“Independent stimulation of either the ghrelin or endocannabinoid system promotes food intake and increases adiposity. Given the similar distribution of their receptors in feeding associated brain regions and organs involved in metabolism, it is not surprising that evidence of their interaction and its importance in modulating energy balance has emerged. This review documents the relationship between ghrelin and endocannabinoid systems within the periphery and hypothalamus (HYP) before presenting evidence suggesting that these two systems likewise work collaboratively within the ventral tegmental area (VTA) to modulate non-homeostatic feeding. Mechanisms, consistent with current evidence and local infrastructure within the VTA, will be proposed.”
Category Archives: Endocannabinoid System
Getting into the weed: the role of the endocannabinoid system in the brain-gut axis.
“The actions of cannabis are mediated by receptors that are part of an endogenous cannabinoid system.
The endocannabinoid system (ECS) consists of the naturally occurring ligands N-arachidonoylethanolamine (anandamide) and 2-arachidonoylglycerol (2-AG), their biosynthetic and degradative enzymes, and the cannabinoid receptors CB1 and CB2.
The ECS is a widely distributed transmitter system that controls gut functions peripherally and centrally. It is an important physiologic regulator of gastrointestinal motility.
Polymorphisms in the gene encoding CB1 (CNR1) have been associated with some forms of irritable bowel syndrome. The ECS is involved in the control of nausea and vomiting and visceral sensation. The homeostatic role of the ECS also extends to the control of intestinal inflammation.
We review the mechanisms by which the ECS links stress and visceral pain. CB1 in sensory ganglia controls visceral sensation, and transcription of CNR1 is modified through epigenetic processes under conditions of chronic stress. These processes might link stress with abdominal pain.
The ECS is also involved centrally in the manifestation of stress, and endocannabinoid signaling reduces the activity of hypothalamic-pituitary-adrenal pathways via actions in specific brain regions-notably the prefrontal cortex, amygdala, and hypothalamus.
Agents that modulate the ECS are in early stages of development for treatment of gastrointestinal diseases. Increasing our understanding of the ECS will greatly advance our knowledge of interactions between the brain and gut and could lead to new treatments for gastrointestinal disorders.”
New review sheds light on cannabinoids anticancer mechanisms
“The palliative effects of cannabinoids on cancer-related symptoms are well established.
In fact, many drugs comprised of delta-9-tetrahydrocannabinol (THC) or its synthetic analogues are currently approved in Canada for use in the management of chemotherapy-induced nausea and vomiting, pain relief, and appetite stimulation.
While this may provide adequate treatment to the symptoms endured by cancer patients, what if cannabis can all together treat and cure cancer?
Latest discoveries on cannabinoids and their anticancer properties focus on their molecular mechanisms of action and have been discussed in a recently published review article in Current Oncology, a peer-reviewed journal (Velasco, Sanchez, & Guzman, 2016).
It is important to begin by understanding that our body possesses an endogenous cannabinoid system.”
https://news.liftcannabis.ca/2016/04/21/new-review-sheds-light-cannabinoids-anticancer-mechanisms/
“Anticancer mechanisms of cannabinoids” http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4791144/
Modulation of breast cancer cell viability by a cannabinoid receptor 2 agonist, JWH-015, is calcium dependent
“Cannabinoid compounds, both nonspecific as well as agonists selective for either cannabinoid receptor 1 (CB1) or cannabinoid receptor 2 (CB2), have been shown to modulate the tumor microenvironment by inducing apoptosis in tumor cells in several model systems.
The mechanism of this modulation remains only partially delineated, and activity induced via the CB1 and CB2 receptors may be distinct despite significant sequence homology and structural similarity of ligands.
The results of this work characterize the actions of a CB2-selective agonist on breast cancer cells in a syngeneic murine model representing how a clinical presentation of cancer progression and metastasis may be significantly modulated by a G-protein-coupled receptor.”
