Category Archives: Endocannabinoid System

The Effect of Chronic Activation of the Novel Endocannabinoid Receptor GPR18 on Myocardial Function and Blood Pressure in Conscious Rats.

Posted on by

Image result for journal of cardiovascular pharmacology

“While acute activation of the novel endocannabinoid receptor GPR18 causes hypotension, there are no reports on GPR18 expression in the heart or its chronic modulation of cardiovascular function. In this study, after demonstrating GPR18 expression in the heart, we show that chronic (2 weeks) GPR18 activation with its agonist abnormal cannabidiol (abn-cbd; 100 µg/kg/day; i.p) produced hypotension, suppressed the cardiac sympathetic dominance, and improved left ventricular (LV) function (increased the contractility index dp/dtmax, and reduced LV end diastolic pressure, LVEDP) in conscious rats. Ex vivo studies revealed increased: (i) cardiac and plasma adiponectin (ADN) levels; (ii) vascular (aortic) endothelial nitric oxide synthase (eNOS) expression, (iii) vascular and serum nitric oxide (NO) levels; (iv) myocardial and plasma cyclic guanosine monophosphate (cGMP) levels; (v) phosphorylation of myocardial protein kinase B (Akt) and extracellular signal regulated kinase 1/2 (ERK1/2) along with reduced myocardial reactive oxygen species (ROS) in abn-cbd treated rats. These biochemical responses contributed to the hemodynamic responses and were GPR18-mediated because concurrent treatment with the competitive GPR18 antagonist (O-1918) abrogated the abn-cbd evoked hemodynamic and biochemical responses. The current findings present new evidence for a salutary cardiovascular role for GPR18, mediated, at least partly, via elevation in the levels of ADN.”

 https://www.ncbi.nlm.nih.gov/pubmed/27676325

Endocannabinoid signaling in social functioning: an RDoC perspective.

Posted on by

Image result for Transl Psychiatry.

“Core deficits in social functioning are associated with various neuropsychiatric and neurodevelopmental disorders, yet biomarker identification and the development of effective pharmacological interventions has been limited.

Recent data suggest the intriguing possibility that endogenous cannabinoids, a class of lipid neuromodulators generally implicated in the regulation of neurotransmitter release, may contribute to species-typical social functioning.

Systematic study of the endogenous cannabinoid signaling could, therefore, yield novel approaches to understand the neurobiological underpinnings of atypical social functioning.

This article provides a critical review of the major components of the endogenous cannabinoid system (for example, primary receptors and effectors-Δ9-tetrahydrocannabinol, cannabidiol, anandamide and 2-arachidonoylglycerol) and the contributions of cannabinoid signaling to social functioning.

Data are evaluated in the context of Research Domain Criteria constructs (for example, anxiety, chronic stress, reward learning, motivation, declarative and working memory, affiliation and attachment, and social communication) to enable interrogation of endogenous cannabinoid signaling in social functioning across diagnostic categories.

The empirical evidence reviewed strongly supports the role for dysregulated cannabinoid signaling in the pathophysiology of social functioning deficits observed in brain disorders, such as autism spectrum disorder, schizophrenia, major depressive disorder, posttraumatic stress disorder and bipolar disorder.

Moreover, these findings indicate that the endogenous cannabinoid system holds exceptional promise as a biological marker of, and potential treatment target for, neuropsychiatric and neurodevelopmental disorders characterized by impairments in social functioning.”

https://www.ncbi.nlm.nih.gov/pubmed/27676446

Cannabidiol, among Other Cannabinoid Drugs, Modulates Prepulse Inhibition of Startle in the SHR Animal Model: Implications for Schizophrenia Pharmacotherapy.

Posted on by

Image result for Front Pharmacol

“Schizophrenia is a severe psychiatric disorder that involves positive, negative and cognitive symptoms. Prepulse inhibition of startle reflex (PPI) is a paradigm that assesses the sensorimotor gating functioning and is impaired in schizophrenia patients as well as in animal models of this disorder. Recent data point to the participation of the endocannabinoid system in the pathophysiology and pharmacotherapy of schizophrenia. Here, we focus on the effects of cannabinoid drugs on the PPI deficit of animal models of schizophrenia, with greater focus on the SHR (Spontaneously Hypertensive Rats) strain, and on the future prospects resulting from these findings.”

 https://www.ncbi.nlm.nih.gov/pubmed/27667973

CB1 receptor activation in the rat paraventricular nucleus induces bi-directional cardiovascular effects via modification of glutamatergic and GABAergic neurotransmission.

