An Unexpected Activity of a Minor Cannabinoid: Cannabicyclol (CBL) Is a Potent Positive Allosteric Modulator of Serotonin 5-HT1A Receptor

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“Cannabicyclol ((±)-CBL), a minor phytocannabinoid, is largely unexplored, with its biological activity previously undocumented. We studied its conversion from cannabichromene (CBC) using various acidic catalysts. Montmorillonite (K30) in chloroform at room temperature had the highest yield (60%) with minimal byproducts. Key reaction conditions, such as solvent, temperature, and time, significantly impacted the yield. The structure of (±)-CBL was confirmed via X-ray crystallography. Stability studies showed that (±)-CBL and its MCT oil dilution remain stable at 25-40 °C for three months. Radioligand binding assays revealed high affinity of CBL for the 5-HT1A receptor but weak interaction with CB1 and CB2 receptors. At 10 μM and 1 μM, (±)-CBL inhibited [3H]-8-hydroxy-DPAT binding to 5-HT1A by 75% and 20%, respectively. Functional assays showed that (±)-CBL acts as a weak agonist at high concentrations but a potent positive allosteric modulator of serotonin-induced activation at low concentrations. At 4 μM, (±)-CBL increased serotonin-induced β-arrestin recruitment from 20% to 80%. This unique modulatory profile highlights the potential of (±)-CBL in drug discovery targeting serotonin receptors.”

https://pubmed.ncbi.nlm.nih.gov/39811943/

https://pubs.acs.org/doi/10.1021/acs.jnatprod.4c00977

“Positive allosteric modulators of the 5-HT1A receptor can help relieve anxiety and depression.”

CBD and the 5-HT1A receptor: A medicinal and pharmacological review

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“Cannabidiol (CBD), a phytocannabinoid, has emerged as a promising candidate for addressing a wide array of symptoms.

It has the ability to bind multiple proteins and receptors, including 5-HT1AR, transient receptor potential vanilloid 1 (TRPV1), and cannabinoid receptors. However, CBD’s pharmacodynamic interaction with 5-HT1AR and its medicinal outcomes are still debated.

This review explores recent literature to elucidate these questions, highlighting the neurotherapeutic outcomes of this pharmacodynamic interaction and proposing a signaling pathway underlying the mechanism by which CBD desensitizes 5-HT1AR signaling.

A comprehensive survey of the literature underscores CBD’s multifaceted neurotherapeutic effects, encompassing antidepressant, anxiolytic, neuroprotective, antipsychotic, antiemetic, anti-allodynic, anti-epileptic, anti-degenerative, and addiction-treating properties, attributable in part to its interactions with 5-HT1AR.

Furthermore, evidence suggests that the pharmacodynamic interaction between CBD and 5-HT1AR is contingent upon dosage. Moreover, we propose that CBD can induce desensitization of 5-HT1AR via both homologous and heterologous mechanisms. Homologous desensitization involves the recruitment of G protein-coupled receptor kinase 2 (GRK2) and β-arrestin, leading to receptor endocytosis. In contrast, heterologous desensitization is mediated by an elevated intracellular calcium level or activation of protein kinases, such as c-Jun N-terminal kinase (JNK), through the activity of other receptors.”

https://pubmed.ncbi.nlm.nih.gov/39778776/

“Cannabis was one of the first inhaled drugs utilized by humans, with evidence of use for gout, rheumatism, and malaria dating to 2737 BCE”

“The concurrent literature revealed that CBD produces several therapeutic effects through its complex pharmacodynamic interactions with 5-HT1AR. Therapeutic applications of CBD, including its anxiolytic, antidepressant, antipsychotic, anti-degenerative, neuroprotective, anti-epileptic, and anti-addictive properties were mediated, at least in part, by its binding to 5-HT1AR.”

https://www.sciencedirect.com/science/article/abs/pii/S0006295225000048?via%3Dihub

Chronic cannabidiol administration modulates depressive and cognitive alterations induced by social isolation in male mice

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“Cannabidiol (CBD), a non-psychotropic compound derived from Cannabis sativa, is known for its potential therapeutic effects on central nervous system (CNS) disorders.

