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Buchborn T, Lyons T, Song C, Feilding A, Knöpfel T. The serotonin 2A receptor agonist 25CN-NBOH increases murine heart rate and neck-arterial blood flow in a temperature-dependent manner. J Psychopharmacol 2020; 34:786-794. [PMID: 32048564 PMCID: PMC7488829 DOI: 10.1177/0269881120903465] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Serotonin 2A receptors, the molecular target of psychedelics, are expressed by neuronal and vascular cells, both of which might contribute to brain haemodynamic characteristics for the psychedelic state. AIM Aiming for a systemic understanding of psychedelic vasoactivity, here we investigated the effect of N-(2-hydroxybenzyl)-2,5-dimethoxy-4-cyanophenylethylamine - a new-generation agonist with superior serotonin 2A receptor selectivity - on brain-supplying neck-arterial blood flow. METHODS We recorded core body temperature and employed non-invasive, collar-sensor based pulse oximetry in anesthetised mice to extract parameters of local blood perfusion, oxygen saturation, heart and respiration rate. Hypothesising an overlap between serotonergic pulse- and thermoregulation, recordings were done under physiological and elevated pad temperatures. RESULTS N-(2-hydroxybenzyl)-2,5-dimethoxy-4-cyanophenylethylamine (1.5 mg/kg, subcutaneous) significantly increased the frequency of heart beats accompanied by a slight elevation of neck-arterial blood flow. Increasing the animal-supporting heat-pad temperature from 37°C to 41°C enhanced the drug's effect on blood flow while counteracting tachycardia. Additionally, N-(2-hydroxybenzyl)-2,5-dimethoxy-4-cyanophenylethylamine promoted bradypnea, which, like tachycardia, quickly reversed at the elevated pad temperature. The interrelatedness of N-(2-hydroxybenzyl)-2,5-dimethoxy-4-cyanophenylethylamine's respiro-cardiovascular effects and thermoregulation was further corroborated by the drug selectively increasing the core body temperature at the elevated pad temperature. Arterial oxygen saturation was not affected by N-(2-hydroxybenzyl)-2,5-dimethoxy-4-cyanophenylethylamine at either temperature. CONCLUSIONS Our findings imply that selective serotonin 2A receptor activation modulates systemic cardiovascular functioning in orchestration with thermoregulation and with immediate relevance to brain-imminent neck (most likely carotid) arteries. As carotid branching is a critical last hub to channel cardiovascular output to or away from the brain, our results might have implications for the brain haemodynamics associated with psychedelia.
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Affiliation(s)
- Tobias Buchborn
- Laboratory for Neuronal Circuit Dynamics, Department of Medicine, Imperial College, London, UK,Centre for Psychedelic Research, Department of Medicine, Imperial College, London, UK,Tobias Buchborn, Laboratory for Neuronal Circuit Dynamics, Department of Medicine, Imperial College, Du Cane Road, Burlington Danes, London, W12 0NN, UK.
| | - Taylor Lyons
- Laboratory for Neuronal Circuit Dynamics, Department of Medicine, Imperial College, London, UK,Centre for Psychedelic Research, Department of Medicine, Imperial College, London, UK
| | - Chenchen Song
- Laboratory for Neuronal Circuit Dynamics, Department of Medicine, Imperial College, London, UK
| | | | - Thomas Knöpfel
- Laboratory for Neuronal Circuit Dynamics, Department of Medicine, Imperial College, London, UK,Centre for Neurotechnology, Institute of Biomedical Engineering, Imperial College, London, UK
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Alcántara-Vázquez O, Villamil-Hernández MT, Sánchez-López A, Pertz HH, Villalón CM, Centurión D. Blocking properties of terguride at the 5-HT 2 receptor subtypes mediating cardiovascular responses in the rat. Can J Physiol Pharmacol 2020; 98:511-521. [PMID: 32268074 DOI: 10.1139/cjpp-2019-0591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In vitro studies have suggested that terguride blocks the contractile and relaxant responses produced by 5-hydroxytryptamine (5-HT) via 5-HT2A/2B receptors. This study has now investigated terguride's blocking properties on central/peripheral 5-HT2 receptors in anaesthetized or pithed rats. Male Wistar anaesthetized/pithed rats were cannulated for recording blood pressure and heart rate and for i.v. administration of several compounds. In both groups of rats, i.v. bolus injections of 5-HT or (±)-DOI (a 5-HT2 receptor agonist; 1-1000 μg/kg) produced dose-dependent increases in diastolic blood pressure and heart rate. These responses were dose-dependently antagonized by terguride (10-3000 μg/kg). In anaesthetized rats, i.v. bolus injections of BW723C86 (a 5-HT2B receptor agonist; 1-1000 μg/kg) produced dose-dependent increases in diastolic blood pressure and not dose-dependent increases in heart rate, while in pithed rats, these responses were attenuated. The vasopressor responses elicited by BW723C86 in anaesthetized rats were dose-dependently blocked by terguride (10-300 μg/kg), whereas its the tachycardic responses were dose-independently blocked. These results, taken together, suggest that terguride behaved as an antagonist at the 5-HT2 receptors located in the central nervous system and (or) the systemic vasculature. This is the first evidence demonstrating that terguride can block central/peripheral 5-HT2 receptors mediating cardiovascular responses in anaesthetized or pithed rats.
