Activation of cannabinoid receptor 2 reduces inflammation in acute experimental pancreatitis via intra-acinar activation of p38 and MK2-dependent mechanisms.

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“The endocannabinoid system has been shown to mediate beneficial effects on gastrointestinal inflammation via cannabinoid receptors 1 (CB(1)) and 2 (CB(2)).

These receptors have also been reported to activate the MAP kinases p38 and c-Jun NH(2)-terminal kinase (JNK), which are involved in early acinar events leading to acute pancreatitis and induction of proinflammatory cytokines.

Our aim was to examine the role of cannabinoid receptor activation in an experimental model of acute pancreatitis and the potential involvement of MAP kinases.

The unselective CB(1)/CB(2) agonist HU210 ameliorated pancreatitis in wild-type and CB(1)-/- mice, indicating that this effect is mediated by CB(2).

Furthermore, blockade of CB(2), not CB(1), with selective antagonists engraved pathology.

Stimulation with a selective CB(2) agonist attenuated acute pancreatitis and an increased activation of p38 was observed in the acini.

With use of MK2-/- mice, it could be demonstrated that this attenuation is dependent on MK2. Hence, using the MK2-/- mouse model we reveal a novel CB(2)-activated and MAP kinase-dependent pathway that modulates cytokine expression and reduces pancreatic injury and affiliated complications.”

https://www.ncbi.nlm.nih.gov/pubmed/23139224

Cannabinoid receptor 2 agonist attenuates pain related behavior in rats with chronic alcohol/high fat diet induced pancreatitis

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“Chronic Pancreatitis (CP) is a complex and multifactorial syndrome. Many contributing factors result in development of dysfunctional pain in a significant number of patients. Drugs developed to treat a variety of pain states fall short of providing effective analgesia for patients with chronic pancreatitis, often providing minimal to partial pain relief over time with significant side effects.

Recently, availability of selective pharmacological tools has enabled great advances in our knowledge of the role of the cannabinoid receptors in pathophysiology. In particular, cannabinoid receptor 2 (CB2) has emerged as an attractive target for management of chronic pain, as demonstrated in several studies with inflammatory and neuropathic preclinical pain models. In this study, the analgesic efficacy of a novel, highly selective CB2 receptor agonist, LY3038404 HCl, is investigated in a chronic pancreatitis pain model, induced with an alcohol/high fat (AHF) diet.

LY3038404 HCl, a potent CB2 receptor agonist, possesses tissue protective and analgesic properties without effects on higher brain function. Thus, activation of CB2 receptors is suggested as a potential therapeutic target for visceral inflammation and pain management.

The major finding of the present study is that LY3038404 HCl, a potent CB2 receptor agonist, possesses tissue protective and analgesic properties. No effects on higher brain functions were observed including the diminished fear responses induced by the alcohol diet. Thus, activation of CB2 receptors is suggested as a potential therapeutic target for pancreas protection and pain management.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4242547/

Cannabinoids Ameliorate Pain and Reduce Disease Pathology in Cerulein-Induced Acute Pancreatitis

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“The endocannabinoid system has been identified as a major regulator of physiological and pathological processes, such as pain, inflammation, cell growth, cell death, and as a regulator of diverse gastrointestinal functions, such as intestinal motility and secretion.

Although cannabinoid-induced analgesia was initially primarily attributed to the activation of cannabinoid receptor 1 (CB1) in the nervous system, later studies demonstrated a contribution of cannabinoid receptor 2 (CB2), localized peripherally on immune cells as well as in the nervous system.

A complex interplay between endogenously released cannabinoids, such as anandamide or 2-arachidonoylglycerol, and their receptors both on inflammatory cells and neurons is involved in modulation of inflammatory pain.

In this article, we demonstrate the in vivo significance and therapeutic potential of cannabinoids in inflammation and pain associated with pancreatitis using human specimens and mouse models as test systems.

Our results are more in line with a recent study reporting a protective role for the endogenous cannabinoid system against colonic inflammation in a mouse model of experimental colitis.