This study investigates the effects of chronic CBD administration on depressive and cognitive alterations induced by social isolation in male C57BL/6 mice. The experimental design involved adult mice subjected to either group housing or 12 weeks of social isolation. Behavioral assessments, including the sucrose preference test, open field test, light/dark box, novel object recognition, and tail suspension test, were performed to evaluate the impact of CBD on emotional and cognitive alterations. Additionally, hippocampal gene expression for cannabinoid type 1 receptors (CB1R), serotonin type 1A receptors (5HT1AR), and brain-derived neurotrophic factor (BDNF) were analyzed.

Results indicate that CBD mitigated anhedonia in isolated mice and reduced immobility episodes in the TST. However, CBD did not exert significant anxiolytic effects and unexpectedly induced anxiety-like behavior in group-housed mice. The study also revealed that social isolation impaired recognition memory and reduced BDNF expression, while CBD treatment protected memory in isolated mice.

These findings suggest that CBD has potential antidepressant and neuroprotective effects in social isolation-induced depressive models, although its anxiogenic effects in non-stressed mice warrant further investigation.”

https://pubmed.ncbi.nlm.nih.gov/39725273/

“Cannabidiol (CBD) is a non-psychotropic, lipophilic phytocannabinoid of Cannabis sativa plants. CBD has been reported as a potential therapeutic agent for central nervous system (CNS) disorders due to its high permeability across the blood-brain barrier and its pleiotropic neuropharmacological effects “

“The results of this study demonstrate that chronic CBD administration attenuates depressive-like behaviors and protects cognitive function in SI male mice. Specifically, CBD mitigated anhedonia, a hallmark of depression, and reduced immobility in the TST, indicating an antidepressant-like effect.”

https://www.sciencedirect.com/science/article/abs/pii/S0166432824005643?via%3Dihub

A novel insight into the antidepressant effect of cannabidiol: possible involvement of the 5-HT1A, CB1, GPR55, and PPARγ receptors

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“Background: Depression is a prevalent and disabling disorder that poses serious problems in mental health care, and rapid antidepressants are novel treatments for this disorder. Cannabidiol (CBD), a non-intoxicating phytocannabinoid, is thought to have therapeutic potential due to its important neurological and anti-inflammatory properties. Despite major advances in pharmacotherapy in experimental animals, the exact mechanism of antidepressant-like effects remains to be elucidated.

Methods: In this paper, we review the current state of knowledge on the antidepressant properties of CBD in numerous experimental and clinical studies.

Results: Accumulating evidence suggests that CBD has antidepressant properties in humans and animals with few side effects, suggesting that CBD may be a potential antidepressant. Furthermore, we discuss CBD may therefore provide a potential treatment to exert antidepressant-like effects through various molecular targets, reducing inflammation, and enhancing neurogenesis.

Conclusions: Taken together with the growing popularity of CBD as a medicine, these findings extend the limited knowledge on the antidepressant effects of CBD. This potentially opens up new therapeutic means for the patients with depression.”

https://pubmed.ncbi.nlm.nih.gov/39657242/

https://academic.oup.com/ijnp/advance-article/doi/10.1093/ijnp/pyae064/7918373?login=false

Therapeutic potential of minor cannabinoids in psychiatric disorders: A systematic review

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“Interest in cannabinoids’ therapeutic potential in mental health is growing, supported by evidence of the involvement of the endocannabinoid system in psychiatric disorders such as anxiety, depression, and addiction.

While the major cannabinoids cannabidiol (CBD) and Δ9-tetrahydrocannabinol (Δ9-THC) have been more extensively researched, approximately 120 minor cannabinoids from the cannabis plant have been identified. Although some displayed promising pharmacological profiles, research on their application for psychiatric disorders is fragmented.

