Tag Archives: CB(1) and CB(2) receptors

Human Immunodeficiency Virus In Late-Stage AIDS Inhibited By Marijuana-Like Chemicals – MedicalNewsToday

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“Mount Sinai School of Medicine researchers have discovered that marijuana-like chemicals trigger receptors on human immune cells that can directly inhibit a type of human immunodeficiency virus (HIV) found in late-stage AIDS, according to new findings published online in the journal PLoS ONE.

Medical marijuana is prescribed to treat pain, debilitating weight loss and appetite suppression, side effects that are common in advanced AIDS. This is the first study to reveal how the marijuana receptors found on immune cells – called cannabinoid receptors CB1 and CB2 – can influence the spread of the virus. Understanding the effect of these receptors on the virus could help scientists develop new drugs to slow the progression of AIDS.

“We knew that cannabinoid drugs like marijuana can have a therapeutic effect in AIDS patients, but did not understand how they influence the spread of the virus itself,” said study author Cristina Costantino, PhD, Postdoctoral Fellow in the Department of Pharmacology and Systems Therapeutics at Mount Sinai School of Medicine. “We wanted to explore cannabinoid receptors as a target for pharmaceutical interventions that treat the symptoms of late-stage AIDS and prevent further progression of the disease without the undesirable side effects of medical marijuana.”

HIV infects active immune cells that carry the viral receptor CD4, which makes these cells unable to fight off the infection. In order to spread, the virus requires that “resting” immune cells be activated. In advanced AIDS, HIV mutates so it can infect these resting cells, gaining entry into the cell by using a signaling receptor called CXCR4. By treating the cells with a cannabinoid agonist that triggers CB2, Dr. Costantino and the Mount Sinai team found that CB2 blocked the signaling process, and suppressed infection in resting immune cells.

Triggering CB1 causes the drug high associated with marijuana, making it undesirable for physicians to prescribe. The researchers wanted to explore therapies that would target CB2 only. The Mount Sinai team infected healthy immune cells with HIV, then treated them with a chemical that triggers CB2 called an agonist. They found that the drug reduced the infection of the remaining cells.

“Developing a drug that triggers only CB2 as an adjunctive treatment to standard antiviral medication may help alleviate the symptoms of late-stage AIDS and prevent the virus from spreading,” said Dr. Costantino. Because HIV does not use CXCR4 to enhance immune cell infection in the early stages of infection, CB2 agonists appear to be an effective antiviral drug only in late-stage disease.

As a result of this discovery, the research team led by Benjamin Chen, MD, PhD, Associate Professor of Infectious Diseases, and Lakshmi Devi, PhD, Professor of Pharmacology and Systems Therapeutics at Mount Sinai School of Medicine, plans to develop a mouse model of late-stage AIDS in order to test the efficacy of a drug that triggers CB2 in vivo. In 2009 Dr. Chen was part of a team that captured on video for the first time the transfer of HIV from infected T-cells to uninfected T-cells.”

http://www.medicalnewstoday.com/releases/243183.php

Synthetic Agents Related To Active Ingredient In Marijuana Weaken HIV Infection – MedicalNewsToday

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“HIV, the virus that causes AIDS, is notorious for hiding within certain types of cells, where it reproduces at a slowed rate and eventually gives rise to chronic inflammation, despite drug therapy. But researchers at Temple University School of Medicine’s Department of Pathology and Laboratory Medicine and Center for Substance Abuse Research (CSAR) recently discovered that synthetic anti-inflammatory substances distantly related to the active ingredient of marijuana may be able to take the punch out of HIV while inside one of its major hideouts – immune cells known as macrophages.

The breakthrough comes at a crucial time in the HIV/AIDS pandemic…

To better understand the connection between inflammation and neurocognitive conditions linked to long-term exposure to HIV, Ramirez and colleagues looked specifically at the CB2 receptor, a protein located on the surface of macrophages. CB2 is a binding site for substances called cannabinoids, the primary active compounds of cannabis (marijuana), and it may play a role in blocking inflammation in the CNS. Unlike its counterpart, the CB1 receptor, which is found primarily on neurons in the brain, CB2 does not mediate the psychoactive effects for which cannabis is popularly known.