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Affiliation(s)
- Oscar Alcántara-Vázquez
- Centro Interdisciplinario de Ciencias de la Salud, Unidad Milpa Alta, IPN, Ex-Hacienda del Mayorazgo, Km. 39.5 Carretera Xochimilco-Oaxtepec, C.P 12000, México City, México
| | - Ma Trinidad Villamil-Hernández
- Centro Interdisciplinario de Ciencias de la Salud, Unidad Milpa Alta, IPN, Ex-Hacienda del Mayorazgo, Km. 39.5 Carretera Xochimilco-Oaxtepec, C.P 12000, México City, México
| | - Araceli Sánchez-López
- Departamento de Farmacobiología, Cinvestav-Coapa, Czda. de los Tenorios 235, Col. Granjas-Coapa, Deleg. Tlalpan, C.P.14330, Mexico City, Mexico
| | - Heinz H Pertz
- Institut für Pharmazie, Freie Universität Berlin, Königin-Luise-Str. 2, 14195 Berlin (Dahlem), Germany
| | - Carlos M Villalón
- Departamento de Farmacobiología, Cinvestav-Coapa, Czda. de los Tenorios 235, Col. Granjas-Coapa, Deleg. Tlalpan, C.P.14330, Mexico City, Mexico
| | - David Centurión
- Departamento de Farmacobiología, Cinvestav-Coapa, Czda. de los Tenorios 235, Col. Granjas-Coapa, Deleg. Tlalpan, C.P.14330, Mexico City, Mexico
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The central serotonin2B receptor as a new pharmacological target for the treatment of dopamine-related neuropsychiatric disorders: Rationale and current status of research. Pharmacol Ther 2018; 181:143-155. [DOI: 10.1016/j.pharmthera.2017.07.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Huang LC, Huang LY, Tseng SY, Hou YM, Hsiao CC. Amisulpride and symptomatic bradycardia: a case report. Gen Hosp Psychiatry 2015; 37:497.e1-2. [PMID: 26162544 DOI: 10.1016/j.genhosppsych.2013.12.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 12/10/2013] [Accepted: 12/10/2013] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Amisulpride is a second-generation antipsychotic agent indicated for the treatment of schizophrenia and other major psychotic illnesses. Amisulpride-induced bradycardia is a rare condition of unknown etiology and mechanism. Asymptomatic bradycardia has been associated with amisulpride in only two cases. In our case, the association was rated as "probable" on the Naranjo adverse drug reaction probability scale. METHOD Case report. RESULTS A 45-year-old male patient developed symptomatic bradycardia during usage of amisulpride (400-800 mg/day), which dramatically improved after the complete termination of amisulpride usage. The psychiatric condition remained relatively stable without bradycardia after administration of another antipsychotic agent [risperidone (3 mg/day)]. CONCLUSION This is the first case report of symptomatic bradycardia associated with the use of amisulpride. Although bradycardia is a rare adverse reaction to antipsychotics, this finding may alert psychiatrists and physicians to this antipsychotic drug side effect. Further study is needed to disclose the role of antipsychotics in bringing about symptomatic bradycardia.
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Affiliation(s)
- Li-Chung Huang
- Department of Psychiatry, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chia-Yi City, Taiwan; Chia Nan University of Pharmacy and Science, Tainan, Taiwan
| | - Li-Yen Huang
- Department of Cardiology, Taoyuan Armed Forces General Hospital, Taoyuan, Taiwan
| | - Shih-Yen Tseng
- Department of Pharmachology, Taichung Veterans General Hospital Chia Yi Branch, Chia-Yi City, Taiwan
| | - Yuh-Ming Hou
- Department of Psychiatry, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chia-Yi City, Taiwan
| | - Cheng-Cheng Hsiao
- Department of Psychiatry, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chia-Yi City, Taiwan.
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Davisson RL, Bates JN, Johnson AK, Lewis SJ. Effects of intracerebroventricular injections of 5-HT on systemic vascular resistances of conscious rats. Microvasc Res 2014; 95:116-23. [PMID: 25128748 PMCID: PMC4188728 DOI: 10.1016/j.mvr.2014.08.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 07/18/2014] [Accepted: 08/07/2014] [Indexed: 12/21/2022]
Abstract
The aims of this study were to determine (i) the effects of intracerebroventricular (i.c.v.) injections of 5-hydroxytryptamine (5-HT, 10μg) on mean arterial blood pressure (MAP), heart rate (HR) and mesenteric (MR), renal (RR) and hindquarter (HQR) vascular resistances of conscious rats, (ii) the central 5-HT receptor subtype which mediates these effects, and (iii) the role of nitric oxide (NO) in the expression of these responses. The i.c.v. injection of 5-HT had minor effects on MAP but produced a decrease in HR (-18±4%), which lasted for 20min. The i.c.v. injection of 5-HT elicited marked increases in MR (+50±7%) and reductions in HQR (-31±3%). These responses occurred promptly and lasted for 25-35min. 5-HT also produced a transient decrease in RR (-26±8% at 10min). All of these responses were prevented by the prior i.c.v. injection of the 5-HT1/5-HT2-receptor antagonist, methysergide (10μg). The intravenous injection of the NO synthesis inhibitor, L-NAME (25μmol/kg), produced a sustained pressor response, bradycardia and increases in MR, RR and HQR. Subsequent i.c.v. injection of 5-HT produced a minor pressor response (+7±2%), bradycardia (-18±3%), an increase in MR (+52±8%) but no decreases in RR or HQR. This study demonstrates that i.c.v. 5-HT differentially affects peripheral vascular resistances by activation of central 5-HT1/5-HT2-receptors. It appears that L-NAME did not interfere with the central actions of 5-HT as it did not prevent the 5-HT-induced bradycardia or mesenteric vasoconstriction. Since the 5-HT-induced falls in RR and HQR were abolished by L-NAME, it is possible that these responses are mediated by an active neurogenic process involving the release of NO within the vasculature.
