Tag Archives: Cannabinoids

Inflammation and aging: can endocannabinoids help?

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“Aging often leads to cognitive decline due to neurodegenerative process in the brain. As people live longer, a growing concern exist linked to long-term, slowly debilitating diseases that have not yet found a cure, such as Alzheimer’s disease. Recently, the role of neuroinflammation has attracted attention due to its slow onset, chronic nature and its possible role in the development of many different neurodegenerative diseases. In the future, treatment of chronic neuroinflammation may help counteract aspects of neurodegenerative disease. Our recent studies have focused upon the endocannabinoid system for its unique effects on the expression of neuroinflammation. The basis for the manipulation of the endocannabinoid system in the brain in combination with existing treatments for Alzheimer’s disease will be discussed in this review.”

“Endocannabinoids

Cannabinoid refers to naturally occurring or synthetic molecules mimicking the activity of plant-derived cannabinoids from Cannabis Sativa. Two types of cannabinoid receptors have been so far identified in the body, named CB1 and CB2. Discovery of cannabinoid receptors (CBr) lead to the finding of endogenous agonists for these receptors called endocannabinoids (EC). EC are derived from arachidonic acid, arachidonoylethanolamide (anandamide), and 2-arachidonoyl glycerol (2-AG), synthesized on-demand post-synaptically and released in response to the entry of calcium ions. These EC in combination with the two known CBr constitute the endocannabinoid system (ECS). In the central nervous system (CNS), CB1 is overwhelmingly represented over CB2 and particularly abundant in cortical regions, the hippocampus, cerebellum and basal ganglia while CB2 may be restricted to microglia or neurons in the brainstem  and cerebellum. Deactivation of the EC is due to a rapid enzymatic degradation in the synaptic cleft or after membrane transport. The ECS is thought to be a neuromodulator and an immunomodulator. In the CNS, the ECS can influence food intake, endocrine release, motor control, cognitive processes, emotions and perception. Cannabinoids treatment has been shown to be neuroprotective under many experimental conditions. Drugs that manipulate the ECS are currently evaluated in various diseases ranging from cancer to AIDS for their peripheral analgesic and immunosuppressive properties. Their anti-inflammatory actions may make them useful in the treatment of multiple sclerosis, Parkinson’s disease and AD. Very little in vivo evidence to support the use of EC receptor agonists has been reported, although in vitro studies have found evidence for their anti-inflammatory effectiveness. Our recent work demonstrated the anti-inflammatory effect of a chronic treatment of a low dose of the CBr agonist WIN-55,212-2 (without psychoactive effects) on the consequences of chronic neuroinflammation induced by the infusion of LPS into the 4th ventricle of young rats. Moreover, that same anti-inflammatory effect was found using a non-psychoactive dose given by slow subcutaneous infusion of WIN-55,212-2 to healthy aged rats; these rats also demonstrated improved spatial memory. Our ongoing work in aged rats has shown that treatment with the CBr agonist WIN-55,212-2 increases neurogenesis in the hippocampus. Our preliminary data suggest that the neurogenic and anti-inflammatory effects in aged rats are due to the agonist/antagonist properties of WIN-55,212-2 at multiple receptors.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2408719/

Cannabinoids attenuate the effects of aging upon neuroinflammation and neurogenesis.

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Abstract

“WIN-55,212-2 (WIN-2) can elicit anti-inflammatory and cognitive-enhancing effect in aged rats. The current study was designed to determine the differential role of the endocannabinoid receptor sub-types 1 (CB1) and 2 (CB2) and transient receptor potential vanilloid 1 receptor (TRPV1) in the reduction of age-associated brain inflammation and their effects on neurogenesis in the dentate gyrus of aged rats. Our results demonstrate that 1) the antagonist actions of WIN-2 at the TRPV1 receptor are responsible for the reduction in microglial activation and 2) the agonist actions of WIN-2 at CB1/2 receptors can trigger neurogenesis in the hippocampus of aged rats. Chronic treatment with WIN-2 established an anti-inflammatory cytokine profile within the hippocampus. Our results provide insight into the role of the endocannabinoid and vanilloid systems upon two different and detrimental aspects of normal and pathological aging, chronic neuroinflammation and decline in neurogenesis.”

http://www.ncbi.nlm.nih.gov/pubmed/19385063

The endocannabinoid system in ageing: a new target for drug development.

