The cannabinoid CB1 receptor antagonist rimonabant attenuates the hypotensive effect of smoked marijuana in male smokers

Cannabinoid Analgesia in Postoperative Pain Management: From Molecular Mechanisms to Clinical Reality

Postoperative pain (POP) is a challenging clinical phenomenon that affects the majority of surgical patients and demands effective management to mitigate adverse outcomes such as persistent pain. The primary goal of POP management is to alleviate suffering and facilitate a seamless return to normal function for the patient. Despite compelling evidence of its drawbacks, opioid analgesia remains the basis of POP treatment. Novel therapeutic approaches rely on multimodal analgesia, integrating different pharmacological strategies to optimize efficacy while minimizing adverse effects. The recognition of the imperative role of the endocannabinoid system in pain regulation has prompted the investigation of cannabinoid compounds as a new therapeutic avenue. Cannabinoids may serve as adjuvants, enhancing the analgesic effects of other drugs and potentially replacing or at least reducing the dependence on other long-term analgesics in pain management. This narrative review succinctly summarizes pertinent information on the molecular mechanisms, clinical therapeutic benefits, and considerations associated with the plausible use of various cannabinoid compounds in treating POP. According to the available evidence, cannabinoid compounds modulate specific molecular mechanisms intimately involved in POP. However, only two of the eleven clinical trials that evaluated the efficacy of different cannabinoid interventions showed positive results.

Cardiotoxic effects of common and emerging drugs: role of cannabinoid receptors

Drug-induced cardiotoxicity has become one of the most common and detrimental health concerns, which causes significant loss to public health and drug resources. Cannabinoid receptors (CBRs) have recently achieved great attention for their vital roles in the regulation of heart health and disease, with mounting evidence linking CBRs with the pathogenesis and progression of drug-induced cardiotoxicity. This review aims to summarize fundamental characteristics of two well-documented CBRs (CB1R and CB2R) from aspects of molecular structure, signaling and their functions in cardiovascular physiology and pathophysiology. Moreover, we describe the roles of CB1R and CB2R in the occurrence of cardiotoxicity induced by common drugs such as antipsychotics, anti-cancer drugs, marijuana, and some emerging synthetic cannabinoids. We highlight the 'yin-yang' relationship between CB1R and CB2R in drug-induced cardiotoxicity and propose future perspectives for CBR-based translational medicine toward cardiotoxicity curation and clinical monitoring.

Role of Cannabinoid Signaling in Cardiovascular Function and Ischemic Injury

Cardiovascular disease represents a leading cause of death, morbidity, and societal economic burden. The prevalence of cannabis use has significantly increased due to legalization and an increased societal acceptance of cannabis. Therefore, it is critically important that we gain a greater understanding of the effects and risks of cannabinoid use on cardiovascular diseases as well as the potential for cannabinoid-directed drugs to be used as therapeutics for the treatment of cardiovascular disease. This review summarizes our current understanding of the role of cannabinoid receptors in the pathophysiology of atherosclerosis and myocardial ischemia and explores their use as therapeutic targets in the treatment of ischemic heart disease. Endocannabinoids are elevated in patients with atherosclerosis, and activation of cannabinoid type 1 receptors (CB1Rs) generally leads to an enhancement of plaque formation and atherosclerosis. In contrast, selective activation of cannabinoid type 2 receptors (CB2Rs) appears to exert protective effects against atherosclerosis. Endocannabinoid signaling is also activated by myocardial ischemia. CB2R signaling appears to protect the heart from ischemic injury, whereas the role of CB1R in ischemic injury is less clear. This narrative review serves to summarize current research on the role of cannabinoid signaling in cardiovascular function with the goal of identifying critical knowledge gaps and future studies to address those gaps in a way that facilitates the development of new treatments and better cardiovascular health. SIGNIFICANCE STATEMENT: Cardiovascular diseases, including atherosclerosis and myocardial infarction, are a leading cause of death. Cannabinoid drugs have well known acute effects on cardiovascular function, including tachycardia and orthostatic hypotension. The recent legalization of marijuana and cannabinoids for both medical and recreational use has dramatically increased their prevalence of use. This narrative review on the role of cannabinoid signaling in cardiovascular disease contributes to a better understanding of this topic by integrating current knowledge and identifying critical gaps.

Evaluation of the cardiovascular risk induced by cannabis use from a series of 43 autopsy cases

The aim of this monocentric observational autopsy study was to confirm the existence of a link between cannabis use and cardiovascular risk. It was based on the analysis of autopsy findings, cardiovascular pathological findings, and toxicological data in 43 autopsy cases of people who died with tetrahydrocannabinol (THC) in their blood over a 2-year period. Hair analysis was performed when available (n = 40) to distinguish between occasional and chronic cannabis use and to take into account other possible exposures, including smoking, drug consumption, and the use of other drugs of abuse (mainly cocaine, heroin, and amphetamine). A statistically significant association (Fisher's exact test, p < 0.001) was found between cannabis use, an undetermined manner of death, and the presence of an arrhythmogenic cardiac condition. An association was also found between cannabis use and the presence of advanced coronary heart disease (p = 0.01), heart disease (including ischemic heart disease, p = 0.003), or cardiomyopathy (p = 0.01). Through its systemic vascular action, cannabis could be a factor in triggering sudden death in subjects with arrhythmogenic cardiac conditions. In view of this finding, the mode of death of subjects who died in the presence of THC in the blood would in most cases be an "accident." These results highlight the potential adverse cardiac effects associated with cannabis use.

How do phytocannabinoids affect cardiovascular health? An update on the most common cardiovascular diseases

Cardiovascular disease (CVD) causes millions of deaths worldwide each year. Despite the great progress in therapies available for patients with CVD, some limitations, including drug complications, still exist. Hence, the endocannabinoid system (ECS) was proposed as a new avenue for CVDs treatment. The ECS components are widely distributed through the body, including the heart and blood vessels, thus the action of its endogenous and exogenous ligands, in particular, phytocannabinoids play a key role in various pathological states. The cardiovascular action of cannabinoids is complex as they affect vasculature and myocardium directly via specific receptors and exert indirect effects through the central and peripheral nervous system. The growing interest in phytocannabinoid studies, however, has extended the knowledge about their molecular targets as well as therapeutical properties; nonetheless, some areas of their actions are not yet fully recognized. Researchers have reported various cannabinoids, especially cannabidiol, as a promising approach to CVDs; hence, the purpose of this review is to summarize and update the cardiovascular actions of the most potent phytocannabinoids and the potential therapeutic role of ECS in CVDs, including ischemic reperfusion injury, arrhythmia, heart failure as well as hypertension.

