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Anti-obesity weight loss medications: Short-term and long-term use. Life Sci 2022; 306:120825. [PMID: 35870619 DOI: 10.1016/j.lfs.2022.120825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 07/13/2022] [Accepted: 07/15/2022] [Indexed: 11/21/2022]
Abstract
As obesity prevalence increases, more and more drugs that assist with weight loss have been developed. Numerous weight loss drugs had been approved, but many have also been withdrawn based on their lack of efficacy as well as safety concerns. Initial approaches in developing weight loss drugs was by increasing physiological energy expenditure and suppressing the appetite. Subsequently, as more physiological mechanisms for weight gain has been unearthed, drugs targeting newly discovered receptors and/or enzymes have been introduced with improved safety profiles and fewer psychological adverse events. Additionally, drugs targeting hunger or satiety signaling have been actively studied, and have shown increased adoption by physicians. Studies have also evaluated drugs that target metabolic tissues-such as adipose tissue or muscle-to promote weight loss, however to-date nothing has carried on into clinical practice. Starting with a brief history of early obesity treatments, this review evaluates current weight loss pharmaceutical options based on their duration of therapy status.
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Limón-Bernal E, Roa-Coria JE, Zúñiga-Romero Á, Huerta-Cruz JC, Ruíz-Velasco IRC, Flores-Murrieta FJ, Lara-Padilla E, Reyes-García JG, Rocha-González HI. Anorectic interaction and safety of 5-hydroxytryptophan/carbidopa plus phentermine or diethylpropion in rat. Behav Pharmacol 2021; 32:368-381. [PMID: 33660661 DOI: 10.1097/fbp.0000000000000625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Drug combinations are being studied as potential therapies to increase the efficacy or improve the safety profile of weight loss medications. This study was designed to determine the anorectic interaction and safety profile of 5-hydroxytryptophan (5-HTP)/carbidopa + diethylpropion and 5-HTP/carbidopa + phentermine combinations in rats. The anorectic effect of individual drugs or in combination was evaluated by the sweetened milk test. Isobologram and interaction index were employed to determine the anorectic interaction between 5-HTP/carbidopa and diethylpropion or phentermine. Plasma serotonin (5-HT) was measured by ELISA. Safety of repeated doses of both combinations in rats was evaluated using the tail sphygmomanometer, cardiac ultrasound, hematic biometry and blood chemistry. A single oral 5-HTP, diethylpropion or phentermine dose increased the anorectic effect, in a dose-dependent fashion, in 12 h-fasted rats. A dose of carbidopa at 30 mg/kg reduced the 5-HTP-induced plasmatic serotonin concentration and augmented the 5-HTP-induced anorectic effect. Isobologram and interaction index indicated a potentiation interaction between 5-HTP/30 mg/kg carbidopa + diethylpropion and 5-HTP/30 mg/kg carbidopa + phentermine. Chronic administration of experimental ED40 of 5-HTP/30 mg/kg carbidopa + phentermine, but not 5-HTP/30 mg/kg carbidopa + diethylpropion, increased the mitral valve leaflets area. Moreover, there were no other significant changes in cardiovascular, hematic or blood parameters. Both combinations induced around 20% body weight loss after 3 months of oral administration. Results suggest that 5-HTP/30 mg/kg carbidopa potentiates the anorectic effect of diethylpropion and phentermine with an acceptable safety profile, but further clinical studies are necessary to establish their therapeutic potential in the obesity treatment.
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Affiliation(s)
- Ernesto Limón-Bernal
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional
| | - José E Roa-Coria
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional
| | - Ángel Zúñiga-Romero
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional
| | - Juan C Huerta-Cruz
- Unidad de Investigación en Farmacología, Instituto Nacional de Enfermedades Respiratorias, Ismael Cosio Villegas
| | - Irma R C Ruíz-Velasco
- Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Ciudad Universitaria, Coyoacán, Ciudad de México, Mexico
| | - Francisco J Flores-Murrieta
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional
- Unidad de Investigación en Farmacología, Instituto Nacional de Enfermedades Respiratorias, Ismael Cosio Villegas
| | - Eleazar Lara-Padilla
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional
| | - Juan G Reyes-García
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional
| | - Héctor I Rocha-González
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional
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Gadde KM, Apolzan JW, Berthoud HR. Pharmacotherapy for Patients with Obesity. Clin Chem 2018; 64:118-129. [PMID: 29054924 PMCID: PMC7379842 DOI: 10.1373/clinchem.2017.272815] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 09/14/2017] [Indexed: 02/06/2023]
Abstract
BACKGROUND Although pharmacotherapy is not the cornerstone of obesity treatment, it is a valuable tool that could be considered for patients who have not had adequate benefit from lifestyle interventions or who have difficulty maintaining initial weight loss over longer periods. CONTENT This review focuses on the role of antiobesity drugs, the mechanisms by which the drugs work, potential pharmacological targets in the neural control of food intake and regulation of body weight, the history of antiobesity drugs, a summary of efficacy and safety data from clinical trials, and the clinical application of pharmacotherapy. Currently, 5 approved drug therapies are available in the US for long-term weight management, with only 2 of these meeting the stronger Food and Drug Administration (FDA) criteria of 5% weight loss relative to a placebo after 1 year and others receiving approval based on the categorical criterion of the proportions of patients achieving 5% weight loss. Interpretation of the results of clinical trials conducted before regulatory agency approval is limited by high dropout rates; thus, the results might not be replicable in clinical practice settings. Many patients who are suitable candidates for pharmacotherapy are not using the new drugs due to lack of insurance coverage and high out-of-pocket costs. SUMMARY With the availability of 4 new drugs since 2012, clinicians in the US now have more tools for long-term weight management. The quality of pharmacotherapy clinical investigations needs considerable improvement. Future research should focus on examining the mediators and moderators of response.
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Abstract
The global pandemic of obesity and overweight now affects between 2.8 and 3.5 billion of the world population and shows no signs of abatement. Treatment for what is now recognized as a chronic disease includes pharmacotherapy, considered an essential component of comprehensive therapy. New drug discovery is robust, but the pace of the US Food and Drug Administration approval for obesity drugs has been glacial, and only a handful of approved drugs are available for treating obesity. In the last 20 years, the US Food and Drug Administration has approved 208 drugs for cancer, 118 for cardiovascular diseases, 168 for neurological diseases, and 223 endocrinologic drugs, but only 6 for obesity, 2 of which have been taken off market. Currently, there are only 9 drugs approved by the FDA for obesity treatment. US physicians have turned to off-label drug use in their effort to care for increasing numbers of patients with excess adiposity. Phentermine is the most commonly used drug for treating obesity. Although approved only for short-term use, US physicians have used it successfully for long-term since its initial approval in 1959. This drug, used off-label for long-term, has proven to be safe and effective, far safer than the disease it is used to treat. Phentermine and diethylpropion, an equally safe but somewhat less effective drug, are both generic and therefore inexpensive. These drugs have been maligned inappropriately because their two-dimensional structure diagrams resemble amphetamine and also because of unproven presumptions about their potential adverse effects. In the face of an increasing epidemic, worldwide obese and overweight patients deserve effective treatment that prescribing these drugs could provide, if rehabilitated and used more frequently. US physicians will likely continue to use any drug proven useful off-label for this illness until such time as more effective drugs are approved.
