Phytocannabinoids: a unified critical inventory.

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“Cannabis sativa L. is a prolific, but not exclusive, producer of a diverse group of isoprenylated resorcinyl polyketides collectively known as phytocannabinoids.

The modular nature of the pathways that merge into the phytocannabinoid chemotype translates in differences in the nature of the resorcinyl side-chain and the degree of oligomerization of the isoprenyl residue, making the definition of phytocannabinoid elusive from a structural standpoint.

A biogenetic definition is therefore proposed, splitting the phytocannabinoid chemotype into an alkyl- and a β-aralklyl version, and discussing the relationships between phytocannabinoids from different sources (higher plants, liverworts, fungi).

The startling diversity of cannabis phytocannabinoids might be, at least in part, the result of non-enzymatic transformations induced by heat, light, and atmospheric oxygen on a limited set of major constituents (CBG, CBD, Δ9-THC and CBC and their corresponding acidic versions), whose degradation is detailed to emphasize this possibility.

The diversity of metabotropic (cannabinoid receptors), ionotropic (thermos-TRPs), and transcription factors (PPARs) targeted by phytocannabinoids is discussed. The integrated inventory of these compounds and their biological macromolecular end-points highlights the opportunities that phytocannabinoids offer to access desirable drug-like space beyond the one associated to the narcotic target CB1.”

Cannabis: A Treasure Trove or Pandora’s Box?

 

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“Cannabis is one of the earliest cultivated plants.

Cannabis of industrial utility and culinary value is generally termed as hemp.

Conversely, cannabis that is bred for medical, spiritual and recreational purposes is called marijuana.

The female marijuana plant produces a significant quantity of bio- and psychoactive phytocannabinoids, which regained the spotlight with the discovery of the endocannabinoid system of the animals in the early 90’s.

Nevertheless, marijuana is surrounded by controversies, debates and misconceptions related to its taxonomic classification, forensic identification, medical potential, legalization and its long-term health consequences.

In the first part, we provide an in-depth review of the botany and taxonomy of Cannabis. We then overview the biosynthesis of phytocannabinoids within the glandular trichomes with emphasis on the role of peculiar plastids in the production of the secreted material. We also compile the analytical methods used to determine the phytocannabinoid composition of glandular trichomes.

In the second part, we revisit the psychobiology and molecular medicine of marijuana. We summarize our current knowledge on the recreational use of cannabis with respect to the modes of consumption, short-term effects, chronic health consequences and cannabis use disorder.

Next, we overview the molecular targets of a dozen major and minor bioactive cannabinoids in the body. This helps us introduce the endocannabinoid system in an unprecedented detail: its up-to-date molecular biology, pharmacology, physiology and medical significance, and beyond.

In conclusion, we offer an unbiased survey about cannabis to help better weigh its medical value versus the associated risks.”

https://www.ncbi.nlm.nih.gov/pubmed/27719666

Dendritic Cell Regulation by Cannabinoid-Based Drugs.

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“Cannabinoid pharmacology has made important advances in recent years after the cannabinoid system was discovered.

Studies in experimental models and in humans have produced promising results using cannabinoid-based drugs for the treatment of obesity and cancer, as well as neuroinflammatory and chronic inflammatory diseases.

Moreover, as we discuss here, additional studies also indicates that these drugs have immunosuppressive and anti-inflammatory properties including modulation of immune cell function.

Thus, manipulation of the endocannabinoid system in vivo may provide novel therapeutic strategies against inflammatory disorders.

At least two types of cannabinoid receptors, cannabinoid 1 and cannabinoid 2 receptors are expressed on immune cells such as dendritic cells (DC). Dendritic cells are recognized for their critical role in initiating and maintaining immune responses.

Therefore, DC are potential targets for cannabinoid-mediated modulation.

Here, we review the effects of cannabinoids on DC and provide some perspective concerning the therapeutic potential of cannabinoids for the treatment of human diseases involving aberrant inflammatory processes.”

https://www.ncbi.nlm.nih.gov/pubmed/27713374

Cannabinoids and Dementia: A Review of Clinical and Preclinical Data.

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“The endocannabinoid system has been shown to be associated with neurodegenerative diseases and dementia.