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Affiliation(s)
- Robin L. Davisson
- Departments of Biomedical Sciences (College of Veterinary Medicine), Ithaca, New York, and Cell and Developmental Biology (Weil Cornell Medical College), New York, New York, USA
| | - James N. Bates
- Department of Anesthesia, University of Iowa, Iowa City, Iowa, USA
| | - Alan Kim Johnson
- Departments of Psychology, Health and Human Physiology, and Pharmacology, and the Francois M. Abboud Cardiovascular Research Center, The University of lowa, Iowa City, Iowa, USA
| | - Stephen J. Lewis
- Departments of Pediatrics and Pharmacology, Case Western Reserve University, Cleveland, Ohio, USA
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Association between the -1438G/A and T102C polymorphisms of 5-HT2A receptor gene and obstructive sleep apnea: a meta-analysis. Mol Biol Rep 2013; 40:6223-31. [PMID: 24065538 DOI: 10.1007/s11033-013-2734-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 09/14/2013] [Indexed: 01/12/2023]
Abstract
The serotonin 2A (5-HT2A) receptor has been implicated in obstructive sleep apnea (OSA). Single nucleotide polymorphisms (SNPs) in the 5-HT2A gene have been found in OSA, the most common being -1438G/A and T102C; however, studies of the association between 5-HT2A SNPs and OSA risk have reported inconsistent findings. A meta-analysis was performed to quantitatively review the association between -1438G/A and T102C SNPs and OSA. Five studies, including 791 subjects for -1438G/A genotype and 1,068 subjects for T102C genotype, were selected. Pooled data analysis of the -1438G/A genotype indicated a significantly increased OSA risk was associated with two variant genotypes (AA vs. AG+GG: OR 3.023, 95 % CI 2.169-4.213, P = 0.506 for heterogeneity; A allele carriers vs. GG: OR 1.938, 95 % CI 0.879-4.274, P = 0.012 for heterogeneity). Stratification analysis by gender supported the association in males, but not females. For the T102C genotype, no significantly increased OSA risk was associated with the two variant genotypes (CC vs. CT+TT: OR 1.065, 95 % CI 0.787-1.442, P = 0.361 for heterogeneity; C allele carriers vs. TT: OR 0.979, 95 % CI 0.737-1.3, P = 0.9 for heterogeneity).In conclusions, meta-analysis indicated that the -1438G/A, and not T102C, polymorphism of 5-HT2A is a positive risk factor of OSA, especially in males.
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Brierley DI, Davidson C. Developments in harmine pharmacology--implications for ayahuasca use and drug-dependence treatment. Prog Neuropsychopharmacol Biol Psychiatry 2012; 39:263-72. [PMID: 22691716 DOI: 10.1016/j.pnpbp.2012.06.001] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 05/16/2012] [Accepted: 06/03/2012] [Indexed: 12/14/2022]
Abstract
Ayahuasca is a hallucinogenic botanical mixture originating in the Amazon area where it is used ritually, but is now being taken globally. The 2 main constituents of ayahuasca are N,N-dimethyltryptamine (DMT), a hallucinogen, and harmine, a monoamine oxidase inhibitor (MAOI) which attenuates the breakdown of DMT, which would otherwise be broken down very quickly after oral consumption. Recent developments in ayahuasca use include the sale of these compounds on the internet and the substitution of related botanical (anahuasca) or synthetic (pharmahuasca) compounds to achieve the same desired hallucinogenic effects. One intriguing result of ayahuasca use appears to be improved mental health and a reduction in recidivism to alternate (alcohol, cocaine) drug use. In this review we discuss the pharmacology of ayahuasca, with a focus on harmine, and suggest pharmacological mechanisms for the putative reduction in recidivism to alcohol and cocaine misuse. These pharmacological mechanisms include MAOI, effects at 5-HT(2A) and imidazoline receptors and inhibition of dual-specificity tyrosine-phosphorylation regulated kinase 1A (DYRK1A) and the dopamine transporter. We also speculate on the therapeutic potential of harmine in other CNS conditions.
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Affiliation(s)
- Daniel I Brierley
- Pharmacology & Cell Physiology, Division of Biomedical Science, St George's, University of London, Cranmer Terrace, London SW17 0RE, United Kingdom
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Watts SW, Morrison SF, Davis RP, Barman SM. Serotonin and blood pressure regulation. Pharmacol Rev 2012; 64:359-88. [PMID: 22407614 DOI: 10.1124/pr.111.004697] [Citation(s) in RCA: 252] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
5-Hydroxytryptamine (5-HT; serotonin) was discovered more than 60 years ago as a substance isolated from blood. The neural effects of 5-HT have been well investigated and understood, thanks in part to the pharmacological tools available to dissect the serotonergic system and the development of the frequently prescribed selective serotonin-reuptake inhibitors. By contrast, our understanding of the role of 5-HT in the control and modification of blood pressure pales in comparison. Here we focus on the role of 5-HT in systemic blood pressure control. This review provides an in-depth study of the function and pharmacology of 5-HT in those tissues that can modify blood pressure (blood, vasculature, heart, adrenal gland, kidney, brain), with a focus on the autonomic nervous system that includes mechanisms of action and pharmacology of 5-HT within each system. We compare the change in blood pressure produced in different species by short- and long-term administration of 5-HT or selective serotonin receptor agonists. To further our understanding of the mechanisms through which 5-HT modifies blood pressure, we also describe the blood pressure effects of commonly used drugs that modify the actions of 5-HT. The pharmacology and physiological actions of 5-HT in modifying blood pressure are important, given its involvement in circulatory shock, orthostatic hypotension, serotonin syndrome and hypertension.
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Affiliation(s)
- Stephanie W Watts
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI 48824-1317, USA.
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Okano K, Tsuruta Y, Yamashita T, Echida Y, Kabaya T, Nitta K. Cardiovascular autonomic neuropathy studied by a laser-Doppler blood flowmeter in hemodialysis patients. Intern Med 2010; 49:2669-75. [PMID: 21173541 DOI: 10.2169/internalmedicine.49.3884] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
OBJECTIVE Orthostatic hypotension during a hemodialysis (HD) session affects not only the modality but daily quality of life for HD patients because many of them have combined dysfunction of both sympathetic and parasympathetic nervous systems. Although various non-invasive methods have been applied for the evaluation of autonomic function, no monitor has been devised for measuring the dysfunction during blood purification therapy. PATIENTS AND METHODS We evaluated the usefulness of laser-Doppler blood flowmeter (LDF) for measuring autonomic function of stable 34 regular HD patients and 24 healthy controls. The LDF device was applied for autonomic test by measuring periflux blood flow decreasing velocity (PDV) accompanied with Valsalva maneuver. We also evaluated the correlation between PDV and conventional tests for atherosclerosis. RESULTS The average PDV (3.79±1.77) in HD population level was significantly lower than that of healthy controls (8.72±6.00). We also found a significant correlation between PDV and conventional methods such as heart rate variability and ankle-brachial blood pressure index. CONCLUSION Measurement of PDV by LDF is as useful as a conventional method for evaluating autonomic function in HD patients. The convenience of the device offers the benefit of daily and frequent measurement of autonomic dysfunction.