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Affiliation(s)
- Ed J Hendricks
- Center for Weight Management, Roseville and Sacramento, CA, USA
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Abstract
PURPOSE OF REVIEW This review provides an overview of the current state of drug therapy for obesity, with a focus on four new drug therapies-lorcaserin, phentermine/topiramate, naltrexone/bupropion, and liraglutide 3.0 mg-which have been approved by the US Food and Drug Administration (FDA) for long-term management of obesity since 2012. Topics discussed in this paper include rationale for pharmacotherapy, history of antiobesity drugs, and efficacy and safety data from randomized controlled trials with implications for clinical practice. RECENT FINDINGS Weight loss achieved by currently approved drugs ranges from approximately 3 to 9%, above and beyond weight loss with lifestyle counseling alone, after a year. Response and attrition rates in clinical trials indicate that the benefits of pharmacotherapy range from substantial for some patients, modest for others, and no benefits for others still. Decisions regarding selection of a suitable drug from the available pharmacotherapy options and duration of treatment should be based on the expected and observed benefit-to-risk balance and tailored to the needs of each individual patient using the principles of shared decision-making.
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Affiliation(s)
- Kishore M Gadde
- Pennington Biomedical Research Center, Louisiana State University, 6400 Perkins Rd, Baton Rouge, LA, 70810, USA.
| | - Y Pritham Raj
- Department of Internal Medicine, Oregon Health & Science University, Portland, OR, 97239, USA
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Singh J, Kumar R. Phentermine-topiramate: First combination drug for obesity. Int J Appl Basic Med Res 2015; 5:157-8. [PMID: 26097830 PMCID: PMC4456896 DOI: 10.4103/2229-516x.157177] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Accepted: 11/28/2014] [Indexed: 11/04/2022] Open
Abstract
Obesity is spreading globally at an alarming speed. The management of obesity is multifaceted and includes lifestyle modifications as the cornerstone. Until only orlistat was approved for long term use in obesity. The US Food and Drug Administration granted approval to a fixed dose mid 2012 combination of phentermine immediate release and topiramate extended release in 2012 for treatment of obese patients or overweight patients with comorbid conditions. The new drug has shown significant weight loss compared with placebo for a period up to 2 years.
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Affiliation(s)
- Jagjit Singh
- Department of Pharmacology, Government Medical College and Hospital, Chandigarh, India
| | - Rajiv Kumar
- Department of Pharmacology, Government Medical College and Hospital, Chandigarh, India
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Targeting oxidative stress in the hypothalamus: the effect of transcription factor STAT3 knockdown on endogenous antioxidants-mediated appetite control. Arch Toxicol 2014; 89:87-100. [DOI: 10.1007/s00204-014-1252-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 04/15/2014] [Indexed: 12/18/2022]
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Bays H. Phentermine, topiramate and their combination for the treatment of adiposopathy (‘sick fat’) and metabolic disease. Expert Rev Cardiovasc Ther 2014; 8:1777-801. [DOI: 10.1586/erc.10.125] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Kim HO, Lee JA, Suh HW, Kim YS, Kim BS, Ahn ES, Roh YJ, Jung SG, Kim JM, Kang MK, Ahn IS, Park YG. Postmarketing surveillance study of the efficacy and safety of phentermine in patients with obesity. Korean J Fam Med 2013; 34:298-306. [PMID: 24106582 PMCID: PMC3791337 DOI: 10.4082/kjfm.2013.34.5.298] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Accepted: 08/22/2013] [Indexed: 11/30/2022] Open
Abstract
Background Obesity is a complex problem that is now considered a chronic metabolic disease. In Korea, phentermine has been widely used for the treatment of obesity in the primary care setting since 2004. However, there have been very few studies on the safety and efficacy of phentermine. To investigate the safety and efficacy of this drug, a postmarketing surveillance study was performed. Methods A total of 795 patients with obesity (body mass index ≥ 25 kg/m2) were enrolled from 30 primary care centers in Korea from September 2006 to November 2007. Patients were examined to ascertain safety and efficacy at 4-, 8-, and 12-week intervals. The criterion for efficacy was defined as a weight loss ≥ 5% of body weight. Results Of the 795 enrolled patients, 735 (92.5%) were evaluated in safety assessments and 711 (89.4%) was included in efficacy assessments. A total of 266 adverse events (AEs) were reported by 218 patients (30.6%), and no serious AEs were reported. Among 711 patients, 324 patients (45.6%) lost ≥ 5% of their body weight. The mean weight loss was 3.8 ± 4.0 kg. Conclusion AEs are commonly associated with phentermine, even though phentermine is effective for weight loss and relatively well-tolerated.
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Affiliation(s)
- Hyun Ok Kim
- Department of Family Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
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An H, Sohn H, Chung S. Phentermine, sibutramine and affective disorders. CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE 2013; 11:7-12. [PMID: 23678348 PMCID: PMC3650299 DOI: 10.9758/cpn.2013.11.1.7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 11/12/2012] [Accepted: 12/04/2012] [Indexed: 12/16/2022]
Abstract
A safe and effective way to control weight in patients with affective disorders is needed, and phentermine is a possible candidate. We performed a PubMed search of articles pertaining to phentermine, sibutramine, and affective disorders. We compared the studies of phentermine with those of sibutramine. The search yielded a small number of reports. Reports concerning phentermine and affective disorders reported that i) its potency in the central nervous system may be comparatively low, and ii) it may induce depression in some patients. We were unable to find more studies on the subject; thus, it is unclear presently whether phentermine use is safe in affective disorder patients. Reports regarding the association of sibutramine and affective disorders were slightly more abundant. A recent study that suggested that sibutramine may have deleterious effects in patients with a psychiatric history may provide a clue for future phentermine research. Three explanations are possible concerning the association between phentermine and affective disorders: i) phentermine, like sibutramine, may have a depression-inducing effect that affects a specific subgroup of patients, ii) phentermine may have a dose-dependent depression-inducing effect, or iii) phentermine may simply not be associated with depression. Large-scale studies with affective disorder patients focusing on these questions are needed to clarify this matter before investigation of its efficacy may be carried out and it can be used in patients with affective disorders.
