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At least 127 records · Page 7Linked to original sources

Cannabinoid control of motor function at the basal ganglia.

Classic and novel data strengthen the idea of a prominent role for the endocannabinoid signaling system in the control of movement. This finding is supported by three-fold evidence: (1) the abundance of the cannabinoid CB1 receptor subtype, but also of CB2 and vanilloid VR1 receptors, as well as of endocannabinoids in the basal ganglia and the cerebellum, the areas that control movement; (2) the demonstration of a powerful action, mostly of an inhibitory nature, of plant-derived, synthetic, and endogenous cannabinoids on motor activity, exerted by modulating the activity of various classic neurotransmitters; and (3) the occurrence of marked changes in endocannabinoid transmission in the basal ganglia of humans affected by several motor disorders, an event corroborated in animal models of these neurological diseases. This three-fold evidence has provided support to the idea that cannabinoid-based compounds, which act at key steps of the endocannabinoid transmission [receptors, transporter, fatty acid amide hydrolase (FAAH)], might be of interest because of their potential ability to alleviate motor symptoms and/or provide neuroprotection in a variety of neurological pathologies directly affecting basal ganglia structures, such as Parkinson's disease and Huntington's chorea, or indirectly, such as multiple sclerosis and Alzheimer's disease. The present chapter will review the knowledge on this issue, trying to establish future lines for research into the therapeutic potential of the endocannabinoid system in motor disorders.

Animals↗

Systemic, but not local, administration of cannabinoid CB1 receptor agonists modulate prefrontal cortical acetylcholine efflux in the rat.

Drugs acting on brain cannabinoid CB(1) receptors exert complex actions on modulatory transmitters that are involved in attention and cognition; however, little is known about the precise pharmacological and anatomical mechanisms that govern these effects. Previously demonstrated effects of cannabinoids on acetylcholine (ACh) in the hippocampus prompted us to evaluate changes in the prefrontal cortex, a site associated with mnemonic and attentional functions. We utilized in vivo microdialysis, coupled with direct reverse perfusion of agents, to study the actions on cannabinoidergic drugs on ACh release within the rat frontal cortex. Systemic administration of the CB(1) receptor agonists Delta(9)-tetrahydrocannabinol (THC) or WIN 55,212-2 (WIN) dose- and time-dependently increased ACh release; these effects were blocked by pretreatment with the selective CB(1) receptor antagonist / partial inverse agonist SR141716A (SR). THC applied by reverse dialysis in the frontal cortex caused no change in ACh release, although intrastriatal infusions of THC decreased ACh efflux. These data indicate that cannabinoid agonists potentiate ACh release in the frontal cortex by activating cannabinoid receptors in brain regions other than the frontal cortex.

Acetylcholine↗

Comparative biology of the endocannabinoid system possible role in the immune response.

In this review we discuss data showing that the endogenous cannabinoid system, represented by cannabinoid receptors, endogenous cannabinoid receptor ligands and enzymes for the biosynthesis and degradation of these ligands, is conserved throughout evolution from coelenterates to man. This signaling system has been suggested to play several roles in animals, including the regulation of cell development and growth, nervous functions, reproduction and feeding behavior. In this article, however, we shall describe with more detail the possible function of the endogenous cannabinoid system in the modulation of immune response in organisms from the lower to the higher levels of animal evolution.

Animals↗

Cannabinoids, opioids and eating behavior: the molecular face of hedonism?

Obesity represents nowadays one of the most devastating health threats. Published reports even project a decline in life expectancy of US citizens due to the rapidly increasing prevalence of obesity. This alarming increase is intimately linked with recent changes of environment and lifestyle in western countries. In this context, the rewarding or even addictive properties of popular food may represent one of the most serious obstacles to overcome for an effective anti-obesity therapy. Therefore, in addition to molecular networks controlling energy homeostasis, now researchers are starting to define central nervous mechanisms governing hedonic and addictive components of food intake. A recently emerging body of data suggests that the endogenous cannabinoid and opioid systems both represent key circuits responding to the rewarding value of food. This review focuses on the role of these two systems for the homeostatic and hedonic aspects of eating behavior and includes their anatomical and functional interactions. Independent from the degree to which eating can be considered an addiction, cannabinoid and opioid receptor antagonists are promising anti-obesity drugs, since they are targeting both hedonic and homeostatic components of energy balance control.

