Cannabinoids elicit antidepressant-like behavior and activate serotonergic neurons through the medial prefrontal cortex

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“Preclinical and clinical studies show that cannabis modulates mood and possesses antidepressant-like properties, mediated by the agonistic activity of cannabinoids on central CB1 receptors (CB1Rs). The action of CB1R agonists on the serotonin (5-HT) system, the major transmitter system involved in mood control and implicated in the mechanism of action of antidepressants, remains however poorly understood.

In this study, we demonstrated that, at low doses, the CB1R agonist WIN55,212-2 [R(+)-[2,3-dihydro-5-methyl-3-[(morpholinyl)]pyrrolo[1,2,3-de]-1,4-benzoxazinyl]-(1-naphthalenyl) methanone mesylate] exerts potent antidepressant-like properties in the rat forced-swim test (FST).

This effect is CB1R dependent because it was blocked by the CB1R antagonist rimonabant and is 5-HT mediated because it was abolished by pretreatment with the 5-HT-depleting agent parachlorophenylalanine. Then, using in vivo electrophysiology, we showed that low doses of WIN55,212-2 dose dependently enhanced dorsal raphe nucleus 5-HT neuronal activity through a CB1R-dependent mechanism.

Conversely, high doses of WIN55,212-2 were ineffective in the FST and decreased 5-HT neuronal activity through a CB1R-independent mechanism. The CB1R agonist-induced enhancement of 5-HT neuronal activity was abolished by total or medial prefrontocortical, but not by lateral prefrontocortical, transection. Furthermore, 5-HT neuronal activity was enhanced by the local microinjection of WIN55,212-2 into the ventromedial prefrontal cortex (mPFCv) but not by the local microinjection of WIN55,212-2 into the lateral prefrontal cortex. Similarly, the microinjection of WIN55,212-2 into the mPFCv produced a CB1R-dependent antidepressant-like effect in the FST.

These results demonstrate that CB1R agonists possess antidepressant-like properties and modulate 5-HT neuronal activity via the mPFCv.”

“These results establish that low doses of a CB1R agonist elicit potent antidepressant-like behavior and enhance 5-HT neurotransmission, mediated by CB1R activation in the mPFCv. Conversely, high doses nullify antidepressant-like behavior and markedly attenuate 5-HT neurotransmission, an effect that appears to be instigated by a non-CB1R mechanism.”

https://pubmed.ncbi.nlm.nih.gov/17959812/

Medicinal cannabis extracts are neuroprotective against Aβ1-42-mediated toxicity in vitro

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“Background: Phytocannabinoids inhibit the aggregation and neurotoxicity of the neurotoxic Alzheimer’s disease protein β amyloid (Aβ). We characterised the capacity of five proprietary medical cannabis extracts, heated and non-heated, with varying ratios of cannabidiol and Δ9-tetrahydrocannabinol and their parent carboxylated compounds to protect against lipid peroxidation and Aβ-evoked neurotoxicity in PC12 cells.

Methods: Neuroprotection against lipid peroxidation and Aβ1-42-induced cytotoxicity was assessed using the thiazolyl blue tetrazolium bromide (MTT) assay. Transmission electron microscopy was used to visualise phytocannabinoid effects on Aβ1-42 aggregation and fluorescence microscopy.

Results: Tetrahydrocannabinol (THC)/tetrahydrocannabinolic acid (THCA)-predominant cannabis extracts demonstrated the most significant overall neuroprotection against Aβ1-42-induced loss of PC12 cell viability. These protective effects were still significant after heating of extracts, while none of the extracts provided significant neuroprotection to lipid peroxidation via tbhp exposure. Modest inhibition of Aβ1-42 aggregation was demonstrated only with the non-heated BC-401 cannabis extract, but overall, there was no clear correlation between effects on fibrils and conferral of neuroprotection.

Conclusions: These findings highlight the variable neuroprotective activity of cannabis extracts containing major phytocannabinoids THC/THCA and cannabidiol (CBD)/cannabidiolic acid (CBDA) on Aβ-evoked neurotoxicity and inhibition of amyloid β aggregation. This may inform the future use of medicinal cannabis formulations in the treatment of Alzheimer’s disease and dementia.”

https://pubmed.ncbi.nlm.nih.gov/39243211/

“With access to approved pathways increasing globally, medicinal cannabis formulations are increasingly being used to treat neuropsychiatric conditions. With laboratory and animal studies now showing benefits of cannabis and cannabinoids in treating neurodegenerative diseases, this study investigated whether whole cannabis extracts could protection neuronal cells against the toxicity of a signature Alzheimer’s disease protein, beta (β) amyloid.

