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Souders CL, Zubcevic J, Martyniuk CJ. Tumor Necrosis Factor Alpha and the Gastrointestinal Epithelium: Implications for the Gut-Brain Axis and Hypertension. Cell Mol Neurobiol 2022; 42:419-437. [PMID: 33594519 PMCID: PMC8364923 DOI: 10.1007/s10571-021-01044-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 01/11/2021] [Indexed: 12/17/2022]
Abstract
The colonic epithelium is the site of production and transport of many vasoactive metabolites and neurotransmitters that can modulate the immune system, affect cellular metabolism, and subsequently regulate blood pressure. As an important interface between the microbiome and its host, the colon can contribute to the development of hypertension. In this critical review, we highlight the role of colonic inflammation and microbial metabolites on the gut brain axis in the pathology of hypertension, with special emphasis on the interaction between tumor necrosis factor α (TNFα) and short chain fatty acid (SCFA) metabolites. Here, we review the current literature and identify novel pathways in the colonic epithelium related to hypertension. A network analysis on transcriptome data previously generated in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats reveals differences in several pathways associated with inflammation involving TNFα (NF-κB and STAT Expression Targets) as well as oxidative stress. We also identify down-regulation of networks associated with gastrointestinal function, cardiovascular function, enteric nervous system function, and cholinergic and adrenergic transmission. The analysis also uncovered transcriptome responses related to glycolysis, butyrate oxidation, and mitochondrial function, in addition to gut neuropeptides that serve as modulators of blood pressure and metabolic function. We present a model for the role of TNFα in regulating bacterial metabolite transport and neuropeptide signaling in the gastrointestinal system, highlighting the complexity of host-microbiota interactions in hypertension.
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Affiliation(s)
- Christopher L. Souders
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida Genetics Institute, Interdisciplinary Program in Biomedical Sciences Neuroscience, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32611 USA
| | - Jasenka Zubcevic
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida Genetics Institute, Interdisciplinary Program in Biomedical Sciences Neuroscience, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32611, USA. .,Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, PO BOX 100274, Gainesville, FL, 32611, USA.
| | - Christopher J. Martyniuk
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida Genetics Institute, Interdisciplinary Program in Biomedical Sciences Neuroscience, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32611 USA,Corresponding authors contact information: Department of Physiological Sciences, College of Veterinary Medicine, University of Florida PO BOX 100274 GAINESVILLE FL 326100274 United States; and
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Lopes LT, Canto-de-Souza L, Baptista-de-Souza D, de Souza RR, Nunes-de-Souza RL, Canto-de-Souza A. The interplay between 5-HT 2C and 5-HT 3A receptors in the dorsal periaqueductal gray mediates anxiety-like behavior in mice. Behav Brain Res 2022; 417:113588. [PMID: 34547341 DOI: 10.1016/j.bbr.2021.113588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 08/17/2021] [Accepted: 09/15/2021] [Indexed: 11/17/2022]
Abstract
The monoamine neurotransmitter serotonin (5-HT) modulates anxiety by its activity on 5-HT2C receptors (5-HT2CR) expressed in the dorsal periaqueductal gray (dPAG). Here, we investigated the presence of 5-HT3A receptors (5-HT3AR) in the dPAG, and the interplay between 5-HT2CR and 5-HT3AR in the dPAG in mediating anxiety-like behavior in mice. We found that 5-HT3AR is expressed in the dPAG and the blockade of these receptors using intra-dPAG infusion of ondansetron (5-HT3AR antagonist; 3.0 nmol) induced an anxiogenic-like effect. The activation of 5-HT3ABR by the infusion of mCPBG [1-(m-Chlorophenyl)-biguanide; 5-HT3R agonist] did not alter anxiety-like behaviors. In addition, blockade of 5-HT3AR (1.0 nmol) prevented the anxiolytic-like effect induced by the infusion of the 5-HT2CR agonist mCPP (1-(3-chlorophenyl) piperazine; 0.03 nmol). None of the treatment effects on anxiety-like behaviors altered the locomotor activity levels. The present results suggest that the anxiolytic-like effect exerted by serotonin activity on 5-HT2CR in the dPAG is modulated by 5-HT3AR expressed in same region.