Functional brain connectomes reflect acute and chronic cannabis use

Resting state fMRI has been employed to identify alterations in functional connectivity within or between brain regions following acute and chronic exposure to Δ9-tetrahydrocannabinol (THC), the psychoactive component in cannabis. Most studies focused a priori on a limited number of local brain areas or circuits, without considering the impact of cannabis on whole-brain network organization. The present study attempted to identify changes in the whole-brain human functional connectome as assessed with ultra-high field (7T) resting state scans of cannabis users (N = 26) during placebo and following vaporization of cannabis. Two distinct data-driven methodologies, i.e. network-based statistics (NBS) and connICA, were used to identify changes in functional connectomes associated with acute cannabis intoxication and history of cannabis use. Both methodologies revealed a broad state of hyperconnectivity within the entire range of major brain networks in chronic cannabis users compared to occasional cannabis users, which might be reflective of an adaptive network reorganization following prolonged cannabis exposure. The connICA methodology also extracted a distinct spatial connectivity pattern of hypoconnectivity involving the dorsal attention, limbic, subcortical and cerebellum networks and of hyperconnectivity between the default mode and ventral attention network, that was associated with the feeling of subjective high during THC intoxication. Whole-brain network approaches identified spatial patterns in functional brain connectomes that distinguished acute from chronic cannabis use, and offer an important utility for probing the interplay between short and long-term alterations in functional brain dynamics when progressing from occasional to chronic use of cannabis.

The Endocannabinoid System and Cannabidiol: Past, Present, and Prospective for Cardiovascular Diseases

In the past, cannabis was commonly associated with mysticism and illegality. Fortunately, in recent years perspectives and discourses have changed. More prominence has been given to the rigorous scientific effort that led to the discovery of cannabis' many physiological actions and endogenous signalling mechanisms. The endocannabinoid system is a complex and heterogeneous pro-homeostatic network comprising different receptors with several endogenous ligands, numerous metabolic enzymes and regulatory proteins. Therefore, it is not surprising that alterations and dysfunctions of the endocannabinoid system are observed in almost every category of disease. Such high degree of pathophysiological involvement suggests the endocannabinoid system is a promising therapeutic target and prompted the translation of resurgent scientific findings into clinical therapies. Shifting attitudes toward cannabis also raised other matters such as increased patient awareness, prescription requests, self-medication, recreational use, recognition of new knowledge gaps, renewed scientific activity, and seemingly exponential growth of the cannabis industry. This review, following a general overview of cannabis and the endocannabinoid system, assiduously describes its role within the context of cardiovascular diseases, paying particular attention to the Janus influence that endocannabinoid system modulators can have on the cardiovascular system.

Cannabis and Athletic Performance

Cannabis is widely used for both recreational and medicinal purposes on a global scale. There is accumulating interest in the use of cannabis and its constituents for athletic recovery, and in some instances, performance. Amidst speculation of potential beneficial applications, the effects of cannabis and its two most abundant constituents, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), remain largely un-investigated. The purpose of this review is to critically evaluate the literature describing the effects of whole cannabis, THC, and CBD, on athletic performance and recovery. While investigations of whole cannabis and THC have generally shown either null or detrimental effects on exercise performance in strength and aerobic-type activities, studies of sufficient rigor and validity to conclusively declare ergogenic or ergolytic potential in athletes are lacking. The ability of cannabis and THC to perturb cardiovascular homeostasis warrants further investigation regarding mechanisms by which performance may be affected across different exercise modalities and energetic demands. In contrast to cannabis and THC, CBD has largely been scrutinized for its potential to aid in recovery. The beneficial effects of CBD on sleep quality, pain, and mild traumatic brain injury may be of particular interest to certain athletes. However, research in each of these respective areas has yet to be thoroughly investigated in athletic populations. Elucidating the effects of whole cannabis, THC, and CBD is pertinent for both researchers and practitioners given the widespread use of these products, and their potential to interact with athletes' performance and recovery.

Cardiovascular Effects of Medical Marijuana: A Systematic Review

Utilization of marijuana as a medicinal agent is becoming increasingly popular, and so far, 25 states have legalized it for medical purposes. However, there is emerging evidence that marijuana use can result in cardiovascular side effects, such as rhythm abnormalities, syncope/dizziness, and myocardial infarction, among others. Further, there are currently no stringent national standards or approval processes, like Food and Drug Administration (FDA) evaluation, in place to assess medical marijuana products. This review includes the largest up-to-date pooled population of patients with exposure to marijuana and reported cardiovascular effects. Although purported as benign by many seeking to advance the use of marijuana as an adjunctive medical therapy across the country, marijuana is associated with its own set of cardiovascular risks and deserves further definitive study and the same level of scrutiny we apply in research of all other types of medications. When used as a medicinal agent, marijuana should be regarded accordingly, and both clinical providers and patients must be aware of potential adverse effects associated with its use for early recognition and management.

The Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of ASP3652 in First-in-Human and Ascending Multiple Oral Dose Studies in Healthy Subjects

INTRODUCTION

Inhibitors of fatty acid amide hydrolase (FAAH) increase the levels of endocannabinoids and have shown analgesic and anti-inflammatory activity in animal models. ASP3652 is a peripherally acting FAAH inhibitor in development for the treatment of chronic bladder and pelvic pain disorders. Here we describe the safety, pharmacokinetics, and pharmacodynamics of single and multiple oral doses of ASP3652 administered in healthy non-elderly and elderly male and female volunteers.

METHODS

Study 1 was a combined single-ascending dose and food-effect study in which ASP3652 was given as single doses (1-600 mg) or matching placebo in healthy subjects. Study 2 was a multiple ascending dose study in which ASP3652 or matching placebo was administered in multiple oral doses (10-300 mg bid and 600 mg qd for 14 days) to healthy subjects. In both studies, the levels of ASP3652, FAAH, endocannabinoids (eCBs) and safety were evaluated.

RESULTS

ASP3652 was readily absorbed to reach C_max at 1 h after a single dose. Steady state was reached within 3 days after the start of multiple dosing. The C_max and AUC of ASP3652 increased in a slightly more than dose-proportional manner after a single dose of ASP3652 at 30-600 mg. There was some accumulation (15-38%) based on C_max and AUC_12h upon multiple doses. C_max was 47% lower in combination with food. There was no significant effect of gender or age on the pharmacokinetics of ASP3652. FAAH activity was inhibited in a dose-dependent manner in all dose groups after single and multiple doses of ASP3652, paralleled by an increase in plasma levels of anandamide (AEA). The incidence of adverse events following multiple doses was similar across all treatment groups including the placebo group.

CONCLUSIONS

Single and multiple doses of ASP3652 were safe and well tolerated and increased endogenous cannabinoid plasma levels.

Role of the Endocannabinoidome in Human and Mouse Atherosclerosis

The Endocannabinoid (eCB) system and its role in many physiological and pathological conditions is well described and accepted, and includes cardiovascular disorders. However, the eCB system has been expanded to an "-ome"; the endocannabinoidome (eCBome) that includes endocannabinoid-related mediators, their protein targets and metabolic enzymes, many of which significantly impact upon cardiometabolic health. These recent discoveries are here summarized with a special focus on their potential involvement in atherosclerosis. We described the role of classical components of the eCB system (eCBs, CB1 and CB2 receptors) and eCB-related lipids, their regulatory enzymes and molecular targets in atherosclerosis. Furthermore, since increasing evidence points to significant cross-talk between the eCBome and the gut microbiome and the gut microbiome and atherosclerosis, we explore the possibility that a gut microbiome - eCBome axis has potential implications in atherosclerosis.