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Affiliation(s)
- Kazuhiro Okano
- Department of Medicine, Kidney Center, Tokyo Women's Medical University, and Minami-Senju Hospital, Tokyo.
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Aizawa N, Ishizuka O, Ogawa T, Mizusawa H, Igawa Y, Nishizawa O. Role of 5-HT Receptor Antagonists in Mediating Intracavernous Pressure Response Induced by Fluvoxamine in Conscious Rats. J Sex Med 2007; 4:1108-16. [PMID: 17627723 DOI: 10.1111/j.1743-6109.2007.00534.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
INTRODUCTION It has been reported that selective serotonin reuptake inhibitor (SSRI) may cause sexual dysfunction. AIM To determine the relationship between serotonin and sexual function, we investigated the role of serotonergic receptors on changes in intracavernous pressure (ICP) and systemic blood pressure (BP) in conscious and free-moving rats. METHODS ICP and BP were measured in male Sprague-Dawley rats after catheters were inserted into the crus corpus cavernosum and carotid artery, respectively. Pressures were recorded 2 hours after catheterization. In other rats, this procedure was performed 2 weeks after spinal cord transection (spinal cord injury [SCI]) between the eighth and ninth thoracic vertebrae. To investigate the role of serotonergic receptors, fluvoxamine (an SSRI), WAY100635 (a 5-HT(1A)-receptor antagonist), and SB242084 (a 5-HT(2C)-receptor antagonist) were administered by intravenous (i.v.) or intracerebroventricular (i.c.v.) routes. MAIN OUTCOME MEASURES BP and parameters of ICP were measured in conscious and free-moving rats. RESULTS Administration of fluvoxamine (1- to 30-micromol/kg i.v. and 1- to 30-nmol i.c.v.) induced a transient increase in the ICP. The ICP parameters responded in a dose-dependent manner, especially the time to first response (TFR), which was significantly shortened. BP also increased in response to fluvoxamine. In contrast, ICP in SCI rats did not change after fluvoxamine administration. WAY100635 (10 or 30-nmol i.c.v.) induced an increase in the ICP. In combination with fluvoxamine, it significantly shortened the TFR in comparison with WAY100635 or fluvoxamine alone. However, SB242084 (10 or 30-nmol i.c.v.) actually had an inhibitory effect on fluvoxamine-induced ICP responses. CONCLUSIONS These findings demonstrated that ICP is regulated at the supraspinal level when endogenous serotonin is increased by fluvoxamine. Furthermore, ICP is facilitated by 5-HT(2C)-receptors and inhibited by 5-HT(1A)-receptors in the rat brain.
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Affiliation(s)
- Naoki Aizawa
- Department of Urology, Shinshu University School of Medicine, Matsumoto, Japan.
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Richards DA, Boehm KA, Anthony SP. Systemic therapy for gastric cancer and adenocarcinoma of the gastroesophageal junction: present status and future directions. Expert Opin Investig Drugs 2007; 16:1059-68. [PMID: 17594189 DOI: 10.1517/13543784.16.7.1059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Gastric cancer is a major worldwide problem and is a leading cause of death. The incidence of distal gastric cancer is declining; however, there has been a rapid rise in the incidence of adenocarcinoma of the gastroesophageal junction, which is a more aggressive entity. Combination chemotherapy has significant activity in the treatment of both of these diseases, improving overall survival and quality of life. Despite these improvements, median survival remains at approximately 9 months in patients who are diagnosed at stage IV. This review examines recent advances in the treatment of gastroesophageal junction adenocarcinoma and gastric cancer, newer agents and the potential agents that are in development, which can be logically applied to the treatment of this devastating disease.
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Stiedl O, Misane I, Koch M, Pattij T, Meyer M, Ogren SO. Activation of the brain 5-HT2C receptors causes hypolocomotion without anxiogenic-like cardiovascular adjustments in mice. Neuropharmacology 2007; 52:949-57. [PMID: 17141810 DOI: 10.1016/j.neuropharm.2006.10.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2005] [Revised: 09/22/2006] [Accepted: 10/19/2006] [Indexed: 11/18/2022]
Abstract
The present study evaluated whether hypolocomotion elicited by subcutaneous administration of the non-specific 5-HT/preferential 5-HT(2C) receptor agonist mCPP during novelty exposure was due to an enhanced anxiety-like state. The effects of mCPP on exploratory behavior during exposure to a new environment (novelty) were studied in male C57BL/6N mice. Subcutaneous injection of mCPP (1 and 3mg/kg) and the preferential 5-HT(2C) receptor agonist MK212 (0.7 and 1mg/kg) induced hypolocomotion during novelty exposure. The selective 5-HT(2C) receptor antagonist SB242084 (0.3mg/kg) reversed the mCPP-induced hypolocomotion into hyperlocomotion. In contrast, MK212 induced hypolocomotion that was blocked by SB242084, indicating a specific 5-HT(2C) receptor involvement. When injected intracerebroventricularly, mCPP (30microg) elicited hypolocomotion, whereas the same dose mildly increased locomotion when injected into the dorsal hippocampus. Since anxiety affects autonomic functions, effects of mCPP on cardiovascular function were studied by radio-telemetry in the home cage of unrestrained mice. Subcutaneous injection of mCPP (3mg/kg) had no significant effect on heart rate and mean arterial blood pressure. In summary, in view of lack of autonomic effects, and the lack of hypoactivity upon forebrain stimulation, the hypolocomotion induced by systemic mCPP cannot be explained by an enhanced anxiety-like state.
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Affiliation(s)
- Oliver Stiedl
- Center for Neurogenomics and Cognitive Research (CNCR) and Institute of Neurosciences (INW), Vrije Universiteit Amsterdam, The Netherlands.