Neuroscientists discover previously unknown function of cannabinoid receptor
“Previously Unknown Function of a Cannabinoid Receptor Identified. Study could improve our insights into brain diseases.” http://neurosciencenews.com/cb2-cannabinoid-receptor-hippocampus-4147/
“In the brain, there is a delicate interplay of signaling substances and cellular activity. Scientists have now identified another key player within this ensemble. In a laboratory study they found that the ‘cannabinoid type 2 receptor’ influences information processing inside the hippocampus. The research results might help advance our understanding of schizophrenia and Alzheimer’s, say the authors.” https://www.sciencedaily.com/releases/2016/05/160502111228.htm
“The cannabinoid type 2 receptor – also called “CB2 receptor” – is a special membrane protein. Its function is to receive chemical signals that control cellular activity. “Until now, this receptor was considered part of the immune system without function in nerve cells. However, our study shows that it also plays an important role in the signal processing of the brain,” explains Professor Dietmar Schmitz, Speaker for the DZNE-Site Berlin and Director of the Neuroscience Research Center of the Charité (NWFZ/NeuroCure).” https://scienceblog.com/483935/neuroscientists-discover-previously-unknown-function-cannabinoid-receptor/
Cannabinoid Type 2 Receptors Mediate a Cell Type-Specific Plasticity in the Hippocampus
“Endocannabinoids (eCBs) exert major control over neuronal activity by activating cannabinoid receptors (CBRs).
The functionality of the eCB system is primarily ascribed to the well-documented retrograde activation of presynaptic CB1Rs.
We find that action potential-driven eCB release leads to a long-lasting membrane potential hyperpolarization in hippocampal principal cells that is independent of CB1Rs.
The hyperpolarization, which is specific to CA3 and CA2 pyramidal cells (PCs), depends on the activation of neuronal CB2Rs, as shown by a combined pharmacogenetic and immunohistochemical approach.
Upon activation, they modulate the activity of the sodium-bicarbonate co-transporter, leading to a hyperpolarization of the neuron.
CB2R activation occurred in a purely self-regulatory manner, robustly altered the input/output function of CA3 PCs, and modulated gamma oscillations in vivo.
To conclude, we describe a cell type-specific plasticity mechanism in the hippocampus that provides evidence for the neuronal expression of CB2Rs and emphasizes their importance in basic neuronal transmission.”
Mustard vesicants alter expression of the endocannabinoid system in mouse skin.
“Vesicants including sulfur mustard (SM) and nitrogen mustard (NM) are bifunctional alkylating agents that cause skin inflammation, edema and blistering. This is associated with alterations in keratinocyte growth and differentiation.
Endogenous cannabinoids, including N-arachidonoylethanolamine (anandamide, AEA) and 2-arachidonoyl glycerol (2-AG), are important in regulating inflammation, keratinocyte proliferation and wound healing.
Their activity is mediated by binding to cannabinoid receptors 1 and 2 (CB1 and CB2), as well as peroxisome proliferator-activated receptor alpha (PPARα). Levels of endocannabinoids are regulated by fatty acid amide hydrolase (FAAH).
We found that CB1, CB2, PPARα and FAAH were all constitutively expressed in mouse epidermis and dermal appendages. Topical administration of NM or SM, at concentrations that induce tissue injury, resulted in upregulation of FAAH, CB1, CB2 and PPARα, a response that persisted throughout the wound healing process.
Inhibitors of FAAH including a novel class of vanillyl alcohol carbamates were found to be highly effective in suppressing vesicant-induced inflammation in mouse skin.
Taken together, these data indicate that the endocannabinoid system is important in regulating skin homeostasis and that inhibitors of FAAH may be useful as medical counter measures against vesicants.”
Design, synthesis and biological evaluation of potent FAAH inhibitors.