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Affiliation(s)
- Hoyoung An
- Department of Psychiatry, Jeju Medical Center, Jeju, Korea
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Pharmacological studies of performance on the free-operant psychophysical procedure. Behav Processes 2013; 95:71-89. [PMID: 23428704 DOI: 10.1016/j.beproc.2013.02.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2012] [Revised: 02/10/2013] [Accepted: 02/11/2013] [Indexed: 12/30/2022]
Abstract
In the free-operant psychophysical procedure (FOPP), reinforcement is provided intermittently for responding on lever A in the first half and lever B in the second half of a trial. Temporal differentiation is measured from the psychometric function (percent responding on B, %B, versus time from trial onset, t), the index of timing being T50, the value of t at %B=50. T50 is reduced by acute treatment with 5-hydroxytryptamine (5-HT1A, 5-HT2A) and dopamine (D1-like, D2-like) receptor agonists. The effects of the agonists can be reversed by the respective antagonists of these receptors. Evidence is reviewed suggesting that the effect of endogenous 5-HT is mediated by 5-HT2A receptors and the effect of endogenous dopamine by D1-like receptors. Data are presented on the effects of lesions of the prefrontal cortex and corpus striatum on the sensitivity of performance on the FOPP to D1-like and D2-like receptor agonists. Lesions of the nucleus accumbens, but not the dorsal striatum or prefrontal cortex, attenuated the effects of a D1-like receptor agonist, 6-chloro-2,3,4,5-tetrahydro-1-phenyl-1H-3-benzazepine [SKF-81297], but not a D2-like receptor agonist, quinpirole, on T50. The results indicate that a population of D1-like receptors in the ventral striatum may contribute to the control of timing performance on the FOPP.
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Shin JH, Gadde KM. Clinical utility of phentermine/topiramate (Qsymia™) combination for the treatment of obesity. Diabetes Metab Syndr Obes 2013; 6:131-9. [PMID: 23630428 PMCID: PMC3626409 DOI: 10.2147/dmso.s43403] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Qsymia™ (Vivus Inc, Mountain View, CA, USA), a combination of phentermine and delayed-release topiramate, has been available in the US since September 2012 for the treatment of obesity. Phentermine is an anorexigenic agent, which is approved for the short-term treatment of obesity, while topiramate is approved for nonweight loss indications - seizure disorders and migraine prophylaxis. The amount of weight loss achieved with combination therapy is of a greater magnitude than what could be achieved with either agent alone. Adverse events that occur with the combination therapy are in line with the known side effect profiles of the constituent drugs; teratogenicity, a slight increase in heart rate, psychiatric and cognitive adverse effects, and metabolic acidosis are concerns.
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Affiliation(s)
- Jin Hee Shin
- Department of Community and Family Medicine, Duke University Medical Center, Durham, NC, USA
| | - Kishore M Gadde
- Obesity Clinical Trials Program, Duke University Medical Center, Durham, NC, USA
- Correspondence: Kishore M Gadde, Box 3292, Duke University Medical Center, Durham, NC 27710, USA, Email
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Kuo DY, Chen PN, Chu SC, Hsieh YS. Knocking down the transcript of NF-kappaB modulates the reciprocal regulation of endogenous antioxidants and feeding behavior in phenylpropanolamine-treated rats. Arch Toxicol 2011; 86:453-63. [PMID: 21989786 DOI: 10.1007/s00204-011-0761-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 09/20/2011] [Indexed: 12/16/2022]
Abstract
It has been reported that oxidative stress, antioxidants, and neuropeptide Y (NPY) are involved in regulating the feeding behavior of phenylpropanolamine (PPA), a sympathomimetic drug. This study explored whether transcription factor NF-κB is involved in this effect. Rats were treated daily with PPA for 4 days. Changes in hypothalamic NF-κB, NPY, superoxide dismutase (SOD), and glutathione peroxidase (GPx) levels during PPA treatment were assessed and compared. Results showed that NF-κB, SOD, and GPx increased, with a maximal response on Day 2, while the food intake and NPY decreased with the biggest reduction on Day 2 during PPA treatment. To further determine whether NF-κB was involved, intracerebroventricular infusion of antisense oligonucleotide was performed at 1 h before daily PPA in free-moving rats. Cerebral NF-κB knockdown could modify PPA anorexia and the expressions of NPY, SOD, and GPx. It is suggested that hypothalamic NF-κB participates in the reciprocal regulation of NPY and antioxidants, which mediated the appetite-suppressing effect of PPA. Results may further the understanding of the molecular mechanisms of PPA.
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Affiliation(s)
- Dong-Yih Kuo
- Department of Physiology, Chung Shan Medical University and Chung Shan Medical University Hospital, Taichung City 40201, Taiwan, ROC
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Koo SH, Choi WS, Lee JW, Park YJ, Lee KW. A Case of Phentermine Hydrochloride Induced Acute Myopia and Acute Angle Closure. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2011. [DOI: 10.3341/jkos.2011.52.7.881] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Kuo DY, Yang SF, Chu SC, Chen CH, Chen PN, Hsieh YS. The effect of protein kinase C-delta knockdown on anti-free radical enzyme and neuropeptide Y gene expression in phenylpropanolamine-treated rats. J Neurochem 2010; 114:1217-30. [PMID: 20533995 DOI: 10.1111/j.1471-4159.2010.06843.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Hypothalamic neuropeptide Y (NPY) has been reported to involve in regulating behavioral response of phenylpropanolamine (PPA), a sympathomimetic agent. This study explored if protein kinase C (PKC)-delta signaling participated in this regulation. Moreover, possible roles of anti-free radical enzyme catalase (CAT) and nitrogen oxide synthase (NOS) were also examined. Rats were treated daily with PPA for 4 days. Changes in food intake and hypothalamic NPY, PKCdelta, CAT, and NOS contents were assessed and compared. Results showed that PKCdelta and CAT increased during PPA treatment, which were concomitant with decreases in NPY content and food intake, while the change of NOS was expressed differently. Moreover, PKCdelta knockdown could modify PPA anorexia as well as NPY and CAT expression, while NOS expression remained unchanged. Furthermore, pre-treatment with NOS inhibitor could modify both PPA anorexia and NPY content. It is suggested that PKCdelta participates in the anorectic response of PPA via the modulation of NPY and CAT, while NOS contribute to this modulation via a different mechanism during PPA treatment. Results provide molecular mechanism of NPY-mediated PPA anorexia and may aid the therapeutic research of PPA and other anti-obesity drugs.
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Affiliation(s)
- Dong-Yih Kuo
- Department of Physiology, Chung Shan Medical University and Chung Shan Medical University Hospital, Taichung City, Taiwan, China.
