Tag Archives: antagonists

Effect of Non-psychotropic Plant-derived Cannabinoids on Bladder Contractility: Focus on Cannabigerol.

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“There are anecdotal reports that some Cannabis preparations may be useful for bladder dysfunctions.

Here, we investigated the effect of a number of non- psychotropic phytocannabinoids, namely cannabidiol (CBD), cannabigerol (CBG), cannabidivarin (CBDV), Δ9-tetrahydrocannabivarin (THCV) and cannabichromene (CBC) on mouse bladder contractility in vitro.

CBG, THCV, CBD and CBDV, but not CBC, at concentration ranging from 10(-8) M to 10(-4) M, decreased (with similar potency), the contractions induced by acetylcholine without significantly modifying the contractions induced by electrical stimulation.

The rank order of efficacy was CBG=THCV>CBD>CBDV.

In depth studies on CBG showed that the effect of this phytocannabinoid on acetylcholine-induced contractions was not affected by CB1 or CB2 receptor antagonists.

Additionally, CBG also reduced acetylcholine-induced contractions in the human bladder.”

http://www.ncbi.nlm.nih.gov/pubmed/26197538

Preclinical evaluation of SMM-189, a cannabinoid receptor 2-specific inverse agonist.

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“Cannabinoid receptor 2 agonists and inverse agonists are emerging as new therapeutic options for a spectrum of autoimmune-related disease.

Of particular interest, is the ability of CB2 ligands to regulate microglia function in neurodegenerative diseases and traumatic brain injury.

We have previously reported the receptor affinity of 3′,5′-dichloro-2,6-dihydroxy-biphenyl-4-yl)-phenyl-methanone (SMM-189) and the characterization of the beneficial effects of SMM-189 in the mouse model of mild traumatic brain injury.

Herein, we report the further characterization of SMM-189 as a potent and selective CB2 inverse agonist, which acts as a noncompetitive inhibitor of CP 55,940.

The ability of SMM-189 to regulate microglial activation, in terms of chemokine expression and cell morphology, has been determined.

Finally, we have determined that SMM-189 possesses acceptable biopharmaceutical properties indicating that the triaryl class of CB2 inverse agonists are viable compounds for continued preclinical development for the treatment of neurodegenerative disorders and traumatic brain injury.”

http://www.ncbi.nlm.nih.gov/pubmed/26196013

Bone cell-autonomous contribution of type 2 cannabinoid receptor to breast cancer induced osteolysis.

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“The cannabinoid type 2 receptor (CB2) has previously been implicated as a regulator of tumour growth, bone remodelling and bone pain.

However, very little is known about the role of the skeletal CB2 receptor in the regulation of osteoblasts and osteoclasts changes associated with breast cancer. Here, we found that the CB2 selective agonists HU308 and JWH133 reduced the viability of a variety of parental and bone-tropic human and mouse breast cancer cells at high micro-molar concentrations…

When combined with published work, these findings suggest that breast cancer and bone cells exhibit differential responses to treatment with CB2 ligands, depending upon cell type and concentration used.

We therefore conclude that both, CB2 selective activation and antagonism have potential efficacy in cancer associated bone disease but further studies are warranted and ongoing.”

Exploring structural requirements for peripherally acting 1,5-diaryl pyrazole-containing cannabinoid 1 receptor antagonists for the treatment of obesity.

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“Peripherally acting cannabinoid 1 (CB1) receptor antagonists are considered as potential therapeutics for the treatment of obesity with desired efficacy and reduced central nervous system side effects.

The prediction accuracy and reliability of the best developed CoMSIA model have been validated using well-established methods. Using the inputs from the best CoMSIA contour maps, several novel highly selective peripherally acting CB1 receptor antagonists have been designed and reported herein.”

A synergistic interaction of 17-β-estradiol with specific cannabinoid receptor type 2 antagonist/inverse agonist on proliferation activity in primary human osteoblasts.

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“The bone remodeling process is influenced by various factors, including estrogens and transmitters of the endocannabinoid system. In osteoblasts, cannabinoid receptors 2 (CB-2) are expressed at a much higher level compared to CB-1 receptors. Previous studies have shown that estrogens could influence CB-2 receptor expression.

In the present study, the possible interactions of a specific CB-2 agonist and a specific CB-2 antagonist/inverse agonist with 17-β-estradiol were investigated in primary human osteoblasts (HOB)…

In conclusion, for the first time a synergistic interaction between 17-β-estradiol and specific CB-2 antagonist/inverse agonist was observed in HOB.

Understanding the molecular pathways of this interaction would be of great importance in developing more efficient and safer drugs for treating or preventing bone diseases.”

http://www.ncbi.nlm.nih.gov/pubmed/26171165

A comprehensive patents review on cannabinoid 1 receptor antagonists as antiobesity agents.

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“Obesity is a rapidly expanding worldwide health problem.

Various targets are investigated presently for the treatment of obesity, but there remains an unmet need for an effective drug therapy with acceptable efficacy levels and reduced side effects.

Targeting peripherally located cannabinoid 1 (CB1) receptors is an attractive strategy as these receptors play a vital role in energy homeostasis.

Areas covered: CB1 receptor antagonists constitute one of the most important categories of compounds of interest for the control of obesity.

In this review, the authors focus on recent advances (since 2007) in diverse chemical classes of patented compounds belonging to the category of CB1 receptor antagonists.

