RESUMO
Here we show that central administration of pyroglutamylated arginine-phenylamine-amide peptide (QRFP/26RFa) increases both food intake and locomotor activity, without any significant effect on energy expenditure, thermogenesis or reward. Germline knock out of either of the mouse QRFP receptor orthologs, Gpr103a and Gpr103b, did not produce a metabolic phenotype. However, both receptors are required for the effect of centrally administered QRFP to increase feeding and locomotor activity. As central injection of QRFP activated orexin/hypocretin neurons in the lateral hypothalamus, we compared the action of QRFP and orexin on behaviour. Both peptides increased arousal and locomotor activity. However, while orexin increased consummatory behaviour, QRFP also affected other appetitive behaviours. Furthermore, the feeding but not the locomotor response to QRFP, was blocked by co-administration of an orexin receptor 1 antagonist. These results suggest that QRFP agonism induces both appetitive and consummatory behaviour, but only the latter is dependent on orexin/hypocretin receptor signalling.
Assuntos
Receptores de Orexina , Peptídeos , Receptores Acoplados a Proteínas G , Animais , Camundongos , Amidas , Compostos de Anilina , Arginina , Peptídeos e Proteínas de Sinalização Intercelular , Locomoção , Neuropeptídeos , Receptores de Orexina/metabolismo , Orexinas , Peptídeos/farmacologia , Receptores Acoplados a Proteínas G/metabolismo , Comportamento AlimentarRESUMO
One approach of modern drug discovery is to identify agents that enhance or diminish signal transduction cascades in various cell types and tissues by modulating the activity of GPCRs. This strategy has resulted in the development of new medicines to treat many conditions, including cardiovascular disease, psychiatric disorders, HIV/AIDS, certain forms of cancer and Type 2 diabetes mellitus (T2DM). These successes justify further pursuit of GPCRs as disease targets and provide key learning that should help guide identifying future therapeutic agents. This report reviews the current landscape of GPCR drug discovery with emphasis on efforts aimed at developing new molecules for treating T2DM and obesity. We analyse historical efforts to generate GPCR-based drugs to treat metabolic disease in terms of causal factors leading to success and failure in this endeavour. LINKED ARTICLES: This article is part of a themed section on Molecular Pharmacology of GPCRs. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.21/issuetoc.
Assuntos
Descoberta de Drogas , Doenças Metabólicas/tratamento farmacológico , Receptores Acoplados a Proteínas G/antagonistas & inibidores , Animais , Humanos , Doenças Metabólicas/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Transdução de Sinais/efeitos dos fármacosRESUMO
Incretin and insulin responses to nutrient loads are suppressed in persons with diabetes, resulting in decreased glycemic control. Agents including sulfonylureas and dipeptidyl peptidase-4 inhibitors (DPP4i) partially reverse these effects and provide therapeutic benefit; however, their modes of action limit efficacy. Because somatostatin (SST) has been shown to suppress insulin and glucagonlike peptide-1 (GLP-1) secretion through the Gi-coupled SST receptor 5 (SSTR5) isoform in vitro, antagonism of SSTR5 may improve glycemic control via intervention in both pathways. Here, we show that a potent and selective SSTR5 antagonist reverses the blunting effects of SST on insulin secretion from isolated human islets, and demonstrate that SSTR5 antagonism affords increased levels of systemic GLP-1 in vivo. Knocking out Sstr5 in mice provided a similar increase in systemic GLP-1 levels, which were not increased further by treatment with the antagonist. Treatment of mice with the SSTR5 antagonist in combination with a DPP4i resulted in increases in systemic GLP-1 levels that were more than additive and resulted in greater glycemic control compared with either agent alone. In isolated human islets, the SSTR5 antagonist completely reversed the inhibitory effect of exogenous SST-14 on insulin secretion. Taken together, these data suggest that SSTR5 antagonism should increase circulating GLP-1 levels and stimulate insulin secretion (directly and via GLP-1) in humans, improving glycemic control in patients with diabetes.