Barriers to the wider adoption of medicinal Cannabis

The use of Cannabis-based preparations for medicinal use has waxed and waned in the multi-millennial history of human co-existence with the plant and its cultivation. Recorded use of preparations from Cannabis is effectively as old as recorded history with examples from China, India and Ancient Egypt. Prohibition and restriction of availability allowed a number of alternatives to take the place of Cannabis preparations. However, there has been a worldwide resurgence in medicinal Cannabis advocacy from the public. Media interest has been piqued by particular evocative cases. Altogether, therefore, there is pressure on healthcare professionals to prescribe and dispense Cannabis-based preparations. This review enunciates some of the barriers which are slowing the wider adoption of medicinal Cannabis.

Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of ASP3652, a Reversible Fatty Acid Amide Hydrolase Inhibitor, in Healthy, Nonelderly, Japanese Men and Elderly, Japanese Men and Women: A Randomized, Double-blind, Placebo-controlled, Single and Multiple Oral Dose, Phase I Study

PURPOSE

This study aimed to evaluate the safety, tolerability, and pharmacokinetic and pharmacodynamic properties of ASP3652, a peripherally acting inhibitor of peripheral fatty acid amide hydrolase (FAAH) after 30-, 100-, 300-, 600-, and 900-mg single and 100- and 300-mg BID multiple oral dose in Japanese patients.

METHODS

This was a randomized, double-blind, placebo-controlled, single and multiple oral dose Phase I study in healthy, nonelderly men and elderly men and women. The study consisted of 2 parts: in the single oral dose part, 40 healthy, nonelderly men were randomized to receive placebo or ASP3652; in the multiple oral dose part, 48 enrolled nonelderly men and elderly men and women were randomized to receive placebo or ASP3652. In both parts, the investigator judged whether the individuals were healthy based on the results of physical examinations and screening. The safety profile was assessed by examining adverse events, defined as any untoward medical occurrence in an individual administered the study drug and that did not necessarily have a causal relationship with the study treatment; clinical laboratory evaluations; vital signs; the Profile of Mood States scale; and standard 12-lead ECGs and 12-lead ECGs for QT assessment. Pharmacokinetic parameters were estimated using unchanged ASP3652 concentrations in plasma and urine. Pharmacodynamic parameters were estimated using FAAH activity and plasma anandamide, oleoylethanolamide, and palmitoylethanolamide concentrations. Safety and tolerability profiles were compared with the placebo group.

FINDINGS

ASP3652 was rapidly absorbed to reach C_max in a single dose and near steady-state at approximately 3 days after the start of multiple dosing. The C_max and AUC of ASP3652 were slightly higher than dose proportional after a single dose of ASP3652 at 30-900 mg. There was no apparent accumulation based on C_max and AUC_0-12 after multiple doses. Although no differences were found in C_max or AUC_0-12 by age in men, C_max and AUC_0-12 were slightly higher in elderly women than elderly men. FAAH activity was inhibited in a dose-dependent manner, and plasma levels of anandamide, oleoylethanolamide, and palmitoylethanolamide increased in all dose groups after single and multiple doses of ASP3652. The incidence of adverse events after multiple doses, which ranged from 44.4% to 66.7%, was similar across all treatment groups, including the placebo group.

IMPLICATIONS

Single and multiple doses of ASP3652 were well tolerated and increased endogenous cannabinoids.

Cerebrovascular and cardiovascular diseases caused by drugs of abuse

Drugs such as stimulants, sedatives, sleeping pills, and narcotics are associated with drug abuse and are therefore regulated by law. Physical dependence on these drugs is sometimes difficult to control despite an awareness of the problems they cause in daily life and the harm they can cause to the body. Drug dependence is a social problem worldwide, and the physical implications are serious. Many of these drugs cause cerebrovascular and cardiovascular diseases, which often require emergency medical treatment. Differential diagnosis is essential because of the likelihood of life-threatening events, especially among young people who exhibit cerebrovascular and cardiovascular diseases without any of the typical risk factors. Drugs of abuse, especially stimulants, induce a hyperadrenergic state that evokes vasoconstriction and tachycardia, as well as subsequent ischemic and hemorrhagic stroke, acute coronary syndrome, arrhythmias, and aortic dissection. Chronic drug abuse can also cause cardiac hypertrophy and left ventricular dysfunction. As a treatment for these conditions, sedative drugs can be effective but the use of vasodilators may also be required. There are concerns that the use of both alpha- and beta-adrenergic receptor blockers may cause tachycardia and increased blood pressure. Therefore, careful differential diagnosis and selection of therapeutic agents is required.

In-hospital outcomes of inflammatory bowel disease in cannabis users: a nationwide propensity-matched analysis in the United States

Background

Literature suggests the role of cannabis (marijuana) as an anti-inflammatory agent. However, the impact of recreational marijuana usage on in-hospital outcomes of inflammatory bowel disease (IBD) remains indistinct. We assessed the outcomes of Crohn's disease (CD) as well as ulcerative colitis (UC) with vs. without recreational marijuana usage using a nationally illustrative propensity-matched sample.

Methods

The Nationwide Inpatient Sample datasets (2010-2014) were queried to identify adults with CD and UC hospitalizations with cannabis use and linked complications using ICD-9 CM codes. Categorical and continuous variables were compared between propensity-matched cohorts using Chi-square and Student's t-test, respectively. Primary endpoints were in-hospital complications, whereas secondary endpoints were the discharge disposition, mean length of stay (LOS) and hospital charges.

Results

Propensity-matched cohorts included 6,002 CD (2,999 cannabis users & 3,003 non-users) and 1,481 UC (742 cannabis users & 739 non-users) hospitalizations. In CD patients, prevalence of colorectal cancer (0.3% vs. 1.2%, P<0.001), need for parenteral nutrition (3.0% vs. 4.7%, P=0.001) and anemia (25.6% vs. 30.1%, P<0.001) were lower in cannabis users. However, active fistulizing disease or intraabdominal abscess formation (8.6% vs. 5.9%, P<0.001), unspecific lower gastrointestinal (GI) hemorrhage (4.0% vs. 2.7%, P=0.004) and hypovolemia (1.2% vs. 0.5%, P=0.004) were higher with recreational cannabis use. The mean hospital stay was shorter (4.2 vs. 5.0 days) with less hospital charges ($28,956 vs. $35,180, P<0.001) in cannabis users. In patients with UC, cannabis users faced the higher frequency of fluid and electrolyte disorders (45.1% vs. 29.6%, P<0.001), and hypovolemia (2.7% vs. <11) with relatively lower frequency of postoperative infections (<11 vs. 3.4%, P=0.010). No other complications were significant enough for comparison between the cannabis users and non-users in this group. Like CD, UC-cannabis patients had shorter mean hospital stay (LOS) (4.3 vs. 5.7 days, P<0.001) and faced less financial burden ($30,393 vs. $41,308, P<0.001).

Conclusions

We found a lower frequency of colorectal cancer, parenteral nutrition, anemia but a higher occurrences of active fistulizing disease or intraabdominal abscess formation, lower GI hemorrhage and hypovolemia in the CD cohort with cannabis usage. In patients with UC, frequency of complications could not be compared between the two cohorts, except a higher frequency of fluid and electrolyte disorders and hypovolemia, and a lower frequency of postoperative infections with cannabis use. A shorter LOS and lesser hospital charges were observed in both groups with recreational marijuana usage.