Consistent with the above, we now show that acute pancreatitis, a visceral inflammatory disease in humans, is associated with an activation of the endocannabinoid system.

In humans, acute pancreatitis is associated with up-regulation of ligands as well as receptors of the endocannabinoid system in the pancreas. Furthermore, our results suggest a therapeutic potential for cannabinoids in abolishing pain associated with acute pancreatitis and in partially reducing inflammation and disease pathology in the absence of adverse side effects.

Because management of visceral inflammatory diseases should ideally include antinociceptive as well as anti-inflammatory components, our results lay a basis for testing the therapeutic value of cannabinoids as supplements to conventional analgesic therapy.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2268094/

Cannabinoids Reduce Markers of Inflammation and Fibrosis in Pancreatic Stellate Cells

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“While cannabinoids have been shown to ameliorate liver fibrosis, their effects in chronic pancreatitis and on pancreatic stellate cells (PSC) are unknown.

The activity of the endocannabinoid system was evaluated in human chronic pancreatitis (CP) tissues.

Augmentation of the endocannabinoid system via exogenously administered cannabinoid receptor agonists specifically induces a functionally and metabolically quiescent pancreatic stellate cell phenotype and may thus constitute an option to treat inflammation and fibrosis in chronic pancreatitis.

Because drugs for the treatment of chronic pancreatitis should ideally exert anti-fibrotic and anti-inflammatory properties, their bimodal effects rather contradict a therapeutic use of CB-receptor antagonists and promote the hypothesis that (re-)activation of the (endo-)cannabinoid system in chronic pancreatitis may be beneficial for suppressing disease progress.

In conclusion, we show that the endocannabinoid system is downregulated in chronic pancreatitis and that its augmentation via exogenously administered cannabinoids specifically reduces activation of pancreatic stellate cells.

These experiments lay a basis for testing the value of synthetic cannabinoids in the treatment of chronic pancreatitis.”

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0001701

Cannabinoids and Cystic Fibrosis

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“Cannabis stimulates appetite and food intake. This property has been exploited to benefit AIDS and cancer patients suffering from wasting disease, by administering the whole plant or its major active ingredient ?-tetrahydrocannabinol (THC). Endogenous cannabinoids (“endocannabinoids”) are found in maternal milk. We have recently shown that endocannabinoids are critical for milk ingestion and survival of newborns because blocking CB1 receptors resulted in death from malnutrition. Lack of appetite resulting in malnutrition is a contributing factor to mortality in many Cystic Fibrosis (CF) patients. It is proposed here for the first time, to administer THC to CF patients. It is hoped that the cannabinoid will alleviate malnutrition and thus help prevent wasting in CF patients. Recent findings suggest that a lipid imbalance (high arachidonic acid/low DHA) is a primary factor in the etiology of CF and that defective CFTR (CF transmembrane conductor regulator) that characterizes the CF condition is responsible for the dysregulation. Endocannabinoids are all fatty acid derivatives. Therefore, it is further proposed here that the CFTR gene product also modulates endocannabinoid synthesis, through regulation of fatty acid biosynthesis. According to this hypothesis, CF patients display decreased levels of endocannabinoids and by elevating these levels, symptoms may improve. Indeed, a number of physiological mechanisms of cannabinoids and endocannabinoids coincide with the pathology of CF. Thus it is suggested that potential benefits from THC treatment, in addition to appetite stimulation, will include antiemetic, bronchodilating, anti-inflammatory, anti-diarrheal and hypo-algesic effects.” https://www.researchgate.net/publication/233294071_Cannabinoids_and_Cystic_Fibrosis

“Cannabinoids and Cystic Fibrosis. A Novel Approach to Etiology and Therapy”  http://www.tandfonline.com/doi/abs/10.1300/J175v02n01_03

Cannabidiol attenuates OGD/R-induced damage by enhancing mitochondrial bioenergetics and modulating glucose metabolism via pentose-phosphate pathway in hippocampal neurons

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“Deficient bioenergetics and diminished redox conservation have been implicated in the development of cerebral ischemia/reperfusion injury.