Animals↗

'Endocannabinoids' and other fatty acid derivatives with cannabimimetic properties: biochemistry and possible physiopathological relevance.

The only endogenous substances isolated and characterised so far that are capable of mimicking the pharmacological actions of the active principle of marijuana, (-)-Delta9-tetrahydrocannabinol, are amides and esters of fatty acids. Some of these compounds, like anandamide (N-arachidonoylethanolamine) and 2-arachidonoylglycerol, act as true 'endogenous cannabinoids' by binding and functionally activating one or both cannabinoid receptor subtypes present on nervous and peripheral cell membranes. The metabolic pathways and molecular mode of actions of these metabolites, as well as their possible implication in physiopathological responses, are reviewed here.

Animals↗

Biochemistry and pharmacology of the endocannabinoids arachidonylethanolamide and 2-arachidonylglycerol.

The purpose of this review is to discuss the cellular synthesis and inactivation of two putative endogenous ligands of the cannabinoid receptor, N-arachidonylethanolamine (AEA) and 2-arachidonylglycerol (2-AG). Both ligands are synthesized by neurons and brain tissue in response to increased intracellular calcium concentrations. Both ligands are substrates for fatty acid amide hydrolase (FAAH). Both AEA and 2-AG bind to the neuronal form of the cannabinoid receptor (CB1). AEA binds the receptor with moderate affinity and has the characteristics of a partial agonist, whereas, 2-AG binds with low affinity but exhibits full efficacy. Two possible physiological roles of the endocannabinoids and the CB1 receptor are discussed: the regulation of gestation and the regulation of gastrointestinal motility.

Adjuvants, Immunologic↗

The endocannabinoid nervous system: unique opportunities for therapeutic intervention.

The active principle in marijuana, Delta(9)-tetrahydrocannabinol (THC), has been shown to have wide therapeutic application for a number of important medical conditions, including pain, anxiety, glaucoma, nausea, emesis, muscle spasms, and wasting diseases. Delta(9)-THC binds to and activates two known cannabinoid receptors found in mammalian tissue, CB1 and CB2. The development of cannabinoid-based therapeutics has focused predominantly on the CB1 receptor, based on its predominant and abundant localization in the CNS. Like most of the known cannabinoid agonists, Delta(9)-THC is lipophilic and relatively nonselective for both receptor subtypes. Clinical studies show that nonselective cannabinoid agonists are relatively safe and provide therapeutic efficacy, but that they also induce psychotropic side effects. Recent studies of the biosynthesis, release, transport, and disposition of anandamide are beginning to provide an understanding of the role of lipid transmitters in the CNS. This review attempts to link current understanding of the basic biology of the endocannabinoid nervous system to novel opportunities for therapeutic intervention. This new knowledge may facilitate the development of cannabinoid receptor-targeted therapeutics with improved safety and efficacy profiles.

Amidohydrolases↗

Cardiovascular effects of cannabinoids.

The prototypic endocannabinoid, anandamide, and synthetic analogues have been shown to elicit pressor and depressor effects, bradycardia, vasorelaxation, and inhibition of neurotransmission in the central and peripheral nervous systems. Cannabinoid-mediated inhibition of neurotransmission is mediated by inhibition of voltage-gated Ca(2+) channels and adenylyl cyclase and activation of inwardly rectifying K(+) channels. The precise mechanisms underlying the vasorelaxant actions of cannabinoids are currently unclear, but might involve both receptor-dependent and -independent and endothelium-dependent and -independent pathways. Mechanisms proposed have included the release of endothelial autacoids, activation of myoendothelial gap junctions, activation of the Na(+) pump, activation of K(+) channels, inhibition of Ca(2+) channels, and activation of vanilloid receptors, leading to the release of sensory neurotransmitters. Pathophysiologically, the vasodilator actions of endocannabinoids have been implicated in the hypotension associated with both septic and haemorrhagic shock, but their physiological significance remains to be determined.

Animals↗

Invertebrate molecular neuroimmune processes.