The Endocannabinoid System and Cannabidiol's Promise for the Treatment of Substance Use Disorder

Substance use disorder is characterized by repeated use of a substance, leading to clinically significant distress, making it a serious public health concern. The endocannabinoid system plays an important role in common neurobiological processes underlying substance use disorder, in particular by mediating the rewarding and motivational effects of substances and substance-related cues. In turn, a number of cannabinoid drugs (e.g., rimonabant, nabiximols) have been suggested for potential pharmacological treatment for substance dependence. Recently, cannabidiol (CBD), a non-psychoactive phytocannabinoid found in the cannabis plant, has also been proposed as a potentially effective treatment for the management of substance use disorder. Animal and human studies suggest that these cannabinoids have the potential to reduce craving and relapse in abstinent substance users, by impairing reconsolidation of drug-reward memory, salience of drug cues, and inhibiting the reward-facilitating effect of drugs. Such functions likely arise through the targeting of the endocannabinoid and serotonergic systems, although the exact mechanism is yet to be elucidated. This article seeks to review the role of the endocannabinoid system in substance use disorder and the proposed pharmacological action supporting cannabinoid drugs' therapeutic potential in addictions, with a focus on CBD. Subsequently, this article will evaluate the underlying evidence for CBD as a potential treatment for substance use disorder, across a range of substances including nicotine, alcohol, psychostimulants, opioids, and cannabis. While early research supports CBD's promise, further investigation and validation of CBD's efficacy, across preclinical and clinical trials will be necessary.

Alcohol and drug intoxications in adolescents admitted to paediatric wards in the Czech Republic: 5-year retrospective study 2006-2010

OBJECTIVES

The aim of the study was to establish frequency, severity and circumstances of alcohol and drug intoxications in adolescents admitted to inpatient wards in the Czech Republic.

METHODS

Chief physician of each participating ward (or their designated deputy) searched the patient records for required information. The data was then statistically processed.

RESULTS

Thirty inpatient paediatric wards participated in the study (27 district wards and 3 university hospital wards), amounting to more than a third of all paediatric wards in the country. The total number of intoxications reported was 2,176, the majority of which were alcohol-related (84.5%), followed by cannabinoids and, to a lesser degree, amphetamines. The number of alcohol intoxications increased by 22% during the 5-year observation period, whilst the frequency of illegal drugs intoxications remained the same. We also observed an increase in the percentage of alcohol intoxications in girls - from 42% to 45.5%. The mean age at intoxication was low - 15.5 years. The Glasgow Coma Scale in individual episodes of intoxication increased during the study duration/follow up period. The proportion of alcohol intoxications originating in pubs, clubs or other public institutions was 25%.

CONCLUSION

The number of alcohol intoxications has risen during the observation period. The age at which these intoxications occurred is very low. Of serious concern is the fact, that 25% of alcohol intoxications originated in places where alcohol is sold, despite the fact that majority of the adolescents were under the legal drinking age limit of 18 years.

Cannabinoids in the Cardiovascular System

Cannabinoids are known to modulate cardiovascular functions including heart rate, vascular tone, and blood pressure in humans and animal models. Essential components of the endocannabinoid system, namely, the production, degradation, and signaling pathways of endocannabinoids have been described not only in the central and peripheral nervous system but also in myocardium, vasculature, platelets, and immune cells. The mechanisms of cardiovascular responses to endocannabinoids are often complex and may involve cannabinoid CB₁ and CB₂ receptors or non-CB_1/2 receptor targets. Preclinical and some clinical studies have suggested that targeting the endocannabinoid system can improve cardiovascular functions in a number of pathophysiological conditions, including hypertension, metabolic syndrome, sepsis, and atherosclerosis. In this chapter, we summarize the local and systemic cardiovascular effects of cannabinoids and highlight our current knowledge regarding the therapeutic potential of endocannabinoid signaling and modulation.

Mechanisms contributing to cognitive deficits in cannabis users

Studies from preclinical animal models indicate that sustained activation of CB1 receptor signaling is a major contributing factor for the onset of cognitive deficits associated to chronic cannabis use, in particular within the working memory and decision-making domains. Yet, very few studies have been designed to directly assess the role of CB1 receptors in mediating the effects of cannabis on human brain function. This perspective review article provides an overview of current state of knowledge on possible neurobiological mechanisms accounting for the detrimental effects of chronic cannabis use on cognition and related changes in brain structure and functional connectivity. This article is part of the Special Issue entitled "A New Dawn in Cannabinoid Neurobiology".

Cannabinoid signaling in health and disease

Cannabis sativa has long been used for medicinal purposes. To improve safety and efficacy, compounds from C. sativa were purified or synthesized and named under an umbrella group as cannabinoids. Currently, several cannabinoids may be prescribed in Canada for a variety of indications such as nausea and pain. More recently, an increasing number of reports suggest other salutary effects associated with endogenous cannabinoid signaling including cardioprotection. The therapeutic potential of cannabinoids is therefore extended; however, evidence is limited and mechanisms remain unclear. In addition, the use of cannabinoids clinically has been hindered due to pronounced psychoactive side effects. This review provides an overview on the endocannabinoid system, including known physiological roles, and conditions in which cannabinoid receptor signaling has been implicated.

Prenatal cannabis exposure - The "first hit" to the endocannabinoid system

As more states and countries legalize medical and/or adult recreational marijuana use, the incidences of prenatal cannabis exposure (PCE) will likely increase. While young people increasingly view marijuana as innocuous, marijuana preparations have been growing in potency in recent years, potentially creating global clinical, public health, and workforce concerns. Unlike fetal alcohol spectrum disorder, there is no phenotypic syndrome associated with PCE. There is also no preponderance of evidence that PCE causes lifelong cognitive, behavioral, or functional abnormalities, and/or susceptibility to subsequent addiction. However, there is compelling circumstantial evidence, based on the principles of teratology and fetal malprogramming, suggesting that pregnant women should refrain from smoking marijuana. The usage of marijuana during pregnancy perturbs the fetal endogenous cannabinoid signaling system (ECSS), which is present and active from the early embryonic stage, modulating neurodevelopment and continuing this role into adulthood. The ECSS is present in virtually every brain structure and organ system, and there is also evidence that this system is important in the regulation of cardiovascular processes. Endocannabinoids (eCBs) undergird a broad spectrum of processes, including the early stages of fetal neurodevelopment and uterine implantation. Delta-9-tetrahydrocannabinol (THC), the psychoactive chemical in cannabis, enters maternal circulation, and readily crosses the placental membrane. THC binds to CB receptors of the fetal ECSS, altering neurodevelopment and possibly rewiring ECSS circuitry. In this review, we discuss the Double-Hit Hypothesis as it relates to PCE. We contend that PCE, similar to a neurodevelopmental teratogen, delivers the first hit to the ECSS, which is compromised in such a way that a second hit (i.e., postnatal stressors) will precipitate the emergence of a specific phenotype. In summary, we conclude that perturbations of the intrauterine milieu via the introduction of exogenous CBs alter the fetal ECSS, predisposing the offspring to abnormalities in cognition and altered emotionality. Based on recent experimental evidence that we will review here, we argue that young women who become pregnant should immediately take a "pregnant pause" from using marijuana.

