Category Archives: Endocannabinoid System

CB2 receptor agonists protect human dopaminergic neurons against damage from HIV-1 gp120.

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“The global pandemic of HIV infection currently afflicts 34 million individuals, has killed over 25 million people since 1981, and is the cause of death in an estimated 1.8 million people per year.

Despite the therapeutic impact of anti-retroviral therapy, HIV-1-associated neurocognitive disorder (HAND) remains a serious threat to AIDS patients…

Synthetic cannabinoids inhibit HIV-1 expression in human microglia, suppress production of inflammatory mediators in human astrocytes, and there is substantial literature demonstrating the neuroprotective properties of cannabinoids in other neuropathogenic processes.

Based on these data, experiments were designed to test the hypothesis that synthetic cannabinoids will protect dopaminergic neurons against the toxic effects of the HIV-1 protein gp120. Using a human mesencephalic neuronal/glial culture model…

These data suggest that synthetic cannabinoids are capable of protecting human dopaminergic neurons from gp120 in a variety of ways, acting principally through the CB2 receptors and microglia.

Overall, this study confirms that gp120 is capable of damaging human dopaminergic neurons, that this damage involves human microglia, and that synthetic cannabinoids can alleviate this damage through mechanisms involving human microglia.

Thus, the results of these experiments set the stage for further studies designed to tease out the role human microglia have in the mechanisms underlying the toxic effects of HIV-1 on human dopaminergic neurons and understanding the microglial-centered mechanisms underlying the protective effects of selected synthetic cannabinoids.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3798286/

Colocalization of cannabinoid receptor 1 with somatostatin and neuronal nitric oxide synthase in rat brain hippocampus.

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“Somatostatin (SST), a growth hormone inhibitory peptide, is expressed in different parts of the brain and functions as a neurotransmitter and neuromodulator. In the central nervous system (CNS), SST inhibits Ca2+ influx and regulates neuronal excitability in the hippocampus, the brain region which plays a major role in seizure, as well as cognitive and memory function.

Much like SST, cannabinoid receptor 1 (CB1 receptor) is also widely distributed in the CNS, associated with memory function ad exerts inhibitory effects on seizure.

It is unknown whether overlapping functional activities of SST and CB1 receptor are also associated with coexpression in the hippocampus.

In the present study, we determined the colocalization between SST and CB1 receptor in adult rat brain hippocampus. In the CNS, the majority of SST positive interneurons coexpress neuronal nitric oxide synthase (nNOS). Accordingly, colocalization studies were also performed to determine whether nNOS positive neurons display comparable colocalization with CB1 receptor.

The findings suggested that SST and nNOS are expressed in most interneurons whereas CB1 receptor is present in both interneurons and projection neurons in hippocampal regions. The distinct neuronal populations either expressing CB1 receptor, SST and nNOS alone or colocalization were observed in a region specific manner.

Taken together, the observations described here anticipate the possibility of crosstalk between somatostatin subtypes and CB1 receptor in regulation of physiological activities in the hippocampus.”

http://www.ncbi.nlm.nih.gov/pubmed/26115586

Activation of cannabinoid receptors prevents antigen-induced asthma-like reaction in guinea pigs.

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“In this study we evaluated the effects of the CB1/CB2 cannabinoid receptor agonist on antigen-induced asthma-like reaction in sensitized guinea pigs…

These findings suggest that targeting cannabinoid receptors could be a novel preventative therapeutic strategy in asthmatic patients.”

http://www.ncbi.nlm.nih.gov/pubmed/18266975

The endogenous cardiac cannabinoid system: a new protective mechanism against myocardial ischemia.

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“The pharmacological (and recreational) effects of cannabis have been known for centuries. However, it is only recently that one has identified two subtypes of G-protein-coupled receptors, namely CB1 and CB2-receptors, which mediate the numerous effects of delta9-tetrahydrocannabinol and other cannabinoids.

Logically, the existence of cannabinoid-receptors implies that endogenous ligands for these receptors (endocannabinoids) exist and exert a physiological role. Hence, arachidonoylethanolamide (anandamide) and sn-2 arachidonoylglycerol, the first two endocannabinoids identified, are formed from plasma membrane phospholipids and act as CB1 and/or CB2 agonists.

