SR141716A, a potent and selective antagonist of the brain cannabinoid receptor
TL;DR: SR141716A is the first selective and orally active antagonist of the brain cannabinoid receptor and should prove to be a powerful tool for investigating the in vivo functions of the anandamide/cannabinoid system.
About: This article is published in FEBS Letters.The article was published on 1994-08-22. It has received 1764 citations till now. The article focuses on the topics: Cannabinoid Receptor Agonists & Cannabinoid Receptor Modulators.
Citations
More filters
TL;DR: It is considered premature to rename cannabinoid receptors after an endogenous agonist as is recommended by the International Union of Pharmacology Committee on Receptor Nomenclature and Drug Classification, because pharmacological evidence for the existence of additional types of cannabinoid receptor is emerging and other kinds of supporting evidence are still lacking.
Abstract: Two types of cannabinoid receptor have been discovered so far, CB(1) (2.1: CBD:1:CB1:), cloned in 1990, and CB(2) (2.1:CBD:2:CB2:), cloned in 1993. Distinction between these receptors is based on differences in their predicted amino acid sequence, signaling mechanisms, tissue distribution, and sensitivity to certain potent agonists and antagonists that show marked selectivity for one or the other receptor type. Cannabinoid receptors CB(1) and CB(2) exhibit 48% amino acid sequence identity. Both receptor types are coupled through G proteins to adenylyl cyclase and mitogen-activated protein kinase. CB(1) receptors are also coupled through G proteins to several types of calcium and potassium channels. These receptors exist primarily on central and peripheral neurons, one of their functions being to inhibit neurotransmitter release. Indeed, endogenous CB(1) agonists probably serve as retrograde synaptic messengers. CB(2) receptors are present mainly on immune cells. Such cells also express CB(1) receptors, albeit to a lesser extent, with both receptor types exerting a broad spectrum of immune effects that includes modulation of cytokine release. Of several endogenous agonists for cannabinoid receptors identified thus far, the most notable are arachidonoylethanolamide, 2-arachidonoylglycerol, and 2-arachidonylglyceryl ether. It is unclear whether these eicosanoid molecules are the only, or primary, endogenous agonists. Hence, we consider it premature to rename cannabinoid receptors after an endogenous agonist as is recommended by the International Union of Pharmacology Committee on Receptor Nomenclature and Drug Classification. Although pharmacological evidence for the existence of additional types of cannabinoid receptor is emerging, other kinds of supporting evidence are still lacking.
2,619 citations
Cites background from "SR141716A, a potent and selective a..."
...…1996 80.3b 32.2 Rhee et al., 1997 35.3b 3.9b Rinaldi-Carmona et al., 1994 8-THC 47.6b 39.3c Busch-Petersen et al., 1996 R-( )-WIN55212 9.94b 16.2b Rinaldi-Carmona et al., 1994 4.4a,b 1.2a,b Hillard et al., 1999 1.89 0.28 Showalter et al., 1996 62.3 3.3 Felder et al., 1995 123 4.1 Shire et al.,…...
[...]
...…11.8 13,200 Felder et al., 1998 11.8 973 Felder et al., 1995 12.3 702 Showalter et al., 1996 5.6 1,000 Rinaldi-Carmona et al., 1994 1.98b 1,000b Rinaldi-Carmona et al., 1994 AM281 12b 4,200c Lan et al., 1999a ACPA 2.2a,b 715a,b Hillard et al., 1999 2-Arachidonylglyceryl ether 21.2b 3,000 Hanus…...
[...]
...…3.4b 3,870b Di Marzo et al., 2001a SR141716A 11.8 13,200 Felder et al., 1998 11.8 973 Felder et al., 1995 12.3 702 Showalter et al., 1996 5.6 1,000 Rinaldi-Carmona et al., 1994 1.98b 1,000b Rinaldi-Carmona et al., 1994 AM281 12b 4,200c Lan et al., 1999a ACPA 2.2a,b 715a,b Hillard et al., 1999…...