We found that cannabis extracts afforded neuronal cells protection against amyloid β toxicity, mostly in extracts with the major phytocannabinoid, Δ9-THC, or its parent compound, Δ9-THC-COOH. These results suggest that medicinal cannabis may have potential in the further treatment of dementia.”

https://onlinelibrary.wiley.com/doi/10.1111/bcpt.14078


A combination of Δ9-tetrahydrocannabinol and cannabidiol modulates glutamate dynamics in the hippocampus of an animal model of Alzheimer’s disease

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“A combination of Δ9-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD) at non-psychoactive doses was previously demonstrated to reduce cognitive decline in APP/PS1 mice, an animal model of Alzheimer’s disease (AD). However, the neurobiological substrates underlying these therapeutic properties of Δ9-THC and CBD are not fully understood.

Considering that dysregulation of glutamatergic activity contributes to cognitive impairment in AD, the present study evaluates the hypothesis that the combination of these two natural cannabinoids might reverse the alterations in glutamate dynamics within the hippocampus of this animal model of AD.

Interestingly, our findings reveal that chronic treatment with Δ9-THC and CBD, but not with any of them alone, reduces extracellular glutamate levels and the basal excitability of the hippocampus in APP/PS1 mice.

These effects are not related to significant changes in the function and structure of glutamate synapses, as no relevant changes in synaptic plasticity, glutamate signaling or in the levels of key components of these synapses were observed in cannabinoid-treated mice. Our data instead indicate that these cannabinoid effects are associated with the control of glutamate uptake and/or to the regulation of the hippocampal network.

Taken together, these results support the potential therapeutic properties of combining these natural cannabinoids against the excitotoxicity that occurs in AD brains.”

https://pubmed.ncbi.nlm.nih.gov/39232876/

https://www.neurotherapeuticsjournal.org/article/S1878-7479(24)00126-0/fulltext

Cannabis sativa L. essential oil: chemical characterisation and antimicrobial activity against methicillin-resistant Staphylococcus pseudintermedius

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“Cannabis sativa L. essential oil has attracted the interest of the scientific community thanks to its numerous biological activities. Several studies have evaluated EOs as alternative therapeutic approaches to limit the use of antibiotics; the present study aimed to evaluate the in vitro inhibitory and bactericidal activity of the essential oils obtained from the leaves and inflorescences of two hemp genotypes against twenty-one multidrug-resistant, methicillin-resistant Staphylococcus pseudintermedius strains isolated from canine clinical samples.

Both EOs were mainly represented by sesquiterpene hydrocarbons, with a prevalence of β-caryophyllene and α-humulene. However, different relative amounts of phytocannabinoids were also detected. Microbiological results evidenced better outcomes for the EO characterised by the highest content of phytocannabinoids, which in turn showed no differences among the tested strains. Nevertheless, both the EOs showed better inhibitory and bactericidal activities than their main constituent, β-caryophyllene, tested individually, highlighting the presence of synergistic effects among the EO compounds.”

https://pubmed.ncbi.nlm.nih.gov/39229937/

https://www.tandfonline.com/doi/full/10.1080/14786419.2024.2398733

The effects of Cannabis sativa and cannabinoids on the inhibition of pancreatic lipase – An enzyme involved in obesity

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“Introduction: Obesity is a chronic noncommunicable disease characterized by excessive body fat that can have negative health consequences. Obesity is a complex disease caused by a combination of genetic, environmental, and lifestyle factors. It is characterized by a discrepancy between caloric intake and expenditure. Obesity increases the risk of acquiring major chronic diseases, including heart disease, stroke, cancer, and Type 2 diabetes mellitus (T2DM). Currently, the inhibition of pancreatic lipases (PL) is a promising pharmacological therapy for obesity and weight management. In this study, the inhibition of pancreatic lipase by Cannabis sativa (C. sativa) plant extract and cannabinoids was investigated.

Methods: The inhibitory effect was assessed using p-nitrophenyl butyrate (pNPB), and the results were obtained by calculating the percentage relative activity and assessed using one-way analysis of variance (ANOVA). Kinetic studies and spectroscopy techniques were used to evaluate the mode of inhibition. Diet-induced; and diabetic rat models were studied to evaluate the direct effects of C. sativa extract on PL activity.

Results: Kinetic analyses showed that the plant extracts inhibited pancreatic lipase, with tetrahydrocannabinol (THC) and cannabinol (CBN) being the potential cause of the inhibition noted for the C. sativa plant extract. CBN and THC inhibited the pancreatic lipase activity in a competitive manner, with the lowest residual enzyme activity of 52 % observed at a 10 μg/mL concentration of CBN and 39 % inhibition at a 25 μg/mL concentration of THC. Circular dichroism (CD) spectroscopy revealed that the inhibitors caused a change in the enzyme’s secondary structure. At low concentrations, THC showed potential for synergistic inhibition with orlistat. C.sativa treatment in an in vivo rat model confirmed its inhibitory effects on pancreatic lipase activity.