Assuntos
Benzoatos/farmacologia , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Hipoglicemiantes/farmacologia , Insulina/metabolismo , Ilhotas Pancreáticas/efeitos dos fármacos , Receptores de Somatostatina/antagonistas & inibidores , Compostos de Espiro/farmacologia , Animais , Células CHO , Células Cultivadas , Cricetinae , Cricetulus , Células HEK293 , Humanos , Secreção de Insulina , Ilhotas Pancreáticas/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Ratos , Ratos Sprague-Dawley , Ratos Zucker , Receptores de Somatostatina/genética , Via Secretória/efeitos dos fármacosRESUMO
The nociceptin (NOP) receptor is a G-protein-coupled receptor whose natural ligand is the NOP/orphanin FQ (N/OFQ) peptide. Evidence from pharmacological studies suggests that the N/OFQ system is implicated in the regulation of several addiction-related phenomena, such as drug intake, withdrawal, and relapse. Here, to further explore the role of NOP system in addiction, we used NOP (-/-) rats to study the motivation for cocaine, heroin, and alcohol self-administration in the absence of N/OFQ function. Conditioned place preference (CPP) and saccharin (0.2% w/v) self-administration were also investigated. Results showed that NOP (-/-) rats self-administer less cocaine (0.25, 0.125, or 0.5 mg/infusion) both under a fixed ratio 1 and a progressive ratio schedule of reinforcement compared with wild-type (Wt) controls. Consistently, cocaine (10 mg/kg, i.p.) was able to induce CPP in Wt but not in NOP (-/-). When NOP (-/-) rats were tested for heroin (20 µg/infusion) and ethanol (10% v/v) self-administration, they showed significantly lower drug intake compared with Wt. Conversely, saccharin self-administration was not affected by NOP deletion, excluding the possibility of nonspecific learning deficits or generalized disruption of reward mechanisms in NOP (-/-) rats. These findings were confirmed with pharmacological experiments using two selective NOP antagonists, SB-612111 and LY2817412. Both drugs attenuated alcohol self-administration in Wt rats but not in NOP (-/-) rats. In conclusion, our results demonstrate that genetic deletion of NOP receptors confers resilience to drug abuse and support a role for NOP receptor antagonism as a potential treatment option for drug addiction.
Assuntos
Comportamento Animal/efeitos dos fármacos , Transtornos Relacionados ao Uso de Cocaína/genética , Cocaína/farmacologia , Inibidores da Captação de Dopamina/farmacologia , Aprendizagem/efeitos dos fármacos , Antagonistas de Entorpecentes/farmacologia , Receptores Opioides/genética , Animais , Cocaína/administração & dosagem , Modelos Animais de Doenças , Inibidores da Captação de Dopamina/administração & dosagem , Ratos , Ratos Transgênicos , Ratos Wistar , Autoadministração , Receptor de NociceptinaRESUMO
In order to decipher the functional involvement of melanin-concentrating hormone 1 (MCH1) receptors in the control of feeding and foraging behaviors, mice with constitutive deletion of MCH1 receptors MCH1R -/- or knockout (KO) were studied and compared to age-matched littermate control mice (MCH1R +/+ or wildtype (WT)). Several challenges to food-motivated behaviors of food-restricted WT and KO mice were implemented. There were no differences between genotypes in the acquisition of a nose-poke response that produced food or in a discrimination between a response that produced food and one that did not. There were also no genotype differences in the rate of extinction of a food-motivated response. However, during the first day of extinction, foraging behaviors were increased significantly more in KO than in WT mice. Likewise, when the response requirement to obtain food was progressively increased, KO mice made significantly more food-directed responses than WT mice. Although adulteration of food with quinine did not suppress food-directed behavior in either genotype when the mice were food-restricted, manipulation of the degree of food-deprivation resulted in suppression of behavior of WT mice without suppressing the behavior of KO mice. Although response-produced foot shock suppressed food-maintained responding of both WT and KO mice, equipotent levels of shock (based upon psychophysical thresholds) suppressed behavior of WT mice without suppressing behavior of the KO mice. Finally, under a Vogel conflict procedure, KO mice had significantly higher levels of both punished and non-punished food maintained responding. Thus, the data from challenges with both appetitive and noxious stimulus challenges support the conclusion that mice with constitutive deletion of MCH1Rs have increased food seeking motivation that is coincident with their higher metabolism. The data also highlight important differences in the biological impact of MCH1 receptor KO and MCH1 receptor antagonism.
Assuntos
Ingestão de Alimentos/genética , Comportamento Alimentar/fisiologia , Receptores de Somatostatina/deficiência , Reforço Psicológico , Animais , Animais Recém-Nascidos , Biofísica , Condicionamento Operante/fisiologia , Estimulação Elétrica , Feminino , Alimentos , Privação de Alimentos , Masculino , Camundongos , Camundongos Transgênicos , Quinina/administração & dosagem , Receptores de Somatostatina/genética , Saciação/fisiologiaRESUMO
Allosteric potentiators amplify the sensitivity of physiologic control circuits, a mode of action that could provide therapeutic advantages. This hypothesis was tested with the dopamine D1 receptor potentiator DETQ [2-(2,6-dichlorophenyl)-1-((1S,3R)-3-(hydroxymethyl)-5-(2-hydroxypropan-2-yl)-1-methyl-3,4-dihydroisoquinolin-2(1H)-yl)ethan-1-one]. In human embryonic kidney 293 (HEK293) cells expressing the human D1 receptor, DETQ induced a 21-fold leftward shift in the cAMP response to dopamine, with a Kb of 26 nM. The maximum response to DETQ alone was â¼12% of the maximum response to dopamine, suggesting weak allosteric agonist activity. DETQ was â¼30-fold less potent at rat and mouse D1 receptors and was inactive at the human D5 receptor. To enable studies in rodents, an hD1 knock-in mouse was generated. DETQ (3-20 mg/kg orally) caused a robust (â¼10-fold) increase in locomotor activity (LMA) in habituated hD1 mice but was inactive in wild-type mice. The LMA response to DETQ was blocked by the D1 antagonist SCH39166 and was dependent on endogenous dopamine. LMA reached a plateau at higher doses (30-240 mg/kg) even though free brain levels of DETQ continued to increase over the entire dose range. In contrast, the D1 agonists SKF 82958, A-77636, and dihydrexidine showed bell-shaped dose-response curves with a profound reduction in LMA at higher doses; video-tracking confirmed that the reduction in LMA caused by SKF 82958 was due to competing stereotyped behaviors. When dosed daily for 4 days, DETQ continued to elicit an increase in LMA, whereas the D1 agonist A-77636 showed complete tachyphylaxis by day 2. These results confirm that allosteric potentiators may have advantages compared with direct-acting agonists.