[...]
...…1999 9-THC 53.3 75.3 Felder et al., 1995 39.5b 40 Bayewitch et al., 1996 40.7 36.4 Showalter et al., 1996 80.3b 32.2 Rhee et al., 1997 35.3b 3.9b Rinaldi-Carmona et al., 1994 8-THC 47.6b 39.3c Busch-Petersen et al., 1996 R-( )-WIN55212 9.94b 16.2b Rinaldi-Carmona et al., 1994 4.4a,b 1.2a,b…...
[...]
...…et al., 1995 0.1b 0.17 Rhee et al., 1997 0.73 0.22 Showalter et al., 1996 CP55940 5 1.8 Ross et al., 1999a 3.72 2.55 Felder et al., 1995 1.37b 1.37b Rinaldi-Carmona et al., 1994 0.58 0.69 Showalter et al., 1996 0.50a,b 2.80a,b Hillard et al., 1999 9-THC 53.3 75.3 Felder et al., 1995 39.5b 40…...
[...]
TL;DR: A comprehensive overview on the current state of knowledge of the endocannabinoid system as a target of pharmacotherapy is provided.
Abstract: The recent identification of cannabinoid receptors and their endogenous lipid ligands has triggered an exponential growth of studies exploring the endocannabinoid system and its regulatory functions in health and disease. Such studies have been greatly facilitated by the introduction of selective cannabinoid receptor antagonists and inhibitors of endocannabinoid metabolism and transport, as well as mice deficient in cannabinoid receptors or the endocannabinoid-degrading enzyme fatty acid amidohydrolase. In the past decade, the endocannabinoid system has been implicated in a growing number of physiological functions, both in the central and peripheral nervous systems and in peripheral organs. More importantly, modulating the activity of the endocannabinoid system turned out to hold therapeutic promise in a wide range of disparate diseases and pathological conditions, ranging from mood and anxiety disorders, movement disorders such as Parkinson9s and Huntington9s disease, neuropathic pain, multiple sclerosis and spinal cord injury, to cancer, atherosclerosis, myocardial infarction, stroke, hypertension, glaucoma, obesity/metabolic syndrome, and osteoporosis, to name just a few. An impediment to the development of cannabinoid medications has been the socially unacceptable psychoactive properties of plant-derived or synthetic agonists, mediated by CB 1 receptors. However, this problem does not arise when the therapeutic aim is achieved by treatment with a CB 1 receptor antagonist, such as in obesity, and may also be absent when the action of endocannabinoids is enhanced indirectly through blocking their metabolism or transport. The use of selective CB 2 receptor agonists, which lack psychoactive properties, could represent another promising avenue for certain conditions. The abuse potential of plant-derived cannabinoids may also be limited through the use of preparations with controlled composition and the careful selection of dose and route of administration. The growing number of preclinical studies and clinical trials with compounds that modulate the endocannabinoid system will probably result in novel therapeutic approaches in a number of diseases for which current treatments do not fully address the patients9 need. Here, we provide a comprehensive overview on the current state of knowledge of the endocannabinoid system as a target of pharmacotherapy.
1,857 citations
Cites background from "SR141716A, a potent and selective a..."
...The development of potent and highly selective CB1 and CB2 receptor antagonists (Rinaldi-Carmona et al., 1994, 1998) is particularly noteworthy as it provided critically important tools to explore the physiological functions of endocannabinoids....
[...]
...After the introduction of SR141716 as the first selective CB1 receptor antagonist (Rinaldi-Carmona et al., 1994), a similar conclusion was reached in normal rats treated with SR141716 for 14 days....
[...]
TL;DR: The results suggest that CB1 and CB2 can be considered as tissue-selective antigens of the central nervous system and immune system, respectively, and cannabinoids may exert specific receptor-mediated actions on the immune system through the CB2 receptor.