In this study, the mechanisms underlying the neuroprotective effects of cannabidiol (CBD), a nonpsychotropic compound derived from Cannabis sativa with FDA-approved antiepilepsy properties, were studied in vitro using an oxygen–glucose-deprivation/reperfusion (OGD/R) model in a mouse hippocampal neuronal cell line.

This study is the first to document the neuroprotective effects of CBD against OGD/R insult, which depend in part on attenuating oxidative stress, enhancing mitochondrial bioenergetics, and modulating glucose metabolism via the pentose-phosphate pathway, thus preserving both energy and the redox balance.

Cannabidiol (CBD) is a nonpsychoactive cannabinoid derived from Cannabis sativa and a weak CB1 and CB2 cannabinoid receptor antagonist, with very low toxicity for humans. It has recently been demonstrated in vivo and in vitro that CBD has a variety of therapeutic properties, exerting antidepressant, anxiolytic, anti-inflammatory, immunomodulatory, and neuroprotective effects.  Our results provide novel insight into the neuroprotective properties of CBD, which involves the regulation of the mitochondrial bioenergetics and the glucose metabolism of hippocampal neurons during OGD/R injury.

In summary, our results suggest that CBD exerts a potent neuroprotective effect against ischemia/reperfusion injury by attenuating intracellular oxidative stress, enhancing mitochondrial bioenergetics, and optimizing glucose metabolism via the pentose-phosphate pathway, thus strengthening the antioxidant defenses and preserving the energy homeostasis of neurons. More in-depth studies are required to investigate the precise mechanism underlying the success of CBD treatment and to determine the actual role of CBD in cerebral ischemia.”  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5247568/

“Cannabidiol may soon be used in the emergency room to fight effects of stroke and cardiac emergencies” http://www.naturalnews.com/2017-02-21-cannabidiol-may-soon-be-used-in-the-emergency-room-to-fight-effects-of-stroke-cardiac-emergencies.html

Pregnenolone blocks cannabinoid-induced acute psychotic-like states in mice.

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“Cannabis-induced acute psychotic-like states (CIAPS) represent a growing health issue, but their underlying neurobiological mechanisms are poorly understood.

The use of antipsychotics and benzodiazepines against CIAPS is limited by side effects and/or by their ability to tackle only certain aspects of psychosis. Thus, safer wide-spectrum treatments are currently needed.

Although the blockade of cannabinoid type-1 receptor (CB1) had been suggested as a therapeutical means against CIAPS, the use of orthosteric CB1 receptor full antagonists is strongly limited by undesired side effects and low efficacy.

The neurosteroid pregnenolone has been recently shown to act as a potent endogenous allosteric signal-specific inhibitor of CB1 receptors. Thus, we tested in mice the potential therapeutic use of pregnenolone against acute psychotic-like effects of Δ9-tetrahydrocannabinol (THC), the main psychoactive component of cannabis.

We found that pregnenolone blocks a wide spectrum of THC-induced endophenotypes typically associated with psychotic-like states, including impairments in cognitive functions, somatosensory gating and social interaction. Overall, this work reveals that signal-specific inhibitors mimicking pregnenolone effects can be considered as promising new therapeutic tools to treat CIAPS.”  https://www.ncbi.nlm.nih.gov/pubmed/28220044

“Pregnenolone can protect the brain from cannabis intoxication. The administration of the main active principle of Cannabis sativa (marijuana), Δ(9)-tetrahydrocannabinol (THC), substantially increases the synthesis of pregnenolone in the brain via activation of the type-1 cannabinoid (CB1) receptor. Pregnenolone then, acting as a signaling-specific inhibitor of the CB1 receptor, reduces several effects of THC. This negative feedback mediated by pregnenolone reveals a previously unknown paracrine/autocrine loop protecting the brain from CB1 receptor overactivation that could open an unforeseen approach for the treatment of cannabis intoxication and addiction.”  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4057431/

Effects of tetrahydrocannabinol on glucose uptake in the rat brain.

