“An improved understanding of the endocannabinoid system has provided new avenues of drug discovery and development toward the management of pain and other behavioral maladies. Exogenous cannabinoid type-1 (CB1) receptor agonists such as Δ9-tetrahydrocannabinol are increasingly utilized for their medicinal actions; however, their utility is constrained by concern regarding abuse-related subjective effects. This has led to growing interest in the clinical benefit of indirectly enhancing the activity of the highly labile endocannabinoids N-arachidonoylethanolamine (anandamide; AEA) and/or 2-arachidonoylglycerol (2-AG) via catabolic enzyme inhibition. The present studies were conducted to determine whether such actions can lead to CB1 agonist-like subjective effects, as reflected in the presence or absence of CB1-related discriminative-stimulus effects in laboratory subjects. Squirrel monkeys (n=8) that discriminated the CB1 full agonist AM4054 (0.01 mg/kg) from vehicle were used to study, first, inhibitors of fatty acid amide hydrolase (FAAH) or monoacylglycerol lipase (MGL) alone or in combination [FAAH (URB597, AM4303); MGL (AM4301); FAAH/MGL (AM4302)] and, second, the ability of the endocannabinoids AEA and 2-AG to produce CB1 agonist-like effects when administered alone or after enzyme inhibition. Results indicate that CB1-related discriminative-stimulus effects were produced by combined, but not selective, inhibition of FAAH and MGL, and that these effects were non-surmountably antagonized by low doses of rimonabant. Additionally, FAAH- or MGL-inhibition revealed CB1-like subjective effects produced by AEA, but not 2-AG. Taken together, the present data suggest that therapeutic effects of combined, but not selective, enhancement of AEA or 2-AG activity via enzyme inhibition may be accompanied by CB1 receptor-mediated subjective effects.” https://www.ncbi.nlm.nih.gov/pubmed/28947487 http://jpet.aspetjournals.org/content/early/2017/09/25/jpet.117.244392]]>
Category Archives: Endocannabinoid System
Targeting the Endocannabinoid System to Treat Sepsis
“Sepsis is a complex immune disorder that can affect the function of almost all organ systems in the body. This disorder is characterised by a malfunctioning immune response to an infection that involves both pro-inflammatory and immunosuppressive mediators. This leads to severe damage and failure of vital organs, resulting in patient death. Sepsis, septic shock, and systemic inflammatory response syndrome are the leading causes of mortality in surgical intensive care unit patients internationally. The current lack of viable therapeutic treatment options for sepsis underscores our insufficient understanding of this complex disease. The endocannabinoid system, a key regulator of essential physiological functions including the immune system, has recently emerged as a potential therapeutic target for sepsis treatment. The endocannabinoid system acquires its name from the plant Cannabis Sativa, which has been used medically to treat a variety of ailments, as well as recreationally for centuries. Cannabis Sativa contains more than 60 active phytocannabinoids with the primary phytocannabinoid Δ9-tetrahydrocannabinol (THC), (6) activating both endogenous endocannabinoid receptors. The endocannabinoid system represents a potential therapeutic target in sepsis due to the presence of cannabinoid receptors (CB2) on immune cells. In this review we discuss how various targets within the endocannabinoid system can be manipulated to treat the immune consequences of sepsis. One of the targets outlined are the endocannabinoid receptors and modulation of their activity through pharmacological agonists and antagonists. Another therapeutic target covered in this review is the modulation of the endocannabinoid degradative enzyme’s activity. Modulation of degradative enzyme activity can change the levels of endogenous cannabinoids thereby altering immune activity. Overall, activation of the CB2 receptors causes immunosuppression and can be beneficial during the hyperactivated immune state of sepsis, while suppression of the CB2 receptors may be beneficial during a hypoimmune septic state. The endocannabinoid system modulates the immune response in experimental sepsis. Manipulating the endocannabinoid system may have potential therapeutic benefit in clinical sepsis where immune and inflammatory dysfunction can be detrimental. Multiple targets exist within the endocannabinoid system, e.g. the system can be targeted at the level of receptors by administration of synthetic compounds, similar to the endocannabinoids, which either increase or inhibit receptor activation to provide the desired therapeutic effect. Alternatively, the endogenous enzymes that degrade endocannabinoids or cannabinoid-like lipids can also be targeted in order to manipulate the levels of endocannabinoids. Proper identification of the septic stage is crucial to determine the adequate therapeutic response that will be most beneficial. Due to the biphasic nature of sepsis immunopathology, immune suppression through endocannabinoid modulation can help mitigate the hyper-immune response during the early septic state, while immune activation may be beneficial in later stages.” http://www.signavitae.com/2013/05/targeting-the-endocannabinoid-system-to-treat-sepsis/ http://www.signavitae.com/2013/05/targeting-the-endocannabinoid-system-to-treat-sepsis/]]>
Effects of Cannabinoid Agonists and Antagonists on Sleep and Breathing in Sprague-Dawley Rats.
