Category Archives: Endocannabinoid System

CB1 receptor activation in the rat paraventricular nucleus induces bi-directional cardiovascular effects via modification of glutamatergic and GABAergic neurotransmission.

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“We have shown previously that the cannabinoid receptor agonist CP55940 microinjected into the paraventricular nucleus of the hypothalamus (PVN) of urethane-anaesthetized rats induces depressor and pressor cardiovascular effects in the absence and presence of the CB1 antagonist AM251, respectively. The aim of our study was to examine whether the hypotension and/or hypertension induced by CP55940 given into the PVN results from its influence on glutamatergic and GABAergic neurotransmission. CP55940 was microinjected into the PVN of urethane-anaesthetized rats twice (S1 and S2, 20 min apart). Antagonists of the following receptors, NMDA (MK801), β2-adrenergic (ICI118551), thromboxane A2-TP (SQ29548), angiotensin II-AT1 (losartan) or GABAA (bicuculline), or the NO synthase inhibitor L-NAME were administered intravenously 5 min before S2 alone or together with AM251. The CP55940-induced hypotension was reversed into a pressor response by AM251, bicuculline and L-NAME, but not by the other antagonists. The CP55940-induced pressor effect examined in the presence of AM251 was completely reversed by losartan, reduced by about 50-60 % by MK801, ICI118551 and SQ29548, prevented by bilateral adrenalectomy but not modified by bicuculline and L-NAME. Parallel, but smaller, changes in heart rate accompanied the changes in blood pressure. The bi-directional CB1 receptor-mediated cardiovascular effects of cannabinoids microinjected into the PVN of anaesthetized rats depend on stimulatory glutamatergic and inhibitory GABAergic inputs to the sympathetic tone; the glutamatergic input is related to AT1, TP and β2-adrenergic receptors and catecholamine release from the adrenal medulla whereas the GABAergic input is reinforced by NO.”

http://www.ncbi.nlm.nih.gov/pubmed/27659492

Cannabinoids: Glutamatergic Transmission and Kynurenines.

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“The endocannabinoid system (ECS) comprises a complex of receptors, enzymes, and endogenous agonists that are widely distributed in the central nervous system of mammals and participates in a considerable number of neuromodulatory functions, including neurotransmission, immunological control, and cell signaling. In turn, the kynurenine pathway (KP) is the most relevant metabolic route for tryptophan degradation to form the metabolic precursor NAD(+).

Recent studies demonstrate that the control exerted by the pharmacological manipulation of the ECS on the glutamatergic system in the brain may offer key information not only on the development of psychiatric disorders like psychosis and schizophrenia-like symptoms, but it also may constitute a solid basis for the development of therapeutic strategies to combat excitotoxic events occurring in neurological disorders like Huntington’s disease (HD).

Part of the evidence pointing to the last approach is based on experimental protocols demonstrating the efficacy of cannabinoids to prevent the deleterious actions of the endogenous neurotoxin and KP metabolite quinolinic acid (QUIN).

These findings intuitively raise the question about what is the precise role of the ECS in tryptophan metabolism through KP and vice versa. In this chapter, we will review basic concepts on the physiology of both the ECS and the KP to finally describe those recent findings combining the components of these two systems and hypothesize the future course that the research in this emerging field will take in the next years.”

 http://www.ncbi.nlm.nih.gov/pubmed/27651254

Dietary fats and pharmaceutical lipid excipients increase systemic exposure to orally administered cannabis and cannabis-based medicines

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“Cannabis sativa, commonly called hemp, has thousands of years-long history of medical use. Cannabis extracts were widely used in Europe and North America for their therapeutic value as sedatives, hypnotics, analgesics, muscle relaxants, and anticonvulsant agents. However, cannabis was removed from British and American Pharmacopoeias in 20th century, partially due to politic bias. Although prohibited, many patients were nevertheless self-medicating to obtain therapeutic benefits from cannabis for various conditions, including AIDS wasting syndrome, multiple sclerosis (MS) and spinal injuries. More recently, a growing interest in the therapeutic effects of cannabis has developed following the isolation of cannabinoids, the principal chemical compounds of cannabis, as well as the discovery of endocannabinoids and their cognate receptors in humans. These advances supported legalisation and wide-spread use of cannabis for therapeutic purposes in many countries.