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Affiliation(s)
- Luana Tenorio Lopes
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, Calgary, Alberta, Canada.
| | - Lucas Canto-de-Souza
- Laboratory of Pharmacology, School of Pharmaceutical Sciences, Univ. Estadual Paulista, UNESP, Araraquara, SP 14801-902, Brazil; Neuroscience and Behavioral Institute, Av. do Café, 2.450, 14050-220 Ribeirão Preto, SP, Brazil.
| | - Daniela Baptista-de-Souza
- Psychobiology Group/Department of Psychology/CECH-UFSCar, São Carlos, SP 13565-905, Brazil; Laboratory of Pharmacology, School of Pharmaceutical Sciences, Univ. Estadual Paulista, UNESP, Araraquara, SP 14801-902, Brazil; Neuroscience and Behavioral Institute, Av. do Café, 2.450, 14050-220 Ribeirão Preto, SP, Brazil.
| | - Rimenez Rodrigues de Souza
- The University of Texas at Dallas, School of Behavior and Brain Sciences, 800 West Campbell Road, Richardson, TX 75080-3021, United States; The University of Texas at Dallas, Texas Biomedical Device Center, 800 West Campbell Road, Richardson, TX 75080-3021, United States.
| | - Ricardo L Nunes-de-Souza
- Psychobiology Group/Department of Psychology/CECH-UFSCar, São Carlos, SP 13565-905, Brazil; Joint Graduate Program in Physiological Sciences UFSCar/UNESP, Rod. Washington Luís, Km 235, São Carlos, SP 13565-905, Brazil; Laboratory of Pharmacology, School of Pharmaceutical Sciences, Univ. Estadual Paulista, UNESP, Araraquara, SP 14801-902, Brazil; Neuroscience and Behavioral Institute, Av. do Café, 2.450, 14050-220 Ribeirão Preto, SP, Brazil.
| | - Azair Canto-de-Souza
- Psychobiology Group/Department of Psychology/CECH-UFSCar, São Carlos, SP 13565-905, Brazil; Joint Graduate Program in Physiological Sciences UFSCar/UNESP, Rod. Washington Luís, Km 235, São Carlos, SP 13565-905, Brazil; Graduate Program in Psychology UFSCar, Rod. Washington Luís, Km 235, São Carlos, SP 13565-905, Brazil; Neuroscience and Behavioral Institute, Av. do Café, 2.450, 14050-220 Ribeirão Preto, SP, Brazil.
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3
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Indole and indoxyl sulfate, gut bacteria metabolites of tryptophan, change arterial blood pressure via peripheral and central mechanisms in rats. Pharmacol Res 2018; 130:172-179. [DOI: 10.1016/j.phrs.2017.12.025] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 12/21/2017] [Accepted: 12/22/2017] [Indexed: 12/21/2022]
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Abstract
The World Health Organization suggests that the cardiovascular diseases (CVDs) are the major cause of mortality and account for two-thirds of the deaths all over the world. These diseases kill about 17 million people every year and 3 in every 10 deaths are due to these diseases. The past decade has seen considerable improvements in diagnosis as well as treatment of various heart diseases. Various new therapeutic targets are being identified through in-depth knowledge of the disease mechanisms which has favored the testing of new strategies leading to newer treatment options. Opioid peptides and G-protein-coupled opioid receptors (ORs) have been previously studied widely in terms of central nervous system actions in mitigating the pain and drug abuse. The OR agonism or antagonism induces cytoprotective states in the myocardium, rendering these receptors as an attractive target for protection of heart from the fatal heart diseases. The opioids can provide an extended window of protection of the heart from various diseases. Although the mechanisms may not be fully understood, they seem to play a crucial role in various CVDs such as hypertension, hyperlipidemia, ischemic heart disease myocardial ischemia, and congestive heart failure. Since these compounds are already being used in acute and chronic pain, soon these compounds might be approved for use as cardioprotective agents. The following review focuses on the new information acquired on the role of the ORs in various CVDs.