During the course of evolution, invertebrates and vertebrates have kept in common similar signaling molecules e.g. neuropeptides, opiates etc... Complete hormonal-enzymatic systems such as the opioid-opiate-cannabinoid systems have been found in both nervous central and immune systems of these animals. These signaling molecules can be found free in blood circulation and act as immunomodulators. The present review is focused on peptides derived from the opioid proopiomelanocortin precursor, the opiates and the endocannabinoids, which are very powerful immunosuppressors, and example models of the bidirectional communications between the endocrine and the immune systems. Parasites use these immunosuppressors with magnificence in their crosstalk with their host.

Animals↗

The endocannabinoid system in invertebrates.

What is the role of the cannabinoid system in invertebrates and can it tell us something about the human system? We discuss in this review the possible presence of the cannabinoid system in invertebrates. Endocannabinoid processes, i.e., enzymatic hydrolysis, as well as cannabinoid receptors and endocannabinoids, have been identified in various species of invertebrates. These signal molecules appear to have multiple roles in invertebrates; diminishing sensory input, control of reproduction, feeding behavior, neurotransmission and antiinflammatory actions. We propose that since this system worked so well, it was retained during evolution, and that invertebrates can serve as a model to study endogenous cannabinoid signaling.

Animals↗

Endocannabinoids, hormone-cytokine networks and human fertility.

Anandamide (N -arachidonoylethanolamine, AEA) is a major endocannabinoid, shown to impair mouse pregnancy and embryo development and to induce apoptosis in blastocysts. Here, we review the roles of AEA, of the AEA-binding cannabinoid (CB) receptors, of the selective AEA membrane transporter (AMT), and of the AEA-hydrolyzing enzyme fatty acid amide hydrolase (FAAH), in human gestation. In particular, we discuss the interplay between the endocannabinoid system and the hormone-cytokine array involved in the control of human pregnancy, showing that the endocannabinoids take part in the immunological adaptation occurring during early pregnancy. In this line, we discuss the critical role of FAAH in human peripheral lymphocytes, showing that the expression of this enzyme is regulated by progesterone, Th1 and Th2 cytokines, which also regulate fertility. Moreover, we show that AEA and the other endocannabinoid, 2-arachidonoylglycerol, inhibit the release of the fertility-promoting cytokine leukemia inhibitory factor from human lymphocytes. Taken together, low FAAH and consistently high blood levels of AEA, but not CB receptors or AMT, can be early (<8 weeks of gestation) markers of spontaneous abortion, potentially useful as diagnostic tools for large-scale, routine monitoring of gestation in humans.

Animals↗

Endocannabinoid signaling in the brain.

The primary psychoactive ingredient in cannabis, Delta9-tetrahydrocannabinol (Delta9-THC), affects the brain mainly by activating a specific receptor (CB1). CB1 is expressed at high levels in many brain regions, and several endogenous brain lipids have been identified as CB1 ligands. In contrast to classical neurotransmitters, endogenous cannabinoids can function as retrograde synaptic messengers: They are released from postsynaptic neurons and travel backward across synapses, activating CB1 on presynaptic axons and suppressing neurotransmitter release. Cannabinoids may affect memory, cognition, and pain perception by means of this cellular mechanism.

Animals↗

Therapeutic potential of cannabinoids in CNS disease.