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Terrón JA. 2-(2-aminoethyl)-quinoline (D-1997): A Novel Agonist at Craniovascular 5-HT1 Receptors Relevant to Migraine Therapy. CNS DRUG REVIEWS 2006. [DOI: 10.1111/j.1527-3458.2000.tb00152.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Silva ALS, Cabral AM, Abreu GR, Pires JGP, Bissoli NS, Ramage AG. Chronic treatment with mianserin prevents DOCA–salt hypertension in rats—evidence for the involvement of central 5-HT2 receptors. Eur J Pharmacol 2005; 518:152-7. [PMID: 16014306 DOI: 10.1016/j.ejphar.2005.05.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2005] [Accepted: 05/20/2005] [Indexed: 11/17/2022]
Abstract
Central 5-HT2A receptors have been implicated in central volume control by activating a central angiotensinergic pathway to cause the release of vasopressin. Interestingly, to induce DOCA-salt hypertension in rats vasopressin release is required. Thus the present experiments were carried out to determine whether continuous blockade of these receptors over 20 days, with the non-selective 5-HT2 receptor antagonist mianserin would prevent the development of deoxycorticosterone acetate (DOCA)-salt hypertension. Mianserin, given i.c.v. 90 or 60 microg twice daily for 20 days prevented the development of hypertension in conscious rats receiving DOCA-salt but did not affect blood pressure in rats on salt alone. Further, the dose of 30 microg given i.c.v. twice daily had no effect nor did the vehicle, polyethylene glycol (PEG), on the development of the hypertension. Mianserin 90 microg twice daily i.c.v. was also shown to prevent the increase in fluid intake, urinary flow and sodium excretion caused by DOCA-salt treatment. These data indicate that this action of mianserin is not due to an intrinsic hypotensive action but an action which involves interference with the mechanism by which DOCA-salt treatment causes hypertension. Thus the data overall support the view that to induce hypertension with DOCA-salt a central 5-HT-containing pathway needs to be activated, which then activates 5-HT2 receptors to cause the release of vasopressin which has previously been shown to be responsible for the initiation of DOCA-salt treatment hypertension.
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Affiliation(s)
- Andréia L S Silva
- Departamento de Ciências Fisiológicas, Centro Biomédico, Universidade Federal do Espírito Santo, Av. Marechal Campos 1468, Vitória, ES 29040-090, Brazil
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Veasey SC. Serotonin agonists and antagonists in obstructive sleep apnea: therapeutic potential. ACTA ACUST UNITED AC 2004; 2:21-9. [PMID: 14720019 DOI: 10.1007/bf03256636] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Obstructive sleep apnea hypopnea syndrome (OSAHS) is a prevalent disorder associated with substantial cardiovascular and neurobehavioral morbidity. Yet this is a disorder for which there are no widely effective pharmacotherapies. The pathophysiology of obstructive sleep apnea namely, normal respiration in waking with disordered breathing only in sleep, suggests that this disorder should be readily amenable to drug therapy. Over the past 10 years, we have gained tremendous insight into the neurochemical mechanisms involved in state-dependent control of respiration. It is apparent from this work that there are many potential avenues for pharmacotherapies, including several seemingly conflicting directions for serotonergic therapies. Serotonin delivery is reduced to upper airway dilator motor neurons in sleep, and this contributes, at least in part, to sleep-related reductions in dilator muscle activity and upper airway obstruction. The dilator motor neuron post-synaptic serotonin receptors are 5-HT(2A) and 5-HT(2C) subtypes, and in adults the presynaptic 5-HT receptor in motor nuclei is 5-HT(1B), an inhibitory receptor. Serotonin receptors are also found within central respiratory neuronal groups, and these receptor subtypes include 5-HT(1A) (inhibitory) and 5-HT(2) receptors. Peripherally, stimulation of 5-HT(2A), 5-HT(2C) and 5-HT(3) receptor subtypes have an inhibitory effect on respiration via action at the nodose ganglion. Many of these receptor subtypes and their signal transduction pathways may be affected by oxidative stress in obstructive sleep apnea. These alterations will make finding drug therapies for sleep apnea more challenging, but not insurmountable. Future directions are suggested for elucidating safe, well-tolerated serotonergic drugs for this disorder. Tryptophan was one of the first serotonergic drugs tested for OSAHS. This drug was withdrawn from the market as a result of reports linking tryptophan use with eosinophilic myalgia syndrome and life-threatening pulmonary hypertension. Newer drugs with serotonergic activity tested in persons with sleep-disordered breathing include buspirone, fluoxetine and paroxetine. Trials are presently being conducted to evaluate the effects of 5-HT(2A) and 5-HT(3) antagonists on OSAHS. Many of the drugs tested have not shown significant improvement in sleep apnea. However, with continued effort to elucidate the pharmacology of neurochemical control of state-dependent changes in respiratory control, the availability of pharmacological therapy for this disorder is not too far away.
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Affiliation(s)
- Sigrid C Veasey
- Department of Medicine, Center for Sleep and Respiratory Neurobiology, University of Pennsylvania, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania 19104-4283, USA.
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Boothman LJ, Allers KA, Rasmussen K, Sharp T. Evidence that central 5-HT2A and 5-HT2B/C receptors regulate 5-HT cell firing in the dorsal raphe nucleus of the anaesthetised rat. Br J Pharmacol 2003; 139:998-1004. [PMID: 12839874 PMCID: PMC1573922 DOI: 10.1038/sj.bjp.0705328] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2003] [Revised: 03/31/2003] [Accepted: 04/15/2003] [Indexed: 11/09/2022] Open
Abstract
1. Systemic administration of phenethylamine-derived, 5-hydroxytryptamine(2) (5-HT(2)) receptor agonists inhibits the firing of midbrain 5-HT neurones, but the 5-HT receptors involved are poorly defined, and the contribution of peripheral mechanisms is uncertain. This study addresses these issues using extracellular recordings of 5-HT neurones in the dorsal raphe nucleus of anaesthetised rats. 2. The 5-HT(2) receptor agonists DOI ((+/-)-2,5-dimethoxy-4-iodoamphetamine hydrochloride) and DOB ((+/-)-2,5-dimethoxy-4-bromoamphetamine hydrobromide), caused a dose-related (10-100 micro g kg(-1) i.v.) inhibition of 5-HT neuronal activity, with the highest dose reducing firing rates by >80%. 3. Pretreatment with the 5-HT(2) receptor antagonist ritanserin (1 mg kg(-1) i.v.) completely blocked the action of DOI. The 5-HT(2A) receptor antagonist MDL 100,907 (0.2 mg kg(-1) i.v.) blocked the action of both DOI and DOB. In comparison, the 5-HT(2B/C) receptor antagonist SB 206553 (0.5 mg kg(-1) i.v.) caused a small, but statistically significant, shift to the right in the dose response to DOI and DOB. 4. Pretreatment with the peripherally acting 5-HT(2) receptor antagonist BW 501C67 (0.1 mg kg(-1) i.v.) had no effect on the DOI-induced inhibition of 5-HT cell firing, but completely blocked the DOI-induced rise in mean arterial blood pressure. 5. These data indicate that the inhibition of 5-HT cell firing induced by systemic administration of DOI and DOB is mediated predominantly by the 5-HT(2A) receptor-subtype, but that 5-HT(2B/C) receptors also play a minor role. Moreover, central and not peripheral mechanisms are involved. Given evidence that 5-HT(2) receptors are not located on 5-HT neurones, postsynaptic 5-HT feedback mechanisms are implicated.