Abstract: Two proteins with seven transmembrane-spanning domains typical of guanosine-nucleotide-binding-protein-coupled receptors have been identified as cannabinoid receptors; the central cannabinoid receptor, CB1, and the peripheral cannabinoid receptor, CB2, initially described in rat brain and spleen, respectively. Here, we report the distribution patterns for both CB1 and CB2 transcripts in human immune cells and in several human tissues, as analysed using a highly sensitive and quantitative PCR-based method. CB1 was mainly expressed in the central nervous system and, to a lower extent, in several peripheral tissues such as adrenal gland, heart, lung, prostate, uterus, ovary, testis, bone marrow, thymus and tonsils. In contrast, the CB2 gene, which is not expressed in the brain, was particularly abundant in immune tissues, with an expression level 10-100-fold higher than that of CB1. Although CB2 mRNA was also detected in some other peripheral tissues, its level remained very low. In spleen and tonsils, the CB2 mRNA content was equivalent to that of CB1 mRNA in the central nervous system. Among the main human blood cell subpopulations, the distribution pattern of the CB2 mRNA displayed important variations. The rank order of CB2 mRNA levels in these cells was B-cells > natural killer cells >> monocytes > polymorphonuclear neutrophil cells > T8 cells > T4 cells. The same rank order was also established in human cell lines belonging to the myeloid, monocytic and lymphoid lineages. The prevailing expression of the CB2 gene in immune tissues was confirmed by Northern-blot analysis. In addition, the expression of the CB2 protein was demonstrated by an immunohistological analysis performed on tonsil sections using specific anti-(human CB2) IgG; this experiment showed that CB2 expression was restricted to B-lymphocyte-enriched areas of the mantle of secondary lymphoid follicles. These results suggest that (a) CB1 and CB2 can be considered as tissue-selective antigens of the central nervous system and immune system, respectively, and (b) cannabinoids may exert specific receptor-mediated actions on the immune system through the CB2 receptor.
1,646 citations
TL;DR: Treatment of wild-type mice with the CB1 antagonist SR141716A mimicked the phenotype of CB1-deficient mice, revealing that CB1 is required at the moment of memory extinction, and proposes that endocannabinoids facilitate extinction of aversive memories through their selective inhibitory effects on local inhibitory networks in the amygdala.
Abstract: Acquisition and storage of aversive memories is one of the basic principles of central nervous systems throughout the animal kingdom. In the absence of reinforcement, the resulting behavioural response will gradually diminish to be finally extinct. Despite the importance of extinction, its cellular mechanisms are largely unknown. The cannabinoid receptor 1 (CB1) and endocannabinoids are present in memory-related brain areas and modulate memory. Here we show that the endogenous cannabinoid system has a central function in extinction of aversive memories. CB1-deficient mice showed strongly impaired short-term and long-term extinction in auditory fear-conditioning tests, with unaffected memory acquisition and consolidation. Treatment of wild-type mice with the CB1 antagonist SR141716A mimicked the phenotype of CB1-deficient mice, revealing that CB1 is required at the moment of memory extinction. Consistently, tone presentation during extinction trials resulted in elevated levels of endocannabinoids in the basolateral amygdala complex, a region known to control extinction of aversive memories. In the basolateral amygdala, endocannabinoids and CB1 were crucially involved in long-term depression of GABA (gamma-aminobutyric acid)-mediated inhibitory currents. We propose that endocannabinoids facilitate extinction of aversive memories through their selective inhibitory effects on local inhibitory networks in the amygdala.
1,641 citations
TL;DR: It is shown that following temporary food restriction, CB1 receptor knockout mice eat less than their wild-type littermates, and the CB1 antagonist SR141716A reduces food intake in wild- type but not knockout mice, which indicates that endocannabinoids in the hypothalamus may tonically activate CB1 receptors to maintain food intake and form part of the neural circuitry regulated by leptin.