Assuntos
Comportamento Animal/efeitos dos fármacos , Técnicas de Introdução de Genes , Isoquinolinas/farmacologia , Locomoção/efeitos dos fármacos , Receptores de Dopamina D1/genética , Receptores de Dopamina D1/metabolismo , Taquifilaxia , Adamantano/análogos & derivados , Adamantano/farmacologia , Regulação Alostérica/efeitos dos fármacos , Animais , Benzopiranos/farmacologia , Relação Dose-Resposta a Droga , Feminino , Células HEK293 , Humanos , Isoquinolinas/efeitos adversos , Masculino , Camundongos , Transporte Proteico/efeitos dos fármacos , Receptores de Dopamina D1/agonistasRESUMO
Therapeutic benefits from nociceptin opioid peptide receptor (NOP) antagonism were proposed for obesity, eating disorders, and depression. LY2940094 ([2-[4-[(2-chloro-4,4-difluoro-spiro[5H-thieno[2,3-c]pyran-7,4'-piperidine]-1'-yl)methyl]-3-methyl-pyrazol-1-yl]-3-pyridyl]methanol) is a novel, orally bioavailable, potent, and selective NOP antagonist. We studied NOP receptor occupancy (RO) after single oral LY2940094 doses in rat hypothalamus and human brain by use of liquid chromatography with tandem mass spectrometry (LC-MS/MS) (LSN2810397) and positron emission tomography (PET) ([(11)C]NOP-1A) tracers, respectively. A bolus plus constant infusion tracer protocol with PET was employed in humans at 2.5 and 26.5 hours after administration of the LY2940094 dose. The RO was calculated from the change in regional distributional volume (VT) corrected for nondisplaceable volume using Lasson plots. The RO followed a simple Emax relationship to plasma LY2940094 concentration, reaching near complete occupancy in both species. For rat hypothalamus, the plasma concentration at half-maximum RO (EC50) was 5.8 ng/ml. In humans, LY2940094 was well tolerated and safe over the 4-40 mg dose range, and it peaked in plasma at 2 to 6 hours after a 1- to 2-hour lag, with approximate dose-proportional exposure. After 4-40 mg doses, NOP RO was similar across the prefrontal cortex, occipital cortex, putamen, and thalamus, with EC50 of 2.94 to 3.46 ng/ml, less than 2-fold lower than in rats. Over 4-40 mg doses, LY2940094 mean plasma levels at peak and 24 hours were 7.93-102 and 1.17-14.1 ng/ml, corresponding to the cross-region average NOP RO of 73%-97% and 28%-82%, respectively. The rat EC50 translates well to humans. LY2940094 readily penetrates the human brain, and a once-daily oral dose of 40 mg achieves sustainably high (>80%) NOP RO levels suitable for testing clinical efficacy.
Assuntos
Piranos/farmacologia , Receptores Opioides/efeitos dos fármacos , Compostos de Espiro/farmacologia , Adolescente , Adulto , Animais , Encéfalo/metabolismo , Voluntários Saudáveis , Humanos , Masculino , Tomografia por Emissão de Pósitrons , Piranos/efeitos adversos , Piranos/farmacocinética , Ratos , Ratos Sprague-Dawley , Compostos de Espiro/efeitos adversos , Compostos de Espiro/farmacocinética , Adulto Jovem , Receptor de NociceptinaRESUMO
BACKGROUND: The nociceptin/orphanin-FQ (or opioid receptor-like [ORL1]) receptor (NOP) is localized in the mesolimbic reward pathway and has been suggested to play a role in feeding, mood, stress, and addiction. Since its deorphanization in 1995, there has been a clear dichotomy in the literature regarding whether an agonist or antagonist would provide therapeutic benefit. Specifically, the literature reports indicate that NOP receptor antagonists produce efficacy in animal models of hyperphagia and antidepressant-like activity, whereas NOP agonists produce anxiolytic-like effects and dampen reward/addiction behaviors including ethanol consumption. METHODS: We characterize here the potent, orally bioavailable NOP antagonist, LY2940094, in rodent models of ethanol consumption, including ethanol self-administration, progressive ratio operant self-administration, stress-induced reinstatement of ethanol seeking, and in vivo microdialysis in the nucleus accumbens. RESULTS: LY2940094 dose dependently reduced homecage ethanol self-administration in Indiana alcohol-preferring (P) and Marchigian Sardinian alcohol-preferring (msP) rats, without affecting food/water intake or locomotor activity. Reduced ethanol intake in P rats did not show significant tolerance over 4 days of subchronic dosing. LY2940094 attenuated progressive ratio operant responding and break points for ethanol in P rats. Moreover, stress-induced reinstatement of ethanol seeking in msP rats was completely blocked by LY2940094. Furthermore, LY2940094 blocked ethanol-stimulated dopamine release in response to ethanol challenge (1.1 g/kg, intraperitoneally). CONCLUSIONS: Our findings demonstrate for the first time that blockade of NOP receptors attenuates ethanol self-administration and ethanol-motivated behaviors, stress-induced ethanol seeking, and ethanol-induced stimulation of brain reward pathways in lines of rats that exhibit excessive ethanol consumption. Results suggest that LY2940094 may have potential therapeutic utility in treating alcohol addiction.