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Abstract
BACKGROUND The serotonin (5-HT) releasers (+/-)-fenfluramine and (+)-fenfluramine were withdrawn from clinical use owing to increased risk of valvular heart disease. One prevailing hypothesis (i.e., the '5-HT hypothesis') suggests that fenfluramine-induced increases in plasma 5-HT underlie the disease. OBJECTIVE Here, we critically evaluate the possible mechanisms responsible for fenfluramine-associated valve disease. METHODS Findings from in vitro and in vivo experiments performed in our laboratory are reviewed. The data are integrated with existing literature to address the validity of the 5-HT hypothesis and suggest alternative explanations. CONCLUSIONS The overwhelming majority of evidence refutes the 5-HT hypothesis. A more likely cause of fenfluramine-induced valvulopathy is activation of 5-HT(2B) receptors on heart valves by the metabolite norfenfluramine. Future serotonergic medications should be designed to lack 5-HT(2B) agonist activity.
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Affiliation(s)
- Richard B Rothman
- Clinical Psychopharmacology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland 21224, USA.
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Phentermine cardiovascular safety. Am J Emerg Med 2009; 27:1010-3. [PMID: 19857423 DOI: 10.1016/j.ajem.2009.07.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2009] [Accepted: 07/19/2009] [Indexed: 11/20/2022] Open
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Abstract
The prevalence of obesity in the United States is a major health problem associated with significant morbidity, mortality, and economic burden. Although obesity and drug addiction are typically considered distinct clinical entities, both diseases involve dysregulation of biogenic amine neuron systems in the brain. Thus, research efforts to develop medications for treating drug addiction can contribute insights into the pharmacotherapy for obesity. Here, we review the neurochemical mechanisms of selected stimulant medications used in the treatment of obesity and issues related to fenfluramine-associated cardiac valvulopathy. In particular, we discuss the evidence that cardiac valve disease involves activation of mitogenic serotonin 2B (5-HT2B) receptors by norfenfluramine, the major metabolite of fenfluramine. Advances in medication discovery suggest that novel molecular entities that target 2 different neurochemical mechanisms, that is, "combination pharmacotherapy," will yield efficacious antiobesity medications with reduced adverse side effects.
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Kuo DY, Yang SF, Chu SC, Chen CH, Hsieh YS. Roles of protein kinase Calpha isozyme in the regulation of oxidative stress and neuropeptide Y gene expression in phenylpropanolamine-mediated appetite suppression. J Neurochem 2009; 108:1495-506. [PMID: 19183253 DOI: 10.1111/j.1471-4159.2009.05909.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Hypothalamic neuropeptide Y (NPY) is an appetite stimulant in the brain. Although regulation of NPY expression has been reported to contribute to the appetite-suppressing effect of phenylpropanolamine (PPA), it is still unknown if protein kinase C (PKC) is involved in this effect. Rats were daily treated with PPA for 4 days. Changes in food intake, hypothalamic NPY, PKC, and proopiomelanocortin (POMC) mRNA levels were assessed and compared. Results showed that the NPY gene was down-regulated following PPA treatment, which was parallel with the decrease of feeding. Moreover, several isotypes of PKC mRNA level (alpha, betaI, betaII, gamma, delta, eta, lambda, epsilon, and zeta) were changed. Among these, alpha, delta, and lambda PKC were up-regulated along with POMC gene expression which coincided with down-regulation of the NPY gene. To further determine if PKCalpha was involved, infusions of antisense oligonucleotide into the cerebroventricle were performed at 1 h before daily PPA treatment in free-moving rats. Results showed that PKCalpha knock-down could modify both anorexia induced by PPA and the NPY mRNA levels. Moreover, PKCalpha knock-down could also modify superoxide dismutase (SOD) gene expression. It is suggested that PKCalpha participates in the regulation of PPA-mediated appetite suppression via the modulation of NPY and SOD gene expression.
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Affiliation(s)
- Dong-Yih Kuo
- Department of Physiology, Chung Shan Medical University, Taiwan, China.
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Rothman RB, Blough BE, Baumann MH. Dual dopamine/serotonin releasers: potential treatment agents for stimulant addiction. Exp Clin Psychopharmacol 2008; 16:458-74. [PMID: 19086767 PMCID: PMC2683464 DOI: 10.1037/a0014103] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
"Agonist therapy" for cocaine and methamphetamine addiction involves administration of stimulant-like medications (e.g., monoamine releasers) to reduce withdrawal symptoms and prevent relapse. A significant problem with this strategy is that many candidate medications possess abuse liability because of activation of mesolimbic dopamine (DA) neurons in the brain. One way to reduce DA-mediated abuse liability of candidate drugs is to add in serotonin (5-HT) releasing properties, since substantial evidence shows that 5-HT neurons provide an inhibitory influence over mesolimbic DA neurons. This article addresses several key issues related to the development of dual DA/5-HT releasers for the treatment of substance use disorders. First, the authors briefly summarize the evidence supporting a dual deficit in DA and 5-HT function during withdrawal from chronic cocaine or alcohol abuse. Second, the authors discuss data demonstrating that 5HT release can dampen DA-mediated stimulant effects, and the "antistimulant" role of 5-HT-sub(2C) receptors is considered. Next, the mechanisms underlying potential adverse effects of 5-HT releasers are described. Finally, the authors discuss recently published data with PAL-287, a novel nonamphetamine DA/5-HT releasing agent that suppresses cocaine self-administration but lacks positive reinforcing properties. It is concluded that DA/5-HT releasers could be useful therapeutic adjuncts for the treatment of cocaine and alcohol addictions, as well as for obesity, attention-deficit disorder, and depression.
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Affiliation(s)
- Richard B Rothman
- Clinical Psychopharmacology Section, IRP/NIDA/NIH, Clinical Psychopharmacology Section, Suite 4500, Triad Building, 333 Cassell Drive, Baltimore, MD 21224, USA.