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Affiliation(s)
- L J Boothman
- University Department of Pharmacology, Mansfield Road, Oxford OX1 3QT
| | - K A Allers
- University Department of Pharmacology, Mansfield Road, Oxford OX1 3QT
| | | | - T Sharp
- University Department of Pharmacology, Mansfield Road, Oxford OX1 3QT
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18
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Koskinen T, Haapalinna A, Sirviö J. Alpha-adrenoceptor-mediated modulation of 5-HT2 receptor agonist induced impulsive responding in a 5-choice serial reaction time task. PHARMACOLOGY & TOXICOLOGY 2003; 92:214-25. [PMID: 12753409 DOI: 10.1034/j.1600-0773.2003.920504.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The activation of 5-HT2A receptors has been shown to enhance the probability of premature responding, regarded as a form of motor impulsive behaviour. At the behavioural level, the interaction of alpha-adrenoceptors and 5-HT2 receptors has been linked to head twitch behaviour, regarded as an experimental model of compulsive behaviour. The aim was to determine whether the probability of premature responding induced by an excess activation of 5-HT2A receptors can be modulated by the blockade of alpha1- or alpha2- adrenoceptors. In the experiments, the 5-choice serial reaction time task was used to measure attention and response control of the rats. The experiments assessed the effects of (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride (DOI) 0.1-0.2 mg/kg subcutaneously, a 5-HT2A/2C agonist, and prazosin, an alpha1-adrenoceptor antagonist, alone or in combination, on the performance of rats. In an additional experiment to examine the possible role of the alpha2-adrenoceptors, a potent, selective and specific alpha2-adrenoceptor antagonist, atipamezole, was given alone or in combination with DOI. Results showed that DOI increased the probability of premature responses, but it did not affect the choice accuracy. Prazosin (0.1 or 0.3 mg/kg, subcutaneously), given on its own had no effects on probability of responding prematurely, but prazosin (0.3 mg/kg.) was able to attenuate the DOI-induced responding. Atipamezole (0.1 mg/kg, s.c.) did not attenuate the effect of DOI on probability of premature responding. When given at lower doses, DOI (0.03 mg/kg) and atipamezole (0.03 mg/kg) synergistically increased the probability of premature responding, whereas a higher dose of atipamezole (0.3 mg/kg) on its own increased the probability of responding prematurely, but this effect was not additive to that of 0.1 mg/kg DOI. These data indicate that 5-HT2 receptor activation enhances impulsive responding and this effect can be diminished by the blockade of alpha1-adrenoceptors. Atipamezole, an alpha2-antagonist, enhances the probability of premature responding and shares the mechanism of action with the 5-HT2 agonist in this respect. These results provide evidence for an interaction between the serotonergic 5-HT2 receptors and alpha-adrenoceptors in the modulation of response control to the motor impulsivity type of behaviour (premature responding) in addition to that of compulsory behaviour (head shakes) found previously.
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MESH Headings
- Adrenergic alpha-Antagonists/pharmacology
- Animals
- Behavior, Animal/drug effects
- Discrimination, Psychological/drug effects
- Dose-Response Relationship, Drug
- Drug Synergism
- Imidazoles/pharmacology
- Impulsive Behavior/psychology
- Indophenol/administration & dosage
- Indophenol/analogs & derivatives
- Indophenol/pharmacology
- Male
- Prazosin/pharmacology
- Rats
- Rats, Wistar
- Receptor, Serotonin, 5-HT2A
- Receptor, Serotonin, 5-HT2C
- Receptors, Adrenergic, alpha/drug effects
- Receptors, Adrenergic, alpha/physiology
- Receptors, Serotonin/drug effects
- Receptors, Serotonin/physiology
- Serial Learning/drug effects
- Serotonin Receptor Agonists/pharmacology
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Affiliation(s)
- Tiina Koskinen
- A I Virtanen Institute, University of Kuopio, Kuopio, Finland
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19
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Acuña-Castillo C, Villalobos C, Moya PR, Sáez P, Cassels BK, Huidobro-Toro JP. Differences in potency and efficacy of a series of phenylisopropylamine/phenylethylamine pairs at 5-HT(2A) and 5-HT(2C) receptors. Br J Pharmacol 2002; 136:510-9. [PMID: 12055129 PMCID: PMC1573376 DOI: 10.1038/sj.bjp.0704747] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The pharmacological profile of a series of (+/-)-2,5-dimethoxy-4-(X)-phenylisopropylamines (X=I, Br, NO(2), CH(3), or H) and corresponding phenylethylamines, was determined in Xenopus laevis oocytes injected with cRNA coding for rat 5-HT(2A) or 5-HT(2C) receptors. The efficacy and relative potency of these drugs were determined and compared to classical 5-HT(2) receptor agonists and antagonists. The rank order of agonist potency at the 5-HT(2A) receptor was: alpha-methyl-5-HT=5-HT>m-CPP>MK-212; at the 5-HT(2C) receptor the order was: 5-HT>alpha-methyl-5-HT>MK-212>m-CPP. All these compounds were full agonists at the 5-HT(2C) receptor, but alpha-methyl-5-HT and m-CPP showed lower efficacy at the 5-HT(2A) receptor. 4-(4-Fluorobenzoyl)-1-(4-phenylbutyl)piperidine (4F 4PP) was 200 times more potent as a 5-HT(2A) antagonist than at 5-HT(2C) receptors. Conversely, RS 102221 was 100 times more potent as a 5-HT(2C) antagonist, confirming their relative receptor selectivities. The phenylisopropylamines were partial agonists at the 5-HT(2A) receptor, with I(max) relative to 5-HT in the 22+/-7 to 58+/-15% range; the corresponding phenylethylamines had lower or undetectable efficacies. All these drugs had higher efficacies at 5-HT(2C) receptors; DOI was a full 5-HT(2C) agonist. 2C-I and the other phenylethylamines examined showed relative efficacies at the 5-HT(2C) receptor ranging from 44+/-10% to 76+/-16%. 2C-N was a 5-HT(2) receptor antagonist; the mechanism was competitive at the 5-HT(2A), but non-competitive at the 5-HT(2C) receptor. The antagonism was time-dependent at the 5-HT(2C) receptor but independent of pre-incubation time at the 5-HT(2A) receptor subtype. The alpha-methyl group determines the efficacy of these phenylalkylamines at the 5-HT(2A) and 5-HT(2C) receptors.