Assuntos
Comportamento de Procura de Droga/efeitos dos fármacos , Etanol/antagonistas & inibidores , Piranos/farmacologia , Receptores Opioides/efeitos dos fármacos , Compostos de Espiro/farmacologia , Administração Oral , Animais , Condicionamento Operante/efeitos dos fármacos , Dopamina/metabolismo , Relação Dose-Resposta a Droga , Etanol/administração & dosagem , Feminino , Masculino , Microdiálise , Antagonistas de Entorpecentes/farmacologia , Núcleo Accumbens/efeitos dos fármacos , Núcleo Accumbens/metabolismo , Piranos/administração & dosagem , Ratos , Ratos Endogâmicos , Autoadministração , Compostos de Espiro/administração & dosagem , Receptor de NociceptinaRESUMO
Nociceptin/Orphanin FQ (N/OFQ) is a 17 amino acid peptide whose receptor is designated ORL1 or nociceptin receptor (NOP). We utilized a potent, selective, and orally bioavailable antagonist with documented engagement with NOP receptors in vivo to assess antidepressant- and anxiolytic-related pharmacological effects of NOP receptor blockade along with measures of cognitive and motor impingement. LY2940094 ([2-[4-[(2-chloro-4,4-difluoro-spiro[5H-thieno[2,3-c]pyran-7,4'-piperidine]-1'-yl)methyl]-3-methyl-pyrazol-1-yl]-3-pyridyl]methanol) displayed antidepressant-like behavioral effects in the forced-swim test in mice, an effect absent in NOP -/- mice. LY2940094 also augmented the behavioral effect of fluoxetine without changing target occupancies (NOP and serotonin reuptake transporter [SERT]). LY2940094 did not have effects under a differential-reinforcement of low rate schedule. Although anxiolytic-like effects were not observed in some animal models (conditioned suppression, 4-plate test, novelty-suppressed feeding), LY2940094 had effects like that of anxiolytic drugs in three assays: fear-conditioned freezing in mice, stress-induced increases in cerebellar cGMP in mice, and stress-induced hyperthermia in rats. These are the first reports of anxiolytic-like activity with a systemically viable NOP receptor antagonist. LY2940094 did not disrupt performance in either a 5-choice serial reaction time or delayed matching-to-position assay. LY2940094 was also not an activator or suppressor of locomotion in rodents nor did it induce failures of rotarod performance. These data suggest that LY2940094 has unique antidepressant- and anxiolytic-related pharmacological effects in rodents. Clinical proof of concept data on this molecule in depressed patients have been reported elsewhere.
RESUMO
Nociceptin/orphanin FQ (N/OFQ), a 17 amino acid peptide, is the endogenous ligand of the ORL1/nociceptin-opioid-peptide (NOP) receptor. N/OFQ appears to regulate a variety of physiologic functions including stimulating feeding behavior. Recently, a new class of thienospiro-piperidine-based NOP antagonists was described. One of these molecules, LY2940094 has been identified as a potent and selective NOP antagonist that exhibited activity in the central nervous system. Herein, we examined the effects of LY2940094 on feeding in a variety of behavioral models. Fasting-induced feeding was inhibited by LY2940094 in mice, an effect that was absent in NOP receptor knockout mice. Moreover, NOP receptor knockout mice exhibited a baseline phenotype of reduced fasting-induced feeding, relative to wild-type littermate controls. In lean rats, LY2940094 inhibited the overconsumption of a palatable high-energy diet, reducing caloric intake to control chow levels. In dietary-induced obese rats, LY2940094 inhibited feeding and body weight regain induced by a 30% daily caloric restriction. Last, in dietary-induced obese mice, LY2940094 decreased 24-hour intake of a high-energy diet made freely available. These are the first data demonstrating that a systemically administered NOP receptor antagonist can reduce feeding behavior and body weight in rodents. Moreover, the hypophagic effect of LY2940094 is NOP receptor dependent and not due to off-target or aversive effects. Thus, LY2940094 may be useful in treating disorders of appetitive behavior such as binge eating disorder, food choice, and overeating, which lead to obesity and its associated medical complications and morbidity.