Conclusion: The findings in this study provided insight into the use of cannabinoids as pancreatic lipase inhibitors and the possibility of using these compounds to develop new pharmacological treatments for obesity.”

https://pubmed.ncbi.nlm.nih.gov/39232382/

https://www.sciencedirect.com/science/article/pii/S0753332224012423?via%3Dihub

Mechanistic Insights into the Impact of WIN 55, 212-2, a Synthetic Cannabinoid, on Adhesion Molecules PECAM-1 and VE-cadherin in HeLa Cells: Implications on Cancer Processes

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“The endocannabinoid (eCB) system comprises endogenous ligands, cannabinoid receptors (CBRs) and proteins involved in their regulation; its alteration leads to many diseases including cancer. Thus, becomes a therapeutic target for synthetic cannabinoids aimed to control cancer cell proliferation, migration, adhesion and invasion. However, little is known about adhesion molecules regulation through CBRs activation.

Consequently, the aim of this study was to evaluate the effects of a CB1/CB2 agonist, WIN-55, 212-2 (WIN), on the regulation of adhesion molecules PECAM-1 and VE-cadherin in HeLa cells. CBRs expression was evaluated by immunofluorescence staining in HeLa cells. Cell viability by MTT, cell adhesion by crystal violet, adhesion molecules expression and location by Western blot and immunofluorescence staining assays were assessed on cells treated with different WIN concentrations.

Results show that CB1, CB2 and GPR55 receptors are expressed in HeLa cells. Additionally, biphasic effects were observed in their metabolic activity and adhesive properties: low WIN concentrations significantly increased them, in contrast, were decreased at high ones as compared to controls (p < 0.0001), demonstrating that WIN elicits opposite effects depending on the concentration and exposure time. PECAM-1 was detected in cytoplasm, membrane and perinuclear region of HeLa cells, whereas VE-cadherin had a nuclear distribution. There were not significant differences in PECAM-1 and VE-cadherin expression and location, suggesting that WIN does not modulate these proteins.

These findings support the potential use of WIN due to its anticancer properties without dysregulating adhesion molecules. WIN possible contribution to inhibit cancer progression should be further investigated.”

https://pubmed.ncbi.nlm.nih.gov/39228102/

https://www.tandfonline.com/doi/full/10.1080/15376516.2024.2399132

Anti-inflammatory effects of phytocannabinoids and terpenes on inflamed Tregs and Th17 cells in vitro

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“Aims: Phytocannabinoids and terpenes from Cannabis sativa have demonstrated limited anti-inflammatory and analgesic effects in several inflammatory conditions. In the current study, we test the hypothesis that phytocannabinoids exert immunomodulatory effects in vitro by decreasing inflammatory cytokine expression and activation.

Key methods: CD3/CD28 and lipopolysaccharide activated peripheral blood mononuclear cells (PBMCs) from healthy donors (n = 6) were treated with phytocannabinoid compounds and terpenes in vitro. Flow cytometry was used to determine regulatory T cell (Treg) and T helper 17 (Th17) cell responses to treatments. Cell pellets were harvested for qRT-PCR gene expression analysis of cytokines, cell activation markers, and inflammation-related receptors. Cell culture supernatants were analysed by ELISA to quantify IL-6, TNF-α and IL-10 secretion.

Main findings: In an initial screen of 20 μM cannabinoids and terpenes which were coded to blind investigators, cannabigerol (GL4a), caryophyllene oxide (GL5a) and gamma-terpinene (GL6a) significantly reduced cytotoxicity and gene expression levels of IL6, IL10, TNF, TRPV1, CNR1, HTR1A, FOXP3, RORC and NFKΒ1. Tetrahydrocannabinol (GL7a) suppression of T cell activation was associated with downregulation of RORC and NFKΒ1 gene expression and reduced IL-6 (p < 0.0001) and IL10 (p < 0.01) secretion. Cannabidiol (GL1b) significantly suppressed activation of Tregs (p < 0.05) and Th17 cells (p < 0.05) in a follow-on in vitro dose-response study. IL-6 (p < 0.01) and IL-10 (p < 0.01) secretion was significantly reduced with 50 μM cannabidiol.

Significance: The study provides the first evidence that cannabidiol and tetrahydrocannabinol suppress extracellular expression of both anti- and pro-inflammatory cytokines in an in vitro PBMC model of inflammation.”

https://pubmed.ncbi.nlm.nih.gov/39208564/

https://www.sciencedirect.com/science/article/pii/S0014480024000431?via%3Dihub


A Comprehensive Exploration of the Multifaceted Neuroprotective Role of Cannabinoids in Alzheimer’s Disease across a Decade of Research

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“Alzheimer’s disease (AD), a progressive neurodegenerative disorder, manifests through dysregulation of brain function and subsequent loss of bodily control, attributed to β-amyloid plaque deposition and TAU protein hyperphosphorylation and aggregation, leading to neuronal death.