Expert opinion: Safer CB1 receptor antagonists for the treatment of obesity can be discovered by developing such compounds that act peripherally. Increasing the polar service area, decreasing the lipophilicity and designing of neutral antagonists and allosteric inhibitors are some interesting strategies that could offer promising results.”

http://www.ncbi.nlm.nih.gov/pubmed/26161824

Cannabinoid and nitric oxide signalling interplay in the modulation of hippocampal hyperexcitability: study on electrophysiological and behavioural models of temporal lobe epilepsy in the rat.

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“A growing bulk of evidence suggests that cannabinoid system plays a pivotal role in the control of hyperexcitability phenomena.

Notwithstanding, the anticonvulsant action of cannabinoids has not been fully addressed, in particular the involvement of potential cellular neuromodulators, for instance nitric oxide.

In the current study, we focused on two distinct rat models of temporal lobe epilepsy, the Maximal Dentate Activation and the Pilocarpine-induced acute seizures, providing both electrophysiological and behavioural data on cannabinoid and nitrergic system interplay.

MDA study showed that these drugs protected animals in a dose-dependent manner from electrically-induced epileptiform discharges.

In the light of this, our findings suggest a putative antagonism between CBr-activated pathway and NO signalling in the context of neuronal hyperexcitability and contribute to elucidate possible synaptic processes underlying neuroprotective properties of cannabinoids, with a view to better integrate antiepileptic therapy.”

http://www.ncbi.nlm.nih.gov/pubmed/26135674

Roles for the endocannabinoid system in ethanol-motivated behavior.

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“Alcohol use disorder represents a significant human health problem that leads to substantial loss of human life and financial cost to society. Currently available treatment options do not adequately address this human health problem, and thus, additional therapies are desperately needed.

The endocannabinoid system has been shown, using animal models, to modulate ethanol-motivated behavior, and it has also been demonstrated that chronic ethanol exposure can have potentially long-lasting effects on the endocannabinoid system.

For example, chronic exposure to ethanol, in either cell culture or preclinical rodent models, causes an increase in endocannabinoid levels that results in down-regulation of the cannabinoid receptor 1 (CB1) and uncoupling of this receptor from downstream G protein signaling pathways.

Using positron emission tomography (PET), similar down-regulation of CB1 has been noted in multiple regions of the brain in human alcoholic patients.

In rodents, treatment with the CB1 inverse agonist SR141716A (Rimonabant), or genetic deletion of CB1 leads to a reduction in voluntary ethanol drinking, ethanol-stimulated dopamine release in the nucleus accumbens, operant self-administration of ethanol, sensitization to the locomotor effects of ethanol, and reinstatement/relapse of ethanol-motivated behavior.

Although the clinical utility of Rimonabant or other antagonists/inverse agonists for CB1 is limited due to negative neuropsychiatric side effects, negative allosteric modulators of CB1 and inhibitors of endocannabinoid catabolism represent therapeutic targets worthy of additional examination.”

Delta-9-tetrahydrocannabinol protects cardiac cells from hypoxia via CB2 receptor activation and nitric oxide production.

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“Delta-9-tetrahydrocannabinol (THC), the major active component of marijuana, has a beneficial effect on the cardiovascular system during stress conditions…

The present study was designed to investigate the central (CB1) and the peripheral (CB2)cannabinoid receptor expression in neonatal cardiomyoctes and possible function in the cardioprotection of THC from hypoxia.

The antagonist for the CB2, but not CB1 receptor antagonist abolished the protective effect of THC.

In agreement with these results using RT-PCR, it was shown that neonatal cardiac cells express CB2, but not CB1 receptors.

Involvement of NO in the signal transduction pathway activated by THC through CB2 was examined. It was found that THC induces nitric oxide (NO) production by induction of NO synthase (iNOS) via CB2 receptors.

L-NAME (NOS inhibitor, 100 microM) prevented the cardioprotection provided by THC.

Taken together, our findings suggest that THC protects cardiac cells against hypoxia via CB2 receptor activation by induction of NO production.

An NO mechanism occurs also in the classical pre-conditioning process; therefore, THC probably pre-trains the cardiomyocytes to hypoxic conditions.”

http://www.ncbi.nlm.nih.gov/pubmed/16444588

Cannabinoid system as a potential target for drug development in the treatment of cardiovascular disease.

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“Although cannabinoids have been recreationally employed for thousands of years, it was not until the discovery of their specific receptors, in the early nineties, that the molecular basis of cannabinoid activity have began to be understood.

Growing research in this field has demonstrated not only that the action of cannabinoids in mammals is mainly receptor-mediated, but also that endogenous cannabinoids, such as anandamide, are produced, metabolized, and taken up across the cell membrane through a facilitated uptake process.

The exogenous administration of cannabinoids, as well as the manipulation of their endogenous levels have been related to a variety of effects, such as analgesia, (temporary) impairment of cognition and learning, appetite enhancement and peripheral vasodilation.

Hence, the endocannabinoid system, including the CB1 and CB2 receptors, the metabolizing enzyme fatty acid amide hydrolase and the anandamide transporter, is a potential target for the development of novel therapeutic drugs in the treatment of various conditions, such as pain, feeding disorders and vascular disease among others.

Although most of the research in the field of cannabinoids has been focused on their effects in the central nervous system, a growing line of evidence indicates that cannabinoids can also play a major role in the control of physiopathological functions in the cardiovascular system.

In this context, endocannabinoids have been proposed as novel possible hypotensive agents, and have been involved in the hypotension observed in septic shock, acute myocardial infarction and cirrhosis. In addition, a protective role for endocannabinoids has been described in ischemia.”

http://www.ncbi.nlm.nih.gov/pubmed/15320476