Category Archives: Cardiovascular Disease

The endocannabinoid system: no longer anonymous in the control of nitrergic signalling?

Posted on by
Reply

Image result for J Mol Cell Biol.

“The endocannabinoid system (ECS) is a key cellular signalling system that has been implicated in the regulation of diverse cellular functions. Importantly, growing evidence suggests that the biological actions of the ECS may, in part, be mediated through its ability to regulate the production and/or release of nitric oxide, a ubiquitous bioactive molecule, which functions as a versatile signalling intermediate. Herein, we review and discuss evidence pertaining to ECS-mediated regulation of nitric oxide production, as well as the involvement of reactive nitrogen species in regulating ECS-induced signal transduction by highlighting emerging work supporting nitrergic modulation of ECS function. Importantly, the studies outlined reveal that interactions between the ECS and nitrergic signalling systems can be both stimulatory and inhibitory in nature, depending on cellular context. Moreover, such crosstalk may act to maintain proper cell function, whereas abnormalities in either system can undermine cellular homoeostasis and contribute to various pathologies associated with their dysregulation. Consequently, future studies targeting these signalling systems may provide new insights into the potential role of the ECS -: nitric oxide signalling axis in disease development and/or lead to the identification of novel therapeutic targets for the treatment of nitrosative stress-related neurological, cardiovascular, and metabolic disorders.”

https://www.ncbi.nlm.nih.gov/pubmed/28130308

Diuretic effects of cannabinoid agonists in mice

Posted on by
Reply

Image result for European Journal of Pharmacology

“Cannabinoids both increase urine output and decrease urinary frequency in human subjects. However, these effects have not been systematically evaluated in intact mice, a species commonly used to evaluate the effects of novel cannabinoids.

The present studies investigated whether cannabinoid agonists reliably produce diuresis in mice at doses comparable to those that produce other cannabinoid effects and, further, identified the receptors that may mediate these effects.

These findings suggest that mice may provide a model for understanding the mixed effects of marijuana on urine output, as described in clinical studies, and aid in the development of targeted cannabinoid based therapies for bladder dysfunction.

Clinical studies have reported beneficial effects of smoked or aerosolized cannabis on bladder dysfunction in patients with multiple sclerosis, primarily by decreasing urinary frequency in these subjects following marijuana use. These reports contrast with the earlier clinical reports demonstrating increase in urine output after cannabis administration.

Our findings in mice demonstrate a dose related increase or decrease in urine output, providing a platform for understanding the mixed effects on urine output observed with marijuana in various clinical studies. As noted earlier in a study with rats, the diuresis induced by THC in mice also is weakly naturetic compared to furosemide and further investigations in this area may yield a new, clinically beneficial diuretic.

In contrast, our data suggest that development of peripherally selective cannabinoid CB1 agonists may be beneficial for patients suffering from bladder dysfunction.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3872476/

Diuretic effects of cannabinoids.

Posted on by
Reply

Image result for journal of pharmacology and experimental therapeutics

“These data indicate that cannabinoids have robust diuretic effects in rats that are mediated via CB1 receptor mechanisms.

Overall, our data indicate that diuresis is a CB1-mediated effect that may serve as a reliable and objective physiologic measure of cannabinoid action in rats; the circumstances under which these results represent a potential therapeutic benefit or potential liability of cannabinoids remain to be determined.

The implications of these findings currently are poorly understood, although a better understanding of mechanisms and sites of action by which cannabinoids increase urine loss may lead to the rational development of novel cannabinergic medications.”  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3533417/

“Diuretics are medicines that help reduce the amount of water in the body. Diuretics are used to treat the buildup of excess fluid in the body that occurs with some medical conditions such ascongestive heart failure, liver disease, and kidney disease. Some diuretics are also prescribed to treat high bloodpressure. These drugs act on the kidneys to increase urine output. This reduces the amount of fluid in the bloodstream,which in turn lowers blood pressure.” http://medical-dictionary.thefreedictionary.com/diuretics

Cannabis, Tobacco, Alcohol Use, and the Risk of Early Stroke

Posted on by
Reply

Image result for ahajournals

“Current knowledge on cannabis use in relation to stroke is based almost exclusively on clinical reports. By using a population-based cohort, we aimed to find out whether there was an association between cannabis use and early-onset stroke, when accounting for the use of tobacco and alcohol.