Screening Medications for the Treatment of Cannabis Use Disorder

Cannabis use has been increasingly accepted legally and in public opinion. However, cannabis has the potential to produce adverse physical and mental health effects, and cannabis use disorder (CUD) occurs in a substantial percentage of both occasional and daily cannabis users. Many people have difficulty discontinuing use despite receiving treatment. Therefore, it would be beneficial to develop safe and effective medications for treating CUD. To achieve this, methods have been developed for screening and evaluating potential medications using animal models and controlled experimental protocols in human volunteers. In this chapter, we describe: (1) animal models available for assessing the effect of potential medications on specific aspects of CUD, (2) the main findings obtained so far with these animal models, (3) the approaches used to assess potential medications in humans in laboratory experiments and clinical trials, and (4) the effectiveness of several potential pharmacotherapies on particular aspects of CUD modeled in these human studies.

Rimonabant effects on anxiety induced by simulated public speaking in healthy humans: a preliminary report

OBJECTIVE

We investigated the hypothesis that rimonabant, a cannabinoid antagonist/inverse agonist, would increase anxiety in healthy subjects during a simulation of the public speaking test.

METHODS

Participants were randomly allocated to receive oral placebo or 90 mg rimonabant in a double-blind design. Subjective effects were measured by Visual Analogue Mood Scale. Physiological parameters, namely arterial blood pressure and heart rate, also were monitored.

RESULTS

Twelve participants received oral placebo and 12 received 90 mg rimonabant. Rimonabant increased self-reported anxiety levels during the anticipatory speech and performance phase compared with placebo. Interestingly, rimonabant did not modulate anxiety prestress and was not associated with sedation, cognitive impairment, discomfort, or blood pressure changes.

CONCLUSIONS

Cannabinoid-1 antagonism magnifies the responses to an anxiogenic stimulus without interfering with the prestress phase. These data suggest that the endocannabinoid system may work on-demand to counteract the consequences of anxiogenic stimuli in healthy humans.

Δ(9)Tetrahydrocannabinol impairs reversal learning but not extra-dimensional shifts in rhesus macaques

Expansion of medical marijuana use in the US and the recently successful decriminalization of recreational marijuana in two States elevates interest in the specific cognitive effects of Δ(9)tetrahydrocannabinol (Δ(9)THC), the major psychoactive constituent of marijuana. Controlled laboratory studies in nonhuman primates provide mixed evidence for specific effects of Δ(9)THC in learning and memory tasks, with a suggestion that frontal-mediated tasks may be the most sensitive. In this study, adult male rhesus monkeys were trained on tasks which assess reversal learning, extradimensional attentional shift learning and spatial delayed-response. Subjects were challenged with 0.1-0.5mg/kg Δ(9)THC, i.m., in randomized order and evaluated on the behavioral measures. Peak plasma levels of Δ(9)THC were observed 30min after 0.2mg/kg (69±29ng/ml) and 60min after 0.5mg/kg (121±23ng/ml) was administered and behavioral effects on a bimanual motor task persisted for up to 2h after injection. An increase in errors-to-criterion (ETC) associated with reversal learning was further increased by Δ(9)THC in a dose-dependent manner. The increase in ETC associated with extradimensional shifts was not affected by Δ(9)THC. Spatial delayed-response performance was impaired by Δ(9)THC in a retention-interval-dependent manner. Overall the pattern of results suggests a more profound effect of Δ(9)THC on tasks mediated by orbitofrontal (reversal learning) versus dorsolateral (extradimensional shifts) prefrontal mechanisms.

Tolerance to effects of high-dose oral δ9-tetrahydrocannabinol and plasma cannabinoid concentrations in male daily cannabis smokers

Oral cannabinoids are taken for medicinal or recreational purposes, yet little is known about tolerance to their effects after high-dose extended exposure. The development of tolerance to effects of around-the-clock oral synthetic Δ9-tetrahydrocannabinol (THC) (20 mg every 3.5-6 h) was evaluated in 13 healthy male daily cannabis smokers residing on a secure research unit: 40 mg on Day 1; 100 mg on Days 2-4; 120 mg on Days 5-6. Systolic and diastolic blood pressure (BP), heart rate, and symptoms of subjective intoxication (100 mm visual-analogue scales, VAS) were assessed the morning of Day 1 (before any oral THC), and on Days 2, 4 and 6, every 30 min for 3 h after the first morning THC dose. Morning subjective intoxication ratings increased from Days 1 to 2, and then declined on Days 4 and 6. The morning THC dose increased intoxication ratings on Day 2, but had less effect on Days 4 and 6, a pattern consistent with tolerance. THC lowered BP and increased heart rate over the six days. Plasma THC and 11-OH-THC concentrations increased significantly over the first five days of dosing. Six days of around-the-clock, oral THC produced tolerance to subjective intoxication, but not to cardiovascular effects.

Triphasic blood pressure responses to cannabinoids: do we understand the mechanism?

The cannabinoids comprise three major classes of substances, including compounds derived from the cannabis plant (e.g. Δ(9) -tetrahydrocannabinol and the chemically related substances CP55940 and HU210), endogenously formed (e.g. anandamide) and synthetic compounds (e.g. WIN55212-2). Beyond their psychotropic effects, cannabinoids have complex effects on blood pressure, including biphasic changes of Δ(9) -tetrahydrocannabinol and WIN55212-2 and an even triphasic effect of anandamide. The differing pattern of blood pressure changes displayed by the three types of compounds is not really surprising since, although they share an agonistic effect at cannabinoid CB(1) and CB(2) receptors, some compounds have additional effects. In particular, anandamide is known for its pleiotropic effects, and there is overwhelming evidence that anandamide influences blood pressure via (i) CB(1) receptors, (ii) TRPV1 receptors, (iii) endothelial cannabinoid receptors and (iv) degradation products. This review is dedicated to the description of the effects of externally added cannabinoids on cardiovascular parameters in vivo. First, the cardiovascular effects of cannabinoids in anaesthetized animals will be highlighted since most data have been generated in experiments of that type. The text will follow the three phases of anandamide on blood pressure, and we will check to which extent cardiovascular changes elicited by other cannabinoids show overlap with those effects or differ. The second part will be dedicated to the cardiovascular effects of the cannabinoids in conscious animals. In the third part, cardiovascular effects in humans will be discussed, and similarities and differences with respect to the data from animals will be examined.

Endocannabinoids and the cardiovascular response to stress

Stress activates the hypothalamic-pituitary-adrenal (HPA) axis and sympathetic nervous system (SNS), resulting in cardiovascular responses. The endocannabinoid system (ECS), a ubiquitously expressed lipid signalling system, modulates both HPA and SNS activity. The purpose of this review is to explore the possible involvement/role of the ECS in the cardiovascular response to stress. The ECS has numerous cardiovascular effects including modulation of blood pressure, heart rate, the baroreflex, and direct vascular actions. It is also involved in a protective manner in response to stressors in cardiac preconditioning, and various stressors (for example, pain, orthostasis and social stress) increase plasma levels of endocannabinoids. Given the multitude of vascular effects of endocannabinoids, this is bound to have consequences. Beneficial effects of ECS upregulation could include cardioprotection, vasodilatation, CB(2)-mediated anti-inflammatory effects and activation of peroxisome proliferator-activated receptors. Negative effects of endocannabinoids could include mediation of the effects of glucocorticoids, CB(1)-mediated metabolic changes, and metabolism to vasoconstrictor products. It is also likely that there is a central role for the ECS in modulating cardiovascular activity via the HPA and SNS. However, much more work is required to fully integrate the role of the ECS in mediating many of the physiological responses to stress, including cardiovascular responses.