There has been an escalating interest in the medicinal use of Cannabis sativa in recent years. Cannabis is often administered orally with fat-containing foods, or in lipid-based pharmaceutical preparations. However, the impact of lipids on the exposure of patients to cannabis components has not been explored. Therefore, the aim of this study is to elucidate the effect of oral co-administration of lipids on the exposure to two main active cannabinoids, Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD). In this study, oral co-administration of lipids enhanced the systemic exposure of rats to THC and CBD by 2.5-fold and 3-fold, respectively, compared to lipid-free formulations. In vitro lipolysis was conducted to explore the effect of lipids on the intestinal solubilisation of cannabinoids. More than 30% of THC and CBD were distributed into micellar fraction following lipolysis, suggesting that at least one-third of the administered dose will be available for absorption following co-administration with lipids. Both cannabinoids showed very high affinity for artificial CM-like particles, as well as for rat and human CM, suggesting high potential for intestinal lymphatic transport. Moreover, comparable affinity of cannabinoids for rat and human CM suggests that similar increased exposure effects may be expected in humans. In conclusion, co-administration of dietary lipids or pharmaceutical lipid excipients has the potential to substantially increase the exposure to orally administered cannabis and cannabis-based medicines. The increase in patient exposure to cannabinoids is of high clinical importance as it could affect the therapeutic effect, but also toxicity, of orally administered cannabis or cannabis-based medicines.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5009397/

Cannabinoid Agonists Show Promise for Anorexia

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“Impairments in the endocannabinoid system in the brain could play an important role in the development of anorexia nervosa, say Italian researchers, who report findings that point to novel cannabis-based therapeutic strategies for the eating disorder.

In a mouse model of anorexia, the team found not only that the density of cannabinoid receptors was significantly reduced in areas associated with appetite but also that administration of receptor agonists led to increases in body weight and a reduction in interest in exercise.”

http://www.medscape.com/viewarticle/868990

Δ9-Tetrahydrocannabinol Reverses TNFα-induced Increase in Airway Epithelial Cell Permeability through CB2 Receptors.

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“Despite pharmacological treatment, bronchial hyperresponsiveness continues to deteriorate as airway remodelling persists in airway inflammation.

Previous studies have demonstrated that the phytocannabinoid Δ9-tetrahydrocannabinol (THC) reverses bronchoconstriction with an anti-inflammatory action.

The aim of this study was to investigate the effects of THC on bronchial epithelial cell permeability after exposure to the pro-inflammatory cytokine, TNFα. Calu-3 bronchial epithelial cells were cultured at air-liquid interface.

These data indicate that THC prevents cytokine-induced increase in airway epithelial permeability through CB2 receptor activation.

This highlights that THC, or other cannabinoid receptor ligands, could be beneficial in the prevention of inflammation-induced changes in airway epithelial cell permeability, an important feature of airways diseases.”

http://www.ncbi.nlm.nih.gov/pubmed/27641813

Comparing the effects of endogenous and synthetic cannabinoid receptor agonists on survival of gastric cancer cells.

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“Anti-neoplastic activity induced by cannabinoids has been extensively documented for a number of cancer cell types; however, this topic has been explored in gastric cancer cells only in a limited number of approaches.

SIGNIFICANCE:

Through a comparative approach, our results support and confirm the therapeutic potential that cannabinoid receptor agonists exert in gastric cancer cells and open possibilities to use cannabinoids as part of a new gastric cancer therapy.”

http://www.ncbi.nlm.nih.gov/pubmed/27640887

The endocannabinoid anandamide causes endothelium-dependent vasorelaxation in human mesenteric arteries.

