The Endocannabinoid System, Our Universal Regulator

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“The endocannabinoid system (ECS) plays a very important role in the human body for our survival. This is due to its ability to play a critical role in maintaining the homeostasis of the human body, which encompasses the brain, endocrine, and immune system, to name a few. ECS is a unique system in multiple dimensions.

To begin with, it is a retrograde system functioning post- to pre-synapse, allowing it to be a “master regulator” in the body. Secondly, it has a very wide scope of influence due to an abundance of cannabinoid receptors located anywhere from immune cells to neurons. Finally, cannabinoids are rapidly synthesized and degraded, so they do not stay in the body for very long in high amounts, possibly enabling cannabinoid therapy to be a safer alternative to opioids or benzodiazepines. This paper will discuss how ECS functions through the regulation of neurotransmitter function, apoptosis, mitochondrial function, and ion-gated channels. The practical applications of the ECS, as well as the avenues for diseases such as epilepsy, cancer, amyotrophic lateral sclerosis (ALS), and autism, which have no known cure as of now, will be explored.

The ECS is one of the, if not the most, important systems in our body. Its role in the homeostatic function of our body is undeniable, and its sphere of influence is incredible. Additionally, it also plays a major role in apoptotic diseases, mitochondrial function, and brain function.

Its contribution is more than maintaining homeostasis; it also has a profound ability in regulation. Working in a retrograde fashion and with a generally inhibitory nature, ECS can act as a “kill switch.” However, it has been shown to play an inhibitory or stimulatory role based on the size of the influx of cannabinoids, resulting in a bimodal regulation. Furthermore, due to the nature of the rate of degradation of cannabinoids, it does not have as many long-term side effects as most of the current drugs on the market.

The ECS may not only provide answers for diseases with no known cures, but it could change the way we approach medicine. This system would allow us to change our focus from invasive pharmacological interventions (i.e. SSRIs for depression, benzodiazepines for anxiety, chemotherapies for cancer) to uncovering the mystery of why the body is failing to maintain homeostasis. Understanding the roles of ECS in these diseases confers a new direction for medicine which may eradicate the use of some of the less tolerable therapeutics.”

https://www.jyi.org/2018-june/2018/6/1/the-endocannabinoid-system-our-universal-regulator

Cannabinoids: a new approach for pain control?

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“To analyze available data related to the use of cannabinoids in medicine, with a special focus on pain management in cancer. The use of cannabis for medical purposes is growing but there are still numerous questions to be solved: effectiveness, safety, and specific indications.

RECENT FINDINGS:

There is considerable variation between countries in the approaches taken, reflecting a variety of historical and cultural factors and despite few randomized controlled studies using natural cannabinoids, there is a trend to state that the use of cannabis should be taken seriously as a potential treatment of cancer-related pain. Cannabidiol, a nontoxic phytocannabinoid with few side-effects is promising in various indications in medicine.

SUMMARY:

The endocannabinoid system is a potential therapeutic target. Cannabinoids may be considered as potential adjuvant in cancer-related pain management. Cannabidiol appears to be the drug of choice. Analgesic trial designs should evolve to get closer to real-life practice and to avoid biases.”

https://www.ncbi.nlm.nih.gov/pubmed/30789867

https://insights.ovid.com/crossref?an=00001622-900000000-00002

Lower circulating endocannabinoid levels in children with autism spectrum disorder.

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“The endocannabinoid system (ECS) is a major regulator of synaptic plasticity and neuromodulation. Alterations of the ECS have been demonstrated in several animal models of autism spectrum disorder (ASD). In some of these models, activating the ECS rescued the social deficits. Evidence for dysregulations of the ECS in human ASD are emerging, but comprehensive assessments and correlations with disease characteristics have not been reported yet.

METHODS:

Serum levels of the main endocannabinoids, N-arachidonoylethanolamine (AEA or anandamide) and 2-arachidonoylglycerol (2-AG), and their related endogenous compounds, arachidonic acid (AA), N-palmitoylethanolamine (PEA), and N-oleoylethanolamine (OEA), were analyzed by liquid chromatography/tandem mass spectrometry in 93 children with ASD (age = 13.1 ± 4.1, range 6-21; 79% boys) and 93 age- and gender-matched neurotypical children (age = 11.8 ± 4.3, range 5.5-21; 79% boys). Results were associated with gender and use of medications, and were correlated with age, BMI, and adaptive functioning of ASD participants as reflected by scores of Autism Diagnostic Observation Schedule (ADOS-2), Vineland Adaptive Behavior Scale-II (VABS-II), and Social Responsiveness Scale-II (SRS-2).

