Monthly Archives: November 2016

Cannabinoid receptor ligand bias: implications in the central nervous system.

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“The G protein-coupled cannabinoid receptors CB1, CB2, GPR18, and GPR55 regulate neurotransmission, pain, and inflammation and have been intensively investigated as potential drug targets. Each of these GPCRs is coupled to multiple effector proteins mediating divergent cellular signals. The ligand bias of cannabinoid-targeted compounds is only beginning to be quantified. Research into cannabinoid bias is now revealing correlations between bias in cell culture and functional outcomes in vivo. We present an example study of cannabinoid bias in the context of Huntington disease. In future, an understanding of cannabinoid receptor structure and quantification of ligand bias will optimize drug selection matched to patient population and disease.”

https://www.ncbi.nlm.nih.gov/pubmed/27835801

PTSD: from neurobiology to pharmacological treatments.

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“Posttraumatic stress disorder (PTSD) is a chronic debilitating psychiatric disorder characterized by symptoms of re-experience, avoidance, and hyperarousal that can arise immediately or many years after exposure to a traumatic event and injury. Although extensive research has been done over the past 30 years, the etiology of PTSD remains largely unknown. Several neurobiological systems have been implicated in the pathophysiology and vulnerability for developing PTSD; however, first-line pharmacotherapies are limited. Less than 30% achieve full remission, and even then, approved pharmacological treatments often take weeks for therapeutic effect. This article aims to review the pathophysiology of PTSD within multiple neurobiological systems and how these mechanisms are used as pharmacologic targets of treatment, as well as their potential for future targets of intervention.”

 https://www.ncbi.nlm.nih.gov/pubmed/27837583

Novel indole-based compounds that differentiate alkylindole-sensitive receptors from cannabinoid receptors and microtubules: Characterization of their activity on glioma cell migration.

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“Indole-based compounds, such as the alkyl-indole (AI) compound WIN55212-2, activate the cannabinoid receptors, CB1 and CB2, two well-characterized G protein-coupled receptors (GPCR). Reports indicate that several indole-based cannabinoid agonists, including WIN55212-2, lack selectivity and interact with at least two additional targets: AI-sensitive GPCRs and microtubules. Studying how indole-based compounds modulate the activity of these 4 targets has been difficult as selective chemical tools were not available. Here we report the pharmacological characterization of six newly-developed indole-based compounds (ST-11, ST-23, ST-25, ST-29, ST-47 and ST-48) that exhibit distinct binding affinities at AI-sensitive receptors, cannabinoid CB1 and CB2 receptors and the colchicine site of tubulin. Several compounds exhibit some level of selectivity for AI-sensitive receptors, including ST-11 that binds AI-sensitive receptors with a Kd of 52nM and appears to have a weaker affinity for the colchicine site of tubulin (Kd=3.2μM) and does not bind CB1/CB2 receptors. Leveraging these characteristics, we show that activation of AI-sensitive receptors with ST-11 inhibits both the basal and stimulated migration of the Delayed Brain Tumor (DBT) mouse glioma cell line. Our study describes a new series of indole-based compounds that enable the pharmacological and functional differentiation of alkylindole-sensitive receptors from cannabinoidreceptors and microtubules.”

https://www.ncbi.nlm.nih.gov/pubmed/27832960

A cannabinoid link between mitochondria and memory.

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“Cellular activity in the brain depends on the high energetic support provided by mitochondria, the cell organelles which use energy sources to generate ATP. Acute cannabinoid intoxication induces amnesia in humans and animals, and the activation of type-1cannabinoid receptors present at brain mitochondria membranes (mtCB1) can directly alter mitochondrial energetic activity. Although the pathological impact of chronic mitochondrial dysfunctions in the brain is well established, the involvement of acute modulation of mitochondrial activity in high brain functions, including learning and memory, is unknown. Here, we show that acute cannabinoid-induced memory impairment in mice requires activation of hippocampal mtCB1 receptors. Genetic exclusion of CB1 receptors from hippocampal mitochondria prevents cannabinoid-induced reduction of mitochondrial mobility, synaptic transmission and memory formation. mtCB1 receptors signal through intra-mitochondrial Gαi protein activation and consequent inhibition of soluble-adenylyl cyclase (sAC). The resulting inhibition of protein kinase A (PKA)-dependent phosphorylation of specific subunits of the mitochondrial electron transport system eventually leads to decreased cellular respiration. Hippocampal inhibition of sAC activity or manipulation of intra-mitochondrial PKA signalling or phosphorylation of the Complex I subunit NDUFS2 inhibit bioenergetic and amnesic effects ofcannabinoids. Thus, the G protein-coupled mtCB1 receptors regulate memory processes via modulation of mitochondrial energy metabolism. By directly linking mitochondrial activity to memory formation, these data reveal that bioenergetic processes are primary acute regulators of cognitive functions.”

https://www.ncbi.nlm.nih.gov/pubmed/27828947

Cannabinoid CB1 Receptors Are Localized in Striated Muscle Mitochondria and Regulate Mitochondrial Respiration.