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22
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Wellman P. Effects of acute administration of phentermine, alone or in combination with dexfenfluramine, on pain reactivity in the adult rat. Pharmacol Biochem Behav 2008; 90:339-43. [DOI: 10.1016/j.pbb.2008.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Revised: 02/19/2008] [Accepted: 03/14/2008] [Indexed: 11/26/2022]
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23
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Hsieh YS, Yang SF, Chu SC, Ho YJ, Kuo CS, Kuo DY. Transcriptional interruption of cAMP response element binding protein modulates superoxide dismutase and neuropeptide Y-mediated feeding behavior in freely moving rats. J Neurochem 2008; 105:1438-49. [DOI: 10.1111/j.1471-4159.2008.05246.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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24
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Dopamine transporter imaging with [123I]FP-CIT SPECT: potential effects of drugs. Eur J Nucl Med Mol Imaging 2007; 35:424-38. [DOI: 10.1007/s00259-007-0621-0] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2007] [Accepted: 09/26/2007] [Indexed: 01/29/2023]
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Abstract
Brain imaging represents a potent tool to characterize biomarkers, biological traits that are pathognomonic for specific neurological and neuropsychiatric disorders. Positron emission tomography (PET) and single photon emission computed tomography (SPECT) are imaging techniques used to identify alterations in the density and distribution of neurotransmitters, neuroreceptors, and transporters in specific regions of the brains of people with these disorders. Brain imaging research currently facilitates the elucidation of dysfunction of dopamine, serotonin, acetylcholine, and other substances in people with Alzheimer's and Parkinson's diseases, schizophrenia, alcoholism and other substance abuse disorders, attention deficit/hyperactivity disorder, and the syndromes of restless legs, Lesch-Nyhan, Rett, and Tourette. Thus, brain imaging research offers great potential for the diagnosis, treatment, prevention, and cure of neurological and neuropsychiatric disorders. Brain imaging research also facilitates new drug development and helps establish therapeutic doses of novel drugs. In particular, studies of specific receptors, such as the dopamine D2 receptor, before and after the administration of doses of drugs that occupy these D2 receptors, provide the means to determine receptor occupancy. For example, an optimal dose of D2 antagonist antipsychotics produces occupancy of 65% to 80% of D2 receptors, while a greater dose carries a risk of extrapyramidal side effects.
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Affiliation(s)
- Dean F Wong
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of Nuclear Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-0807, USA.
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26
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Hsieh YS, Yang SF, Chu SC, Kuo DY. Interrupting activator protein-1 signaling in conscious rats can modify neuropeptide Y gene expression and feeding behavior of phenylpropanolamine. J Neurochem 2007; 104:50-61. [PMID: 17868324 DOI: 10.1111/j.1471-4159.2007.04919.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The mechanism for phenylpropanolamine (PPA)-induced anorexia has been attributed to its inhibitory action on hypothalamic neuropeptide Y (NPY), an orexigenic agent abundant in the brain. However, molecular mechanisms behind this effect are not well known. In this study, we investigated whether activator protein-1 (AP-1) signaling was involved. Rats were daily treated with PPA for 4 days. Changes in hypothalamic NPY, c-fos, c-jun, superoxide dismutase (SOD)-1, and SOD-2 mRNA contents were measured and compared. Results showed that c-fos and c-jun mRNA levels were increased following PPA treatment, which were relevant to a reduction in NPY mRNA level. To further determine if c-fos/c-jun genes were involved in PPA anorexia, infusions of antisense oligonucleotide into cerebroventricle were performed before daily PPA treatment in freely moving rats. Results showed that either c-fos or c-jun knock down could block PPA anorexia and restore NPY mRNA content to normal level. It is suggested that AP-1 signaling may participate in the central regulation of PPA-mediated appetite suppression via the modulation of NPY gene expression. Moreover, this modulation might be partly because of the neuroprotective effect of AP-1 since SOD gene was activated during PPA treatment.
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Affiliation(s)
- Yih-Shou Hsieh
- Institute of Biochemistry, Chung Shan Medical University, Taichung City, Taiwan
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27
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Hsieh YS, Yang SF, Chu SC, Kuo DY. Transcript of protein kinase A knock-down modulates feeding behavior and neuropeptide Y gene expression in phenylpropanolamine-treated rats. Physiol Genomics 2007; 31:306-14. [PMID: 17684035 DOI: 10.1152/physiolgenomics.00110.2007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Neuropeptide Y (NPY) is an appetite-controlling neuromodulator that contributes to the appetite-suppressing effect of phenylpropanolamine (PPA). Aims of this study were to investigate whether protein kinase A (PKA) signaling is involved in regulating NPY gene expression and PPA-induced anorexia. Rats were given daily with PPA for 5 days. Changes in daily food intake and hypothalamic NPY, PKA, cAMP response element binding protein (CREB), and pro-opiomelanocortin (POMC) gene expression were measured and compared. To further determine if PKA was involved, intracerebroventricular infusions of antisense oligodeoxynucleotide were performed at 60 min before daily PPA treatment in freely moving rats. Results showed that daily PKA, CREB, and POMC expression were increased following PPA treatment, which showed a closely reverse relationship with alterations of decreased feeding behaviors and NPY mRNA levels. Results also showed that PKA knock-down could block PPA-induced anorexia as well as restore NPY mRNA level, indicating the involvement of PKA signaling in the regulation of NPY gene expression. It is suggested that hypothalamic PKA signaling may participate in the central regulation of PPA-mediated appetite suppression via the modulation of hypothalamic NPY gene expression. The present findings reveal that manipulations at the molecular level of PKA or cAMP may allow the development of therapeutic agents to improve the undesirable properties of PPA or other amphetamine-like anorectic drugs.
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Affiliation(s)
- Yih-Shou Hsieh
- Institute of Biochemistry, Central Taiwan University of Science and Technology, Taichung City, Taiwan, Republic of China
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28
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Cheung THC, Bezzina G, Body S, Fone KCF, Bradshaw CM, Szabadi E. Tolerance to the effect of 2,5-dimethoxy-4-iodoamphetamine (DOI) on free-operant timing behaviour: interaction between behavioural and pharmacological mechanisms. Psychopharmacology (Berl) 2007; 192:521-35. [PMID: 17333133 DOI: 10.1007/s00213-007-0743-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2006] [Accepted: 02/09/2007] [Indexed: 12/25/2022]
Abstract
RATIONALE The psychostimulant d-amphetamine, the D(2/3) dopamine receptor agonist quinpirole and the 5-HT(2) receptor agonist 2,5-dimethoxy-4-iodoamphetamine (DOI) have similar effects on free-operant timing behaviour. There is evidence that tolerance develops to the effects of psychostimulants on timing performance during chronic treatment; this tolerance is generally attributed to behavioural adaptation rather than to pharmacological desensitisation. There have been no previous investigations of tolerance to the effect of DOI on free-operant timing behaviour. OBJECTIVE To demonstrate tolerance to DOI's effect on timing performance and to examine the nature of this tolerance. MATERIALS AND METHODS Rats were trained under the free-operant psychophysical procedure to press two levers (A and B) in 80-s trials in which reinforcement was provided intermittently for responding on A in the first half and B in the second half of the trial. Percent responding on B (%B) was recorded in successive 8-s epochs of the trials; logistic functions were fitted to the data from each rat for the derivation of timing indices (T (50) [time corresponding to %B = 50]; Weber fraction). RESULTS In experiment 1, DOI (0.25 mg kg(-1)) reduced T (50) compared to vehicle; tolerance to this effect was seen after repeated daily treatments with DOI if the rats were exposed to behavioural training during the period of treatment but not if the repeated treatments took place during a 'holiday' from behavioural training. In experiment 2, repeated treatment with DOI resulted in tolerance to the effect of DOI on T (50) and cross-tolerance to the effect of d-amphetamine (0.4 mg kg(-1)), but no cross-tolerance was seen to the effect of quinpirole (0.08 mg kg(-1)). CONCLUSIONS The results indicate that behavioural adaptation is involved in the development of tolerance to DOI's effect on timing. The finding of cross-tolerance to d-amphetamine but not to quinpirole suggests that the reduction of T (50) in the free-operant psychophysical procedure may be brought about by two distinct pharmacological mechanisms, one activated by DOI and d-amphetamine, and the other by quinpirole.