RESULTS:

Children with ASD had lower levels (pmol/mL, mean ± SEM) of AEA (0.722 ± 0.045 vs. 1.252 ± 0.072, P < 0.0001, effect size 0.91), OEA (17.3 ± 0.80 vs. 27.8 ± 1.44, P < 0.0001, effect size 0.94), and PEA (4.93 ± 0.32 vs. 7.15 ± 0.37, P < 0.0001, effect size 0.65), but not AA and 2-AG. Serum levels of AEA, OEA, and PEA were not significantly associated or correlated with age, gender, BMI, medications, and adaptive functioning of ASD participants. In children with ASD, but not in the control group, younger age and lower BMI tended to correlate with lower AEA levels. However, these correlations were not statistically significant after a correction for multiple comparisons.

CONCLUSIONS:

We found lower serum levels of AEA, PEA, and OEA in children with ASD. Further studies are needed to determine whether circulating endocannabinoid levels can be used as stratification biomarkers that identify clinically significant subgroups within the autism spectrum and if they reflect lower endocannabinoid “tone” in the brain, as found in animal models of ASD.”

https://www.ncbi.nlm.nih.gov/pubmed/30728928

https://molecularautism.biomedcentral.com/articles/10.1186/s13229-019-0256-6

Cutting Edge: Dysregulated Endocannabinoid-Rheostat for Plasmacytoid Dendritic Cell Activation in a Systemic Lupus Endophenotype.

The Journal of Immunology

“Systemic lupus erythematosus (SLE) is a systemic autoimmune disease, characterized by loss of tolerance toward self nuclear Ags. Systemic induction of type I IFNs plays a pivotal role in SLE, a major source of type I IFNs being the plasmacytoid dendritic cells (pDCs). Several genes have been linked with susceptibility to SLE in genome-wide association studies. We aimed at exploring the role of one such gene, α/β-hydrolase domain-containing 6 (ABHD6), in regulation of IFN-α induction in SLE patients. We discovered a regulatory role of ABHD6 in human pDCs through modulating the local abundance of its substrate, the endocannabinoid 2-arachidonyl glycerol (2-AG), and elucidated a hitherto unknown cannabinoid receptor 2 (CB2)-mediated regulatory role of 2-AG on IFN-α induction by pDCs. We also identified an ABHD6High SLE endophenotype wherein reduced local abundance of 2-AG relieves the CB2-mediated steady-state resistive tuning on IFN-α induction by pDCs, thereby contributing to SLE pathogenesis.”

https://www.ncbi.nlm.nih.gov/pubmed/30728209

http://www.jimmunol.org/content/early/2019/02/05/jimmunol.1801521

Synergistic action of CB1 and 5-HT2B receptors in preventing pilocarpine-induced status epilepticus in rats.

Neurobiology of Disease

“Endocannabinoids (eCBs) and serotonin (5-HT) play a neuromodulatory role in the central nervous system. Both eCBs and 5-HT regulate neuronal excitability and their pharmacological potentiation has been shown to control seizures in pre-clinical and human studies.

Compelling evidence indicates that eCB and 5-HT systems interact to modulate several physiological and pathological brain functions, such as food intake, pain, drug addiction, depression, and anxiety.

Nevertheless, there is no evidence of an eCB/5-HT interaction in experimental and human epilepsies, including status epilepticus (SE). Here, we performed video-EEG recording in behaving rats treated with the pro-convulsant agent pilocarpine (PILO), in order to study the effect of the activation of CB1/5-HT2receptors and their interaction on SE.

Synthetic cannabinoid agonist WIN55,212-2 (WIN) decreased behavioral seizure severity of PILO-induced SE at 2 mg/kg (but not at 1 and 5 mg/kg, i.p.), while 5-HT2B/2C receptor agonist RO60-0175 (RO; 1, 3, 10 mg/kg, i.p.) was devoid of any effect. RO 3 mg/kg was instead capable of potentiating the effect of WIN 2 mg/kg on the Racine scale score.

Surprisingly, neither WIN 2 mg/kg nor RO 3 mg/kg had any effect on the incidence and the intensity of EEG seizures when administered alone. However, WIN+RO co-administration reduced the incidence and the severity of EEG SE and increased the latency to SE onset after PILO injection. WIN+RO effects were blocked by the selective CB1R antagonist AM251 and the 5-HT2BR antagonist RS127445, but not by the 5-HT2CR antagonist SB242084 or the 5-HT2AR antagonist MDL11,939.

These data revealed a synergistic interaction between CB1R/5-HT2BR in the expression of PILO-induced SE.”

https://www.ncbi.nlm.nih.gov/pubmed/30716469

https://www.sciencedirect.com/science/article/pii/S0969996119300336?via%3Dihub

Ketamine induces central antinociception mediated by endogenous cannabinoids and activation of CB1 receptors.

Neuroscience Letters

“The participation of endocannabinoids in central and peripheral antinociception induced by several compounds has been shown by our group.

In this study, we investigated the effect of endocannabinoids on the central antinociception induced by ketamine.

It was concluded that central antinociception induced by ketamine involves the activation of CB1 cannabinoidreceptors.

