Category Archives: Endocannabinoid System

GPR55 – a putative “type 3” cannabinoid receptor in inflammation.

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“G protein-coupled receptor 55 (GPR55) shares numerous cannabinoid ligands with CB1 and CB2 receptors despite low homology with those classical cannabinoid receptors. The pharmacology of GPR55 is not yet fully elucidated; however, GPR55 utilizes a different signaling system and downstream cascade associated with the receptor.

Therefore, GPR55 has emerged as a putative “type 3″ cannabinoid receptor, establishing a novel class of cannabinoid receptor.

Furthermore, the recent evidence of GPR55-CB1 and GPR55-CB2 heteromerization along with its broad distribution from central nervous system to peripheries suggests the importance of GPR55 in various cellular processes and pathologies and as a potential therapeutic target in inflammation.”

 http://www.ncbi.nlm.nih.gov/pubmed/26669245

Small Molecules from Nature Targeting G-Protein Coupled Cannabinoid Receptors: Potential Leads for Drug Discovery and Development.

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“The cannabinoid molecules are derived from Cannabis sativa plant which acts on the cannabinoid receptors types 1 and 2 (CB1 and CB2) which have been explored as potential therapeutic targets for drug discovery and development.

Currently, there are numerous cannabinoid based synthetic drugs used in clinical practice like the popular ones such as nabilone, dronabinol, and Δ9-tetrahydrocannabinol mediates its action through CB1/CB2receptors.

In recent years, many phytocannabinoids have been isolated from plants other than Cannabis. Several studies have shown that these phytocannabinoids show affinity, potency, selectivity, and efficacy towards cannabinoid receptors and inhibit endocannabinoid metabolizing enzymes, thus reducing hyperactivity of endocannabinoid systems.

Also, these naturally derived molecules possess the least adverse effects opposed to the synthetically derived cannabinoids. Therefore, the plant based cannabinoid molecules proved to be promising and emerging therapeutic alternative.

The present review provides an overview of therapeutic potential of ligands and plants modulating cannabinoid receptors that may be of interest to pharmaceutical industry in search of new and safer drug discovery and development for future therapeutics.”

The therapeutic aspects of the endocannabinoid system (ECS) for cancer and their development: from nature to laboratory.

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“The endocannabinoid system (ECS) is a group of neuromodulatory lipids and their receptors, which are widely distributed in mammalian tissues. ECS regulates various cardiovascular, nervous, and immune system functions inside cells.

In recent years, there has been a growing body of evidence for the use of synthetic and natural cannabinoids as potential anticancer agents.

For instance, the CB1 and CB2 receptors are assumed to play an important role inside the endocannabinoid system. These receptors are abundantly expressed in the brain and fatty tissue of the human body.

Despite recent developments in molecular biology, there is still a lack of knowledge about the distribution of CB1 and CB2 receptors in the human kidney and their role in kidney cancer. To address this gap, we explore and demonstrate the role of the endocannabinoid system in renal cell carcinoma (RCC).

In this brief overview, we elucidate the therapeutic aspects of the endocannabinoid system for various cancers and explain how this system can be used for treating kidney cancer.

Overall, this review provides new insights into cannabinoids’ mechanisms of action in both in vivo and in vitro models, and focuses on recent discoveries in the field.”

Therapy with a Selective Cannabinoid Receptor Type 2 Agonist Limits Albuminuria and Renal Injury in Mice with Type 2 Diabetic Nephropathy.

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“A critical involvement of the endocannabinoid/cannabinoid receptor system in diabetes and its complications has been recognized.

Experimental evidence suggested that activation of the cannabinoid receptor type 2 (CB2), which is expressed in the kidney by podocytes and inflammatory cells, had a protective role in early streptozotocin-induced type 1 diabetes in mice.

In this study, we investigated the effects of a CB2 agonist given at a phase of overt disease on renal functional and structural changes in BTBR ob/ob mice, a model of type 2 diabetic nephropathy.

These results suggest that CB2 agonism is a potential option to be added to the available therapeutic armamentarium for type 2 diabetic nephropathy.”

http://www.ncbi.nlm.nih.gov/pubmed/26646377

Endocannabinoid Signaling in Motivation, Reward, and Addiction: Influences on Mesocorticolimbic Dopamine Function.

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“Evidence suggests that the endocannabinoid system has been conserved in the animal kingdom for 500 million years, and this system influences many critical behavioral processes including associative learning, reward signaling, goal-directed behavior, motor skill learning, and action-habit transformation.

Additionally, the neurotransmitter dopamine has long been recognized to play a critical role in the processing of natural rewards, as well as of motivation that regulates approach and avoidance behavior. This motivational role of dopamine neurons is also based upon the evidence provided by several studies investigating disorders of dopamine pathways such as drug addiction and Parkinson’s disease.

From an evolutionary point of view, individuals engage in behaviors aimed at maximizing and minimizing positive and aversive consequences, respectively.

Accordingly, those with the greatest fitness have a better potential to survival. Hence, deviations from fitness can be viewed as a part of the evolutionary process by means of natural selection.

Given the long evolutionary history of both the endocannabinoid and dopaminergic systems, it is plausible that they must serve as fundamental and basic modulators of physiological functions and needs.

Notably, endocannabinoids regulate dopamine neuronal activity and its influence on behavioral output.

