no new clinically relevant morphological changes were observed.

Overall, 19 subjects (25.0%) in the supratherapeutic (24/36 daily sprays of THC/CBD spray) dose group and one (1.6%) in the moxifloxacin group withdrew early due to intolerable AEs. Four psychiatric serious adverse events (AEs) in the highest dose group resulted in a reduction in the surpatherapeutic dose to 24 sprays/day.

In conclusion, THC/CBD spray does not significantly affect ECG parameters. Additionally, THC/CBD spray is well tolerated at therapeutic doses with an AE profile similar to previous clinical studies.”

http://www.ncbi.nlm.nih.gov/pubmed/27121791

Mustard vesicants alter expression of the endocannabinoid system in mouse skin.

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“Vesicants including sulfur mustard (SM) and nitrogen mustard (NM) are bifunctional alkylating agents that cause skin inflammation, edema and blistering. This is associated with alterations in keratinocyte growth and differentiation.

Endogenous cannabinoids, including N-arachidonoylethanolamine (anandamide, AEA) and 2-arachidonoyl glycerol (2-AG), are important in regulating inflammation, keratinocyte proliferation and wound healing.

Their activity is mediated by binding to cannabinoid receptors 1 and 2 (CB1 and CB2), as well as peroxisome proliferator-activated receptor alpha (PPARα). Levels of endocannabinoids are regulated by fatty acid amide hydrolase (FAAH).

We found that CB1, CB2, PPARα and FAAH were all constitutively expressed in mouse epidermis and dermal appendages. Topical administration of NM or SM, at concentrations that induce tissue injury, resulted in upregulation of FAAH, CB1, CB2 and PPARα, a response that persisted throughout the wound healing process.

Inhibitors of FAAH including a novel class of vanillyl alcohol carbamates were found to be highly effective in suppressing vesicant-induced inflammation in mouse skin.

Taken together, these data indicate that the endocannabinoid system is important in regulating skin homeostasis and that inhibitors of FAAH may be useful as medical counter measures against vesicants.”

http://www.ncbi.nlm.nih.gov/pubmed/27125198

Fatty Acid Binding Protein-1 (FABP1) and the Human FABP1 T94A Variant: Roles in the Endocannabinoid System and Dyslipidemias.

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“The first discovered member of the mammalian FABP family, liver fatty acid binding protein (FABP1, L-FABP), occurs at high cytosolic concentration in liver, intestine, and in the case of humans also in kidney.

While the rat FABP1 is well studied, the extent these findings translate to human FABP1 is not clear-especially in view of recent studies showing that endocannabinoids and cannabinoids represent novel rat FABP1 ligands and FABP1 gene ablation impacts the hepatic endocannabinoid system, known to be involved in non-alcoholic fatty liver (NAFLD) development.

Although not detectable in brain, FABP1 ablation nevertheless also impacts brain endocannabinoids. Despite overall tertiary structure similarity, human FABP1 differs significantly from rat FABP1 in secondary structure, much larger ligand binding cavity, and affinities/specificities for some ligands. Moreover, while both mouse and human FABP1 mediate ligand induction of peroxisome proliferator activated receptor-α (PPARα), they differ markedly in pattern of genes induced.

This is critically important because a highly prevalent human single nucleotide polymorphism (SNP) (26-38 % minor allele frequency and 8.3 ± 1.9 % homozygous) results in a FABP1 T94A substitution that further accentuates these species differences. The human FABP1 T94A variant is associated with altered body mass index (BMI), clinical dyslipidemias (elevated plasma triglycerides and LDL cholesterol), atherothrombotic cerebral infarction, and non-alcoholic fatty liver disease (NAFLD).

Resolving human FABP1 and the T94A variant’s impact on the endocannabinoid and cannabinoid system is an exciting challenge due to the importance of this system in hepatic lipid accumulation as well as behavior, pain, inflammation, and satiety.”

http://www.ncbi.nlm.nih.gov/pubmed/27117865

WHERE’s MY ENTOURAGE? THE CURIOUS CASE OF 2-oleoylglycerol, 2-linolenoylglycerol, and 2-palmitoylglycerol.

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“2-arachidonoylglycerol (2-AG) is the most abundant endogenous cannabinoid in the brain and an agonist at two cannabinoid receptors (CB1 and CB2). The synthesis, degradation and signaling of 2-AG have been investigated in detail but its relationship to other endogenous monoacylglycerols has not been fully explored.

Three congeners that have been isolated from the CNS are 2-linoleoylglycerol (2-LG), 2-oleoylglycerol (2-OG), and 2-palmitoylglycerol (2-PG). These lipids do not orthosterically bind to cannabinoid receptors but are reported to potentiate the activity of 2-AG, possibly through inhibition of 2-AG degradation. This phenomenon has been dubbed the ‘entourage effect’ and has been proposed to regulate synaptic activity of 2-AG. To clarify the activity of these congeners of 2-AG we tested them in neuronal and cell-based signaling assays.