Mobilization of cannabinoids might be required for the activation of those receptors, since inhibitors of the endogenous cannabinoids potentiate the effect of Ketamine.”

https://www.ncbi.nlm.nih.gov/pubmed/30716423

https://www.sciencedirect.com/science/article/abs/pii/S0304394019300771?via%3Dihub

Hemisphere-dependent endocannabinoid system activity in prefrontal cortex and hippocampus of the Flinders Sensitive Line rodent model of depression.

Neurochemistry International“Altered endocannabinoid (eCB) signaling is suggested as an important contributor to the pathophysiology of depression.

In summary, our data suggest a decreased eCB signalling in the FSL rats, which could contribute to the depressive-like behaviour.

Interestingly, the altered eCB system activity appear to be hemisphere-specific in the limbic regions.

Our study support the existing literature and showed altered eCB system activity in this particular animal model of depression.”

https://www.ncbi.nlm.nih.gov/pubmed/30716357

https://www.sciencedirect.com/science/article/abs/pii/S0197018618305151?via%3Dihub

“Antidepressant-like effect of delta9-tetrahydrocannabinol and other cannabinoids isolated from Cannabis sativa L. Results of this study show that Delta(9)-THC and other cannabinoids exert antidepressant-like actions, and thus may contribute to the overall mood-elevating properties of cannabis.”   https://www.ncbi.nlm.nih.gov/pubmed/20332000

Cannabinoids and Bone Regeneration.

 Publication Cover“Bone is a complex tissue of the with unique properties such as high strength and regeneration capabilities while carrying out multiple functions. Bone regeneration occurs both in physiological situations (bone turnover) and pathological situations (e.g. fractures), being performed by osteoblasts and osteoclasts. If this process is inadequate, fracture nonunion or aseptic loosening of implants occurs and requires a complex treatment.

Exogenous factors are currently used to increase bone regeneration process when needed, such as bisphosphonates and vitamin D, but limitations do exist. Cannabinoid system has been shown to have positive effects on bone metabolism. Cannabinoids at bone level mainly act on two receptors called CB-1 and CB-2, but GPR55, GPR119, TPRV1, TPRV4 receptors may also be involved. The CB-2 receptors are found in bone cells at higher levels compared to other receptors.

Endocannabinods represented by anandamide and 2-arachidonoylglycerol, can stimulate osteoblast formation, bone formation and osteoclast activity. CB-2 agonists including HU-308, HU-433, JWH133 and JWH015 can stimulate osteoblast proliferation and activity, while CB-2 antagonists such as AM630 and SR144528 can inhibit osteoclast differentiation and function. CB-1 antagonist AM251 has been shown to inhibit osteoclast differentiation and activity, while GPR55 antagonist cannabidiol increases osteoblast activity and decreases osteoclast function.

An optimal correlation of dose, duration, moment of action and affinity can lead to an increased bone regeneration capacity, with important benefits in many pathological situations which involve bone tissue. As adverse reactions of cannabinoids haven’t been described in patients under controlled medication, cannabinoids can represent future treatment for bone regeneration.”

https://www.ncbi.nlm.nih.gov/pubmed/30702341

https://www.tandfonline.com/doi/abs/10.1080/03602532.2019.1574303?journalCode=idmr20

[Endogenous Cannabinoid System of the Brain as the Target for Influences at Neurodegenerate Diseases]

“The review represents the analysis of works about role of endogenous cannabinoid (EC) system in the neuro- degenerate diseases (ND), in which the cellular death and disturbances of neuronal functions of the hippo- campus, neocortex and striatum are observed. Here, the diseases.ofAlzheimer, of Parkinson, of Hangtington, and the temporal lobe epilepsy are considered. In recent years the fundamental role of EC system in regu- lation of neuroexcitability, energy metabolism, inflammatory and many other processes has been opened in ND pathogenesis. It points to possibility of development of therapeutic approaches which use the prepara- tions for activation of EC system. In the review various mechanisms of cellular survival and their reparations provided to EC system during action of pathological factors are stated.”

https://www.ncbi.nlm.nih.gov/pubmed/30695519

Targeting CB1 and GPR55 Endocannabinoid Receptors as a Potential Neuroprotective Approach for Parkinson’s Disease.

 “Cannabinoid CB1 receptors (CB1R) and the GPR55 receptor are expressed in striatum and are potential targets in the therapy of Parkinson’s disease (PD), one of the most prevalent neurodegenerative diseases in developed countries.

The aim of this paper was to address the potential of ligands acting on those receptors to prevent the action of a neurotoxic agent, MPP+, that specifically affects neurons of the substantia nigra due to uptake via the dopamine DAT transporter.

These results show that neurons expressing heteromers are more resistant to cell death but question the real usefulness of CB1R, GPR55, and their heteromers as targets to afford PD-related neuroprotection.”

https://www.ncbi.nlm.nih.gov/pubmed/30687889

https://link.springer.com/article/10.1007%2Fs12035-019-1495-4