The major psychoactive constituent of Cannabis sativa, delta(9)-tetrahydrocannabinol (delta(9)-THC), and endogenous cannabinoid ligands, such as anandamide, signal through G-protein-coupled cannabinoid receptors localised to regions of the brain associated with important neurological processes. Signalling is mostly inhibitory and suggests a role for cannabinoids as therapeutic agents in CNS disease where inhibition of neurotransmitter release would be beneficial. Anecdotal evidence suggests that patients with disorders such as multiple sclerosis smoke cannabis to relieve disease-related symptoms. Cannabinoids can alleviate tremor and spasticity in animal models of multiple sclerosis, and clinical trials of the use of these compounds for these symptoms are in progress. The cannabinoid nabilone is currently licensed for use as an antiemetic agent in chemotherapy-induced emesis. Evidence suggests that cannabinoids may prove useful in Parkinson's disease by inhibiting the excitotoxic neurotransmitter glutamate and counteracting oxidative damage to dopaminergic neurons. The inhibitory effect of cannabinoids on reactive oxygen species, glutamate and tumour necrosis factor suggests that they may be potent neuroprotective agents. Dexanabinol (HU-211), a synthetic cannabinoid, is currently being assessed in clinical trials for traumatic brain injury and stroke. Animal models of mechanical, thermal and noxious pain suggest that cannabinoids may be effective analgesics. Indeed, in clinical trials of postoperative and cancer pain and pain associated with spinal cord injury, cannabinoids have proven more effective than placebo but may be less effective than existing therapies. Dronabinol, a commercially available form of delta(9)-THC, has been used successfully for increasing appetite in patients with HIV wasting disease, and cannabinoid receptor antagonists may reduce obesity. Acute adverse effects following cannabis usage include sedation and anxiety. These effects are usually transient and may be less severe than those that occur with existing therapeutic agents. The use of nonpsychoactive cannabinoids such as cannabidiol and dexanabinol may allow the dissociation of unwanted psychoactive effects from potential therapeutic benefits. The existence of other cannabinoid receptors may provide novel therapeutic targets that are independent of CB(1) receptors (at which most currently available cannabinoids act) and the development of compounds that are not associated with CB(1) receptor-mediated adverse effects. Further understanding of the most appropriate route of delivery and the pharmacokinetics of agents that act via the endocannabinoid system may also reduce adverse effects and increase the efficacy of cannabinoid treatment. This review highlights recent advances in understanding of the endocannabinoid system and indicates CNS disorders that may benefit from the therapeutic effects of cannabinoid treatment. Where applicable, reference is made to ongoing clinical trials of cannabinoids to alleviate symptoms of these disorders.

Analgesia↗

Cannabinoid drugs and enhancement of endocannabinoid responses: strategies for a wide array of disease states.

The endogenous cannabinoid system has revealed potential avenues to treat many disease states. Medicinal indications of cannabinoid drugs including compounds that result in enhanced endocannabinoid responses (EER) have expanded markedly in recent years. The wide range of indications covers chemotherapy complications, tumor growth, addiction, pain, multiple sclerosis, glaucoma, inflammation, eating disorders, age-related neurodegenerative disorders, as well as epileptic seizures, traumatic brain injury, cerebral ischemia, and other excitotoxic insults. Indeed, a great effort has led to the discovery of agents that selectively activate the cannabinoid system or that enhance the endogenous pathways of cannabinergic signaling. The endocannabinoid system is comprised of three primary components: (i) cannabinoid receptors, (ii) endocannabinoid transport system, and (iii) hydrolysis enzymes that break down the endogenous ligands. Two known endocannabinoids, anandamide (AEA) and 2-arachidonoyl glycerol (2-AG), are lipid molecules that are greatly elevated in response to a variety of pathological events. This increase in endocannabinoid levels is suggested to be part of an on-demand compensatory response. Furthermore, activation of signaling pathways mediated by the endogenous cannabinoid system promotes repair and cell survival. Similar cell maintenance effects are elicited by EER through inhibitors of the endocannabinoid deactivation processes (i.e., internalization and hydrolysis). The therapeutic potential of the endocannabinoid system has yet to be fully determined, and the number of medical maladies that may be treated will likely continue to grow. This review will underline studies that demonstrate medicinal applications for agents that influence the endocannabinoid system.

Animals↗

[Cardiovascular effects of cannabinoids].