Assuntos
Transtorno da Compulsão Alimentar/metabolismo , Ingestão de Energia/fisiologia , Comportamento Alimentar/fisiologia , Antagonistas de Entorpecentes/farmacologia , Receptores Opioides/fisiologia , Animais , Transtorno da Compulsão Alimentar/tratamento farmacológico , Células CHO , Cricetinae , Cricetulus , Ingestão de Energia/efeitos dos fármacos , Comportamento Alimentar/efeitos dos fármacos , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Knockout , Antagonistas de Entorpecentes/química , Antagonistas de Entorpecentes/uso terapêutico , Ratos , Ratos Long-Evans , Resultado do Tratamento , Receptor de NociceptinaRESUMO
Leptin is a critical regulator of metabolism, which acts on brain receptors (Lepr) to reduce energy intake and increase energy expenditure. Some of the cellular pathways mediating leptin's anorectic actions are identified, but those mediating the thermogenic effects have proven more difficult to decipher. We define a population of neurons in the dorsomedial hypothalamic nucleus (DMH) containing the RFamide PrRP, which is activated by leptin. Disruption of Lepr selectively in these cells blocks thermogenic responses to leptin and causes obesity. A separate population of leptin-insensitive PrRP neurons in the brainstem is required, instead, for the satiating actions of the gut-derived hormone cholecystokinin (CCK). Global deletion of PrRP (in a loxSTOPlox-PrRP mouse) results in obesity and attenuated responses to leptin and CCK. Cre-recombinase-mediated reactivation of PrRP in brainstem rescues the anorectic actions of CCK, but reactivation in the hypothalamus is required to re-establish the thermogenic effect of leptin.
Assuntos
Núcleo Hipotalâmico Dorsomedial/metabolismo , Leptina/metabolismo , Hormônio Liberador de Prolactina/metabolismo , Alelos , Animais , Colecistocinina/metabolismo , Metabolismo Energético , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Neurônios/metabolismo , Neurônios/patologia , Obesidade/etiologia , Hormônio Liberador de Prolactina/deficiência , Hormônio Liberador de Prolactina/genética , Receptores para Leptina/deficiência , Receptores para Leptina/genética , Receptores para Leptina/metabolismo , TermogêneseRESUMO
Nociceptin/OFQ (N/OFQ) is a 17 amino acid peptide that is the endogenous ligand for the ORL1/NOP receptor. Nociceptin appears to regulate a host of physiological functions such as biological reactions to stress, anxiety, mood, and drug abuse, in addition to feeding behaviors. To develop tools to study the function of nociceptin and NOP receptor, our research effort sought to identify orally available NOP antagonists. Our effort led to the discovery of a novel chemical series based on the dihydrospiro(piperidine-4,7'-thieno[2,3-c]pyran) scaffold. Herein we show that dihydrospiro(piperidine-4,7'-thieno[2,3-c]pyran)-derived compounds are potent NOP antagonists with high selectivity versus classical opioid receptors (µ, δ, and κ). Moreover, these compounds exhibit sufficient bioavailability to produce a high level of NOP receptor occupancy in the brain following oral administration in rats.
Assuntos
Antagonistas de Entorpecentes , Piranos/síntese química , Administração Oral , Animais , Descoberta de Drogas , Masculino , Piranos/farmacocinética , Piranos/farmacologia , Ratos , Ratos Sprague-Dawley , Receptores Opioides , Relação Estrutura-Atividade , Receptor de NociceptinaRESUMO
Kappa opioid receptors and their endogenous neuropeptide ligand, dynorphin A, are densely localized in limbic and cortical areas comprising the brain reward system, and appear to play a key role in modulating stress and mood. Growing literature indicates that kappa receptor antagonists may be beneficial in the treatment of mood and addictive disorders. However, existing literature on kappa receptor antagonists has used extensively JDTic and nor-BNI which exhibit long-lasting pharmacokinetic properties that complicate experimental design and interpretation of results. Herein, we report for the first time the in vitro and in vivo pharmacological profile of a novel, potent kappa opioid receptor antagonist with excellent selectivity over other receptors and markedly improved drug-like properties over existing research tools. LY2456302 exhibits canonical pharmacokinetic properties that are favorable for clinical development, with rapid absorption (t(max): 1-2 h) and good oral bioavailability (F = 25%). Oral LY2456302 administration selectively and potently occupied central kappa opioid receptors in vivo (ED50 = 0.33 mg/kg), without evidence of mu or delta receptor occupancy at doses up to 30 mg/kg. LY2456302 potently blocked kappa-agonist-mediated analgesia and disruption of prepulse inhibition, without affecting mu-agonist-mediated effects at doses >30-fold higher. Importantly, LY2456302 did not block kappa-agonist-induced analgesia one week after administration, indicating lack of long-lasting pharmacodynamic effects. In contrast to the nonselective opioid antagonist naltrexone, LY2456302 produced antidepressant-like effects in the mouse forced swim test and enhanced the effects of imipramine and citalopram. LY2456302 reduced ethanol self-administration in alcohol-preferring (P) rats and, unlike naltrexone, did not exhibit significant tolerance upon 4 days of repeated dosing. LY2456302 is a centrally-penetrant, potent, kappa-selective antagonist with pharmacokinetic properties favorable for clinical development and activity in animal models predictive of efficacy in mood and addictive disorders.