This systematic review evaluates, for the first time, both preclinical and clinical studies exploring minor cannabinoids’ therapeutic potential in psychiatric disorders. 22 preclinical studies and one clinical study were included, investigating various minor cannabinoids in substance use disorders, anxiety disorders, depressive disorders, trauma and stressor-related disorders, psychotic disorders, neurodevelopmental disorders, and eating disorders. Despite the heterogeneous results and the moderate to high risk of bias in several articles, certain compounds demonstrate promise for further investigation.

Δ8-tetrahydrocannabidivarin (Δ8-THCV) exhibited potential for nicotine addiction; Δ9-tetrahydrocannabidivarin (Δ9-THCV) for psychotic-like symptoms; cannabidiolic acid methyl ester (CBDA-ME) alleviated anxiety and depression-like symptoms, and cannabidivarin (CBDV) autism spectrum disorder-like symptoms.”

https://pubmed.ncbi.nlm.nih.gov/39541799/

https://www.sciencedirect.com/science/article/pii/S0924977X24007508?via%3Dihub

Antidepressant-like Effects of Cannabis sativa L. Extract in an Lipopolysaccharide Model: Modulation of Mast Cell Activation in Deep Cervical Lymph Nodes and Dura Mater

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“Background: Lipopolysaccharide (LPS)-induced neuroinflammation is a well-established model for studying depression-like behavior, driven by pro-inflammatory cytokines such as TNF-α and IL-1β. Mast cells (MCs) contribute to neuroinflammation by releasing mediators that exacerbate depressive-like symptoms. This study evaluates the antidepressant-like and anti-inflammatory effects of Cannabis sativa L. inflorescence extract (CSL) in an LPS-induced neuroinflammation model.

Methods: Male C57BL/6 mice were intraperitoneally injected with CSL at doses of 10, 20, and 30 mg/kg, 30 min prior to LPS (0.83 mg/kg) administration. Depressive behaviors were assessed using the sucrose preference test (SPT), tail suspension test (TST), and forced swimming test (FST). The neutrophil-to-lymphocyte ratio (NLR) was measured to assess systemic inflammation. Cytokine levels in the prefrontal cortex (PFC) were measured, and mast cell degranulation in the lymph nodes and dura mater was analyzed histologically (approval number: WKU24-64).

Results: CSL significantly improved depressive-like behaviors and decreased the NLR, indicating reduced systemic inflammation. CSL also significantly reduced TNF-α and IL-1β levels in the PFC. Furthermore, CSL inhibited MC degranulation in the deep cervical lymph nodes and dura mater, with the strongest effects observed at 30 mg/kg.

Conclusions: CSL demonstrated antidepressant-like and anti-inflammatory effects in an LPS-induced neuroinflammation model, likely through the modulation of cytokine expression and mast cell activity. These results suggest the potential of CSL as a therapeutic option for treating inflammation-related depression.”

https://pubmed.ncbi.nlm.nih.gov/39459047/

“We demonstrated that CSL exhibits significant antidepressant-like and anti-inflammatory effects in an LPS-induced neuroinflammatory model. CSL administration effectively reduced depressive-like behaviors, as observed in the SPT, TST, and FST, and modulated the degranulation of MCs in LNs and the dura mater. Furthermore, CSL decreased the expression of pro-inflammatory cytokines TNF-α and IL-1β in the PFC in a dose-dependent manner. These findings suggest that CSL acts both through immune modulation and neuroinflammation suppression, possibly via the endocannabinoid system and pathways such as NF-κB, PPAR-γ, and VEGF-C. The synergistic interaction between cannabinoids and terpenes in CSL likely contributes to its therapeutic potential, supporting the notion of the “entourage effect”. While these results are promising, further studies are required to clarify the exact mechanisms involved and to assess the long-term safety and efficacy of CSL in chronic depression models.”