Ramirez explained that there has been much pharmacological interest in developing agents that selectively target CB2. Ideally, these compounds would help limit chronic inflammatory responses and would not bind to CB1.

The most promising compounds are those derived from THC (tetrahydrocannabinol), the main active substance in cannabis.”

More: http://www.medicalnewstoday.com/releases/259980.php

Synthetic derivatives of THC may weaken HIV-1 infection to enhance antiviral therapies – MedicalXpress

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“A new use for compounds related in composition to the active ingredient in marijuana may be on the horizon: a new research report published in the Journal of Leukocyte Biology shows that compounds that stimulate the cannabinoid type 2 (CB2) receptor in white blood cells, specifically macrophages, appear to weaken HIV-1 infection. The CB2 receptor is the molecular link through which the pharmaceutical properties of cannabis are manifested. Diminishing HIV-1 infection in this manner might make current anti-viral therapies more effective and provide some protection against certain HIV-1 complications.

“The synthetic compounds we used in our study may show promise in helping the body fight HIV-1 infection,'” said Yuri Persidsky, M.D., Ph.D., a researcher involved in the work from the Department of Pathology and Laboratory Medicine at Temple University School of Medicine in Philadelphia, PA. “As compounds like these are improved further and made widely available, we will continue to explore their potential to fight other viral diseases that are notoriously difficult to treat.”

To make this discovery, scientists used a cell culture model to infect human macrophages with HIV-1 and added synthetic compounds similar to the active ingredient in marijuana to activate the CB2 receptor. At different times during the infection, samples from the culture were taken to see if the replication of the HIV virus was decreased. The researchers observed diminished HIV growth and a possible protective effect from some HIV-1 complications.

“HIV/AIDS has posed one of the most significant health challenges in modern medicine,” said John Wherry, Ph.D., Deputy Editor of the Journal of Leukocyte Biology. “Recent high profile vaccine failures mean that all options need to be on the table to prevent or treat this devastating infection. Research on the role of cannabinoid type 2 receptors and viral infection may one day allow targeting these receptors to be part of combination therapies that use exploit multiple weaknesses of the virus simultaneously.””

http://medicalxpress.com/news/2013-04-synthetic-derivatives-thc-weaken-hiv-.html

Delta–9 Tetrahydrocannabinol inhibits growth and metastasis of lung cancer – Harvard University

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“Lung cancer is the major cause of cancer-related mortality worldwide.Many of these over-express epidermal growth factor receptor(EGFR), and are usually highly aggressive and resistant to chemotherapy.

Recent studies have shown that {Delta}-9 Tetrahydrocannabinol (THC),the major component of Cannabis sativa, possess anti-tumor propertiesagainst various types of cancers.

 However, not much is knownabout its effect on lung cancer. In this study, we sought tocharacterize the effect of THC on EGF-induced growth and metastasisof human non small lung cancer cell (NSCLC) lines A549 and SW-1573.

We demonstrate that these cell lines and primary tumor samplesderived from lung cancer patients express cannabinoids receptorsCB1 and CB2, the known targets for THC action. We further showthat THC inhibits EGF-induced growth in these cell lines. Inaddition THC attenuated EGF-stimulated chemotaxis and chemoinvasion.Next we characterized the effect of THC on in vivo lung cancergrowth and metastasis in a murine model. A549 cells were implantedin SCID mice (n=6 per group) through subcutaneous and intravenousinjections to generate subcutaneous and lung metastatic cancer,respectively. THC (5mg/kg body wt.) was administered once dailythrough intraperitoneal injections for 21 days. The mice wereanalyzed for tumor growth and lung metastasis.