Cannabis in sport: anti-doping perspective

Since 2004, when the World Anti-Doping Agency assumed the responsibility for establishing and maintaining the list of prohibited substances and methods in sport (i.e. the Prohibited List), cannabinoids have been prohibited in all sports during competition. The basis for this prohibition can be found in the World Anti-Doping Code, which defines the three criteria used to consider banning a substance. In this context, we discuss the potential of cannabis to enhance sports performance, the risk it poses to the athlete's health and its violation of the spirit of sport. Although these compounds are prohibited in-competition only, we explain why the pharmacokinetics of their main psychoactive compound, Δ(9)-tetrahydrocannabinol, may complicate the results management of adverse analytical findings. Passive inhalation does not appear to be a plausible explanation for a positive test. Although the prohibition of cannabinoids in sports is one of the most controversial issues in anti-doping, in this review we stress the reasons behind this prohibition, with strong emphasis on the evolving knowledge of cannabinoid pharmacology.

Uso terapêutico dos canabinoides em psiquiatria

OBJETIVO: Revisar os principais avanços no potencial uso terapêutico de alguns compostos canabinoides em psiquiatria. MÉTODO: Foi realizada busca nos bancos de dado PubMed, SciELO e Lilacs e identificados estudos e revisões da literatura sobre o uso terapêutico dos canabinoides em psiquiatria, em particular canabidiol, rimonabanto, Δ9-tetraidrocanabinol e seus análogos. RESULTADOS: O canabidiol demonstrou apresentar potencial terapêutico como antipsicótico, ansiolítico, antidepressivo e em diversas outras condições. O Δ9-tetraidrocanabinol e seus análogos demonstraram efeitos ansiolíticos, na dependência de cannabis, bem como adjuvantes no tratamento de esquizofrenia, apesar de ainda carecerem de mais estudos. O rimonabanto demonstrou eficácia no tratamento de sintomas subjetivos e fisiológicos da intoxicação pela cannabis e como adjuvante no tratamento do tabagismo. Os potenciais efeitos colaterais, de induzir depressão e ansiedade limitaram o uso clínico deste antagonista CB1. CONCLUSÃO: Os canabinoides têm demonstrado que podem ter amplo interesse terapêutico em psiquiatria, porém mais estudos controlados são necessários para confirmar estes achados e determinar a segurança destes compostos.

CB1 cannabinoid receptors promote oxidative stress and cell death in murine models of doxorubicin-induced cardiomyopathy and in human cardiomyocytes

AIMS

Here we investigated the mechanisms by which cardiovascular CB1 cannabinoid receptors may modulate the cardiac dysfunction, oxidative stress, and interrelated cell death pathways associated with acute/chronic cardiomyopathy induced by the widely used anti-tumour compound doxorubicin (DOX).

METHODS AND RESULTS

Both load-dependent and -independent indices of left-ventricular function were measured by the Millar pressure-volume conductance system. Mitogen-activated protein kinase (MAPK) activation, cell-death markers, and oxidative/nitrosative stress were measured by molecular biology/biochemical methods and flow cytometry. DOX induced left-ventricular dysfunction, oxidative/nitrosative stress coupled with impaired antioxidant defense, activation of MAPK (p38 and JNK), and cell death and/or fibrosis in hearts of wide-type mice (CB1(+/+)), and these effects were markedly attenuated in CB1 knockouts (CB1(-/-)). In human primary cardiomyocytes expressing CB1 receptors (demonstrated by RT-PCR, western immunoblot, and flow cytometry) DOX, likewise the CB1 receptor agonist HU210 and the endocannabinoid anandamide (AEA), induced MAPK activation and cell death. The DOX-induced MAPK activation and cell death were significantly enhanced when DOX was co-administered with CB1 agonists AEA or HU210. Remarkably, cell death and MAPK activation induced by AEA, HU210, and DOX +/- AEA/HU210 were largely attenuated by either CB1 antagonists (rimonabant and AM281) or by inhibitors of p38 and JNK MAPKs. Furthermore, AEA or HU210 in primary human cardiomyocytes triggered increased reactive oxygen species generation.

CONCLUSION

CB1 activation in cardiomyocytes may amplify the reactive oxygen/nitrogen species-MAPK activation-cell death pathway in pathological conditions when the endocannabinoid synthetic or metabolic pathways are dysregulated by excessive inflammation and/or oxidative/nitrosative stress, which may contribute to the pathophysiology of various cardiovascular diseases.

Endocannabinoids and cardiac contractile function: pathophysiological implications

Endocannabinoids are part of a bioactive lipid signaling system, not only in the central nervous system but also in various peripheral organs. Accumulating evidence implicates dysregulation of the endocannabinoid system (ECS) in the pathogenesis of various cardiovascular diseases, including hypertension, atherosclerosis, myocardial infarction, hemorrhagic or septic shock, heart failure and cardiovascular complications of liver cirrhosis. Even though the benefit of chronic cannabinoid 1 (CB1) receptor blockade with the currently available compounds may not outweigh the risks in chronic conditions such as obesity, modulation of the ECS may hold great therapeutic promise in various cardiovascular conditions/disorders. In this review we will discuss recent advances in understanding the role of CB1 receptors and endocannabinoids in the regulation of cardiac function in cirrhotic cardiomyopathy and in doxorubicin-induced heart failure.

Substitution profile of Delta9-tetrahydrocannabinol, triazolam, hydromorphone, and methylphenidate in humans discriminating Delta9-tetrahydrocannabinol

RATIONALE

Preclinical evidence suggests that non-cannabinoid neurotransmitter systems are involved in the behavioral and physiological effects of cannabinoids, but relatively little research has been conducted in humans.

OBJECTIVES

The aims of this study were to assess whether oral Delta(9)-tetrahydrocannabinol (Delta(9)-THC) would function as a discriminative stimulus in humans and to examine the substitution profile of drugs acting at opioid, GABA, and dopamine systems.

METHODS

Healthy subjects who reported moderate cannabis use were enrolled. Subjects learned to identify when they received oral 25 mg Delta(9)-THC or placebo under double-blind conditions. Once subjects acquired the discrimination (i.e., > or =80% drug-appropriate responding for four consecutive sessions), multiple doses of Delta(9)-THC, the GABA(A) positive modulator triazolam, the micro-opioid agonist hydromorphone and the dopamine reuptake inhibitor methylphenidate were tested to determine if they shared discriminative-stimulus effects with the training dose of Delta(9)-THC.