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Affiliation(s)
- T H C Cheung
- Psychopharmacology Section, Division of Psychiatry, University of Nottingham, Medical School, Queen's Medical Centre, Nottingham, UK.
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Pedersen K, Simonsen M, Østergaard SD, Munk OL, Rosa-Neto P, Olsen AK, Jensen SB, Møller A, Cumming P. Mapping the amphetamine-evoked changes in [11C]raclopride binding in living rat using small animal PET: Modulation by MAO-inhibition. Neuroimage 2007; 35:38-46. [PMID: 17223363 DOI: 10.1016/j.neuroimage.2006.11.038] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2006] [Revised: 10/24/2006] [Accepted: 11/01/2006] [Indexed: 11/19/2022] Open
Abstract
The performance of small animal PET for neuroreceptor studies in a psychopharmacological challenge paradigm is not yet well-described. Therefore, we used microPET and [(11)C]raclopride to map the availability of dopamine D(2/3) receptors in brain of anesthetized rats, first in a baseline condition, and again after challenge with saline or d-amphetamine. Parametric maps of the specific binding (binding potential, pB) were calculated using a reference tissue input from cerebellum, and spatially normalized to a digitized stereotaxic coordinate system for rat brain. In volumes of interest (VOIs), the mean baseline pB (n=6) was 2.05 in dorsal striatum (caudate-putamen), and 1.34 in ventral striatum (nucleus accumbens), and did not significantly differ upon retest 2 h later. The availability of [(11)C]raclopride binding sites at baseline was 8% higher in the right striatum. Challenge with amphetamine sulfate (1 mg/kg, i.v., n=4) decreased pB by 19% in both ventral and dorsal striatum. We have earlier predicted that blockade of monoamine oxidase (MAO) should potentiate the amphetamine-evoked dopamine release, thus enhancing the displacement of [(11)C]raclopride binding in vivo. However, pretreatment of rats with pargyline hydrochloride (4 mg/kg, n=4; 20 mg/kg, n=4) 1 day prior to PET did not potentiate the amphetamine-evoked reduction in dopamine receptor availability within the extended striatum. We conclude that small animal PET can be used to investigate stimulant-induced dopamine release, but that the spatial resolution is insufficient to detect differences between relative changes in dorsal vs. ventral divisions of the rat striatum. Furthermore, the present results do not reveal potentiation of the amphetamine-evoked release of dopamine in rats with MAO inhibition.
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Affiliation(s)
- Kasper Pedersen
- Centre for Functionally Integrative Neuroscience, Aarhus University, Denmark
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30
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Rothman RB, Blough BE, Baumann MH. Dual dopamine/serotonin releasers as potential medications for stimulant and alcohol addictions. AAPS JOURNAL 2007; 9:E1-10. [PMID: 17408232 PMCID: PMC2751297 DOI: 10.1208/aapsj0901001] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We have advocated the idea of agonist therapy for treating cocaine addiction. This strategy involves administration of stimulant-like medications (eg, monoamine releasers) to alleviate withdrawal symptoms and prevent relapse. A major limitation of this approach is that many candidate medicines possess significant abuse potential because of activation of mesolimbic dopamine (DA) neurons in central nervous system reward circuits. Previous data suggest that serotonin (5-HT) neurons can provide an inhibitory influence over mesolimbic DA neurons. Thus, it might be predicted that the balance between DA and 5-HT transmission is important to consider when developing medications with reduced stimulant side effects. In this article, we discuss several issues related to the development of dual DA/5-HT releasers for the treatment of substance use disorders. First, we discuss evidence supporting the existence of a dual deficit in DA and 5-HT function during withdrawal from chronic cocaine or alcohol abuse. Then we summarize studies that have tested the hypothesis that 5-HT neurons can dampen the effects mediated by mesolimbic DA. For example, it has been shown that pharmacological manipulations that increase extracellular 5-HT attenuate stimulant effects produced by DA release, such as locomotor stimulation and self-administration behavior. Finally, we discuss our recently published data about PAL-287 (naphthylisopropylamine), a novel non-amphetamine DA-/5-HT-releasing agent that suppresses cocaine self-administration but lacks positive reinforcing properties. It is concluded that DA/5-HT releasers might be useful therapeutic adjuncts for the treatment of cocaine and alcohol addiction, obesity, and even attention deficit disorder and depression.
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Affiliation(s)
- Richard B Rothman
- Clinical Psychopharmacology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, MD 21224, USA.
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31
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Body S, Cheung THC, Bezzina G, Asgari K, Fone KCF, Glennon JC, Bradshaw CM, Szabadi E. Effects of d-amphetamine and DOI (2,5-dimethoxy-4-iodoamphetamine) on timing behavior: interaction between D1 and 5-HT2A receptors. Psychopharmacology (Berl) 2006; 189:331-43. [PMID: 17051415 DOI: 10.1007/s00213-006-0575-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2006] [Accepted: 08/17/2006] [Indexed: 12/25/2022]
Abstract
RATIONALE The dopamine-releasing agent d-amphetamine and the 5-HT(2) receptor agonist 2,5-dimethoxy-4-iodoamphetamine (DOI) have similar effects on free-operant timing behavior. The selective D(1) dopamine receptor antagonist 8-bromo-2,3,4,5-tetrahydro-3-methyl-5-phenyl-1H-3-benzazepin-7-ol (SKF-83566), but not the D(2) dopamine receptor antagonist haloperidol, can antagonize the effect of d-amphetamine, and the selective 5-HT(2A) receptor antagonist (+/-)2,3-dimethoxyphenyl-1-(2-(4-piperidine)-methanol (MDL-100907) can antagonize the effect of DOI. However, it is not known whether the effect of d-amphetamine can be reversed by MDL-100907 and the effect of DOI by dopamine receptor antagonists. OBJECTIVE The objective of this work is to examine the interactions of d-amphetamine and DOI with MDL-100907, SKF-83566, and haloperidol on timing performance. MATERIALS AND METHODS Rats (n = 12-15 per experiment) were trained under the free-operant psychophysical procedure to press two levers (A and B) in 50-s trials in which reinforcement was provided intermittently for responding on A in the first half, and B in the second half of the trial. Percent responding on B (%B) was recorded in successive 5-s epochs of the trials; logistic functions were fitted to the data from each rat for the derivation of timing indices [T (50) (time corresponding to %B = 50); Weber fraction]. Rats were treated systemically with d-amphetamine or DOI, alone and in combination with haloperidol, SKF-83566, or MDL-100907. RESULTS d-Amphetamine (0.4 mg kg(-1)) reduced T (50) compared to vehicle; this effect was antagonized by SKF-83566 (0.03 mg kg(-1)) and MDL-100907 (0.5 mg kg(-1)), but not by haloperidol (0.05, 0.1 mg kg(-1)). DOI (0.25 mg kg(-1)) also reduced T (50); this effect was reversed by MDL-100907 (0.5 mg kg(-1)), but not by SKF-83566 (0.03 mg kg(-1)) or haloperidol (0.05 mg kg(-1)). CONCLUSIONS The results suggest that both 5-HT(2A) and D(1) receptors, but not D(2) receptors, are involved in d-amphetamine's effect on timing behavior in the free-operant psychophysical procedure. DOI's effect on timing is mediated by 5-HT(2A) receptors, but neither D(1) nor D(2) receptors are involved in this effect.