 A significantreduction (~50%) in tumor weight and volume were observed inTHC treated animals compared to the vehicle treated animals.THC treated animals also showed a significant (~60%) reductionin macroscopic lesions on the lung surface in comparison tovehicle treated control. Immunohistochemical analysis of thetumor samples from THC treated animals revealed anti-proliferativeand anti-angiogenic effects of THC with significant reductionin staining for Ki67, a proliferative marker and CD31, an endothelialmarker indicative of vascularization. Investigation into thesignaling events associated with reduced EGF-induced functionaleffects revealed that THC also inhibits EGF-induced Akt phosphorylation.Akt is a central signaling molecule of EGFR-mediated signalingpathways and it regulates a diverse array of cellular functions,including proliferation, angiogenesis, invasion and apoptosis.

Cumulatively, these studies indicate that THC has anti-tumorigenic and anti-metastatic effects against lung cancer. Novel therapies against EGFR overexpressing, aggressive and chemotherapy resistant lung cancers may include targeting the cannabinoids receptors.”

http://www.aacrmeetingabstracts.org/cgi/content/meeting_abstract/2007/1_Annual_Meeting/4749%20?maxtoshow&hits=80&RESULTFORMAT&fulltext=cannabinoid&searchid=1&FIRSTINDEX=1760&resourcetype=HWCIT

[From cannabis to selective CB2R agonists: molecules with numerous therapeutical virtues].

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“Originally used in Asia for the treatment of pain, spasms, nausea and insomnia, marijuana is the most consumed psychotropic drug worldwide. The interest of medical cannabis has been reconsidered recently, leading to many scientific researches and commercialization of these drugs.

Natural and synthetic cannabinoids display beneficial antiemetic, anti-inflammatory and analgesic effects in numerous diseases, however accompanied with undesirable effects due to the CB1 receptor. Present researches focus on the design of therapeutical molecules targeting the CB2 receptors, and thus avoiding central side effects and therefore psychotropic effects caused by the CB1 receptor.”

http://www.ncbi.nlm.nih.gov/pubmed/23732102

An Effective Prodrug Strategy to Selectively Enhance Ocular Exposure of a Cannabinoid Receptor (CB1/2) Agonist.

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“Glaucoma is a leading cause of vision loss and blindness, with increased intraocular pressure (IOP) a prominent risk factor. IOP can be efficaciously reduced by administration of topical agents. However, the repertoire of approved IOP-lowering drug classes is limited, and effective new alternatives are needed. Agonism of the cannabinoid receptors CB1/2 significantly reduces IOP clinically, and experimentally. However, development of CB1/2 agonists has been complicated by the need to avoid cardiovascular and psychotropic side effects. Compound A is a potent CB1/2 agonist that is highly excluded from the brain. In a phase I study, compound A eyedrops were well tolerated and generated an IOP-lowering trend, but were limited in dose and exposure due to poor solubility and ocular absorption. Here we present an innovative strategy to rapidly identify compound A prodrugs that are efficiently metabolized to the parent compound, for improved solubility and ocular permeability, while maintaining low systemic exposures.”

http://www.ncbi.nlm.nih.gov/pubmed/23738526

Phytocannabinoids

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“Phytocannabinoids, also called ”natural cannabinoids”, ”herbal cannabinoids”, and ”classical cannabinoids”, are only known to occur naturally in significant quantity in the cannabis plant, and are concentrated in a viscous resin that is produced in glandular structures known as trichomes.

In addition to cannabinoids, the resin is rich in terpenes, which are largely responsible for the odour of the cannabis plant.

Phytocannabinoids are nearly insoluble in water but are soluble in lipids, alcohols, and other non-polar organic solvents. However, as phenols, they form more water-soluble phenolate salts under strongly alkaline conditions.

All-natural cannabinoids are derived from their respective 2-carboxylic acids (2-COOH) by decarboxylation (catalyzed by heat, light, or alkaline conditions).

Types

At least 66 cannabinoids have been isolated from the cannabis plant. To the right the main classes of natural cannabinoids are shown. All classes derive from cannabigerol-type compounds and differ mainly in the way this precursor is cyclized.