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“Δ9-Tetrahydrocannabinol (THC) is the psychoactive component of the plant Cannabis sativa and acts as a partial agonist at cannabinoid type 1 and type 2 receptors in the brain.

The goal of this study was to assess the effect of THC on the cerebral glucose uptake in the rat brain.

Low blood THC levels of <1 ng/ml corresponded to an increased glucose uptake while blood THC levels > 10 ng/ml coincided with a decreased glucose uptake. The effective concentration in this region was estimated 2.4 ng/ml.

This glucose PET study showed that stimulation of CB1 receptors by THC affects the glucose uptake in the rat brain, whereby the effect of THC is regionally different and dependent on dose – an effect that may be of relevance in behavioural studies.”

https://www.ncbi.nlm.nih.gov/pubmed/28219717

Extinction of avoidance behavior by safety learning depends on endocannabinoid signaling in the hippocampus.

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“The development of exaggerated avoidance behavior is largely responsible for the decreased quality of life in patients suffering from anxiety disorders. Studies using animal models have contributed to the understanding of the neural mechanisms underlying the acquisition of avoidance responses. However, much less is known about its extinction.

Here we provide evidence in mice that learning about the safety of an environment (i.e., safety learning) rather than repeated execution of the avoided response in absence of negative consequences (i.e., response extinction) allowed the animals to overcome their avoidance behavior in a step-down avoidance task.

This process was context-dependent and could be blocked by pharmacological (3 mg/kg, s.c.; SR141716) or genetic (lack of cannabinoid CB1 receptors in neurons expressing dopamine D1 receptors) inactivation of CB1 receptors. In turn, the endocannabinoid reuptake inhibitor AM404 (3 mg/kg, i.p.) facilitated safety learning in a CB1-dependent manner and attenuated the relapse of avoidance behavior 28 days after conditioning.

Safety learning crucially depended on endocannabinoid signaling at level of the hippocampus, since intrahippocampal SR141716 treatment impaired, whereas AM404 facilitated safety learning.

Other than AM404, treatment with diazepam (1 mg/kg, i.p.) impaired safety learning. Drug effects on behavior were directly mirrored by drug effects on evoked activity propagation through the hippocampal trisynaptic circuit in brain slices: As revealed by voltage-sensitive dye imaging, diazepam impaired whereas AM404 facilitated activity propagation to CA1 in a CB1-dependent manner. In line with this, systemic AM404 enhanced safety learning-induced expression of Egr1 at level of CA1.

Together, our data render it likely that AM404 promotes safety learning by enhancing information flow through the trisynaptic circuit to CA1.”

https://www.ncbi.nlm.nih.gov/pubmed/28222356

Involvement of Cannabinoid Signaling in Vincristine-Induced Gastrointestinal Dysmotility in the Rat.

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“In different models of paralytic ileus, cannabinoid receptors are overexpressed and endogenous cannabinoids are massively released, contributing to gastrointestinal dysmotility. The antitumoral drug vincristine depresses gastrointestinal motility and a similar mechanism could participate in this effect. Therefore, our aim was to determine, using CB1 and CB2 antagonists, whether an increased endocannabinoid tone is involved in vincristine-induced gastrointestinal ileus.

Key results: Vincristine induced damage to the mucosa of ileum and colon and reduced gastrointestinal motor function at 0.5 mg/kg. The effect on motor function was particularly evident when the study started 24 h after administration. AM251, but not AM630, significantly prevented vincristine effect, particularly in the small intestine, when administered thrice. AM251 alone did not significantly alter gastrointestinal motility.

Conclusions: The fact that AM251, but not AM630, is capable of reducing the effect of vincristine suggests that, like in other experimental models of paralytic ileus, an increased cannabinoid tone develops and is at least partially responsible for the alterations induced by the antitumoral drug on gastrointestinal motor function. Thus, CB1 antagonists might be useful to prevent/treat ileus induced by vincristine.”  https://www.ncbi.nlm.nih.gov/pubmed/28220074

“Paralytic ileus: Obstruction of the intestine due to paralysis of the intestinal muscles.”  http://www.medicinenet.com/script/main/art.asp?articlekey=7886