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“The cannabinoid type 1 (CB1) receptor is widely distributed in the brain and peripheral organs where it regulates cellular functions and metabolism. In the brain, CB1 is mainly localized on presynaptic axon terminals but is also found on mitochondria (mtCB1), where it regulates cellular respiration and energy production. Likewise, CB1 is localized on muscle mitochondria, but very little is known about it. The aim of this study was to further investigate in detail the distribution and functional role of mtCB1 in three different striated muscles.

Immunoelectron microscopy for CB1 was used in skeletal muscles (gastrocnemius and rectus abdominis) and myocardium from wild-type and CB1 -KO mice. Functional assessments were performed in mitochondria purified from the heart of the mice and the mitochondrial oxygen consumption upon application of different acute delta-9-tetrahydrocannabinol (Δ9-THC) concentrations (100 nM or 200 nM) was monitored. About 26% of the mitochondrial profiles in gastrocnemius, 22% in the rectus abdominis and 17% in the myocardium expressed CB1. Furthermore, the proportion of mtCB1 versus total CB1 immunoparticles was about 60% in the gastrocnemius, 55% in the rectus abdominis and 78% in the myocardium. Importantly, the CB1 immunolabeling pattern disappeared in muscles of CB1 -KO mice.

Functionally, acute 100 nM or 200 nM THC treatment specifically decreased mitochondria coupled respiration between 12 and 15% in wild-type isolated mitochondria of myocardial muscles but no significant difference was noticed between THC treated and vehicle in mitochondria isolated from CB1 -KO heart. Furthermore, gene expression of key enzymes involved in pyruvate synthesis, tricarboxylic acid (TCA) cycle and mitochondrial respiratory chain was evaluated in the striated muscle of CB1 -WT and CB1 -KO. CB1 -KO showed an increase in the gene expression of Eno3, Pkm2, and Pdha1, suggesting an increased production of pyruvate. In contrast, no significant difference was observed in the Sdha and Cox4i1 expression, between CB1 -WT andCB1 -KO.

In conclusion, CB1 receptors in skeletal and myocardial muscles are predominantly localized in mitochondria. The activation of mtCB1 receptors may participate in the mitochondrial regulation of the oxidative activity probably through the relevant enzymes implicated in the pyruvate metabolism, a main substrate for TCA activity.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5078489/

Tetrahydrocannabinol:Cannabidiol Oromucosal Spray for Multiple Sclerosis-Related Resistant Spasticity in Daily Practice.

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“Tetrahydrocannabinol:cannabidiol (THC:CBD) oromucosal spray (Sativex®) is an add-on therapy for moderate-to-severe multiple sclerosis (MS)-related drug-resistant spasticity (MSS).

In everyday clinical practice, THC:CBD oromucosal spray provided symptomatic relief of MSS and related troublesome symptoms.”

https://www.ncbi.nlm.nih.gov/pubmed/27732980

Cannabinoid Buccal Spray for Chronic Non-Cancer or Neuropathic Pain: A Review of Clinical Effectiveness, Safety, and Guidelines [Internet].

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“Chronic pain is a complex, severe and debilitating condition which can lead to a considerable reduction in function and quality of life. Patients may present with different forms of chronic pain resulting from a number of identifiable causes, including pain due to lesion or dysfunction of the nerves, spinal cord or brain (neuropathic pain), or persistent pain caused by other non-malignant conditions, such as low-back pain or pain due to inflammation of various arthritic conditions. The prevalence of chronic non-cancer pain or neuropathic pain among Canadian adults is not well known. However, prevalence estimates using large, population-based questionnaires have shown that 4% to 8% of the general population in the developed world experiences neuropathic pain, suggesting that approximately two million Canadians may be affected by this disabling condition. Chronic pain is of particular concern among Canadians aged 65 years and older; based on cross-sectional data from the 1996/1997 National Population Health Survey and the 2005 Canadian Community Health Survey, chronic pain was estimated to affect 27% and 38% of seniors living in households and health care institutions, respectively. A number of treatments are available for the management of neuropathic pain or chronic non-cancer pain. These include tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors (duloxetine, venlafaxine), anticonvulsants (pregabalin, gabapentin, carbamazepine, phenytoin), topical lidocaine, and opioid analgesics. However, these medications are associated with limited pain relief and numerous adverse effects. The therapeutic use of several synthetic cannabinoid products for the symptomatic relief of chronic pain has also been studied. In particular, a combination of two products, delta-9-tetrahydrocannabinol and cannabidiol (THC:CBD) marketed under the name Sativex® is available for use as a buccal spray. This cannabis-based agent is approved for use in Canada as an add-on therapy for adult patients experiencing muscle spasticity caused by multiple sclerosis (MS), and it has received a Notice of Compliance with conditions for MS-related central neuropathic pain and the treatment of cancer pain unresponsive to opioids. The purpose of this review is to examine the available published literature relating to THC:CBD buccal spray for the treatment of chronic non-cancer or neuropathic pain in adults.”