https://www.mdpi.com/1424-8247/17/10/1409

Effects of Cannabidiol (CBD) on Doxorubicin-Induced Anxiety and Depression-like Behaviors and mRNA Expression of Inflammatory Markers in Rats

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“Background: Post-treatment side effects of chemotherapy can include cognitive deficits commonly known as Chemo-brain. The treatment of patients with Doxorubicin (DOX), one of the most widely used chemotherapeutic drugs in the treatment of cancer, can induce depression, anxiety, and impaired cognitive function. Cannabidiol (CBD) is a non-psychoactive component of Cannabis sativa that has been identified as a possible therapeutic agent against many neurodegenerative disorders, including traumatic brain injury, spinal cord injury, Tau-protein-induced neurodegeneration, and neuropathic pain. Therefore, this study aimed to assess whether oral CBD administration could reduce DOX-induced anxiety and depression-like behaviors and alter the expression of mRNA associated with neuroinflammation. 

Methods: Female Long Evans Hooded rats received intraperitoneal injections of DOX (6 mg/kg) or the vehicle (0.9% saline) once a week for four weeks, followed by oral administration of CBD (10 mg/kg) three times a week for the same period. 

Results: CBD was significantly protective against DOX-induced anxiety and depression-like behaviors, as measured by several behavioral tests. Furthermore, CBD improved DOX-induced alterations in the gene expression of biomarkers of neuroinflammation in the hippocampus and prefrontal cortex. 

Conclusions: This provides insights into future studies on possible mechanisms by which DOX-induced cognitive dysfunction could be alleviated by CBD.”

https://pubmed.ncbi.nlm.nih.gov/39452013/

“In conclusion, this study demonstrated that the chronic, systemic administration of DOX impairs cognitive abilities in rats, increases anxiety and depression-like behaviors, and regulates the expression of genes involved in neuroinflammation. We found that CBD-treated rats had fewer anxiety and depression-like behaviors than rats treated with DOX alone.”

https://www.mdpi.com/2076-3425/14/10/999

Cannabidiol partially rescues behavioral, neuroinflammatory and endocannabinoid dysfunctions stemming from maternal obesity in the adult offspring

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“Maternal obesity is known to increase the risk of psychiatric disorders, such as anxiety, depression, schizophrenia and autism spectrum disorder in the offspring. While preventive measures are well-documented, practical approaches for addressing the damages once they are already established are limited.

We have recently demonstrated the interplay between maternal obesity and treatment with cannabidiol (CBD) on neuroinflammation and peripheral metabolic disturbances during adolescence, however, it is known that both factors tend to vary throughout life. Therefore, here we investigated the potential of CBD to mitigate these alterations in the adult offspring of obese dams.

Female Wistar rats were fed a cafeteria diet for 12 weeks prior to mating, and during gestation and lactation. Offspring received CBD (50 mg/kg) for 3 weeks from the 70th day of life. Behavioral tests assessed anxiety-like manifestations and social behavior, while neuroinflammatory and endocannabinoid markers were evaluated in the hypothalamus, prefrontal cortex (PFC) and hippocampus, as well as the biochemical profile in the plasma.

CBD treatment attenuated maternal obesity-induced anxiety-like and social behavioral alterations, restoring exacerbated astrocytic and microglial markers in the hypothalamus, PFC and hippocampus of the offspring, as well as endocannabinoid levels in the PFC, with notable sex differences. Additionally, CBD attenuated plasma glucose and lipopolysaccharides (LPS) concentrations in females.

These findings underscore the persistent influence of maternal obesity on the offspring’s health, encompassing metabolic irregularities and behavioral impairments, as well as the role of the endocannabinoid system in mediating these outcomes across the lifespan.”

https://pubmed.ncbi.nlm.nih.gov/39447736/

“Treatment with cannabidiol rescues anxiety and social disturbances in the offspring.”

https://www.sciencedirect.com/science/article/abs/pii/S0028390824003654?via%3Dihub


Psychiatric comorbidities before and after cannabidiol treatment in adult patients with drug resistant focal epilepsy

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“Cannabidiol oil (CBD) has been approved as an antiseizure medication for the treatment of drug -resistant epilepsy in pediatric patients in 2018 for some special types of epilepsy.