The psychoactive properties of cannabinoids, the biologically active constituents of the marijuana plant, have long been recognized. Recent research has revealed that cannabinoids elicit not only neurobehavioral, and immunological, but also profound cardiovascular effects. Similar effects can be elicited by the endogenous ligand arachidonyl ethanolamine (anandamide) and 2-arachidonoyl-glycerol. The biological effects of cannabinoids are mediated by specific receptors. Two cannabinoid receptors have been identified so far: CB1-receptors are expressed by different cells of the brain and in peripheral tissues, while CB2-receptors were found almost exclusively in immune cells. Through the use of a selective CB1 receptor antagonist and CB1 receptor-knockout mice the hypotensive and bradycardic effects of cannabinoids in rodents could be attributed to activation of peripheral CB1 receptors. In hemodynamic studies using the radioactive microsphere technique in anesthetized rats, cannabinoids were found to be potent CB1-receptor dependent vasodilators in the coronary and cerebrovascular beds. Recent findings implicate the endogenous cannabinoid system in the pathomechanism of haemorrhagic, endotoxic and cardiogenic shock. Finally, there is evidence that the extreme mesenteric vasodilation, portal hypertension and systemic hypotension present in advanced liver cirrhosis are also mediated by the endocannabinoid system. These exciting, recent research developments indicate that the endogenous cannabinoid system plays an important role in cardiovascular regulation, and pharmacological manipulation of this system may offer novel therapeutic approaches in a variety of pathological conditions.

Animals↗

The endogenous cannabinoid system and the basal ganglia. biochemical, pharmacological, and therapeutic aspects.

New data strengthen the idea of a prominent role for endocannabinoids in the modulation of a wide variety of neurobiological functions. Among these, one of the most important is the control of movement. This finding is supported by 3 lines of evidence: (1) the demonstration of a powerful action, mostly inhibitory in nature, of synthetic and plant-derived cannabinoids and, more recently, of endocannabinoids on motor activity; (2) the presence of the cannabinoid CB(1) receptor subtype and the recent description of endocannabinoids in the basal ganglia and the cerebellum, the areas that control movement; and (3) the fact that CB(1) receptor binding was altered in the basal ganglia of humans affected by several neurological diseases and also of rodents with experimentally induced motor disorders. Based on this evidence, it has been suggested that new synthetic compounds that act at key steps of endocannabinoid activity (i.e., more-stable analogs of endocannabinoids, inhibitors of endocannabinoid reuptake or metabolism, antagonists of CB(1) receptors) might be of interest for their potential use as therapeutic agents in a variety of pathologies affecting extrapyramidal structures, such as Parkinson's and Huntington's diseases. Currently, only a few data exist in the literature studying such relationships in humans, but an increasing number of journal articles are revealing the importance of this new neuromodulatory system and arguing in favour of the funding of more extensive research in this field. The present article will review the current knowledge of this neuromodulatory system, trying to establish the future lines for research on the therapeutic potential of the endocannabinoid system in motor disorders.

Aging↗

Attenuation of nerve growth factor-induced visceral hyperalgesia via cannabinoid CB(1) and CB(2)-like receptors.

Cannabinoids have previously been shown to possess analgesic properties in a model of visceral hyperalgesia in which the neurotrophin, nerve growth factor (NGF), plays a pivotal role. The purpose of this study was to investigate the antihyperalgesic effects of two cannabinoids in NGF-evoked visceral hyperalgesia in order to test the hypothesis that endocannabinoids may modulate the NGF-driven elements of inflammatory hyperalgesia. Intra-vesical installation of NGF replicates many features of visceral hyperalgesia, including a bladder hyper-reflexia and increased expression of the immediate early gene c fos in the spinal cord. We investigated the action of anandamide and palmitoylethanolamide (PEA) on these parameters. Both anandamide (at a dose of 25 mg/kg) and PEA (at a dose of 2.5 mg/kg) attenuated the bladder hyper-reflexia induced by intra-vesical NGF. The use of cannabinoid CB1 receptor (SR141617A) and CB2 receptor (SR144528) antagonists suggested that the effect of anandamide was mediated by both CB1 and CB2 cannabinoid receptors whilst the action of PEA was via CB2 (or CB2-like) receptors only. Furthermore, anandamide (25 mg/kg) and PEA (2.5 mg/kg) reduced intra-vesical NGF-evoked spinal cord Fos expression at the appropriate level (L6) by 35 and 43%, respectively. However, neither CB1 nor CB2 receptor antagonists altered the action of anandamide. PEA-induced reduction in Fos expression was abrogated by SR144528. These data add to the growing evidence of a therapeutic potential for cannabinoids, and support the hypothesis that the endogenous cannabinoid system modulates the NGF-mediated components of inflammatory processes.

Amides↗