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Affiliation(s)
- Hemangi Rawal
- Institute of Pharmacy, Nirma University, Ahmedabad, Gujarat, India
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de Almeida DO, Ferreira HS, Pereira LB, Fregoneze JB. Hypertensive response to stress: the role of histaminergic H1 and H2 receptors in the medial amygdala. Physiol Behav 2015; 144:95-102. [PMID: 25748254 DOI: 10.1016/j.physbeh.2015.03.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Revised: 03/03/2015] [Accepted: 03/04/2015] [Indexed: 01/31/2023]
Abstract
Different brain areas seem to be involved in the cardiovascular responses to stress. The medial amygdala (MeA) has been shown to participate in cardiovascular control, and acute stress activates the MeA to a greater extent than any of the other amygdaloid structures. It has been demonstrated that the brain histaminergic system may be involved in behavioral, autonomic and neuroendocrine responses to stressful situations. The aim of the present study was to investigate the role of the histaminergic receptors H1 and H2 in cardiovascular responses to acute restraint stress. Wistar rats (280-320g) received bilateral injections of cimetidine, mepyramine or saline into the MeA and were submitted to 45min of restraint stress. Mepyramine microinjections at doses of 200, 100 and 50nmol promoted a dose-dependent blockade of the hypertensive response induced by the restraint stress. Cimetidine (200 and 100nmol) promoted a partial blockade of the hypertensive response to stress only at the highest dose administered. Neither drugs altered the typical stress-evoked tachycardiac responses. Furthermore, mepyramine and cimetidine were unable to modify the mean arterial pressure or heart rate of freely moving rats under basal conditions (non-stressed rats). The data suggest that in the MeA the histaminergic H1 receptors appear to be more important than H2 receptors in the hypertensive response to stress. Furthermore, there appears to be no histaminergic tonus in the MeA controlling blood pressure during non-stress conditions.
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Affiliation(s)
| | - Hilda Silva Ferreira
- Life Sciences Department, Bahia State University, 41195-001 Salvador, Bahia, Brazil
| | - Luana Bomfim Pereira
- Department of Physiology, Health Sciences Institute, Federal University of Bahia, 40110-100 Salvador, Bahia, Brazil
| | - Josmara Bartolomei Fregoneze
- Department of Physiology, Health Sciences Institute, Federal University of Bahia, 40110-100 Salvador, Bahia, Brazil.
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Urzedo-Rodrigues LS, Ferreira HS, Santana RC, Luz CP, Perrone CF, Fregoneze JB. Blockade of 5-Ht3 receptors in the septal area increases Fos expression in selected brain areas. Auton Neurosci 2014; 181:55-68. [DOI: 10.1016/j.autneu.2014.01.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 12/02/2013] [Accepted: 01/08/2014] [Indexed: 02/07/2023]
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7
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Pahikkala T, Okser S, Airola A, Salakoski T, Aittokallio T. Wrapper-based selection of genetic features in genome-wide association studies through fast matrix operations. Algorithms Mol Biol 2012; 7:11. [PMID: 22551170 PMCID: PMC3606421 DOI: 10.1186/1748-7188-7-11] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 04/23/2012] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Through the wealth of information contained within them, genome-wide association studies (GWAS) have the potential to provide researchers with a systematic means of associating genetic variants with a wide variety of disease phenotypes. Due to the limitations of approaches that have analyzed single variants one at a time, it has been proposed that the genetic basis of these disorders could be determined through detailed analysis of the genetic variants themselves and in conjunction with one another. The construction of models that account for these subsets of variants requires methodologies that generate predictions based on the total risk of a particular group of polymorphisms. However, due to the excessive number of variants, constructing these types of models has so far been computationally infeasible. RESULTS We have implemented an algorithm, known as greedy RLS, that we use to perform the first known wrapper-based feature selection on the genome-wide level. The running time of greedy RLS grows linearly in the number of training examples, the number of features in the original data set, and the number of selected features. This speed is achieved through computational short-cuts based on matrix calculus. Since the memory consumption in present-day computers can form