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“The endocannabinoid anandamide (AEA) causes vasorelaxation in animal studies.

Although circulating AEA levels are increased in many pathologies, little is known about its vascular effects in humans. The aim of this work was to characterise the effects of AEA in human arteries.

Post hoc analysis of the data set showed that overweight patients and those taking paracetamol had reduced vasorelaxant responses to AEA.

These data show that AEA causes moderate endothelium-dependent, NO-dependent vasorelaxation in human mesenteric arteries via activation of CB1 receptors.”

http://www.ncbi.nlm.nih.gov/pubmed/27633407

From Phytocannabinoids to Cannabinoid Receptors and Endocannabinoids: Pleiotropic Physiological and Pathological Roles Through Complex Pharmacology.

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“Apart from having been used and misused for at least four millennia for, among others, recreational and medicinal purposes, the cannabis plant and its most peculiar chemical components, the plant cannabinoids (phytocannabinoids), have the merit to have led humanity to discover one of the most intriguing and pleiotropic endogenous signaling systems, the endocannabinoid system (ECS).

This review article aims to describe and critically discuss, in the most comprehensive possible manner, the multifaceted aspects of 1) the pharmacology and potential impact on mammalian physiology of all major phytocannabinoids, and not only of the most famous one Δ9-tetrahydrocannabinol, and 2) the adaptive pro-homeostatic physiological, or maladaptive pathological, roles of the ECS in mammalian cells, tissues, and organs.

In doing so, we have respected the chronological order of the milestones of the millennial route from medicinal/recreational cannabis to the ECS and beyond, as it is now clear that some of the early steps in this long path, which were originally neglected, are becoming important again. The emerging picture is rather complex, but still supports the belief that more important discoveries on human physiology, and new therapies, might come in the future from new knowledge in this field.”

http://www.ncbi.nlm.nih.gov/pubmed/27630175

The syntheses of isotopically labelled CB-1 antagonists for the treatment of obesity.

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“BMS-725519, BMS-811064, and BMS-812204 are potent and selective central cannabinoid receptor antagonists that have been investigated for the treatment of human obesity. To further understand their biotransformation profiles, radiolabelled and stable-labelled products were required. This paper describes the utility of [14 C]1,1-carbonyldiimidazole as a radiolabelling reagent for the syntheses of carbonyl-labelled [14 C]BMS-725519, [14 C]BMS-811064, and [14 C]BMS-812204. The syntheses of stable-labelled [13 C6 ]BMS-725519 and [13 CD3 13 CD2 ]BMS-812204 synthesized from of [13 C6 ]4-chloroacetophenone and [13 CD3 13 CD2 ]iodoethane, respectively, are also described.”

http://www.ncbi.nlm.nih.gov/pubmed/27624665

Important role of endocannabinoid signaling in the development of functional vision and locomotion in zebrafish.

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“The developmental role of the endocannabinoid system still remains to be fully understood.

Here, we report the presence of a complete endocannabinoid system during zebrafish development and show that the genes that code for enzymes that catalyze the anabolism and catabolism (mgll and dagla) of the endocannabinoid, 2-AG (2-arachidonoylglycerol), as well as 2-AG main receptor in the brain, cannabinoid receptor type 1, are coexpressed in defined regions of axonal growth.

By using morpholino-induced transient knockdown of the zebrafish Daglα homolog and its pharmacologic rescue, we suggest that synthesis of 2-AG is implicated in the control of axon formation in the midbrain-hindbrain region and that animals that lack Daglα display abnormal physiological behaviors in tests that measure stereotyped movement and motion perception.

Our results suggest that the well-established role for 2-AG in axonal outgrowth has implications for the control of vision and movement in zebrafish and, thus, is likely common to all vertebrates.”

http://www.ncbi.nlm.nih.gov/pubmed/27623930