https://www.ncbi.nlm.nih.gov/pubmed/27831665

Cannabinoids in the Management of Musculoskeletal or Rheumatic Diseases.

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“The endocannabinoid system impacts pain and inflammation with potential for therapeutic effect on patients with rheumatic diseases. The current treatment options include the herbal product derived from the plant Cannabis sativa, as well as pharmaceutical preparations. The legalization of medicinal cannabis (marijuana) in many jurisdictions and widespread public advocacy has propelled an interest in use either by prescription or self-medication. In this review, we examine current evidence for efficacy and adverse effects of any cannabinoid product in rheumatic conditions. The evidence to date is scant and precludes making recommendations for the use of cannabinoid preparations in rheumatology patients. In particular, the risks of herbal cannabis in patients are not well defined. Anecdote and advocacy cannot supersede sound evidence.”

https://www.ncbi.nlm.nih.gov/pubmed/27832442

The cannabinoid receptor CB1 contributes to the development of ectopic lesions in a mouse model of endometriosis.

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“Does signaling via the cannabinoid (CB1) receptor play a role in the pathogenesis of endometriosis in a mouse model?

The expression of components of the endocannabinoid system has been demonstrated in both mouse and human uteri. CB1 receptors are expressed in human epithelial and stromal cell lines derived from eutopic endometrium and deep infiltrating endometriosis nodules.

This was a randomized study in a mouse model of endometriosis.

We provide evidence that endocannabinoid signaling via CB1 receptor plays a role in the development of endometriosis in a mouse model.

However, the relative contribution of the CB1-mediated signaling pathways active in inflammatory, uterine and peritoneal cells remains to be ascertained. Since the study was performed in a mouse model, the significance of the findings in the human system warrants further investigation.

Clarifying the function and regulation of CB1 and its molecular interactions with endogenous ligands, and how endocannabinoids levels are regulated in women with endometriosis, represent critical areas of research for the potential development of a novel medical treatment of the disease.”

https://www.ncbi.nlm.nih.gov/pubmed/27821707

Quantitative analyses of synergistic responses between cannabidiol and DNA-damaging agents on the proliferation and viability of glioblastoma and neural progenitor cells in culture.

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“Evidence suggests that the non-psychotropic cannabis-derived compound, cannabidiol (CBD), has anti-neoplastic activity in multiple types of cancers, including glioblastoma multiforme (GBM).

DNA-damaging agents remain the main standard of care treatment available for patients diagnosed with GBM.

Here we studied the anti-proliferative and cell-killing activity of CBD alone and in combination with DNA-damaging agents (temozolomide, carmustine or cisplatin) in several human GBM cell lines and in mouse primary GBM cells in cultures.

This activity was also studied in mouse neural progenitor cells (NPCs) in culture to assess for potential central nervous system (CNS) toxicity.

We found that CBD induced a dose-dependent reduction of both proliferation and viability of all cells with similar potencies, suggesting no preferential activity for cancer cells.

Hill plot analysis indicates an allosteric mechanism of action triggered by CBD in all cells.

Co-treatment regiments combining CBD and DNA-damaging agents produced synergistic anti-proliferating and cell-killing responses over a limited range of concentrations in all human GBM cell lines and mouse GBM cells as well as in mouse NPCs.

Remarkably, antagonistic responses occurred at low concentrations in select human GBM cell lines and in mouse GBM cells.

Our study suggests limited synergistic activity when combining CBD and DNA-damaging agents in treating GBM cells, along with little-to-no therapeutic window when considering NPCs.”

https://www.ncbi.nlm.nih.gov/pubmed/27821713

“Definition of antineoplastic: inhibiting or preventing the growth and spread of tumors or malignant cells”  http://www.merriam-webster.com/dictionary/antineoplastic