The presence of both CB1 and CB2-receptors in the rat heart is noteworthy.

This endogenous cardiac cannabinoid system is involved in several phenomena associated with cardioprotective effects.

The reduction in infarct size following myocardial ischemia, observed in rats exposed to either LPS or heat stress 24 hours before, is abolished in the presence of a CB2-receptor antagonist.

Endocannabinoids and synthetic cannabinoids, the latter through either CB1 or CB2-receptors, exert direct cardioprotective effects in rat isolated hearts.

The ability of cannabinoids to reduce infarct size has been confirmed in vivo in anesthetized mice and rats. This latter effect appears to be mediated through CB2-receptors.

Thus, the endogenous cardiac cannabinoid system, through activation of CB2-receptors, appears to be an important mechanism of protection against myocardial ischemia.”

https://pubmed.ncbi.nlm.nih.gov/16618028

An ultra-low dose of tetrahydrocannabinol provides cardioprotection.

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“Tetrahydrocannabinol (THC), the major psychoactive component of marijuana, is a cannabinoid agonist that exerts its effects by activating at least two specific receptors (CB1 and CB2) that belong to the seven transmembrane G-protein coupled receptor (GPCR) family.

Both CB1 and CB2 mRNA and proteins are present in the heart.

THC treatment was beneficial against hypoxia in neonatal cardiomyocytes in vitro.

We also observed a neuroprotective effect of an ultra low dose of THC when applied to mice before brain insults.

The present study was aimed to test and characterize the cardioprotective effects of a very low dose of THC…

All protocols of THC administration were found to be beneficial.

CONCLUSION:

A single ultra low dose of THC before ischemia is a safe and effective treatment that reduces myocardial ischemic damage.”

http://www.ncbi.nlm.nih.gov/pubmed/23537701

Delta-9-tetrahydrocannabinol protects cardiac cells from hypoxia via CB2 receptor activation and nitric oxide production.

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“Delta-9-tetrahydrocannabinol (THC), the major active component of marijuana, has a beneficial effect on the cardiovascular system during stress conditions…

The present study was designed to investigate the central (CB1) and the peripheral (CB2)cannabinoid receptor expression in neonatal cardiomyoctes and possible function in the cardioprotection of THC from hypoxia.

The antagonist for the CB2, but not CB1 receptor antagonist abolished the protective effect of THC.

In agreement with these results using RT-PCR, it was shown that neonatal cardiac cells express CB2, but not CB1 receptors.

Involvement of NO in the signal transduction pathway activated by THC through CB2 was examined. It was found that THC induces nitric oxide (NO) production by induction of NO synthase (iNOS) via CB2 receptors.

L-NAME (NOS inhibitor, 100 microM) prevented the cardioprotection provided by THC.

Taken together, our findings suggest that THC protects cardiac cells against hypoxia via CB2 receptor activation by induction of NO production.

An NO mechanism occurs also in the classical pre-conditioning process; therefore, THC probably pre-trains the cardiomyocytes to hypoxic conditions.”

http://www.ncbi.nlm.nih.gov/pubmed/16444588

Cannabidiol, a nonpsychoactive Cannabis constituent, protects against myocardial ischemic reperfusion injury

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Heart and Circulatory Physiology

“CANNABINOIDS ARE NATURAL and synthetic compounds structurally or pharmacologically related to the constituents of the plant Cannabis sativa or to the endogenous agonists (endocannabinoids) of the cannabinoid CB1 and CB2 receptors.

Cannabidiol (CBD) is a major cannabinoid constituent of Cannabis.

In contrast to tetrahydrocannabinol, CBD binds very weakly to CB1 and CB2 receptors. Contrary to most cannabinoids, CBD does not induce psychoactive or cognitive effects.

CBD has been shown to have anti-inflammatory properties. CBD (together with tetrahydrocannabinol) has been successfully tested in a few preliminary human trials related to autoimmune diseases…

Cannabidiol (CBD) is a major, nonpsychoactive Cannabis constituent with anti-inflammatory activity mediated by enhancing adenosine signaling.

Inasmuch as adenosine receptors are promising pharmaceutical targets for ischemic heart diseases, we tested the effect of CBD on ischemic rat hearts.

Our study shows that CBD induces a substantial in vivo cardioprotective effect from ischemia that is not observed ex vivo.