Conclusions—We found no evident association between cannabis use in young adulthood and stroke, including strokes before 45 years of age. Tobacco smoking, however, showed a clear, dose–response shaped association with stroke.”

http://stroke.ahajournals.org/content/early/2016/12/27/STROKEAHA.116.015565

 “New Study: Cigarettes Tied To Increased Stroke Risk But Not Marijuana”  http://www.weednews.co/new-study-cigarettes-tied-to-increased-stroke-risk-but-not-marijuana/

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

Posted on by
Reply

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

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

Posted on by
Reply

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

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

Posted on by
Reply

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

Activation of Cannabinoid Receptor Type II by AM1241 Ameliorates Myocardial Fibrosis via Nrf2-Mediated Inhibition of TGF-β1/Smad3 Pathway in Myocardial Infarction Mice.

Posted on by
Reply

Image result for Cell Physiol Biochem

“Myocardial interstitial fibrosis is a major histologic landmark resulting in cardiac dysfunction after myocardial infarction (MI).

Activation of cannabinoid receptor type II (CB2 receptor) have been demonstrated to reduce fibrosis in hepatic cirrhotic rat.

In this study, we aimed to investigate the effects of a CB2 receptor selective agonist AM1241 on myocardial fibrosis post MI in mice.

CONCLUSION:

CB2 receptor agonist AM1241 alleviated myocardial interstitial fibrosis via Nrf2 -mediated down-regulation of TGF-β1/Smad3 pathway, which suggested that CB2 receptor activation might represent a promising target for retarding cardiac fibrosis after MI.”

http://www.ncbi.nlm.nih.gov/pubmed/27614871

Cannabidiol-2′,6′-dimethyl ether as an effective protector of 15-lipoxygenase-mediated low-density lipoprotein oxidation in vitro.

Posted on by
Reply

“15-Lipoxygenase (15-LOX) is one of the key enzymes responsible for the formation of oxidized low-density lipoprotein (ox-LDL), a major causal factor for atherosclerosis.

We have recently reported that cannabidiol-2′,6′-dimethyl ether (CBDD) is a selective and potent inhibitor of 15-LOX-catalyzed linoleic acid oxygenation.

The results obtained demonstrate that CBDD is a potent and selective inhibitor of ox-LDL formation generated by the 15-LOX pathway.

These studies establish CBDD as both an important experimental tool for characterizing 15-LOX-mediated ox-LDL formation, and as a potentially useful therapeutic agent for treatment of atherosclerosis.

In sum, these findings suggest that CBDD may be a useful adjuvant in the treatment of atherosclerosis as well as an experimental tool for analyzing the mechanistic details of PUFAs oxygenation by 15-LOX.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4012644/

“Cannabidiol-2′,6′-dimethyl ether, a cannabidiol derivative, is a highly potent and selective 15-lipoxygenase inhibitor. Thus, 15-LOX is suggested to be involved in development of atherosclerosis, and CBDD may be a useful prototype for producing medicines for atherosclerosis.”  http://www.ncbi.nlm.nih.gov/pubmed/19406952

Blood pressure regulation by endocannabinoids and their receptors

Posted on by
Reply

Logo of nihpa

“Cannabinoids and their endogenous and synthetic analogs exert powerful hypotensive and cardiodepressor effects by complex mechanisms involving direct and indirect effects on myocardium and vasculature.

On the one hand, endocannabinoids and cannabinoid receptors have been implicated in the hypotensive state associated with hemorrhagic, endotoxic and cardiogenic shock, and advanced liver cirrhosis.

On the other hand, there is emerging evidence suggesting that the endocannabinergic system plays an important role in the cardiovascular regulation in hypertension.

This review is aimed to discuss the in vivo hypotensive and cardiodepressant effects of cannabinoids mediated by cannabinoid and TRPV1 receptors, and focuses on the novel therapeutical strategies offered by targeting the endocannabinoid system in the treatment of hypertension.

The endocannabinergic system plays an important cardiovascular regulatory role not only in pathophysiological conditions associated with excessive hypotension but also in hypertension.

Thus, the pharmacological manipulation of this system may offer novel therapeutic approaches in a variety of cardiovascular disorders.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2225528/