“A new series of 3-carboxamido-5-aryl-isoxazoles was designed, synthesized and evaluated for their biological activity. Different pharmacomodulations have been explored and the lipophilicity of these compounds was assessed. Investigation of the in vitro biological activity led to the identification of 5 compounds as potent FAAH inhibitors, their good FAAH inhibition capacity is probably correlated with their suitable lipophilicity. Specifically, compound 25 showed similar inhibition potency against FAAH in comparison with URB597, one of the most potent FAAH inhibitor known to date.”
Fatty Acid Binding Protein-1 (FABP1) and the Human FABP1 T94A Variant: Roles in the Endocannabinoid System and Dyslipidemias.
“The first discovered member of the mammalian FABP family, liver fatty acid binding protein (FABP1, L-FABP), occurs at high cytosolic concentration in liver, intestine, and in the case of humans also in kidney.
While the rat FABP1 is well studied, the extent these findings translate to human FABP1 is not clear-especially in view of recent studies showing that endocannabinoids and cannabinoids represent novel rat FABP1 ligands and FABP1 gene ablation impacts the hepatic endocannabinoid system, known to be involved in non-alcoholic fatty liver (NAFLD) development.
Although not detectable in brain, FABP1 ablation nevertheless also impacts brain endocannabinoids. Despite overall tertiary structure similarity, human FABP1 differs significantly from rat FABP1 in secondary structure, much larger ligand binding cavity, and affinities/specificities for some ligands. Moreover, while both mouse and human FABP1 mediate ligand induction of peroxisome proliferator activated receptor-α (PPARα), they differ markedly in pattern of genes induced.
This is critically important because a highly prevalent human single nucleotide polymorphism (SNP) (26-38 % minor allele frequency and 8.3 ± 1.9 % homozygous) results in a FABP1 T94A substitution that further accentuates these species differences. The human FABP1 T94A variant is associated with altered body mass index (BMI), clinical dyslipidemias (elevated plasma triglycerides and LDL cholesterol), atherothrombotic cerebral infarction, and non-alcoholic fatty liver disease (NAFLD).
Resolving human FABP1 and the T94A variant’s impact on the endocannabinoid and cannabinoid system is an exciting challenge due to the importance of this system in hepatic lipid accumulation as well as behavior, pain, inflammation, and satiety.”
WHERE’s MY ENTOURAGE? THE CURIOUS CASE OF 2-oleoylglycerol, 2-linolenoylglycerol, and 2-palmitoylglycerol.
“2-arachidonoylglycerol (2-AG) is the most abundant endogenous cannabinoid in the brain and an agonist at two cannabinoid receptors (CB1 and CB2). The synthesis, degradation and signaling of 2-AG have been investigated in detail but its relationship to other endogenous monoacylglycerols has not been fully explored.
Three congeners that have been isolated from the CNS are 2-linoleoylglycerol (2-LG), 2-oleoylglycerol (2-OG), and 2-palmitoylglycerol (2-PG). These lipids do not orthosterically bind to cannabinoid receptors but are reported to potentiate the activity of 2-AG, possibly through inhibition of 2-AG degradation. This phenomenon has been dubbed the ‘entourage effect’ and has been proposed to regulate synaptic activity of 2-AG. To clarify the activity of these congeners of 2-AG we tested them in neuronal and cell-based signaling assays.
The signaling profile for these compounds is inconsistent with an entourage effect. None of the compounds inhibited neurotransmission via CB1 in autaptic neurons. Interestingly, each failed to potentiate 2-AG-mediated depolarization-induced suppression of excitation (DSE), behaving instead as antagonists. Examining other signaling pathways we found that 2-OG interferes with agonist-induced CB1 internalization while 2-PG modestly internalizes CB1 receptors. However in tests of pERK, cAMP and arrestin recruitment, none of the acylglycerols altered CB1 signaling.
Our results suggest 1) that these compounds do not serve as entourage compounds under the conditions examined, and 2) that they may instead serve as functional antagonists. Our results suggest that the relationship between 2-AG and its congeners is more nuanced than previously appreciated.”