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Affiliation(s)
- Claudio Acuña-Castillo
- Centro de Regulación Celular y Patología, MIFAB, Instituto Milenio de Biología Fundamental y Aplicada, Departamento de Fisiología, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Casilla 114-D, Santiago 1, Chile
| | - Claudio Villalobos
- Centro de Regulación Celular y Patología, MIFAB, Instituto Milenio de Biología Fundamental y Aplicada, Departamento de Fisiología, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Casilla 114-D, Santiago 1, Chile
| | - Pablo R Moya
- Centro de Regulación Celular y Patología, MIFAB, Instituto Milenio de Biología Fundamental y Aplicada, Departamento de Fisiología, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Casilla 114-D, Santiago 1, Chile
| | - Patricio Sáez
- Faculty of Medical Sciences, Universidad de Santiago, Chile
| | - Bruce K Cassels
- Millennium Institute for Advanced Studies in Cell Biology and Biotechnology and Department of Chemistry, Faculty of Sciences, Universidad de Chile, Casilla 653, Santiago, Chile
| | - J Pablo Huidobro-Toro
- Centro de Regulación Celular y Patología, MIFAB, Instituto Milenio de Biología Fundamental y Aplicada, Departamento de Fisiología, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Casilla 114-D, Santiago 1, Chile
- Author for correspondence: .
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20
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Brasil D, Temsah RM, Kumar K, Kumamoto H, Takeda N, Dhalla NS. Blockade of 5-HT(2A) receptors by sarpogrelate protects the heart against myocardial infarction in rats. J Cardiovasc Pharmacol Ther 2002; 7:53-9. [PMID: 12000979 DOI: 10.1177/107424840200700i108] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND It has been shown that serotonin (5-hydroxytryptamine, 5-HT) is involved in exacerbating vascular abnormalities; however, its role in mediating changes in cardiac function due to myocardial injury has yet to be established. This study examined the effect of sarpogrelate, a 5-HT(2A) receptor blocker, in preventing cardiac dysfunction due to myocardial infarction (MI). METHODS AND RESULTS Rats were treated 3 days before surgery with or without 5 mg x kg(-1) x day(-1) sarpogrelate, and the left coronary artery was ligated for 3 weeks to induce MI. Sarpogrelate reduced the mortality from 40% to 30%, infarct size from 35% to 25%, and left ventricular end diastolic pressure from 15 mm Hg to 10 mm Hg in MI rats. Electrocardiographic (ECG) tracings showed a marked deviation in the ST-segment and prolongation of the QTc interval in MI rats during the 3 weeks; these changes were attenuated by sarpogrelate pretreatment. In another set of experiments, MI rats were treated with 5 mg x kg(-1) x day(-1) sarpogrelate 1 hour after the surgery, and the hemodynamic and electrocardiograph changes were assessed at 3 weeks. This posttreatment was also found to reduce infarct size, improve cardiac function, and attenuate ECG changes. CONCLUSIONS Sarpogrelate attenuates cardiac dysfunction, infarct size, and changes in the ECG due to MI. These results also support the view that serotonin and 5-HT(2A) may contribute to the deleterious effects of ischemic injury in the heart.
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Affiliation(s)
- David Brasil
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre and Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada
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21
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Abstract
Evidence is provided to support the view that central 5-HT(1A) and 5-HT(2) receptors are the major receptor subtypes important in cardiovascular regulation. Data are also provided to implicate 5-HT(1B/1D/1F) receptors in central cardiovascular regulation. Activation of 5-HT(2) receptors generally causes sympathoexcitation and a rise in blood pressure and this is mainly mediated by 5-HT(2A) receptors. However, presympathetic vasomotor neurones located in the hindbrain (RVLM), controlling sympathetic outflow to the heart, are not activated in the same way as other presympathetic vasomotor neurones, although activation of 5-HT(2) receptors located in the midbrain can activate sympathetic outflow to the heart. Furthermore, at least in the rat, these midbrain 5-HT(2A) receptors are also responsible for the release of vasopressin by activation of a central angiotensinergic pathway. The ability of vasopressin directly and/or indirectly to modify renal sympathetic outflow involves the activation of central 5-HT(2B) receptors, which in turn, when activated via the i.c.v. route, can cause selective renal sympathoexcitation. Evidence is also provided which indicates that the reflex control of parasympathetic outflow to the heart and to other organs involves central 5-HT(1A) receptors located in the vicinity of these preganglionic vagal neurones. Finally, 5-HT(3) receptors are implicated in the afferent regulation of central sympathetic and parasympathetic tone.