The goal of this chapter is to examine the endocannabinoid influence on dopamine signaling specifically related to (i) those behavioral processes that allow us to successfully adapt to ever-changing environments (i.e., reward signaling and motivational processes) and (ii) derangements from behavioral flexibility that underpin drug addiction.”

http://www.ncbi.nlm.nih.gov/pubmed/26638769

The Role of the Brain’s Endocannabinoid System in Pain and Its Modulation by Stress.

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“Stress has a complex, bidirectional modulatory influence on pain. Stress may either reduce (stress-induced analgesia) or exacerbate (stress-induced hyperalgesia) pain depending on the nature, duration, and intensity of the stressor.

The endogenous cannabinoid (endocannabinoid) system is present throughout the neuroanatomical pathways that mediate and modulate responses to painful stimuli.

The specific role of the endocannabinoid system in the brain in pain and the modulation of pain by stress is reviewed herein.

We first provide a brief overview of the endocannabinoid system, followed by a review of the evidence that the brain’s endocannabinoid system modulates pain.

We provide a comprehensive evaluation of the role of the endocannabinoid system supraspinally, and particularly in the rostral ventromedial medulla, periaqueductal gray, amygdala, and prefrontal cortex, in pain, stress-induced analgesia, and stress-induced hyperalgesia.

Increased understanding of endocannabinoid-mediated regulation of pain and its modulation by stress will inform the development of novel therapeutic approaches for pain and its comorbidity with stress-related disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/26638768

Endocannabinoid Regulation of Neuroendocrine Systems.

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“The hypothalamus is a part of the brain that is critical for sustaining life through its homeostatic control and integrative regulation of the autonomic nervous system and neuroendocrine systems. Neuroendocrine function in mammals is mediated mainly through the control of pituitary hormone secretion by diverse neuroendocrine cell groups in the hypothalamus.

Cannabinoid receptors are expressed throughout the hypothalamus, and endocannabinoids have been found to exert pronounced regulatory effects on neuroendocrine function via modulation of the outputs of several neuroendocrine systems.

Here, we review the physiological regulation of neuroendocrine function by endocannabinoids, focusing on the role of endocannabinoids in the neuroendocrine regulation of the stress response, food intake, fluid homeostasis, and reproductive function.

Cannabis sativa (marijuana) has a long history of recreational and/or medicinal use dating back to ancient times. It was used as an analgesic, anesthetic, and antianxiety herb as early as 2600 B.C.

The hedonic, anxiolytic, and mood-elevating properties of cannabis have also been cited in ancient records from different cultures. However, it was not until 1964 that the psychoactive constituent of cannabis, Δ(9)-tetrahydrocannabinol, was isolated and its chemical structure determined (Gaoni & Mechoulam, 1964).”

Endocannabinoid Mechanisms Influencing Nausea.

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“One of the first recognized medical uses of Δ(9)-tetrahydrocannabinol was treatment of chemotherapy-induced nausea and vomiting.

Although vomiting is well controlled with the currently available non-cannabinoid antiemetics, nausea continues to be a distressing side effect of chemotherapy and other disorders.

Indeed, when nausea becomes conditionally elicited by the cues associated with chemotherapy treatment, known as anticipatory nausea (AN), currently available antiemetics are largely ineffective.

Considerable evidence demonstrates that the endocannabinoid system regulates nausea in humans and other animals.

In this review, we describe recent evidence suggesting that cannabinoids and manipulations that enhance the functioning of the natural endocannabinoid system are promising treatments for both acute nausea and AN.”

The Endocannabinoid System and Its Role in Regulating the Intrinsic Neural Circuitry of the Gastrointestinal Tract.

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“Endocannabinoids are important neuromodulators in the central nervous system.

They regulate central transmission through pre- and postsynaptic actions on neurons and indirectly through effects on glial cells.

Cannabinoids (CBs) also regulate neurotransmission in the enteric nervous system (ENS) of the gastrointestinal (GI) tract.

The ENS consists of intrinsic primary afferent neurons, interneurons, and motor neurons arranged in two ganglionated plexuses which control all the functions of the gut.

Increasing evidence suggests that endocannabinoids are potent neuromodulators in the ENS.

In this review, we will highlight key observations on the localization of CB receptors and molecules involved in the synthesis and degradation of endocannabinoids in the ENS.

We will discuss endocannabinoid signaling mechanisms, endocannabinoid tone and concepts of CB receptor metaplasticity in the ENS. We will also touch on some examples of enteric neural signaling in relation neuromuscular, secretomotor, and enteroendocrine transmission in the ENS. Finally, we will briefly discuss some key future directions.”

The Endocannabinoid Signaling System in the CNS: A Primer.

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“The purpose of this chapter is to provide an introduction to the mechanisms for the regulation of endocannabinoid signaling through CB1 cannabinoid receptors in the central nervous system.

The processes involved in the synthesis and degradation of the two most well-studied endocannabinoids, 2-arachidonoylglycerol and N-arachidonylethanolamine are outlined along with information regarding the regulation of the proteins involved.

Signaling mechanisms and pharmacology of the CB1 cannabinoid receptor are outlined, as is the paradigm of endocannabinoid/CB1 receptor regulation of neurotransmitter release.

The reader is encouraged to appreciate the importance of the endocannabinoid/CB1 receptor signaling system in the regulation of synaptic activity in the brain.”