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Abstract

“Endocannabinoids are a new class of lipids, which include amides, esters and ethers of long chain polyunsaturated fatty acids. Anandamide (N-arachidonoylethanolamine; AEA) and 2-arachidonoylglycerol are the main endogenous agonists of cannabinoid receptors able to mimic several pharmacological effects of Delta(9)-tetrahydrocannabinol, the active principle of Cannabis sativa preparations like hashish and marijuana. AEA is released “on demand” from membrane lipids, and its activity at the receptors is limited by cellular uptake followed by intracellular hydrolysis. Together with AEA and congeners, the proteins which bind, synthesize, transport and hydrolyze AEA form the “endocannabinoid system”. Endogenous cannabinoids are present in the central nervous system and in peripheral tissues, suggesting a physiological role as broad spectrum modulators. This review summarizes the main features of the endocannabinoid system, and the latest advances on its involvement in ageing of central and peripheral cells. In addition, the therapeutic potential of recently developed drugs able to modulate the endocannabinoid tone for the treatment of ageing and age-related human pathologies will be reviewed.”

http://www.ncbi.nlm.nih.gov/pubmed/17100593

Curing addiction with cannabis medicines

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“Smokers trying to quit in the future could do it with the help of cannabis based medicines, according to research from The University of Nottingham.

Teams of pharmacologists, studying the cannabis-like compounds which exist naturally in our bodies (endocannabinoids), are exploring the potential for medical treatment. This includes treating conditions as diverse as obesity, diabetes, depression and addiction to substances like nicotine.

Scientists have known about endocannabinoids since the mid-1990s. This led to an explosion in the number of researchers looking into the future medical uses of cannabinoids and cannabis compounds.

Dr Steve Alexander, Associate Professor in the School of Biomedical Sciences, focused on a number of these projects in editing the first themed podcast for the British Journal of Pharmacology.

Dr Alexander said: “It is clear that there is very realistic potential for cannabinoids as medicines. Scientists are looking at a range of possible applications.”

One of these researchers is Professor David Kendall, a cellular pharmacologist at the University: “The brain is full of cannabinoid receptors. And so, not surprisingly with diseases like depression and anxiety, there’s a great deal of interest in exploiting these receptors and in doing so, developing anti-depressant compounds.”

Addiction is a real target – researchers like Professor Kendall believe the endocannabinoids could be a crucial link to addictive behaviour: “We know that the endocannabinoid system is intimately involved in reward pathways and drug seeking behaviour. So this tends to indicate that that if the link involving endocannabinoids and the reward pathway, using inhibitors, can be interrupted, it could turn down the drive to seek addictive agents like nicotine.”

Because cannabinoids have also been shown to bring down blood pressure, it is hoped that related compounds can be used in patients with conditions like hypertension.

Dr Michael Randall, a cardiovascular pharmacologist at the University has looked at how endocannabinoids cause blood vessels to relax. “This could have many implications,” Dr Randall said. “The endocannabinoids appear to lower blood pressure under certain conditions; states of shock for example. If the endocannabinoids are of physiological importance, this could have real therapeutic possibilities.”

“In terms of getting better medicines the endocannabinoid system has a lot to offer,” said Dr Alexander. “The range of cannabis-related medicines is currently limited, but by increasing our knowledge in this area we can increase our stock.”

The University of Nottingham”

http://www.brightsurf.com/news/headlines/36296/Curing_addiction_with_cannabis_medicines.html

Involvement of the endogenous cannabinoid system in the effects of alcohol in the mesolimbic reward circuit: electrophysiological evidence in vivo.

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Abstract

“RATIONALE:

Several lines of evidence indicate that the endogenous cannabinoid system is involved in the pharmacological and behavioural effects of alcohol. The mesolimbic dopaminergic (DA) system and the nucleus accumbens (NAc) process rewarding properties of drugs of abuse, including alcohol and cannabinoids, whereas endocannabinoids in these regions modulate synaptic function and mediate short- and long-term forms of synaptic plasticity.