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Affiliation(s)
- A G Ramage
- Department of Pharmacology, University College London, London, UK.
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22
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Lazartigues E, Brefel-Courbon C, Bagheri H, Costes S, Gharib C, Tran MA, Senard JM, Montastruc JL. Fluoxetine-induced pressor response in freely moving rats: a role for vasopressin and sympathetic tone. Fundam Clin Pharmacol 2000; 14:443-51. [PMID: 11129084 DOI: 10.1111/j.1472-8206.2000.tb00426.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The present study was performed in order to assess, in freely moving rats, the cardiovascular effects of central administration of fluoxetine, a serotonin reuptake inhibitor. Two kinds of experiments were performed: 1) acute central administration of fluoxetine. and 2) chronic intraperitoneal administration of fluoxetine plus selegiline, a monoamine oxidase B inhibitor. Intracerebroventricular (i.c.v.) administration of fluoxetine (5-50 microg) induced an increase in blood pressure. This fluoxetine-induced pressor response reached its maximal 1 hour after injection without any significant change in heart rate. At the dose of 10 microg i.c.v., fluoxetine significantly increased mean blood pressure by 16 +/- 4 mmHg. This pressor response was reduced by an intravenous (i.v.) pretreatment with the alpha1-adrenoceptor antagonist, prazosin (500 microg kg(-1)) (+ 7 +/- 4 mmHg, P <0.05) or with the V1A-vasopressin receptor antagonist (20 microg kg(-1)) (+5 +/- 3 mmHg, P < 0.05). The pressor response was completely abolished by a concomitant pretreatment with prazosin plus the V1A-vasopressin receptor antagonist. Pretreatment with the beta-adrenoceptor antagonist, propranolol (1 mg kg(-1) i.v.), or the 5-HT2 receptor antagonist, ketanserine (5 mg kg(-1) i.v.), did not modify the fluoxetine-induced pressor response. In freely moving rats receiving fluoxetine (10 microg i.c.v.), vasopressin plasma levels were significantly higher (39 +/- 5 pg mL(-1) than in rats receiving 10 microL i.c.v. saline (14 +/- 4 pg mL(-1)). A 30 day intraperitoneal (i.p.) administration of fluoxetine in association with selegiline induced an increase in noradrenaline plasma levels and locomotor activity without any significant change in blood pressure and heart rate. These data suggest that, the pressor response elicited by central acute administration of fluoxetine is mediated by both an increase in sympathetic tone and vasopressin release. This observation could suggest the putative interest of alpha1-adrenoceptor and or V1A-vasopressin receptor antagonists in the treatment of "Serotonin Syndrome".
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Affiliation(s)
- E Lazartigues
- Laboratoire de Pharmacologie Médicale et Clinique, Inserm U317 and Centre Midi-Pyrénées de Pharmacovigilance, de Pharmacoépidémiologie et d'Informations sur le Médicament, Faculté de Médecine, Toulouse, France
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23
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Orallo F, Rosa E, García-Ferreiro T, Campos-Toimil M, Cadavid MI, Loza MI. Cardiovascular effects of ketanserin on normotensive rats in vivo and in vitro. GENERAL PHARMACOLOGY 2000; 35:95-105. [PMID: 11707316 DOI: 10.1016/s0306-3623(01)00099-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In this work, we report for first time that: (1) low doses of ketanserin (0.2 mg/kg) produce a transient hypotensive response in anaesthetized rats, which is basically due to the blockade of 5-hydroxytryptamine (2A) (5-HT)2A receptors, whereas high doses (1 mg/kg) of ketanserin cause a sustained hypotension also mediated by the blockage of alpha1-adrenergic receptors; (2) the in vitro vasorelaxant action of high concentrations of ketanserin (>10 microM) involves Ca2+ antagonism, which may also be responsible, at least in part, for the inhibition of high-K+-induced 45Ca2+ uptake, the inhibition of Ca2+-induced contractions in initially Ca2+-free high-K+ medium, and the negative chronotropic effects on isolated atria. This Ca2+ antagonistic activity does not seem to contribute to the in vivo cardiovascular effects of ketanserin at therapeutic doses.
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Affiliation(s)
- F Orallo
- Departamento de Farmacología, Facultad de Farmacia, Universidad de Santiago de Compostela, 15782, Santiago de Compostela, Spain
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Knowles ID, Ramage AG. Evidence that activation of central 5-HT(2B) receptors causes renal sympathoexcitation in anaesthetized rats. Br J Pharmacol 2000; 129:177-83. [PMID: 10694218 PMCID: PMC1621132 DOI: 10.1038/sj.bjp.0703011] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The effects of injections i.c.v. of alpha-methyl-5-(2-thienylmethoxy)-1H-indole-3-ethanamine (BW723C86; 0.02 - 2 micromol kg(-1)), a 5-HT(2B) receptor agonist, on renal sympathetic and phrenic nerve activity, mean arterial blood pressure and heart rate were investigated in alpha-chloralose anaesthetized rats pretreated with a peripherally acting 5-HT(2) receptor antagonist. BW723C86 i.c.v. caused a dose-related increase in renal nerve activity reaching a maximum of 67+/-6%, which at the highest dose was associated with a small and maintained fall in mean arterial blood pressure of 7+/-3 mmHg. These changes were not associated with any significant changes in heart rate or phrenic nerve activity. BW723C86-evoked increases in renal nerve activity and hypotension were attenuated by pretreatment (i.c.v.) with SB204741 (300 nmol kg(-1); a 5-HT(2B) receptor antagonist) but not by the same dose (i.c.v.) of ketanserin (a 5-HT(2A) receptor antagonist) or RS102221 (a 5-HT(2C) receptor antagonist). None of these antagonists alone had any effect on the variables being measured. It is concluded that central 5-HT(2B) receptors may play a selective role in the control of sympathetic supply to the kidney, which could be important in the central mechanisms involved in blood volume regulation. British Journal of Pharmacology (2000) 129, 177 - 183
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Affiliation(s)
- I D Knowles
- Department of Pharmacology, University College London, Royal Free Campus, Rowland Hill Street, Hampstead, London, UK
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