Tetrahydrocannabinol (THC), cannabidiol (CBD) and cannabinol (CBN) are the most prevalent natural cannabinoids and have received the most study. Other common cannabinoids are listed below:

  • CBG Cannabigerol
  • CBC Cannabichromene
  • CBL Cannabicyclol
  • CBV Cannabivarin
  • THCV Tetrahydrocannabivarin
  • CBDV Cannabidivarin
  • CBCV Cannabichromevarin
  • CBGV Cannabigerovarin
  • CBGM Cannabigerol Monoethyl Ether

Tetrahydrocannabinol

Tetrahydrocannabinol (THC) is the primary psychoactive component of the plant. It appears to ease moderate pain (analgetic) and to be neuroprotective. THC has approximately equal affinity for the CB1 and CB2 receptors. Its effects are perceived to be more cerebral.

”Delta”-9-Tetrahydrocannabinol (Δ9-THC, THC) and ”delta”-8-tetrahydrocannabinol (Δ8-THC), mimic the action of anandamide, a neurotransmitter produced naturally in the body. The THCs produce the ”high” associated with cannabis by binding to the CB1 cannabinoid receptors in the brain.

Cannabidiol

Cannabidiol (CBD) is not psychoactive, and was thought not to affect the psychoactivity of THC. However, recent evidence shows that smokers of cannabis with a higher CBD/THC ratio were less likely to experience schizophrenia-like symptoms.

This is supported by psychological tests, in which participants experience less intense psychotic effects when intravenous THC was co-administered with CBD (as measured with a PANSS test).

It has been hypothesized that CBD acts as an allosteric antagonist at the CB1 receptor and thus alters the psychoactive effects of THC.

It appears to relieve convulsion, inflammation, anxiety, and nausea. CBD has a greater affinity for the CB2 receptor than for the CB1 receptor.

Cannabigerol

Cannabigerol (CBG) is non-psychotomimetic but still affects the overall effects of Cannabis. It acts as an α2-adrenergic receptor agonist, 5-HT1A receptor antagonist, and CB1 receptor antagonist. It also binds to the CB2 receptor.

Tetrahydrocannabivarin

Tetrahydrocannabivarin (THCV) is prevalent in certain South African and Southeast Asian strains of Cannabis. It is an antagonist of THC at CB1 receptors and attenuates the psychoactive effects of THC.

Cannabichromene

Cannabichromene (CBC) is non-psychoactive and does not affect the psychoactivity of THC It is found in nearly all tissues in a wide range of animals.

Two analogs of anandamide, 7,10,13,16-docosatetraenoylethanolamide and ”homo”-γ-linolenoylethanolamine, have similar pharmacology.

All of these are members of a family of signalling lipids called ”N”-acylethanolamides, which also includes the noncannabimimetic palmitoylethanolamide and oleoylethanolamine, which possess anti-inflammatory and orexigenic effects, respectively. Many ”N”-acylethanolamines have also been identified in plant seeds and in molluscs.

  • 2-arachidonoyl glycerol (2-AG)

Another endocannabinoid, 2-arachidonoyl glycerol, binds to both the CB1 and CB2 receptors with similar affinity, acting as a full agonist at both, and there is some controversy over whether 2-AG rather than anandamide is chiefly responsible for endocannabinoid signalling ”in vivo”.

In particular, one ”in vitro” study suggests that 2-AG is capable of stimulating higher G-protein activation than anandamide, although the physiological implications of this finding are not yet known.

  • 2-arachidonyl glyceryl ether (noladin ether)

In 2001, a third, ether-type endocannabinoid, 2-arachidonyl glyceryl ether (noladin ether), was isolated from porcine brain.

Prior to this discovery, it had been synthesized as a stable analog of 2-AG; indeed, some controversy remains over its classification as an endocannabinoid, as another group failed to detect the substance at “any appreciable amount” in the brains of several different mammalian species.