Since this time its use was extended to other forms of epilepsy. However, to date, there are few publications on the use of CBD in adult patients with drug-resistant focal epilepsy and psychiatric comorbidities. We conducted a prospective, observational, open cohort study, with a before-after design, in adult patients, we assessed the effectiveness, dosage, and tolerance of adjunctive CBD treatment.

Our study concluded that CBD was effective and safe.

Our study in line with others examining CBD use in adult patients with drug-resistant epilepsy, omits consideration of psychiatric aspects. The aim of this study was to evaluate, in the same patient population that was part of a previous observational study, depression, quality of life, anxious symptoms and daytime sleepiness before and after CBD treatment.

RESULTS: Forty-four patients were enrolled in the study. Prior to CBD treatment, 50 % of participants exhibited symptoms of depression. Following CBD treatment, 95.4 % of these individuals demonstrated a marked improvement (p = 0.001). Among this cohort, 71.5 % of patients reported minimal or no depressive symptoms post-treatment. Moreover, 68 % of patients experienced an enhancement in their overall quality of life. Comparative analysis of BDI-II and QOLIE-10 scores before and after CBD treatment revealed a statistically significant positive correlation (p < 0.036 and < 0.001, respectively). Improvements in depressive symptoms were found to correspond with enhancements in quality of life. In terms of anxiety symptoms, 54.5 % of patients exhibited such symptoms prior to CBD treatment, with 71 % showing improvement post-treatment.

Adjunctive CBD treatment in adult patients with drug-resistant focal epilepsy was effective, safe, well tolerated and associated with significant improvement in depressive symptoms, anxiety and quality of life.”

https://pubmed.ncbi.nlm.nih.gov/39433001/

https://www.epilepsybehavior.com/article/S1525-5050(24)00414-1/abstract

Changes in Pain and Mental Health Symptoms Associated with Prescribed Medicinal Cannabis Use: A One-Year Longitudinal Study

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“Chronic pain and mental health issues like depression and anxiety significantly contribute to disease burden in Western countries.

While cannabinoids are suggested to have analgesic, anxiolytic and antidepressant properties, evidence, especially for long-term use, is inconclusive. This 12-month observational study evaluated the effects of prescribed medicinal cannabis for 96 patients suffering from pain, as well as sleep disturbances, depression and anxiety. Treatment outcomes for pain, depression, anxiety and sleep problems were assessed at 3, 6, and 12 months using validated instruments.

Significant reductions were observed in pain scores and the interference of pain on daily functions, alongside improvements in mental health and sleep. Many patients reported notable improvements in pain severity and reduced use of pain medications in the first 6 months, with a decline at 12 months. Additionally, sustained improvements in depression, anxiety, stress and sleep were observed, with about half reporting substantial improvement. Adverse effects were common but mostly mild or moderate, most commonly dry mouth and sleepiness.

These results show that prescribed medicinal cannabis treatment is associated with improvements in chronic pain and mental health symptoms, such as depression, anxiety and stress. However, findings also suggest reduced effectiveness with longer-term use, emphasizing the need for additional research.”

https://pubmed.ncbi.nlm.nih.gov/39432717/

“Cannabis is a plant that has been used for thousands of years as a traditional medicine to treat various medical ailments, including pain.

Overall, we found that the use of medicinal cannabis was associated with reduced pain during the first 6 months and improved mental well-being over 12 months. Patients reported not only less pain but also experienced reduced interference from pain in their daily functions. Furthermore, they reported decreased use of pain medications and a large proportion felt that their pain symptoms had significantly improved, as reflected in their reported changes in the severity of pain.”

https://www.tandfonline.com/doi/full/10.1080/15360288.2024.2414898