We review the preclinical and clinical data on cannabinoids and four neurodegenerative diseases: Alzheimer’s disease (AD), Huntington’s disease (HD), Parkinson’s disease (PD) and vascular dementia (VD).

Numerous studies have demonstrated an involvement of the cannabinoid system in neurotransmission, neuropathology and neurobiology of dementias. In addition, several candidate compounds have demonstrated efficacy in vitro.

However, some of the substances produced inconclusive results in vivo. Therefore, only few trials have aimed to replicate the effects seen in animal studies in patients. Indeed, the literature on cannabinoid administration in patients is scarce.

While preclinical findings suggest causal treatment strategies involving cannabinoids, clinical trials have only assessed the suitability of cannabinoid receptor agonists, antagonists and cannabidiol for the symptomatic treatment of dementia.

Further research is needed, including in vivo models of dementia and human studies.”

https://www.ncbi.nlm.nih.gov/pubmed/27713372

Dysregulation of the endocannabinoid signaling system in the cerebellum and brainstem in a transgenic mouse model of spinocerebellar ataxia type-3

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“Spinocerebellar ataxia type-3 (SCA-3) is a rare disease but it is the most frequent type within the autosomal dominant inherited ataxias. The disease lacks an effective treatment to alleviate major symptoms and to modify disease progression.

Our recent findings that endocannabinoid receptors and enzymes are significantly altered in the post-mortemcerebellum of patients affected by autosomal-dominant hereditary ataxias suggest that targeting the endocannabinoid signaling system may be a promising therapeutic option.

Our goal was to investigate the status of the endocannabinoid signaling system in a transgenic mouse model of SCA-3, in the two CNS structures most affected in this disease –cerebellum and brainstem-.

These animals exhibited progressive motor incoordination, imbalance, abnormal gait, muscle weakness, and dystonia, in parallel to reduced in vivobrain glucose metabolism, deterioration of specific neuron subsets located in the dentate nucleus and pontine nuclei, small changes in microglial morphology, and reduction in glial glutamate transporters.

Concerning the endocannabinoid signaling, our data indicated no changes in CB2 receptors. By contrast, CB1 receptors increased in the Purkinje cell layer, in particular in terminals of basket cells, but they were reduced in the dentate nucleus.

We also measured the levels of endocannabinoid lipids and found reductions in anandamide and oleanolamideoyleth in the brainstem. These changes correlated with an increase in the FAAH enzyme in the brainstem, which also occurred in some cerebellar areas, whereas other endocannabinoid-related enzymes were not altered.

Collectively, our results in SCA-3 mutant mice confirm a possible dysregulation in the endocannabinoid system in the most important brain structures affected in this type of ataxia, suggesting that a pharmacological manipulation addressed to correct these changes could be a promising option in SCA-3.”

http://www.sciencedirect.com/science/article/pii/S0306452216305012

From Fertilisation to Implantation in Mammalian Pregnancy-Modulation of Early Human Reproduction by the Endocannabinoid System.

 

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“There is an increasing recognition that the endocannabinoid system is the crucial cytokine-hormone system regulating early human pregnancy. The synchronous development of the fertilized embryo and the endometrium to ensure timely implantation has been shown to be one of the pivotal steps to successful implantation. This development is thought to be regulated by a finely balanced relationship between various components of the endocannabinoid system in the endometrium, the embryo and the Fallopian tube. In addition, this system has also been shown to be involved in the regulation of the development and maturation of the gametes prior to fertilization. In this review, we will examine the evidence from animal and human studies to support the role of the endocannabinoid system in gametogenesis, fertilization, implantation, early pregnancy maintenance, and in immunomodulation of pregnancy. We will discuss the role of the cannabinoid receptors and the enzymes involved in the synthesis and degradation of the key endocannabinoid ligands (e.g., anandamide and 2-arachinoylglycerol) in early reproduction.”

https://www.ncbi.nlm.nih.gov/pubmed/27713383

Synthesis, Biodistribution and In vitro Evaluation of Brain Permeable High Affinity Type 2 Cannabinoid Receptor Agonists [11C]MA2 and [18F]MA3.

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“The type 2 cannabinoid receptor (CB2) is a member of the endocannabinoid system and is known for its important role in (neuro)inflammation.