It binds to the CB1 cannabinoid receptor (”K”i = 21.2 nmol/L) and causes sedation, hypothermia, intestinal immobility, and mild antinociception in mice. It binds primarily to the CB1 receptor, and only weakly to the CB2 receptor.

Like anandamide, NADA is also an agonist for the vanilloid receptor subtype 1 (TRPV1), a member of the vanilloid receptor family.

  • Virodhamine (OAE)

A fifth endocannabinoid, virodhamine, or ”O”-arachidonoyl-ethanolamine (OAE), was discovered in June 2002. Although it is a full agonist at CB2 and a partial agonist at CB1, it behaves as a CB1 antagonist ”in vivo”.

In rats, virodhamine was found to be present at comparable or slightly lower concentrations than anandamide in the brain, but 2- to 9-fold higher concentrations peripherally.

Function

Endocannabinoids serve as intercellular ‘lipid messengers’, signaling molecules that are released from one cell and activate the cannabinoid receptors present on other nearby cells.

Although in this intercellular signaling role they are similar to the well-known monoamine neurotransmitters, such as acetylcholine and dopamine, endocannabinoids differ in numerous ways from them. For instance, they use retrograde signaling.

Furthermore, endocannabinoids are lipophilic molecules that are not very soluble in water. They are not stored in vesicles, and exist as integral constituents of the membrane bilayers that make up cells. They are believed to be synthesized ‘on-demand’ rather than made and stored for later use.

The mechanisms and enzymes underlying the biosynthesis of endocannabinoids remain elusive and continue to be an area of active research.

The endocannabinoid 2-AG has been found in bovine and human maternal milk.

Retrograde signal

Conventional neurotransmitters are released from a ‘presynaptic’ cell and activate appropriate receptors on a ‘postsynaptic’ cell, where presynaptic and postsynaptic designate the sending and receiving sides of a synapse, respectively.

Endocannabinoids, on the other hand, are described as retrograde transmitters because they most commonly travel ‘backwards’ against the usual synaptic transmitter flow.

They are, in effect, released from the postsynaptic cell and act on the presynaptic cell, where the target receptors are densely concentrated on axonal terminals in the zones from which conventional neurotransmitters are released.

Activation of cannabinoid receptors temporarily reduces the amount of conventional neurotransmitter released.

This endocannabinoid mediated system permits the postsynaptic cell to control its own incoming synaptic traffic.

The ultimate effect on the endocannabinoid-releasing cell depends on the nature of the conventional transmitter being controlled.

For instance, when the release of the inhibitory transmitter GABA is reduced, the net effect is an increase in the excitability of the endocannabinoid-releasing cell.

On the converse, when release of the excitatory neurotransmitter glutamate is reduced, the net effect is a decrease in the excitability of the endocannabinoid-releasing cell.

Range

Endocannabinoids are hydrophobic molecules. They cannot travel unaided for long distances in the aqueous medium surrounding the cells from which they are released, and therefore act locally on nearby target cells. Hence, although emanating diffusely from their source cells, they have much more restricted spheres of influence than do hormones, which can affect cells throughout the body.

Other thoughts

Endocannabinoids constitute a versatile system for affecting neuronal network properties in the nervous system.

”Scientific American” published an article in December 2004, entitled “The Brain’s Own Marijuana” discussing the endogenous cannabinoid system.

The current understanding recognizes the role that endocannabinoids play in almost every major life function in the human body.

U.S. Patent # 6630507

In 2003 The U.S.A.’s Government as represented by the Department of Health and Human Services was awarded a patent on cannabinoids as antioxidants and neuroprotectants. U.S. Patent 6630507.”

http://www.news-medical.net/health/Phytocannabinoids.aspx

Cannabinoid Receptors

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“Before the 1980s, it was often speculated that cannabinoids produced their physiological and behavioral effects via nonspecific interaction with cell membranes, instead of interacting with specific membrane-bound receptors.

The discovery of the first cannabinoid receptors in the 1980s helped to resolve this debate.

These receptors are common in animals, and have been found in mammals, birds, fish, and reptiles.