OBJECTIVES:

The present study was designed to investigate the contribution of the endogenous cannabinoid system in alcohol electrophysiological effects in the mesolimbic reward circuit.

METHODS:

We utilized extracellular single cell recordings from ventral tegmental area (VTA) DA and NAc neurons in anesthetized rats. DA neurons were antidromically identified as projecting to the shell of NAc, whereas NAc putative medium spiny neurons were identified by their evoked responses to basolateral amygdala (BLA) stimulation.

RESULTS:

Alcohol stimulated firing rate of VTA DA neurons and inhibited BLA-evoked NAc neuron spiking responses. The cannabinoid type-1 receptor (CB1) antagonist rimonabant (SR141716A) fully antagonized alcohol effect in both regions. In the NAc, either inhibition of the major catabolic enzyme of the endocannabinoid anandamide, the fatty-acid amyd hydrolase, with URB597 or a pretreatment with the CB1 receptor agonist WIN55212-2 significantly depressed alcohol-induced effects in the NAc.

CONCLUSIONS:

These results corroborate the notion of the involvement of endocannabinoids and their receptors in the actions of alcohol and highlight the endocannabinoid system as a valuable target in the therapy for alcoholism.”

http://www.ncbi.nlm.nih.gov/pubmed/16228194

Blockade of the cannabinoid CB1 receptor and alcohol dependence: preclinical evidence and preliminary clinical data.

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Abstract

“The present paper summarizes the results of a number of pharmacological studies implicating the cannabinoid CB(1) receptor in the neural circuitry regulating different alcohol-related behaviors in rodents. Specifically, cannabinoid CB(1) receptor antagonists–including the prototype, rimonabant–have been reported to suppress: (a) acquisition and maintenance of alcohol drinking behavior under the 2-bottle “alcohol vs water” choice regimen; (b) the increase in alcohol intake occurring after a period of alcohol abstinence (an experimental model of alcohol relapse); (c) alcohol’s reinforcing and motivational properties measured in rats trained to perform a specific task (e.g., lever-pressing) to access alcohol; (d) reinstatement of extinguished alcohol-seeking behavior triggered in rats by a nicotine challenge or presentation of cues previously associated to alcohol availability (another model of alcohol relapse). Additional data indicate that the opioid receptor antagonists, naloxone and naltrexone, synergistically potentiate the suppressing effect of rimonabant on alcohol intake and alcohol’s motivational properties in rats. Conversely, the two clinical studies conducted to date (one in alcohol-dependent individuals and one in nontreatment-seeking heavy alcohol drinkers) yielded less conclusive results. Unfortunately, the recent discontinuation–due to the occurrence of some psychiatric adverse effects–of all trials with cannabinoid CB(1) receptor antagonists apparently hinders further investigations on the potential of rimonabant in the treatment of alcohol dependence.”

http://www.ncbi.nlm.nih.gov/pubmed/20201816

Positron Emission Tomography Shows Elevated Cannabinoid CB (1) Receptor Binding in Men with Alcohol Dependence.

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Abstract

“BACKGROUND:

Several lines of evidence link cannabinoid (CB) type 1 (CB (1) ) receptor-mediated endogenous CB (eCB) signaling to the etiology of alcohol dependence (AD). However, to date, only peripheral measures of eCB function have been collected in living humans with AD and no human in vivo data on the potentially critical role of the brain CB (1) receptor in AD have been published. This is an important gap in the literature, because recent therapeutic developments suggest that these receptors could be targeted for the treatment for AD.”

 

“CONCLUSIONS:

These findings agree with preclinical evidence and provide the first, albeit still preliminary in vivo evidence suggesting a role for brain CB (1) receptors in AD. The current study design does not answer the important question of whether elevated CB (1) receptors are a preexisting vulnerability factor for AD or whether elevations develop as a consequence of AD.”

http://www.ncbi.nlm.nih.gov/pubmed/22551199

[The role of the cannabinoid system in the pathogenesis and treatment of alcohol dependence].