an even tighter bottleneck than running time, we also developed a space efficient variation of greedy RLS which trades running time for memory. These approaches are then compared to traditional wrapper-based feature selection implementations based on support vector machines (SVM) to reveal the relative speed-up and to assess the feasibility of the new algorithm. As a proof of concept, we apply greedy RLS to the Hypertension - UK National Blood Service WTCCC dataset and select the most predictive variants using 3-fold external cross-validation in less than 26 minutes on a high-end desktop. On this dataset, we also show that greedy RLS has a better classification performance on independent test data than a classifier trained using features selected by a statistical p-value-based filter, which is currently the most popular approach for constructing predictive models in GWAS. CONCLUSIONS Greedy RLS is the first known implementation of a machine learning based method with the capability to conduct a wrapper-based feature selection on an entire GWAS containing several thousand examples and over 400,000 variants. In our experiments, greedy RLS selected a highly predictive subset of genetic variants in a fraction of the time spent by wrapper-based selection methods used together with SVM classifiers. The proposed algorithms are freely available as part of the RLScore software library at http://users.utu.fi/aatapa/RLScore/.
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Affiliation(s)
- Tapio Pahikkala
- Department of Information Technology, University of Turku, Turku, Finland
- Turku Centre for Computer Science, Turku, Finland
| | - Sebastian Okser
- Department of Information Technology, University of Turku, Turku, Finland
- Turku Centre for Computer Science, Turku, Finland
| | - Antti Airola
- Department of Information Technology, University of Turku, Turku, Finland
- Turku Centre for Computer Science, Turku, Finland
| | - Tapio Salakoski
- Department of Information Technology, University of Turku, Turku, Finland
- Turku Centre for Computer Science, Turku, Finland
| | - Tero Aittokallio
- Turku Centre for Computer Science, Turku, Finland
- Department of Mathematics, University of Turku, Turku, Finland
- Data Mining and Modeling group, Turku Centre for Biotechnology, Turku, Finland
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
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8
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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: 255] [Impact Index Per Article: 21.3] [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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Fregoneze JB, Oliveira EF, Ribeiro VF, Ferreira HS, De Castro E Silva E. Multiple opioid receptors mediate the hypotensive response induced by central 5-HT(3) receptor stimulation. Neuropeptides 2011; 45:219-27. [PMID: 21514668 DOI: 10.1016/j.npep.2011.03.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2010] [Revised: 03/14/2011] [Accepted: 03/29/2011] [Indexed: 02/06/2023]
Abstract
The aim of the present work was to investigate the role of brain μ, κ and δ opioid receptors in the central serotonergic mechanisms regulating blood pressure in rats. The data obtained show that: (1) pharmacological activation of central 5-HT(3) receptors yields a significant decrease in blood pressure; (2) the blockade of those receptors by a selective antagonist induces an acute hypertensive response; (3) the pharmacological blockade of central opioid receptors by three different opioid antagonists exhibiting variable degrees of selectivity to μ, κ and δ opioid receptors always suppressed the hypotensive response induced by central 5-HT(3) receptor stimulation; (4) the blockade of opioid receptors by the same opioid antagonists that impaired the hypotensive effect of central 5-HT(3) receptor stimulation failed to modify blood pressure in animals not submitted to pharmacological manipulations of central 5-HT(3) receptor function. It is shown that a 5-HT(3) receptor-dependent mechanism seems to be part of the brain serotonergic system that contributes to cardiovascular regulation since the hypertensive response observed after ondansetron administration indicates that central 5-HT(3) receptors exert a tonic inhibitory drive on blood pressure. Furthermore, the data obtained here clearly indicate that the hypotensive response observed after pharmacological stimulation of central 5-HT(3) receptors depends on the functional integrity of brain μ, κ and δ opioid receptors, suggesting that a functional interaction between serotonergic and opiatergic pathways in the brain is part of the complex, multifactorial system that regulates blood pressure in the central nervous system.