RESULTS

Eight subjects (N = 8) accurately discriminated Delta(9)-THC and completed the study. The training dose of Delta(9)-THC functioned as a discriminative stimulus and produced prototypical subject-rated drug effects. All of the drugs tested produced significant effects on the self-report questionnaires, but only Delta(9)-THC substituted for the training dose.

CONCLUSION

These results suggest that the discriminative-stimulus effects of Delta(9)-THC in humans are not directly mediated through central neurotransmitter systems acted upon by the drugs tested in this study.

Pharmacotherapy for cannabis dependence: how close are we?

Cannabis is the most widely used illicit drug in the world. Treatment admissions for cannabis use disorders have risen considerably in recent years, and the identification of medications that can be used to improve treatment outcomes among this population is a priority for researchers and clinicians. To date, several medications have been investigated for indications of clinically desirable effects among cannabis users (e.g. reduced withdrawal, attenuation of subjective or reinforcing effects, reduced relapse). Medications studied have included those: (i) known to be effective in the treatment of other drug use disorders; (ii) known to alleviate symptoms of cannabis withdrawal (e.g. dysphoric mood, irritability); or (iii) that directly affect endogenous cannabinoid receptor function. Results from controlled laboratory studies and small open-label clinical studies indicate that buspirone, dronabinol, fluoxetine, lithium and lofexidine may have therapeutic benefit for those seeking treatment for cannabis-related problems. However, controlled clinical trials have not been conducted and are needed to both confirm the potential clinical efficacy of these medications and to validate the laboratory models being used to study candidate medications. Although the recent increase in research towards the development of pharmacotherapy for cannabis use disorders has yielded promising leads, well controlled clinical trials are needed to support broad clinical use of these medications to treat cannabis use disorders.

Novel medications to treat addictive disorders

Recent discoveries about the effects of drugs of abuse on the brain and the mechanisms of their addictions; new chemical compounds, including immunotherapies; and new actions of available medications are offering many opportunities for the discovery and development of novel medications to treat addictive disorders. Furthermore, advancements in the understanding of the genetic and epigenetic basis of drug addiction and the pharmacogenetics of the safety and/or efficacy of the medications are providing opportunities for more individualized pharmacotherapy approaches. Although multiple medications have been investigated for treating addictions, only a handful have shown acceptable safety and efficacy and are approved by the US Food and Drug Administration. This article reviews the current medications that are medically safe and have shown promising results for treating opioid, cocaine, methamphetamine, and cannabis addictions.

Cannabis withdrawal in the United States: results from NESARC

OBJECTIVE

Although cannabis is the most widely abused illicit drug, little is known about the prevalence of cannabis withdrawal and its factor structure, clinical validity, and psychiatric correlates in the general population.

METHOD

National Epidemiologic Survey on Alcohol and Related Conditions participants were assessed, in 2001-2002, with structured in-person interviews covering substance history, DSM-IV Axis I and II disorders, and withdrawal symptoms after cessation of use. Of these, 2613 had been frequent cannabis users (> or = 3 times/week), and a "cannabis-only" subset (N = 1119) never binge-drank or used other drugs > or = 3 times/week.

RESULTS

In the full sample and subset, 44.3% (SE = 1.19) and 44.2% (SE = 1.75), respectively, experienced > or = 2 cannabis withdrawal symptoms, while 34.4% (SE = 1.21) and 34.1% (SE = 1.76), respectively, experienced > or = 3 symptoms. The symptoms formed 2 factors, one characterized by weakness, hypersomnia, and psychomotor retardation and the second by anxiety, restlessness, depression, and insomnia. Both symptom types were associated with significant distress/impairment (p < .01), substance use to relieve/avoid cannabis withdrawal symptoms (p <.01), and quantity of cannabis use (among the cannabis-only users p < .05). Panic (p < .01) and personality (p > .01) disorders were associated with anxiety symptoms in both samples, family history of drug problems was associated with weakness symptoms in the subset (p = .01), and depression was associated with both sets of symptoms in the subset (p < or = .05).

CONCLUSION

Cannabis withdrawal was prevalent and clinically significant among a representative sample of frequent cannabis users. Similar results in the subset without polysubstance abuse confirmed the specificity of symptoms to cannabis. Cannabis withdrawal should be added to DSM-V, and the etiology and treatment implications of cannabis withdrawal symptoms should be investigated.

The endocannabinoid system as a target for the treatment of cannabis dependence

The endocannabinoid system modulates neurotransmission at inhibitory and excitatory synapses in brain regions relevant to the regulation of pain, emotion, motivation, and cognition. This signaling system is engaged by the active component of cannabis, Delta9-tetrahydrocannabinol (Delta9-THC), which exerts its pharmacological effects by activation of G protein-coupled type-1 (CB1) and type-2 (CB2) cannabinoid receptors. During frequent cannabis use a series of poorly understood neuroplastic changes occur, which lead to the development of dependence. Abstinence in cannabinoid-dependent individuals elicits withdrawal symptoms that promote relapse into drug use, suggesting that pharmacological strategies aimed at alleviating cannabis withdrawal might prevent relapse and reduce dependence. Cannabinoid replacement therapy and CB1 receptor antagonism are two potential treatments for cannabis dependence that are currently under investigation. However, abuse liability and adverse side-effects may limit the scope of each of these approaches. A potential alternative stems from the recognition that (i) frequent cannabis use may cause an adaptive down-regulation of brain endocannabinoid signaling, and (ii) that genetic traits that favor hyperactivity of the endocannabinoid system in humans may decrease susceptibility to cannabis dependence. These findings suggest in turn that pharmacological agents that elevate brain levels of the endocannabinoid neurotransmitters, anandamide and 2-arachidonoylglycerol (2-AG), might alleviate cannabis withdrawal and dependence. One such agent, the fatty-acid amide hydrolase (FAAH) inhibitor URB597, selectively increases anandamide levels in the brain of rodents and primates. Preclinical studies show that URB597 produces analgesic, anxiolytic-like and antidepressant-like effects in rodents, which are not accompanied by overt signs of abuse liability. In this article, we review evidence suggesting that (i) cannabis influences brain endocannabinoid signaling and (ii) FAAH inhibitors such as URB597 might offer a possible therapeutic avenue for the treatment of cannabis withdrawal.

Endocannabinoids, blood pressure and the human heart

The effects of exogenous and endogenous cannabinoids on the cardiovascular system have been the focus of extensive research. The direct and indirect effects of cannabinoids on heart and blood vessels depend upon experimental conditions, animal species, and, in humans, clinical background. Cannabinoids decrease blood pressure in hypertensive rodents primarily because of decrease cardiac contractility, leading researchers to postulate a role in the treatment of hypertension and cardiac hypertrophy. Rimonabant, the CB(1) receptor blocker in clinical use in many countries, induced a marked and sustained increase in cardiac contractility and blood pressure in hypertensive rats but, on the contrary, contributed to decrease blood pressure in weight-loss clinical trials especially in obese patients with hypertension. In the midst of the obesity pandemic and from the cardiometabolic point of view, the overactivation of the endocannabinoid system present in intra-abdominal obesity appears to be very harmful. Moreover, novel human findings suggest a relationship between CB(1)-mediated overactive endocannabinoid system and nephrovascular damage. Overall, it appears that CB(1) blockade in obese patients behaves as a 'multiplier' of the many beneficial effects of body weight loss induced by a hypocaloric diet and increased physical activity (the 'lifestyle changes' that are so difficult to start and maintain). Thus, the concept - based mostly on experimental results using in vitro or animal models - that CB(1)-mediated endocannabinoid effects are beneficial for the cardiovascular system should be revised at least in obese patients. The results of long-term clinical trials such as the STRADIVARIUS and the CRESCENDO trials will tell whether the improvement in the cardiometabolic risk profile induced by Rimonabant translates into vascular changes, reducing the risk of myocardial infarction, stroke and cardiovascular death in patients with abdominal obesity. Time (and much more work) will tell us much more about cannabinoids and the human heart.