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Abstract

“The lack of satisfactory results of alcohol dependence treatment force us to search for new directions of research. Recent studies concentrate on endocannabinoid transmission. The results show an interplay between the endocannabinoid and dopaminergic signaling in activation of the limbic reward system. The mechanisms leading to development of dependence are very complex and poorly recognized. Endogenous cannabinoids seem to have an important role in the functioning of this system, both directly and indirectly affecting the level of different neurotransmitters. The effect of alcohol on the endocannabinoid system is also complex and involves changes at the molecular level. Experimental studies have demonstrated an important role of the CB1 receptors in the neurochemical mechanism of alcohol consumption and its regulation. SR141716 (rimonabant), a CB1 receptor antagonist, significantly lowers voluntary alcohol intake and motivation for its consumption in various experimental studies. Very encouraging results of preclinical studies were not completely confirmed in the clinical studies. However, further clinical studies are still necessary.”

http://www.ncbi.nlm.nih.gov/pubmed/21934185

Endocannabinoid system and alcohol addiction: pharmacological studies.

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Abstract

“The present paper describes the results of recent pharmacological studies implicating the cannabinoid CB1 receptor in the neural circuitry regulating alcohol consumption and motivation to consume alcohol. Cannabinoid CB1 receptor agonists have been found to specifically stimulate alcohol intake and alcohol’s motivational properties in rats. Conversely, the cannabinoid CB1 receptor antagonist, SR 141716, has been reported to specifically suppress acquisition and maintenance of alcohol drinking behavior, relapse-like drinking and alcohol’s motivational properties in rats. More recent data indicate that opioid receptor antagonists a) blocked the stimulatory effect of cannabinoids on alcohol intake, and b) synergistically potentiated the suppressing effect of SR 141716 on alcohol intake and alcohol’s motivational properties. Consistently, SR 141716 blocked the stimulatory effect of morphine on alcohol intake. These results suggest a) the existence of a functional link between the cannabinoid and opioid receptor systems in the control of alcohol intake and motivation to consume alcohol, and b) that novel and potentially effective therapeutic strategies for alcoholism may come from the combination of cannabinoid and opioid receptor antagonists.”

http://www.ncbi.nlm.nih.gov/pubmed/15939463

Neuromodulatory role of the endocannabinoid signaling system in alcoholism: an overview.

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Abstract

“The current review evaluates the evidence that some of the pharmacological and behavioral effects of ethanol (EtOH), including EtOH-preferring behavior, may be mediated through the endocannabinoid signaling system. The recent advances in the understanding of the neurobiological basis of alcoholism suggest that the pharmacological and behavioral effects of EtOH are mediated through its action on neuronal signal transduction pathways and ligand-gated ion channels, receptor systems, and receptors that are coupled to G-proteins. The identification of a G-protein-coupled receptor, namely, the cannabinoid receptor (CB1 receptor) that was activated by Delta(9)-tetrahydrocannabinol (Delta(9)-THC), the major psychoactive component of marijuana, led to the discovery of endogenous cannabinoid agonists. To date, two fatty acid derivatives identified to be arachidonylethanolamide (AEA) and 2-arachidonylglycerol (2-AG) have been isolated from both nervous and peripheral tissues. Both these compounds have been shown to mimic the pharmacological and behavioral effects of Delta(9)-THC. The involvement of the endocannabinoid signaling system in the development of tolerance to the drugs of abuse including EtOH has not been known until recently. Recent studies from our laboratory have demonstrated for the first time the down-regulation of CB1 receptor function and its signal transduction by chronic EtOH. The observed down-regulation of CB1 receptor binding and its signal transduction results from the persistent stimulation of the receptors by the endogenous CB1 receptor agonists, AEA and 2-AG, the synthesis of which has been found to be increased by chronic EtOH treatment. This enhanced formation of endocannabinoids may subsequently influence the release of neurotransmitters. It was found that the DBA/2 mice, known to avoid EtOH intake, have significantly reduced brain-CB1-receptor function consistent with other studies, where the CB1 receptor antagonist SR141716A has been shown to block voluntary EtOH intake in rodents. Similarly, activation of the CB1 receptor system promoted alcohol craving, suggesting a role for the CB1 receptor gene in excessive EtOH drinking behavior and development of alcoholism. Ongoing investigations may lead to the development of potential therapeutic strategies for the treatment of alcoholism.”

http://www.ncbi.nlm.nih.gov/pubmed/12052043