A PET-imaging agent that allows in vivo visualization of CB2 expression may thus allow quantification of neuroinflammation.

In this paper, we report the synthesis, radiosynthesis, biodistribution and in vitro evaluation of a carbon-11 ([11C]MA2) and a fluorine-18 ([18F]MA3) labeled analog of a highly potent N-arylamide oxadiazole CB2 agonist (EC50 = 0.015 nM). MA2 and MA3 behaved as potent CB2 agonist (EC50: 3 nM and 0.1 nM, respectively) and their in vitro binding affinity for hCB2 was found to be 87 nM and 0.8 nM, respectively.

Also MA3 (substituted with a fluoro ethyl group) was found to have higher binding affinity and EC50 values when compared to the originally reported trifluoromethyl analog 12. [11C]MA2 and [18F]MA3 were successfully synthesized with good radiochemical yield, high radiochemical purity and high specific activity. In mice, both tracers were efficiently cleared from blood and all major organs by the hepatobiliary pathway and importantly these compounds showed high brain uptake.

In conclusion, [11C]MA2 and [18F]MA3 are shown to be high potent CB2 agonists with good brain uptake, these favorable characteristics makes them potential PET probes for in vivo imaging of brain CB2 receptors. However, in view of its higher affinity and selectivity, further detailed evaluation of MA3 as a PET tracer for CB2 is warranted.”

https://www.ncbi.nlm.nih.gov/pubmed/27713686

Cannabinoids and GI Disorders: Endogenous and Exogenous.

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“Despite the political and social controversy affiliated with it, the medical community must come to the realization that cannabinoids exist as a ubiquitous signaling system in many organ systems. Our understanding of cannabinoids and how they relate not only to homeostasis but also in disease states must be furthered through research, both clinically and in the laboratory. The identification of the cannabinoid receptors in the early 1990s have provided us with the perfect target of translational research. Already, much has been done with cannabinoids and the nervous system. Here, we explore the implications it has for the gastrointestinal tract. Most therapeutics currently on the market presently target only one aspect of the cannabinoid system. Our main purpose here is to highlight areas of research and potential avenues of discovery that the cannabinoid system has yet to reveal.”

https://www.ncbi.nlm.nih.gov/pubmed/27699625

Cannabinoid CB1 receptors in distinct circuits of the extended amygdala determine fear responsiveness to unpredictable threat.

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“The brain circuits underlying behavioral fear have been extensively studied over the last decades.

Here, we show that the endocannabinoid system acting in synaptic circuits of the extended amygdala can explain the fear response profile during exposure to unpredictable threat.

Using fear training with predictable or unpredictable cues in mice, combined with local and cell-type-specific deficiency and rescue of cannabinoid type 1 (CB1) receptors, we found that presynaptic CB1 receptors on distinct amygdala projections to bed nucleus of the stria terminalis (BNST) are both necessary and sufficient for the shift from phasic to sustained fear in response to an unpredictable threat.

These results thereby identify the causal role of a defined protein in a distinct brain pathway for the temporal development of a sustained state of anxious apprehension during unpredictability of environmental influences, reminiscent of anxiety symptoms in humans.”

https://www.ncbi.nlm.nih.gov/pubmed/27698427

Vascular Dysfunction in a Transgenic Model of Alzheimer’s Disease: Effects of CB1R and CB2R Cannabinoid Agonists.

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“There is evidence of altered vascular function, including cerebrovascular, in Alzheimer’s disease (AD) and transgenic models of the disease.

Indeed vasoconstrictor responses are increased, while vasodilation is reduced in both conditions. β-Amyloid (Aβ) appears to be responsible, at least in part, of alterations in vascular function.

Cannabinoids, neuroprotective and anti-inflammatory agents, induce vasodilation both in vivo and in vitro.

We have demonstrated a beneficial effect of cannabinoids in models of AD by preventing glial activation.

In this work we have studied the effects of these compounds on vessel density in amyloid precursor protein (APP) transgenic mice, line 2576, and on altered vascular responses in aortae isolated ring.

In summary, we have confirmed and extended the existence of altered vascular responses in Tg APP mice.

Moreover, our results suggest that treatment with cannabinoids may ameliorate the vascular responses in AD-type pathology.”