Abstract: Leptin is the primary signal through which the hypothalamus senses nutritional state and modulates food intake and energy balance1. Leptin reduces food intake by upregulating anorexigenic (appetite-reducing) neuropeptides, such as α-melanocyte-stimulating hormone2,3, and downregulating orexigenic (appetite-stimulating) factors, primarily neuropeptide Y4. Genetic defects in anorexigenic signalling, such as mutations in the melanocortin-4 (ref. 5) or leptin receptors6, cause obesity. However, alternative orexigenic pathways maintain food intake in mice deficient in neuropeptide Y7. CB1 cannabinoid receptors8 and the endocannabinoids anandamide and 2-arachidonoyl glycerol are present in the hypothalamus9, and marijuana10 and anandamide11,12 stimulate food intake. Here we show that following temporary food restriction, CB1 receptor knockout mice eat less than their wild-type littermates, and the CB1 antagonist SR141716A reduces food intake in wild-type but not knockout mice. Furthermore, defective leptin signalling is associated with elevated hypothalamic, but not cerebellar, levels of endocannabinoids in obese db/db and ob/ob mice and Zucker rats. Acute leptin treatment of normal rats and ob/ob mice reduces anandamide and 2-arachidonoyl glycerol in the hypothalamus. These findings indicate that endocannabinoids in the hypothalamus may tonically activate CB1 receptors to maintain food intake and form part of the neural circuitry regulated by leptin.
1,540 citations
Cites methods from "SR141716A, a potent and selective a..."
...When CB1 p/p mice were treated with 3 µg g -1 of the selective CB1 receptor antagonist SR141716A (ref...
[...]
References
More filters
TL;DR: In this article, an arachidonylethanthanolamide (anandamide) was identified in a screen for endogenous ligands for the cannabinoid receptor and its structure was determined by mass spectrometry and nuclear magnetic resonance spectroscopy and confirmed by synthesis.
Abstract: Arachidonylethanolamide, an arachidonic acid derivative in porcine brain, was identified in a screen for endogenous ligands for the cannabinoid receptor. The structure of this compound, which has been named "anandamide," was determined by mass spectrometry and nuclear magnetic resonance spectroscopy and was confirmed by synthesis. Anandamide inhibited the specific binding of a radiolabeled cannabinoid probe to synaptosomal membranes in a manner typical of competitive ligands and produced a concentration-dependent inhibition of the electrically evoked twitch response to the mouse vas deferens, a characteristic effect of psychotropic cannabinoids. These properties suggest that anandamide may function as a natural ligand for the cannabinoid receptor.
5,283 citations
TL;DR: The cloning and expression of a complementary DNA that encodes a G protein-coupled receptor that is involved in cannabinoid-induced CNS effects (including alterations in mood and cognition) experienced by users of marijuana are suggested.
Abstract: Marijuana and many of its constituent cannabinoids influence the central nervous system (CNS) in a complex and dose-dependent manner. Although CNS depression and analgesia are well documented effects of the cannabinoids, the mechanisms responsible for these and other cannabinoid-induced effects are not so far known. The hydrophobic nature of these substances has suggested that cannabinoids resemble anaesthetic agents in their action, that is, they nonspecifically disrupt cellular membranes. Recent evidence, however, has supported a mechanism involving a G protein-coupled receptor found in brain and neural cell lines, and which inhibits adenylate cyclase activity in a dose-dependent, stereoselective and pertussis toxin-sensitive manner. Also, the receptor is more responsive to psychoactive cannabinoids than to non-psychoactive cannabinoids. Here we report the cloning and expression of a complementary DNA that encodes a G protein-coupled receptor with all of these properties. Its messenger RNA is found in cell lines and regions of the brain that have cannabinoid receptors. These findings suggest that this protein is involved in cannabinoid-induced CNS effects (including alterations in mood and cognition) experienced by users of marijuana.
4,806 citations
TL;DR: The cloning of a receptor for cannabinoids is reported that is not expressed in the brain but rather in macrophages in the marginal zone of spleen, which helps clarify the non-psychoactive effects of cannabinoids.