The signaling profile for these compounds is inconsistent with an entourage effect. None of the compounds inhibited neurotransmission via CB1 in autaptic neurons. Interestingly, each failed to potentiate 2-AG-mediated depolarization-induced suppression of excitation (DSE), behaving instead as antagonists. Examining other signaling pathways we found that 2-OG interferes with agonist-induced CB1 internalization while 2-PG modestly internalizes CB1 receptors. However in tests of pERK, cAMP and arrestin recruitment, none of the acylglycerols altered CB1 signaling.

Our results suggest 1) that these compounds do not serve as entourage compounds under the conditions examined, and 2) that they may instead serve as functional antagonists. Our results suggest that the relationship between 2-AG and its congeners is more nuanced than previously appreciated.”

http://www.ncbi.nlm.nih.gov/pubmed/27117667

Marijuana is medicine, Journal of the American Medical Association concludes

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“Marijuana is one hundred percent a form of medicine, researchers conclude in a bombshell series of reports released by the Journal of the American Medical Association. Cannabis has been used medicinally for thousands of years” http://blog.sfgate.com/smellthetruth/2015/06/23/marijuana-is-medicine-journal-of-the-american-medical-association-concludes/

http://blog.sfgate.com/smellthetruth/2015/06/23/marijuana-is-medicine-journal-of-the-american-medical-association-concludes/

“Cannabinoids for Medical Use. A Systematic Review and Meta-analysis.”  http://jama.jamanetwork.com/article.aspx?articleid=2338251

The Endocannabinoid System: An Osteopathic Perspective

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“A person is the product of dynamic interaction between body, mind, and spirit—This holistic principle is exemplified by cannabinoid receptors, which span the field of psychoneuroimmunology. Taken together, CB1, CB2, and their endocannabinoid ligands represent a microcosm of mind-body medicine. The primary purpose of the current article is to review the expanding endocannabinoid literature beginning with exogenous compounds—Cannabis and plant cannabinoids—and then shift to the endogenous system, highlighting embryology and development, neuroprotection, autonomics and immunity, inflammation, apoptosis, hunger and feeding, and nociception and pain.” http://jaoa.org/article.aspx?articleid=2093607

Modulation of cellular redox homeostasis by the endocannabinoid system

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“The endocannabinoid system (ECS) and reactive oxygen species (ROS) constitute two key cellular signalling systems that participate in the modulation of diverse cellular functions.

Importantly, growing evidence suggests that cross-talk between these two prominent signalling systems acts to modulate functionality of the ECS as well as redox homeostasis in different cell types…

To conclude, there is growing appreciation that the ECS may play an important role in the regulation of cellular redox homeostasis…

Indeed, the studies highlighted in this review show that ECS function can impact upon free radical production in a number of different ways.

Crucially, given the importance of redox status in the development of numerous pathologies, these findings identify ECS components as potential therapeutic targets for the treatment of oxidative stress-related neurological, cardiovascular and metabolic disorders.”

http://rsob.royalsocietypublishing.org/content/6/4/150276

Natural Phytochemicals in the Treatment and Prevention of Dementia: An Overview.

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“The word dementia describes a class of heterogeneous diseases which etiopathogenetic mechanisms are not well understood. There are different types of dementia, among which, Alzheimer’s disease (AD), vascular dementia (VaD), dementia with Lewy bodies (DLB) and frontotemporal dementia (FTD) are the more common.

Currently approved pharmacological treatments for most forms of dementia seem to act only on symptoms without having profound disease-modifying effects. Thus, alternative strategies capable of preventing the progressive loss of specific neuronal populations are urgently required.

In particular, the attention of researchers has been focused on phytochemical compounds that have shown antioxidative, anti-amyloidogenic, anti-inflammatory and anti-apoptotic properties and that could represent important resources in the discovery of drug candidates against dementia.

In this review, we summarize the neuroprotective effects of the main phytochemicals belonging to the polyphenol, isothiocyanate, alkaloid and cannabinoid families in the prevention and treatment of the most common kinds of dementia.

We believe that natural phytochemicals may represent a promising sources of alternative medicine, at least in association with therapies approved to date for dementia.”

http://www.ncbi.nlm.nih.gov/pubmed/27110749

Advances towards the Discovery of GPR55 Ligands.

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“The G-protein-coupled receptor 55 (GPR55) was identified in 1999.

It was proposed as a novel member of the endocannabinoid system due to the fact that some endogenous, plant-derived and synthetic cannabinoid ligands act on GPR55. However, the complexity of the cellular downstream signaling pathways related to GPR55 activation delayed the discovery of selective GPR55 ligands.

It was only a few years ago that the high throughput screening of libraries of pharmaceutical companies and governmental organizations allowed to identify selective GPR55 agonists and antagonists. Since then, several GPR55 modulator scaffolds have been reported.

The relevance of GPR55 has been explored in diverse physiological and pathological processes revealing its role in inflammation, neuropathic pain, bone physiology, diabetes and cancer.

Considering GPR55 as a new promising therapeutic target, there is a clear need for new selective and potent GPR55 modulators. This review will address a current structural update of GPR55 ligands.”

http://www.ncbi.nlm.nih.gov/pubmed/27109575