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Affiliation(s)
- J B Fregoneze
- Department of Physiology, Health Sciences Institute, Federal University of Bahia, Salvador, Brazil.
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10
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Blockade of 5-HT3 receptors at septal area increase blood pressure in unanaesthetized rats. Auton Neurosci 2011; 159:51-61. [DOI: 10.1016/j.autneu.2010.07.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Revised: 07/10/2010] [Accepted: 07/30/2010] [Indexed: 11/20/2022]
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11
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Central 5-HT receptors in cardiovascular control during stress. Neurosci Biobehav Rev 2008; 33:95-106. [PMID: 18573276 DOI: 10.1016/j.neubiorev.2008.05.026] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Revised: 05/03/2008] [Accepted: 05/28/2008] [Indexed: 11/22/2022]
Abstract
Our aim is to consolidate recent data on relationship between central serotonergic neurotransmission and stress-elicited cardiovascular changes. Activation of central of 5-HT1A receptors attenuates tachycardic and pressor changes elicited by a wide range of stressors (airjet, restraint, open field, fear conditioning, social defeat), supporting the previous view of these receptors as "sympathoinhibitory". Their likely location is the medullary raphe. It is still unknown whether 5-TH1A receptors are sympathoinhibitory in physiological condition, as 5-HT1A antagonists do not affect basal or stress-altered cardiovascular parameters. In contrast to the established view that central 5-HT2A receptors are "sympathoexcitatory", experiments with new selective antagonists indicate that these receptors do not mediate stress-induced pressor and tachycardic responses, and are not involved in cardiovascular control at rest. The exception is control of cutaneous vascular bed, both at rest and during stress, likely at the spinal level. 5-HT3 receptors located in the nucleus tractus silitarius (NTS) contribute to stress-induced suppression of the baroreflex. 5-HT3 receptors located in sympathetic ganglia possibly contribute to the development of sustained hypertension in chronically stressed rats.
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Drisdel RC, Sharp D, Henderson T, Hales TG, Green WN. High affinity binding of epibatidine to serotonin type 3 receptors. J Biol Chem 2008; 283:9659-65. [PMID: 17702741 PMCID: PMC2442297 DOI: 10.1074/jbc.m703672200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2007] [Revised: 08/15/2007] [Indexed: 01/22/2023] Open
Abstract
Epibatidine and mecamylamine are ligands used widely in the study of nicotinic acetylcholine receptors (nAChRs) in the central and peripheral nervous systems. In the present study, we find that nicotine blocks only 75% of (125)I-epibatidine binding to rat brain membranes, whereas ligands specific for serotonin type 3 receptors (5-HT(3)Rs) block the remaining 25%. (125)I-Epibatidine binds with a high affinity to native 5-HT(3)Rs of N1E-115 cells and to receptors composed of only 5-HT(3A) subunits expressed in HEK cells. In these cells, serotonin, the 5-HT(3)R-specific antagonist MDL72222, and the 5-HT(3)R agonist chlorophenylbiguanide readily competed with (125)I-epibatidine binding to 5-HT(3)Rs. Nicotine was a poor competitor for (125)I-epibatidine binding to 5-HT(3)Rs. However, the noncompetitive nAChR antagonist mecamylamine acted as a potent competitive inhibitor of (125)I-epibatidine binding to 5-HT(3)Rs. Epibatidine inhibited serotonin-induced currents mediated by endogenous 5-HT(3)Rs in neuroblastoma cell lines and 5-HT(3A)Rs expressed in HEK cells in a competitive manner. Our results demonstrate that 5-HT(3)Rs are previously uncharacterized high affinity epibatidine binding sites in the brain and indicate that epibatidine and mecamylamine act as 5-HT(3)R antagonists. Previous studies that depended on epibatidine and mecamylamine as nAChR-specific ligands, in particular studies of analgesic properties of epibatidine, may need to be reinterpreted with respect to the potential role of 5-HT(3)Rs.