At present, there are two known types of cannabinoid receptors, termed CB1 and CB2, with mounting evidence of more.

Cannabinoid receptor type 1

CB1 receptors are found primarily in the brain, to be specific in the basal ganglia and in the limbic system, including the hippocampus.

They are also found in the cerebellum and in both male and female reproductive systems. CB1 receptors are absent in the medulla oblongata, the part of the brain stem responsible for respiratory and cardiovascular functions. Thus, there is not a risk of respiratory or cardiovascular failure as there is with many other drugs. CB1 receptors appear to be responsible for the euphoric and anticonvulsive effects of cannabis.

Cannabinoid receptor type 2

CB2 receptors are almost exclusively found in the immune system, with the greatest density in the spleen.

While found only in the peripheral nervous system, a report does indicate that CB2 is expressed by a subpopulation of microglia in the human cerebellum.

CB2 receptors appear to be responsible for the anti-inflammatory and possibly other therapeutic effects of cannabis.”

http://www.news-medical.net/health/Cannabinoid-Receptors.aspx

Cannabinoids.

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“Since the discovery of an endogenous cannabinoid system, research into the pharmacology and therapeutic potential of cannabinoids has steadily increased. Two subtypes of G-protein coupled cannabinoid receptors, CB(1) and CB(1), have been cloned and several putative endogenous ligands (endocannabinoids) have been detected during the past 15 years. The main endocannabinoids are arachidonoyl ethanolamide (anandamide) and 2-arachidonoyl glycerol (2-AG), derivatives of arachidonic acid, that are produced “on demand” by cleavage of membrane lipid precursors.

 Besides phytocannabinoids of the cannabis plant, modulators of the cannabinoid system comprise synthetic agonists and antagonists at the CB receptors and inhibitors of endocannabinoid degradation. Cannabinoid receptors are distributed in the central nervous system and many peripheral tissues, including immune system, reproductive and gastrointestinal tracts, sympathetic ganglia, endocrine glands, arteries, lung and heart. There is evidence for some non-receptor dependent mechanisms of cannabinoids and for endocannabinoid effects mediated by vanilloid receptors.

Properties of CB receptor agonists that are of therapeutic interest include analgesia, muscle relaxation, immunosuppression, anti-inflammation, antiallergic effects, improvement of mood, stimulation of appetite, antiemesis, lowering of intraocular pressure, bronchodilation, neuroprotection and antineoplastic effects. The current main focus of clinical research is their efficacy in chronic pain and neurological disorders. CB receptor antagonists are under investigation for medical use in obesity and nicotine addiction. Additional potential was proposed for the treatment of alcohol and heroine dependency, schizophrenia, conditions with lowered blood pressure, Parkinson’s disease and memory impairment in Alzheimer’s disease.”

http://www.ncbi.nlm.nih.gov/pubmed/16266285

Beta-caryophyllene is a dietary cannabinoid

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“The psychoactive cannabinoids from Cannabis sativa L. and the arachidonic acid-derived endocannabinoids are nonselective natural ligands for cannabinoid receptor type 1 (CB(1)) and CB(2) receptors. Although the CB(1) receptor is responsible for the psychomodulatory effects, activation of the CB(2) receptor is a potential therapeutic strategy for the treatment of inflammation, pain, atherosclerosis, and osteoporosis.

 Here, we report that the widespread plant volatile (E)-beta-caryophyllene [(E)-BCP] selectively binds to the CB(2) receptor and that it is a functional CB(2) agonist.

 Intriguingly, (E)-BCP is a common constituent of the essential oils of numerous spice and food plants and a major component in Cannabis.

 …this natural product exerts cannabimimetic effects in vivo. These results identify (E)-BCP as a functional nonpsychoactive CB(2) receptor ligand in foodstuff and as a macrocyclic antiinflammatory cannabinoid in Cannabis…

 Because (E)-BCP is a major constituent in Cannabis essential oil and shows significant cannabimimetic effects, it may also contribute to the overall effect of Cannabis preparations…”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2449371/