Abstract: THE major active ingredient of marijuana, Δ9-tetrahydrocannabi-nol (Δ9-THC), has been used as a psychoactive agent for thousands of years. Marijuana, and Δ9-THC, also exert a wide range of other effects including analgesia, anti-inflammation, immunosuppression, anticonvulsion, alleviation of intraocular pressure in glaucoma, and attenuation of vomiting1. The clinical application of cannabinoids has, however, been limited by their psychoactive effects, and this has led to interest in the biochemical bases of their action. Progress stemmed initially from the synthesis of potent derivatives of δ9-THC4,5, and more recently from the cloning of a gene encoding a G-protein-coupled receptor for cannabinoids6. This receptor is expressed in the brain but not in the periphery, except for a low level in testes. It has been proposed that the non-psychoactive effects of cannabinoids are either mediated centrally or through direct interaction with other, non-receptor proteins1,7,8. Here we report the cloning of a receptor for cannabinoids that is not expressed in the brain but rather in macrophages in the marginal zone of spleen.
4,782 citations
Journal Article•
TL;DR: A simple, rapid method for determining the pain threshold in the rat was applied to the determination of analgesic properties of several substances, including cobra venom, where no analgesic property in the latter could be demonstrated.
Abstract: 1. A simple, rapid method for determining the pain threshold in the rat is described. 2. The individual variation, under a variety of conditions, was found to be surprisingly small. 3. The method was applied to the determination of analgesic properties of several substances, including cobra venom. No analgesic property in the latter could be demonstrated. 4. A comparative assay of five opiates gave results in good agreement with clinical experience.
3,373 citations
Journal Article•
TL;DR: The criteria for a high affinity, stereoselective, pharmacologically distinct cannabinoid receptor in brain tissue have been fulfilled.
Abstract: The determination and characterization of a cannabinoid receptor from brain are reported. A biologically active bicyclic cannabinoid analgetic CP-55,940 was tritium-labeled to high specific activity. Conditions for binding to rat brain P2 membranes and synaptosomes were established. The pH optimum was between 7 and 8, and specific binding could be eliminated by heating the membranes to 60 degrees. Binding to the P2 membranes was linear within the range of 10 to 50 micrograms of protein/ml. Specific binding (defined as total binding displaced by 1 microM delta 9-tetrahydrocannabinol (delta 9-THC) or 100 nM desacetyllevonantradol) was saturable. The Kd determined from Scatchard analysis was 133 pM, and the Bmax for rat cortical P2 membranes was 1.85 pmol/mg of protein. The Hill coefficient for [3H]CP-55,940 approximated 1, indicating that, under the conditions of assay, a single class of binding sites was determined that did not exhibit cooperativity. The binding was rapid (kon approximately 2.6 x 10(-4) pM-1 min-1) and reversible (Koff approximately 0.016 min-1) and (koff' greater than 0.06 min-1). The two Kd values estimated from the kinetic constants approximately 55 pM and exceeded 200 pM, respectively. The binding of the agonist ligand [3H]CP-55,940 was decreased by the nonhydrolyzable GTP analog guanylylimidodiphosphate. The guanine nucleotide induced a more rapid dissociation of the ligand from the binding site, consistent with an allosteric regulation of the putative receptor by a G protein. The binding was also sensitive to MgCl2 and CaCl2. Binding of [3H]CP-55,940 was displaced by cannabinoid drugs in the following order of potency: CP-55,940 greater than or equal to desacetyllevonantradol greater than 11-OH-delta 9-THC = delta 9-THC greater than cannabinol. Cannabidiol and cannabigerol displaced [3H]CP-55,940 by less than 50% at 1 microM concentrations. The (-)-isomer of CP-55,940 displaced with 50-fold greater potency than the (+)-isomer. This pharmacology is comparable to both the inhibition of adenylate cyclase in vitro and the analgetic activity of these compounds in vivo. The criteria for a high affinity, stereoselective, pharmacologically distinct cannabinoid receptor in brain tissue have been fulfilled.
2,242 citations