Assuntos
Benzamidas/farmacologia , Depressão/tratamento farmacológico , Antagonistas de Entorpecentes/farmacologia , Pirrolidinas/farmacologia , Receptores Opioides kappa/antagonistas & inibidores , Reflexo de Sobressalto/efeitos dos fármacos , Filtro Sensorial/efeitos dos fármacos , Analgesia , Animais , Antidepressivos/farmacocinética , Antidepressivos/farmacologia , Antidepressivos/uso terapêutico , Benzamidas/farmacocinética , Benzamidas/uso terapêutico , Modelos Animais de Doenças , Etanol/administração & dosagem , Masculino , Camundongos , Antagonistas de Entorpecentes/farmacocinética , Antagonistas de Entorpecentes/uso terapêutico , Pirrolidinas/farmacocinética , Pirrolidinas/uso terapêutico , Ratos , AutoadministraçãoRESUMO
Nociceptin/Orphanin FQ (N/OFQ) is a 17 amino acid peptide that was deorphanized in 1995. The generation of specific agonists, antagonists and receptor deficient mice and rats has enabled progress in elucidating the biological functions of N/OFQ. Additionally, radio-imaging technologies have been advanced for investigation of this system in animals and humans. Together with traditional neurobehavioral techniques, these tools have been utilized to identify the biological significance of the N/OFQ system and its interacting partners. The present review focuses on the role of N/OFQ in the regulation of feeding, body weight homeostasis, stress, the stress-related psychiatric disorders of depression and anxiety, and in drug and alcohol dependence. Critical evaluation of the current scientific preclinical literature suggests that small molecule modulators of nociceptin opioid peptide receptors (NOP) might be useful in the treatment of diseases related to these biological functions. In particular, the literature data suggest that antagonism of NOP receptors will produce anti-obesity and antidepressant activities in humans. However, there are also contradictory data discussed. The current literature on the role of N/OFQ in anxiety and addiction, on the other hand points primarily to a role of agonist modulation being potentially therapeutic. Some drug-like molecules that function either as agonists or antagonists of NOP receptors have been optimized for human clinical study to test some of these hypotheses. The discovery of PET ligands for NOP receptors, combined with the pharmacological tools and burgeoning preclinical data set discussed here bodes well for a rapid advancement of clinical understanding and potential therapeutic benefit.
Assuntos
Desenho de Fármacos , Peptídeos Opioides/metabolismo , Receptores Opioides/metabolismo , Animais , Ansiedade/tratamento farmacológico , Ansiedade/fisiopatologia , Humanos , Camundongos , Transtornos do Humor/tratamento farmacológico , Transtornos do Humor/fisiopatologia , Antagonistas de Entorpecentes , Obesidade/tratamento farmacológico , Obesidade/fisiopatologia , Ratos , Receptores Opioides/agonistas , Estresse Psicológico/tratamento farmacológico , Estresse Psicológico/fisiopatologia , Transtornos Relacionados ao Uso de Substâncias/tratamento farmacológico , Transtornos Relacionados ao Uso de Substâncias/fisiopatologia , Receptor de Nociceptina , NociceptinaRESUMO
BACKGROUND: Selective kappa opioid receptor antagonism is a promising experimental strategy for the treatment of depression. The kappa opioid receptor antagonist, LY2456302, exhibits ~30-fold higher affinity for kappa opioid receptors over mu opioid receptors, which is the next closest identified pharmacology. METHODS: Here, we determined kappa opioid receptor pharmacological selectivity of LY2456302 by assessing mu opioid receptor antagonism using translational pupillometry in rats and humans. RESULTS: In rats, morphine-induced mydriasis was completely blocked by the nonselective opioid receptor antagonist naloxone (3mg/kg, which produced 90% mu opioid receptor occupancy), while 100 and 300 mg/kg LY2456302 (which produced 56% and 87% mu opioid receptor occupancy, respectively) only partially blocked morphine-induced mydriasis. In humans, fentanyl-induced miosis was completely blocked by 50mg naltrexone, and LY2456302 dose-dependently blocked miosis at 25 and 60 mg (minimal-to-no blockade at 4-10mg). CONCLUSIONS: We demonstrate, for the first time, the use of translational pupillometry in the context of receptor occupancy to identify a clinical dose of LY2456302 achieving maximal kappa opioid receptor occupancy without evidence of significant mu receptor antagonism.