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MESH Headings
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/analogs & derivatives
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology
- Amphetamine/pharmacology
- Amphetamines/pharmacology
- Animals
- Conditioning, Operant
- Drug Interactions
- Female
- Fluorobenzenes/pharmacology
- Piperidines/pharmacology
- Rats
- Rats, Wistar
- Receptor, Serotonin, 5-HT2A/metabolism
- Receptors, Dopamine D2/metabolism
- Serotonin Antagonists/pharmacology
- Serotonin Receptor Agonists/pharmacology
- Time Perception/drug effects
- Time Perception/physiology
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Affiliation(s)
- S Body
- Psychopharmacology Section, Division of Psychiatry, University of Nottingham, Room B109, Medical School, Queen's Medical Centre, Nottingham, NG7 2UH, UK.
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Kim KK, Cho HJ, Kang HC, Youn BB, Lee KR. Effects on weight reduction and safety of short-term phentermine administration in Korean obese people. Yonsei Med J 2006; 47:614-25. [PMID: 17066505 PMCID: PMC2687747 DOI: 10.3349/ymj.2006.47.5.614] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The phentermine, an appetite suppressant, has been widely applied in Korea since 2004. However, there have been relatively few reports about the efficacy and the safety of phentermine in Korea. The aim of this study is to verify the effect of phentermine on weight reduction and the safety in Korean patients. This randomized, double-blind, placebo- controlled study had been performed between February and July, 2005, in Seoul on 68 relatively healthy obese adults whose body mass index was 25 kg/m2 or greater. They received phentermine-HCl 37.5 mg or placebo once daily with behavioral therapy for obesity. The primary endpoints were the changes of body weight and waist circumference from the baseline in the intention-to-treat population. Mean decrease of both body weight and waist circumference in phentermine-treated subjects were significantly greater than that of placebo group (weight: -6.7 +/- 2.5 kg, p < 0.001; waist circumference: -6.2 +/- 3.5 cm, p < 0.001). Significant number of subjects in phentermine group accomplished weight reduction of 5% or greater from the baseline and 10% or more (p < 0.001). There were no significant differences in systolic and diastolic blood pressure between the groups (p = 0.122 for systolic BP; p = 0.219 for diastolic BP). Dry mouth and insomnia were the only statistically significant adverse events that occurred more frequently in phentermine group. Most side effects of phentermine were mild to moderate in intensity. Short-term phentermine administration induced significant weight reduction and reduction of waist circumference without clinically problematic adverse events on relatively healthy Korean obese people.
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Affiliation(s)
- Kyoung Kon Kim
- Department of Family Medicine, Gachon University Gil Medical Center, Incheon, Korea
| | - Hi-Jung Cho
- Department of Family Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Hee-Cheol Kang
- Department of Family Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Bang-Bu Youn
- Department of Family Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Kyu-Rae Lee
- Department of Family Medicine, Gachon University Gil Medical Center, Incheon, Korea
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Zolkowska D, Rothman RB, Baumann MH. Amphetamine Analogs Increase Plasma Serotonin: Implications for Cardiac and Pulmonary Disease. J Pharmacol Exp Ther 2006; 318:604-10. [PMID: 16644904 DOI: 10.1124/jpet.106.101618] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Elevations in plasma serotonin (5-HT) have been implicated in the pathogenesis of cardiac and pulmonary disease. Normally, plasma 5-HT concentrations are kept low by transporter-mediated uptake of 5-HT into platelets and by metabolism to 5-hydroxyindoleacetic acid (5-HIAA). Many abused drugs (e.g., substituted amphetamines) and prescribed medications (e.g., fluoxetine) target 5-HT transporters and could thereby influence circulating 5-HT. We evaluated the effects of amphetamines analogs [(+/-)-fenfluramine, (+/-)-3,4-methylenedioxymethamphetamine, (+)-methamphetamine, (+)-amphetamine, phentermine] on extracellular levels (i.e., plasma levels) of 5-HT and 5-HIAA in blood from catheterized rats. Effects of the 5-HT uptake blocker fluoxetine were examined for comparison. Drugs were tested in vivo and in vitro; plasma indoles were measured using a novel microdialysis method in whole blood. We found that baseline dialysate levels of 5-HT are approximately 0.22 nM, and amphetamine analogs evoke large dose-dependent increases in plasma 5-HT ranging from 4 to 20 nM. The ability of drugs to elevate plasma 5-HT is positively correlated with their potency as 5-HT transporter substrates. Fluoxetine produced small, but significant, increases in plasma 5-HT. Although the drug-evoked 5-HT concentrations are below the micromolar levels required for contraction of pulmonary arteries, they approach concentrations reported to stimulate mitogenesis in pulmonary artery smooth muscle cells. Additional studies are needed to determine the effects of chronic administration of amphetamines on circulating 5-HT.