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Affiliation(s)
- Renaldo C Drisdel
- Department of Neurobiology, University of Chicago, Chicago, IL 60637, USA
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Magrani J, de Castro E Silva E, Athanazio R, Improta L, Fregoneze JB. Involvement of central H1 and H2 receptors in water intake induced by hyperosmolarity, hypovolemia and central cholinergic stimulation. Physiol Behav 2006; 89:241-9. [PMID: 16844153 DOI: 10.1016/j.physbeh.2006.06.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2005] [Revised: 02/20/2006] [Accepted: 06/08/2006] [Indexed: 11/24/2022]
Abstract
In the present study we investigated the participation of central H1 and H2 histaminergic receptors in water intake induced by hyperosmolarity (evoked by intragastric salt load), by hypovolemia (promoted by the subcutaneous administration of polyethyleneglycol) and by the pharmacological stimulation of central cholinergic pathways by the muscarinic agonist carbachol in male Wistar rats. The data presented here show that the pharmacological blockade of central H1 histaminergic receptors by third ventricle injections of mepyramine significantly decreased water intake induced by hyperosmolarity, hypovolemia and by the intracerebroventricular injections of carbachol. On the other hand, the pharmacological blockade of central H2 histaminergic receptors by third ventricle injections of cimetidine significantly reduced water intake in hypovolemic and hyperosmotic animals, but failed to alter water intake induced by central cholinergic stimulation by carbachol. We conclude that H1 and H2 brain histaminergic receptors are involved in inducing thirst during hyperosmolarity and hypovolemia and that H1 histaminergic receptors located post-synaptically in relation to cholinergic pathways seem to be important in triggering drinking following central pharmacological cholinergic stimulation.
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Affiliation(s)
- Janeide Magrani
- Department of Physiology, Health Sciences Institute, Federal University of Bahia, 40110-100 Salvador-Bahia, Brazil
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Ferreira HS, Oliveira E, Faustino TN, Silva EDCE, Fregoneze JB. Effect of the activation of central 5-HT2C receptors by the 5-HT2C agonist mCPP on blood pressure and heart rate in rats. Brain Res 2005; 1040:64-72. [PMID: 15804427 DOI: 10.1016/j.brainres.2005.01.054] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2004] [Revised: 01/18/2005] [Accepted: 01/19/2005] [Indexed: 10/25/2022]
Abstract
In the present study we investigated the role of central 5-HT2C receptors in the control of blood pressure and heart rate in non-stressed and stressed, adult, male, Wistar rats. Third ventricle injections of the 5-HT2C agonist mCPP elicited a significant increase in blood pressure in non-stressed animals. The initial period of this hypertensive response (10-30 min after mCPP administration) was accompanied by baroreflex-mediated bradycardia, while after this period the coexistence of hypertension and tachycardia was observed. These cardiovascular effects promoted by the central administration of mCPP were blocked by pretreatment with the 5-HT2C antagonist, SDZ SER 082. The administration of SDZ SER 082 alone induced no significant changes in blood pressure or heart rate. The pharmacological stimulation of central 5-HT2C receptors by mCPP did not change the hypertensive or tachycardic responses induced by restraint stress. Conversely, the blockade of central 5-HT2C receptors by SDZ SER 082 blunted stress-induced hypertension without modifying stress-induced tachycardia. It is concluded that the activation of central 5-HT2C receptors induces hypertension in non-stressed rats and that the normal function of these receptors is essential for the rise in blood pressure that occurs in the course of restraint stress.
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Affiliation(s)
- Hilda Silva Ferreira
- Life Sciences Department, Bahia State University, 41195-001 Salvador, Bahia, Brazil
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