“There are no pharmacological treatments for obstructive sleep apnea syndrome, but dronabinol showed promise in a small pilot study. In anesthetized rats, dronabinol attenuates reflex apnea via activation of cannabinoid (CB) receptors located on vagal afferents; an effect blocked by cannabinoid type 1 (CB1) and/or type 2 (CB2) receptor antagonists. Here, using a natural model of central sleep apnea, we examine the effects of dronabinol, alone and in combination with selective antagonists in conscious rats chronically instrumented to stage sleep and measure cessation of breathing.
RESULTS:
Dronabinol decreased the percent time spent in rapid eye movement (REM) sleep. CB receptor antagonists did not reverse this effect. Dronabinol also decreased apneas during sleep, and this apnea suppression was reversed by CB1 or CB1/CB2 receptor antagonism.CONCLUSIONS:
Dronabinol’s effects on apneas were dependent on CB1 receptor activation, while dronabinol’s effects on REM sleep were CB receptor-independent.”Targeting fatty acid amide hydrolase as a therapeutic strategy for antitussive therapy.
“Cough is the most common reason to visit a primary care physician, yet it remains an unmet medical need. Fatty acid amide hydrolase (FAAH) is an enzyme that breaks down endocannabinoids, and inhibition of FAAH produces analgesic and anti-inflammatory effects. Cannabinoids inhibit vagal sensory nerve activation and the cough reflex, so it was hypothesised that FAAH inhibition would produce antitussive activity via elevation of endocannabinoids. Primary vagal ganglia neurons, tissue bioassay, in vivoelectrophysiology and a conscious guinea pig cough model were utilised to investigate a role for fatty acid amides in modulating sensory nerve activation in vagal afferents. FAAH inhibition produced antitussive activity in guinea pigs with concomitant plasma elevation of the fatty acid amides N-arachidonoylethanolamide (anandamide), palmitoylethanolamide, N-oleoylethanolamide and linoleoylethanolamide. Palmitoylethanolamide inhibited tussive stimulus-induced activation of guinea pig airway innervating vagal ganglia neurons, depolarisation of guinea pig and human vagus, and firing of C-fibre afferents. These effects were mediated via a cannabinoid CB2/Gi/o-coupled pathway and activation of protein phosphatase 2A, resulting in increased calcium sensitivity of calcium-activated potassium channels. These findings identify FAAH inhibition as a target for the development of novel, antitussive agents without the undesirable side-effects of direct cannabinoid receptor agonists.” https://www.ncbi.nlm.nih.gov/pubmed/28931663 http://erj.ersjournals.com/content/50/3/1700782]]>
Re-visiting the Endocannabinoid System and Its Therapeutic Potential in Obesity and Associated Diseases.
“In a high percentage (≥85%) of both sporadic and familial adenomatous polyposis forms of colorectal cancer (CRC), the inactivation of the APC tumor suppressor gene initiates tumor formation and modulates the Wnt/β-Catenin transduction pathways involved in the control of cell proliferation, adhesion and metastasis.
Increasing evidence showed that the endocannabinoids control tumor growth and progression, both in vitro and in vivo.
We evaluated the effect of Rimonabant, a