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Affiliation(s)
- Dorota Zolkowska
- Clinical Psychopharmacology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, 5500 Nathan Shock Drive, Baltimore, MD 21224, USA
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34
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Cheung THC, Bezzina G, Asgari K, Body S, Fone KCF, Bradshaw CM, Szabadi E. Evidence for a role of D1 dopamine receptors in d-amphetamine's effect on timing behaviour in the free-operant psychophysical procedure. Psychopharmacology (Berl) 2006; 185:378-88. [PMID: 16538470 DOI: 10.1007/s00213-006-0339-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2005] [Accepted: 01/31/2006] [Indexed: 10/24/2022]
Abstract
RATIONALE Temporal differentiation of operant behaviour is sensitive to dopaminergic manipulations. Studies using the fixed-interval peak procedure implicated D2 dopamine receptors in these effects. Less is known about the effects of dopaminergic manipulations on temporal differentiation in other timing schedules. OBJECTIVE To examine the effects of a D1 antagonist,8-bromo-2,3,4,5-tetrahydro-3-methyl-5-phenyl-1H-3-benzazepin-7-ol (SKF-83566), and a D2 antagonist, haloperidol, on performance on the free-operant psychophysical procedure, and the ability of these antagonists to reverse the effects of the catecholamine-releasing agent, d-amphetamine on performance. The antagonists' ability to reverse d-amphetamine-induced hyperlocomotion was also examined. MATERIALS AND METHODS Rats responded on two levers (A and B) under a free-operant psychophysical schedule, in which reinforcement was provided intermittently for responding on A during the first half, and B during the second half, of 50-s trials. Logistic functions were fitted to the relative response rate data (percent responding on B [%B] vs time [t]) in each treatment condition, and quantitative timing indices [T50 (value of t corresponding to %B=50) and Weber fraction] were compared among treatments. Effects of the treatments on locomotion were measured in a separate experiment. RESULTS SKF-83566 (0.015, 0.03, 0.06 mg kg(-1)) did not affect timing performance. Haloperidol (0.025, 0.05 mg kg(-1)) had no effect; a higher dose (0.1 mg kg(-1)) reduced T (50). d-Amphetamine (0.4 mg kg(-1)) reduced T50; this effect was antagonised by SKF-83566 but not by haloperidol. Both antagonists reduced d-amphetamine-induced hyperlocomotion. CONCLUSIONS The results suggest that d-amphetamine's effect on performance in the free-operant psychophysical procedure is mediated by D1 rather than D2 receptors.
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MESH Headings
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/analogs & derivatives
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology
- Animals
- Conditioning, Operant/drug effects
- Dextroamphetamine/pharmacology
- Dopamine D2 Receptor Antagonists
- Dose-Response Relationship, Drug
- Female
- Haloperidol/pharmacology
- Motor Activity/drug effects
- Rats
- Rats, Wistar
- Receptors, Dopamine D1/antagonists & inhibitors
- Receptors, Dopamine D1/physiology
- Receptors, Dopamine D2/physiology
- Time Perception/drug effects
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Affiliation(s)
- T H C Cheung
- Psychopharmacology Section, Division of Psychiatry, University of Nottingham, Room B109, Medical School, Queen's Medical Centre Nottingham, Nottingham, NG7 2UH, UK
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35
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Boos TL, Greiner E, Calhoun WJ, Prisinzano TE, Nightingale B, Dersch CM, Rothman RB, Jacobson AE, Rice KC. Structure-activity relationships of substituted N-benzyl piperidines in the GBR series: Synthesis of 4-(2-(bis(4-fluorophenyl)methoxy)ethyl)-1-(2-trifluoromethylbenzyl)piperidine, an allosteric modulator of the serotonin transporter. Bioorg Med Chem 2006; 14:3967-73. [PMID: 16563775 DOI: 10.1016/j.bmc.2006.01.065] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2006] [Revised: 01/17/2006] [Accepted: 01/20/2006] [Indexed: 11/28/2022]
Abstract
A series of 4-(2-(bis(4-fluorophenyl)methoxy)ethyl)-(substituted benzyl) piperidines with substituents at the ortho and meta positions in the aromatic ring of the N-benzyl side chain were synthesized and their affinities and selectivities for the dopamine transporter (DAT), serotonin transporter (SERT), and norepinephrine transporter (NET) were determined. One analogue, 4-(2-(bis(4-fluorophenyl)methoxy)ethyl)-1-(2-trifluoromethylbenzyl)piperidine (the C(2)-trifluoromethyl substituted compound), has been found to act as an allosteric modulator of hSERT binding and function. It had little affinity for any of the transporters. Several compounds showed affinity for the DAT in the low nanomolar range and displayed a broad range of SERT/DAT selectivity ratios and very little affinity for the NET. The pharmacological tools provided by the availability of compounds with varying transporter affinity and selectivity could be used to obtain additional information about the properties a compound should have to act as a useful pharmacotherapeutic agent for cocaine addiction and help unravel the pharmacological mechanisms relevant to stimulant abuse.
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Affiliation(s)
- Terrence L Boos
- Laboratory of Medicinal Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20892, USA
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36
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Munhall AC, Johnson SW. Dopamine-mediated actions of ephedrine in the rat substantia nigra. Brain Res 2006; 1069:96-103. [PMID: 16386715 DOI: 10.1016/j.brainres.2005.11.044] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2005] [Revised: 11/04/2005] [Accepted: 11/06/2005] [Indexed: 10/25/2022]
Abstract
Although ephedrine is a centrally active stimulant, its effect on midbrain dopamine neurons is not known. To study the effect of ephedrine on dopamine-containing cells, current-clamp microelectrode recordings were made from substantia nigra pars compacta (SNC) neurons in horizontal brain slice preparations. Ephedrine (100-1000 microM) slowed spontaneous firing and produced a modest concentration-dependent hyperpolarization of membrane potential (EC50 279 microM), with a concomitant net decrease in membrane resistance. These effects were blocked by the D2-like dopamine antagonist sulpiride (1 microM). Electrically evoked inhibitory synaptic potentials mediated by GABAB receptors were reduced 28% by ephedrine. However, ephedrine did not reduce fast synaptic potentials mediated by GABAA or ionotropic glutamate receptors. Inhibition of the GABAB response appeared to be mediated by a postsynaptic mechanism because ephedrine also reduced baclofen-induced hyperpolarization by 28%. Both ephedrine-induced hyperpolarization and inhibition of baclofen-induced hyperpolarization were abolished when slices were superfused with the tyrosine hydroxylase inhibitor alpha-methyl-para-tyrosine (AMPT). Despite perfusion with AMPT, the ability of ephedrine to cause hyperpolarization was restored after perfusing the slice with dopamine (30 microM). Taken together, these results suggest that ephedrine causes hyperpolarization and suppresses GABAB receptor-mediated effects by releasing endogenous dopamine. However, the high concentrations required to observe these effects in vitro suggest that biologically relevant central effects of ephedrine are more likely to be mediated either by non-dopamine systems, such as those involving noradrenaline, or by dopamine systems outside the SNC.
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Affiliation(s)
- Adam C Munhall
- Department of Neurology, Oregon Health and Science University, Portland, OR 97239, USA
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