Concurrently, similar cannabinoids to the ones derived from Cannabis sativa are present in the endocannabinoid system, acting through receptors CB1R and CB2R and other related receptors such as Trpv-1 and GPR-55, and are being extensively investigated for AD therapy.

Given the limited efficacy and adverse effects of current available treatments, alternative approaches are crucial. Therefore, this review aims to identify effective natural and synthetic cannabinoids and elucidate their beneficial actions for AD treatment. PubMed and Scopus databases were queried (2014-2024) using keywords such as “Alzheimer’s disease” and “cannabinoids”.

The majority of natural (Δ9-THC, CBD, AEA, etc.) and synthetic (JWH-133, WIN55,212-2, CP55-940, etc.) cannabinoids included showed promise in improving memory, cognition, and behavioral symptoms, potentially via pathways involving antioxidant effects of selective CB1R agonists (such as the BDNF/TrkB/Akt pathway) and immunomodulatory effects of selective CB2R agonists (TLR4/NF-κB p65 pathway).

Combining anticholinesterase properties with a cannabinoid moiety may enhance therapeutic responses, addressing cholinergic deficits of AD brains. Thus, the positive outcomes of the vast majority of studies discussed support further advancing cannabinoids in clinical trials for AD treatment.”

https://pubmed.ncbi.nlm.nih.gov/39201317/

“As understood from the above, cannabinoids exhibit efficacy in reversing several of the manifestations of AD.”

https://www.mdpi.com/1422-0067/25/16/8630

Use of phytocanabinoids in animal models of parkinson’s disease: systematic review

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“This systematic review was carried out with the aim of evaluating the use of medicinal Cannabis for the treatment of Parkinson’s disease in experimental models. Furthermore, we sought to understand the main intracellular mechanisms capable of promoting the effects of phytocannabinoids on motor disorders, neurodegeneration, neuroinflammation and oxidative stress.

The experimental models were developed in mice, rats and marmosets. There was a predominance of using only males in relation to females; in three studies, the authors evaluated treatments in males and females. Drugs were used as inducers of Parkinson’s disease: 6-hydroxydopamine (6-OHDA), 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), lipopolysaccharide (LPS), and rotenone. Substances capable of promoting catalepsy in animals were also used: haloperidol, L-nitro-N-arginine (L-NOARG), WIN55,212-2, and reserpine. The inducing agent was injected stereotaxically or intraperitoneally. The most commonly used treatments were cannabidiol (CBD), Delta-9-tetrahydrocannabinol (Δ-9 THC) and Delta-9-tetrahydrocannabivarin (Δ-9 THCV), administered intraperitoneally, orally, subcutaneously and intramuscularly.

The use of phytocannabinoids improved locomotor activity and involuntary movement and reduced catalepsy. There was an improvement in the evaluation of dopaminergic neurons, while in relation to dopamine content, the treatment had no effect. Inflammation, microglial/astrocyte activation and oxidative stress were reduced after treatment with phytocannabinoids, the same was observed in the results of tests for allodynia and hyperalgesia.”

https://pubmed.ncbi.nlm.nih.gov/39182852/

https://www.sciencedirect.com/science/article/abs/pii/S0161813X24000986?via%3Dihub

Bioelectronic sensing platform emulating the human endocannabinoid system for assessing and modulating of cannabinoid activity

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“Cannabinoids are involved in physiological and neuromodulatory processes through their interactions with the human cannabinoid receptor-based endocannabinoid system. Their association with neurodegenerative diseases and brain reward pathways underscores the importance of evaluating and modulating cannabinoid activity for both understanding physiological mechanisms and developing therapeutic drugs. The use of agonists and antagonists could be strategic approaches for modulation.

In this study, we introduce a bioelectronic sensor designed to monitor cannabinoid binding to receptors and assess their agonistic and antagonistic properties. We produced human cannabinoid receptor 1 (hCB1R) via an Escherichia coli expression system and incorporated it into nanodiscs (NDs). These hCB1R-NDs were then immobilized on a single-walled carbon nanotube field-effect transistor (swCNT-FET) to construct a bioelectronic sensing platform. This novel system can sensitively detect the cannabinoid ligand anandamide (AEA) at concentrations as low as 1 fM, demonstrating high selectivity and real-time response. It also successfully identified the hCB1R agonist Δ9-tetrahydrocannabinol and observed that the hCB1R antagonist rimonabant diminished the sensor signal upon AEA binding, indicating the antagonism-based modulation of ligand interaction. Consequently, our bioelectronic sensing platform holds potential for ligand detection and analysis of agonism and antagonism.”

https://pubmed.ncbi.nlm.nih.gov/39173339/

https://www.sciencedirect.com/science/article/abs/pii/S0956566324006924?via%3Dihub