Posted on by

Image result for Naunyn Schmiedebergs Arch Pharmacol.

“We have shown previously that the cannabinoid receptor agonist CP55940 microinjected into the paraventricular nucleus of the hypothalamus (PVN) of urethane-anaesthetized rats induces depressor and pressor cardiovascular effects in the absence and presence of the CB1 antagonist AM251, respectively. The aim of our study was to examine whether the hypotension and/or hypertension induced by CP55940 given into the PVN results from its influence on glutamatergic and GABAergic neurotransmission. CP55940 was microinjected into the PVN of urethane-anaesthetized rats twice (S1 and S2, 20 min apart). Antagonists of the following receptors, NMDA (MK801), β2-adrenergic (ICI118551), thromboxane A2-TP (SQ29548), angiotensin II-AT1 (losartan) or GABAA (bicuculline), or the NO synthase inhibitor L-NAME were administered intravenously 5 min before S2 alone or together with AM251. The CP55940-induced hypotension was reversed into a pressor response by AM251, bicuculline and L-NAME, but not by the other antagonists. The CP55940-induced pressor effect examined in the presence of AM251 was completely reversed by losartan, reduced by about 50-60 % by MK801, ICI118551 and SQ29548, prevented by bilateral adrenalectomy but not modified by bicuculline and L-NAME. Parallel, but smaller, changes in heart rate accompanied the changes in blood pressure. The bi-directional CB1 receptor-mediated cardiovascular effects of cannabinoids microinjected into the PVN of anaesthetized rats depend on stimulatory glutamatergic and inhibitory GABAergic inputs to the sympathetic tone; the glutamatergic input is related to AT1, TP and β2-adrenergic receptors and catecholamine release from the adrenal medulla whereas the GABAergic input is reinforced by NO.”

http://www.ncbi.nlm.nih.gov/pubmed/27659492

Cannabinoids: Glutamatergic Transmission and Kynurenines.

Posted on by

Image result for Adv Neurobiol.

“The endocannabinoid system (ECS) comprises a complex of receptors, enzymes, and endogenous agonists that are widely distributed in the central nervous system of mammals and participates in a considerable number of neuromodulatory functions, including neurotransmission, immunological control, and cell signaling. In turn, the kynurenine pathway (KP) is the most relevant metabolic route for tryptophan degradation to form the metabolic precursor NAD(+).

Recent studies demonstrate that the control exerted by the pharmacological manipulation of the ECS on the glutamatergic system in the brain may offer key information not only on the development of psychiatric disorders like psychosis and schizophrenia-like symptoms, but it also may constitute a solid basis for the development of therapeutic strategies to combat excitotoxic events occurring in neurological disorders like Huntington’s disease (HD).

Part of the evidence pointing to the last approach is based on experimental protocols demonstrating the efficacy of cannabinoids to prevent the deleterious actions of the endogenous neurotoxin and KP metabolite quinolinic acid (QUIN).

These findings intuitively raise the question about what is the precise role of the ECS in tryptophan metabolism through KP and vice versa. In this chapter, we will review basic concepts on the physiology of both the ECS and the KP to finally describe those recent findings combining the components of these two systems and hypothesize the future course that the research in this emerging field will take in the next years.”

 http://www.ncbi.nlm.nih.gov/pubmed/27651254

Dietary fats and pharmaceutical lipid excipients increase systemic exposure to orally administered cannabis and cannabis-based medicines

Posted on by

Logo of amjtr

“Cannabis sativa, commonly called hemp, has thousands of years-long history of medical use. Cannabis extracts were widely used in Europe and North America for their therapeutic value as sedatives, hypnotics, analgesics, muscle relaxants, and anticonvulsant agents. However, cannabis was removed from British and American Pharmacopoeias in 20th century, partially due to politic bias. Although prohibited, many patients were nevertheless self-medicating to obtain therapeutic benefits from cannabis for various conditions, including AIDS wasting syndrome, multiple sclerosis (MS) and spinal injuries. More recently, a growing interest in the therapeutic effects of cannabis has developed following the isolation of cannabinoids, the principal chemical compounds of cannabis, as well as the discovery of endocannabinoids and their cognate receptors in humans. These advances supported legalisation and wide-spread use of cannabis for therapeutic purposes in many countries.