Inasmuch as CBD has previously been administered to humans without causing side effects, it may represent a promising novel treatment for myocardial ischemia.”

http://ajpheart.physiology.org/content/293/6/H3602

CB(2) cannabinoid receptor activation is cardioprotective in a mouse model of ischemia/reperfusion.

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“Preventive treatment with cannabinoid agonists has been reported to reduce the infarct size in a mouse model of myocardial ischemia/reperfusion.

Here we investigated the possible cardioprotective effect of selective CB(2) cannabinoid receptor activation during ischemia.

Our data suggest that administration during ischemia reduces the infarct size in a mouse model of myocardial ischemia/reperfusion through a direct cardioprotective activity on cardiomyocytes and neutrophils.”

http://www.ncbi.nlm.nih.gov/pubmed/19162037

The cannabinoid receptor type 2 promotes cardiac myocyte and fibroblast survival and protects against ischemia/reperfusion-induced cardiomyopathy

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“Post-myocardial infarction (MI) heart failure is a major public health problem in Western countries and results from ischemia/reperfusion (IR)-induced cell death, remodeling, and contractile dysfunction.

Ex vivo studies have demonstrated the cardioprotective anti-inflammatory effect of the cannabinoid type 2 (CB2) receptor agonists within hours after IR.

Herein, we evaluated the in vivo effect of CB2 receptors on IR-induced cell death, fibrosis, and cardiac dysfunction and investigated the target role of cardiac myocytes and fibroblasts… CB2 receptor activation may protect against post-IR heart failure through direct inhibition of cardiac myocyte and fibroblast death and prevention of myofibroblast activation…

In conclusion, modulation of the endocannabinoid system is emerging as a novel approach for the therapy of various inflammatory, metabolic, cardiovascular, hepatic, and neurodegenerative disorders.

CB1 receptors exert cardioprotective effects in cirrhotic rats and against doxorubicin toxicity. Pharmacological inhibition of the endocannabinoid degradative pathway, fatty acid aminohydrolase, represents a novel protective strategy against chronic inflammation, oxidative and nitrative stresses, and apoptosis associated with cardiovascular aging and atherosclerosis.

CB2 receptor activation is thought to be anti-inflammatory and involved in protective mechanisms during atherosclerosis. In addition, selective CB2 agonists protect against cerebral and hepatic IR injuries.

We demonstrated a highly protective role of CB2 receptors in post-IR cardiac remodeling, potentially related to activation of antiapoptotic, prosurvival, and antifibrogenic pathways.

Our results infer that CB2 agonists may be useful in preventing reperfusion injury in acute coronary syndrome and provide novel evidence for the pivotal role of CB2 receptors in post-IR-induced cardiomyopathy.”

http://www.fasebj.org/content/23/7/2120.long

Cannabinoid system as a potential target for drug development in the treatment of cardiovascular disease.

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“Although cannabinoids have been recreationally employed for thousands of years, it was not until the discovery of their specific receptors, in the early nineties, that the molecular basis of cannabinoid activity have began to be understood.

Growing research in this field has demonstrated not only that the action of cannabinoids in mammals is mainly receptor-mediated, but also that endogenous cannabinoids, such as anandamide, are produced, metabolized, and taken up across the cell membrane through a facilitated uptake process.

The exogenous administration of cannabinoids, as well as the manipulation of their endogenous levels have been related to a variety of effects, such as analgesia, (temporary) impairment of cognition and learning, appetite enhancement and peripheral vasodilation.

Hence, the endocannabinoid system, including the CB1 and CB2 receptors, the metabolizing enzyme fatty acid amide hydrolase and the anandamide transporter, is a potential target for the development of novel therapeutic drugs in the treatment of various conditions, such as pain, feeding disorders and vascular disease among others.

Although most of the research in the field of cannabinoids has been focused on their effects in the central nervous system, a growing line of evidence indicates that cannabinoids can also play a major role in the control of physiopathological functions in the cardiovascular system.

In this context, endocannabinoids have been proposed as novel possible hypotensive agents, and have been involved in the hypotension observed in septic shock, acute myocardial infarction and cirrhosis. In addition, a protective role for endocannabinoids has been described in ischemia.”

http://www.ncbi.nlm.nih.gov/pubmed/15320476