Signaling via CNS cannabinoid receptors

Because of the prominent psychoactive effects of cannabis and its preparations, much research has focused on the actions of cannabinoids, the primary psychoactive components of cannabis, on neuronal function. A convergence of research has identified (1) cannabinoid receptors, (2) endogenous compounds that activate these receptors (endocannabinoids), and (3) drugs that interact with these receptors and the proteins that synthesize and degrade the endocannabinoids. This review will first consider how endogenous cannabinoids signal through cannabinoid receptors and the various forms of synaptic plasticity mediated by endocannabinoids. Next the interactions between exogenous cannabinoids such as Delta9-tetrahydrocannabinol and endocannabinoids and endocannabinoid-mediated plasticity will be examined. Finally, a model will be presented that can explain the prominent psychoactivity of these plant-derived cannabinoids.

Cannabinoids in health and disease

Cannabis sativa L. preparations have been used in medicine for millenia. However, concern over the dangers of abuse led to the banning of the medicinal use of marijuana in most countries in the 1930s. Only recently, marijuana and individual natural and synthetic cannabinoid receptor agonists and antagonists, as well as chemically related compounds, whose mechanism of action is still obscure, have come back to being considered of therapeutic value. However, their use is highly restricted. Despite the mild addiction to cannabis and the possible enhancement of addiction to other substances of abuse, when combined with cannabis, the therapeutic value of cannabinoids is too high to be put aside. Numerous diseases, such as anorexia, emesis, pain, inflammation, multiple sclerosis, neurodegenerative disorders (Parkinson's disease, Huntington's disease, Tourette's syndrome, Alzheimer's disease), epilepsy, glaucoma, osteoporosis, schizophrenia, cardiovascular disorders, cancer, obesity, and metabolic syndrome-related disorders, to name just a few, are being treated or have the potential to be treated by cannabinoid agonists/antagonists/cannabinoid-related compounds. In view of the very low toxicity and the generally benign side effects of this group of compounds, neglecting or denying their clinical potential is unacceptable--instead, we need to work on the development of more selective cannabinoid receptor agonists/antagonists and related compounds, as well as on novel drugs of this family with better selectivity, distribution patterns, and pharmacokinetics, and--in cases where it is impossible to separate the desired clinical action and the psychoactivity--just to monitor these side effects carefully.

Marijuana neurobiology and treatment

Marijuana is the number one illicit drug of abuse worldwide and a major public health problem, especially in the younger population. The objective of this article is to update and review the state of the science and treatments available for marijuana dependence based on a pre-meeting workshop that was presented at ISAM 2006. At the workshop, several papers were presented addressing the neurobiology and pharmacology of marijuana and treatment approaches, both psychotherapy and medications, for marijuana withdrawal. Medicolegal and ethical issues concerning marijuana medical use were also discussed. Concise summaries of these presentations are incorporated in this article, which is meant to be an updated review of the state of the science. Major advances have been made in understanding the underpinning of marijuana dependence and the role of the CNS cannabinoid system, which is a major area for targeting medications to treat marijuana withdrawal and dependence, as well as other addictions. Behavioral therapies are efficacious for facilitating abstinence from marijuana. Nefazadone, Marinol, and buspirone are showing early positive signals for efficacy in ameliorating marijuana withdrawal symptoms. Effective psychotherapeutic approaches are available and promising medications studies need to be confirmed in outpatient trials. The next few years looking promising for translational research efforts to make treatment widely accessible to patients with marijuana dependence.

Impact of weight-loss medications on the cardiovascular system: focus on current and future anti-obesity drugs

Overweight and obesity have been rising dramatically worldwide and are associated with numerous co-morbidities such as cardiovascular disease (CVD), type 2 diabetes mellitus, hypertension, certain cancers, and sleep apnea. In fact, obesity is an independent risk factor for CVD and CVD risks have also been documented in obese children. The majority of overweight and obese patients who achieve a significant short-term weight loss do not maintain their lower bodyweight in the long term. This may be due to a lack of intensive counseling and support from a facilitating environment including dedicated healthcare professionals such as nutritionists, kinesiologists, and behavior specialists. As a result, there has been a considerable focus on the role of adjunctive therapy such as pharmacotherapy for long-term weight loss and weight maintenance. Beyond an unfavorable risk factor profile, overweight and obesity also impact upon heart structure and function. Since the beginning, the quest for weight loss drugs has encountered warnings from regulatory agencies and the withdrawal from the market of efficient but unsafe medications. Fenfluramine was withdrawn from the market because of unacceptable pulmonary and cardiac adverse effects. Nevertheless, there is extensive research directed at the development of new anti-obesity compounds. The effect of these molecules on CVD risk factors has been studied and reported but information regarding their impact on the cardiovascular system is sparse. Thus, instead of looking at the benefit of weight loss on metabolism and risk factor management, this article discusses the impact of weight loss medications on the cardiovascular system. The potential interaction of available and potential new weight loss drugs with heart function and structure is reviewed.

Rimonabant: endocannabinoid inhibition for the metabolic syndrome

Rimonabant is the first drug to target the endocannabinoid (CB) pathway by inhibiting the actions of anandamide and 2-archidonyl-glycerol on CB1 receptors. This review gives an overview of rimonabant and the CB system and how this system relates to obesity. Rimonabant blocks the central effects of this neurotransmitter pathway involved in obesity and weight control and also blocks the direct effects of CBs on adipocyte and hepatocyte metabolism. Blockade of CB1 receptors leads to a decrease in appetite and also has direct actions in adipose tissue and the liver to improve glucose, fat and cholesterol metabolism so improving insulin resistance, triglycerides and high-density lipoprotein cholesterol (HDL-C) and in some patients, blood pressure. The Rimonabant in Obesity (RIO) trials have shown that rimonabant induces weight loss > 5% in 30-40% of patients and > 10% in 10-20% above both a dietary run-in and long-term hypocaloric management over a 2 year period with a low level of drug-related side effects. Rimonabant therapy is associated with an extra 8-10% increase in HDL-C and a 10-30% reduction in triglycerides and improvements in insulin resistance, glycaemic control in patients with diabetes and also adipokines and cytokines including C-reactive protein over hypocaloric diet therapy. In addition rimonabant abolishes the weight gain associated with smoking cessation and improves the chances of quitting smoking. Thus rimonabant has major effects on both the metabolic syndrome and cardiovascular risk factors thus has the potential to reduce the risks of type 2 diabetes and cardiovascular disease associated with the cardiometabolic phenotype.