There has been an escalating interest in the medicinal use of Cannabis sativa in recent years. Cannabis is often administered orally with fat-containing foods, or in lipid-based pharmaceutical preparations. However, the impact of lipids on the exposure of patients to cannabis components has not been explored. Therefore, the aim of this study is to elucidate the effect of oral co-administration of lipids on the exposure to two main active cannabinoids, Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD). In this study, oral co-administration of lipids enhanced the systemic exposure of rats to THC and CBD by 2.5-fold and 3-fold, respectively, compared to lipid-free formulations. In vitro lipolysis was conducted to explore the effect of lipids on the intestinal solubilisation of cannabinoids. More than 30% of THC and CBD were distributed into micellar fraction following lipolysis, suggesting that at least one-third of the administered dose will be available for absorption following co-administration with lipids. Both cannabinoids showed very high affinity for artificial CM-like particles, as well as for rat and human CM, suggesting high potential for intestinal lymphatic transport. Moreover, comparable affinity of cannabinoids for rat and human CM suggests that similar increased exposure effects may be expected in humans. In conclusion, co-administration of dietary lipids or pharmaceutical lipid excipients has the potential to substantially increase the exposure to orally administered cannabis and cannabis-based medicines. The increase in patient exposure to cannabinoids is of high clinical importance as it could affect the therapeutic effect, but also toxicity, of orally administered cannabis or cannabis-based medicines.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5009397/

Cannabinoid Agonists Show Promise for Anorexia

Posted on by

Image result for medscape

“Impairments in the endocannabinoid system in the brain could play an important role in the development of anorexia nervosa, say Italian researchers, who report findings that point to novel cannabis-based therapeutic strategies for the eating disorder.

In a mouse model of anorexia, the team found not only that the density of cannabinoid receptors was significantly reduced in areas associated with appetite but also that administration of receptor agonists led to increases in body weight and a reduction in interest in exercise.”

http://www.medscape.com/viewarticle/868990

Δ9-Tetrahydrocannabinol Reverses TNFα-induced Increase in Airway Epithelial Cell Permeability through CB2 Receptors.

Posted on by

Image result for Biochem Pharmacol

“Despite pharmacological treatment, bronchial hyperresponsiveness continues to deteriorate as airway remodelling persists in airway inflammation.

Previous studies have demonstrated that the phytocannabinoid Δ9-tetrahydrocannabinol (THC) reverses bronchoconstriction with an anti-inflammatory action.

The aim of this study was to investigate the effects of THC on bronchial epithelial cell permeability after exposure to the pro-inflammatory cytokine, TNFα. Calu-3 bronchial epithelial cells were cultured at air-liquid interface.

These data indicate that THC prevents cytokine-induced increase in airway epithelial permeability through CB2 receptor activation.

This highlights that THC, or other cannabinoid receptor ligands, could be beneficial in the prevention of inflammation-induced changes in airway epithelial cell permeability, an important feature of airways diseases.”

http://www.ncbi.nlm.nih.gov/pubmed/27641813

Comparing the effects of endogenous and synthetic cannabinoid receptor agonists on survival of gastric cancer cells.

Posted on by

Image result for life sciences journal

“Anti-neoplastic activity induced by cannabinoids has been extensively documented for a number of cancer cell types; however, this topic has been explored in gastric cancer cells only in a limited number of approaches.

SIGNIFICANCE:

Through a comparative approach, our results support and confirm the therapeutic potential that cannabinoid receptor agonists exert in gastric cancer cells and open possibilities to use cannabinoids as part of a new gastric cancer therapy.”

http://www.ncbi.nlm.nih.gov/pubmed/27640887

The endocannabinoid anandamide causes endothelium-dependent vasorelaxation in human mesenteric arteries.

Posted on by

Image result for Pharmacol Res.

“The endocannabinoid anandamide (AEA) causes vasorelaxation in animal studies.

Although circulating AEA levels are increased in many pathologies, little is known about its vascular effects in humans. The aim of this work was to characterise the effects of AEA in human arteries.

Post hoc analysis of the data set showed that overweight patients and those taking paracetamol had reduced vasorelaxant responses to AEA.

These data show that AEA causes moderate endothelium-dependent, NO-dependent vasorelaxation in human mesenteric arteries via activation of CB1 receptors.”

http://www.ncbi.nlm.nih.gov/pubmed/27633407