Assuntos
Benzamidas/farmacologia , Antagonistas de Entorpecentes/farmacologia , Pupila/efeitos dos fármacos , Pirrolidinas/farmacologia , Receptores Opioides kappa/antagonistas & inibidores , Adolescente , Adulto , Animais , Benzamidas/sangue , Estudos Cross-Over , Relação Dose-Resposta a Droga , Método Duplo-Cego , Fentanila/farmacologia , Humanos , Masculino , Pessoa de Meia-Idade , Miose/induzido quimicamente , Miose/tratamento farmacológico , Morfina/farmacologia , Midríase/induzido quimicamente , Midríase/tratamento farmacológico , Naltrexona/farmacologia , Antagonistas de Entorpecentes/sangue , Entorpecentes/farmacologia , Pupila/fisiologia , Pirrolidinas/sangue , Ratos Sprague-Dawley , Receptores Opioides kappa/agonistas , Receptores Opioides kappa/metabolismo , Adulto JovemRESUMO
Obesity continues to be a global health problem, and thus it is imperative that new pathways regulating energy balance be identified. Recently, it was reported: (Hayashi K, Cao T, Passmore H, Jourdan-Le Saux C, Fogelgren B, Khan S, Hornstra I, Kim Y, Hayashi M, Csiszar K. J Invest Dermatol 123: 864-871, 2004) that mice carrying a missense mutation in myelin protein zero-like 3 (Mpzl3rc) have reduced body weight. To determine how Mpzl3 controls energy balance in vivo, we generated mice deficient in myelin protein zero-like 3 (Mpzl3-KO). Interestingly, KO mice were hyperphagic yet had reduced body weight and fat mass. Moreover, KO mice were highly resistant to body weight and fat mass gain after exposure to a high-fat, energy-dense diet. These effects on body weight and adiposity were driven, in part, by a pronounced increase in whole body energy expenditure levels in KO mice. KO mice also had reduced blood glucose levels during an intraperitoneal glucose challenge and significant reductions in circulating insulin levels suggesting an increase in insulin sensitivity. In addition, there was an overall increase in oxidative capacity and contractile force in skeletal muscle isolated from KO mice. Hepatic triglyceride levels were reduced by 92% in livers of KO mice, in part due to a reduction in de novo lipid synthesis. Interestingly, Mpzl3 mRNA expression in liver was increased in diet-induced obese mice. Moreover, KO mice exhibited an increase in insulin-stimulated Akt signaling in the liver, further demonstrating that Mpzl3 can regulate insulin sensitivity in this tissue. We have determined that Mpzl3 has a novel physiological role in controlling body weight regulation, energy expenditure, glycemic control, and hepatic triglyceride synthesis in mice.
Assuntos
Glicemia/fisiologia , Metabolismo Energético/fisiologia , Lipídeos/biossíntese , Fígado/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/fisiologia , Adiposidade/genética , Adiposidade/fisiologia , Animais , Análise Química do Sangue , Western Blotting , Temperatura Corporal/fisiologia , Dieta , Dislipidemias/genética , Dislipidemias/metabolismo , Teste de Tolerância a Glucose , Hiperglicemia/genética , Hiperglicemia/metabolismo , Fígado/patologia , Masculino , Camundongos , Camundongos Knockout , Contração Muscular/fisiologia , Obesidade/genética , Obesidade/metabolismo , Obesidade/patologia , Reação em Cadeia da Polimerase em Tempo Real , Triglicerídeos/metabolismo , Aumento de Peso/fisiologiaRESUMO
Currently, a lack of sufficient tools has limited the understanding of the relationship between neuropsychiatric disorders and the nociceptin/orphanin FQ (N/OFQ) peptide (NOP) receptor. Herein, we describe the discovery and development of an antagonist NOP receptor occupancy (RO) tracer and a novel positron emission tomography (PET) radioligand suitable to probe the NOP receptor in human clinical studies. A thorough structure-activity relationship (SAR) around the high-affinity 3-(2'-fluoro-4',5'-dihydrospiro[piperidine-4,7'-thieno[2,3-c]pyran]-1-yl)-2-(2-halobenzyl)-N-alkylpropanamide scaffold identified a series of subnanomolar, highly selective NOP antagonists. Subsequently, these unlabeled NOP ligands were evaluated in vivo by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in rat to determine brain uptake, kinetics and specific binding. (S)-27 was identified as a suitable unlabeled preclinical RO tracer to accurately quantify NOP receptor engagement in rat brain. Three compounds were selected for evaluation in nonhuman primates as PET tracers: (-)-26, (-)-30, and (-)-33. Carbon-11 labeling of (+)-31 yielded [(11)C]-(S)-30, which exhibited minimal generation of central nervous system (CNS) penetrant radiometabolites, improved brain uptake, and was an excellent PET radioligand in both rat and monkey. Currently [(11)C]-(S)-30 is being evaluated as a PET radiotracer for the NOP receptor in human subjects.
Assuntos
Compostos Radiofarmacêuticos/síntese química , Receptores Opioides/metabolismo , Compostos de Espiro/síntese química , Tiofenos/síntese química , Animais , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Células CHO , Radioisótopos de Carbono , Cromatografia Líquida , Cricetinae , Cricetulus , Células HEK293 , Humanos , Macaca , Masculino , Antagonistas de Entorpecentes , Tomografia por Emissão de Pósitrons , Ensaio Radioligante , Compostos Radiofarmacêuticos/química , Compostos Radiofarmacêuticos/farmacocinética , Ratos , Ratos Sprague-Dawley , Receptores Opioides/agonistas , Compostos de Espiro/química , Compostos de Espiro/farmacocinética , Estereoisomerismo , Relação Estrutura-Atividade , Espectrometria de Massas em Tandem , Tiofenos/química , Tiofenos/farmacocinética , Receptor de NociceptinaRESUMO
Pharmacological manipulation of opioid receptors alters feeding behavior. However, the individual contributions of each opioid receptor subtype on energy balance remain largely unknown. Herein, we investigated whether genetic disruption of the δ-opioid receptor (DOR) also controls energy homeostasis. Mice lacking DOR and wild-type mice were fed with standard diet and high-energy diet (HED). Mice were analyzed in vivo with the indirect calorimetry system, and tissues were analyzed by real-time PCR and Western blot analysis. DOR-knockout (KO) mice gained less weight (P<0.01) and had lower fat mass (P<0.01) when compared to WT mice fed an HED. Although DOR-KO mice were hyperphagic, they showed higher energy expenditure (P<0.05), which was the result of an increased activation of the thermogenic program in brown adipose tissue. The increased nonshivering thermogenesis involved the stimulation of uncoupling protein 1 (UCP1; P<0.01), peroxisome proliferator-activated receptor γ coactivator (PGC1α; P<0.05), and fibroblast growth factor 21 (FGF21; P<0.01). DOR deficiency also led to an attenuation of triglyceride content in the liver (P<0.05) in response to an HED. These findings reveal a novel role of DOR in the control of thermogenic markers and energy expenditure, and they provide a potential new therapeutic approach for the treatment of obesity.
Assuntos
Obesidade/etiologia , Receptores Opioides delta/deficiência , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/metabolismo , Animais , Dieta Hiperlipídica , Metabolismo Energético/genética , Glucose/metabolismo , Homeostase/fisiologia , Fígado/metabolismo , Masculino , Camundongos , Camundongos Knockout , Termogênese/fisiologia , Triglicerídeos/metabolismoRESUMO
Arylphenylpyrrolidinylmethylphenoxybenzamides were found to have high affinity and selectivity for κ opioid receptors. On the basis of receptor binding assays in Chinese hamster ovary (CHO) cells expressing cloned human opioid receptors, (S)-3-fluoro-4-(4-((2-(3-fluorophenyl)pyrrolidin-1-yl)methyl)phenoxy)benzamide (25) had a K(i) = 0.565 nM for κ opioid receptor binding while having a K(i) = 35.8 nM for µ opioid receptors and a K(i) = 211 nM for δ opioid receptor binding. Compound 25 was also a potent antagonist of κ opioid receptors when tested in vitro using a [(35)S]-guanosine 5'O-[3-thiotriphosphate] ([(35)S]GTP-γ-S) functional assay in CHO cells expressing cloned human opioid receptors. Compounds were also evaluated for potential use as receptor occupancy tracers. Tracer evaluation was done in vivo, using liquid chromatography-tandem mass spectrometry (LC/MS/MS) methods, precluding the need for radiolabeling. (S)-3-Chloro-4-(4-((2-(pyridine-3-yl)pyrrolidin-1-yl)methyl)phenoxy)benzamide (18) was found to have favorable properties for a tracer for receptor occupancy, including good specific versus nonspecific binding and good brain uptake.
Assuntos
Benzamidas/síntese química , Pirrolidinas/síntese química , Receptores Opioides kappa/antagonistas & inibidores , Animais , Benzamidas/química , Benzamidas/farmacologia , Encéfalo/metabolismo , Células CHO , Cromatografia Líquida , Cricetinae , Cricetulus , Células HEK293 , Humanos , Pirrolidinas/química , Pirrolidinas/farmacologia , Ensaio Radioligante , Ratos , Receptores Opioides kappa/metabolismo , Estereoisomerismo , Relação Estrutura-Atividade , Espectrometria de Massas em TandemRESUMO
Existing monotherapies for the treatment of obesity provide only modest weight loss and/or have adverse side effects, and this is also the case with the cannabinoid receptor 1 (CB1) inverse agonist, rimonabant. We aimed to investigate the possibility of improving efficacy and reducing side effects of rimonabant by cotreatment with opioid system antagonists. Using both genetic and pharmacological removal of opioid signaling in mice, we investigated changes in body weight, food intake, and fat mass as well as behavioral outcomes of interactions between opioid ligands and the CB1 using the inverse agonist, rimonabant. The ability of rimonabant to reduce weight is enhanced by removal of with µ-opioid receptor signaling, while not being greatly affected by κ-opioid receptor blockade. Additionally, lack of opioid signaling, especially κ-opioid receptor, attenuated the ability of rimonabant to decrease immobility time in the Porsolt forced-swim test, a preclinical model of depression. These results indicate that the endogenous opioid system is involved in modulating both the metabolic and mood effects of rimonabant.