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Singh N, Wanjari A, Sinha AH. Effects of Nicotine on the Central Nervous System and Sleep Quality in Relation to Other Stimulants: A Narrative Review. Cureus 2023; 15:e49162. [PMID: 38130519 PMCID: PMC10733894 DOI: 10.7759/cureus.49162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 11/20/2023] [Indexed: 12/23/2023] Open
Abstract
Nicotine is used extensively across the globe despite the common awareness of the fact that it might stimulate the neurological system in those who indulge in its consumption. Nicotine can be consumed in a wide number of various forms and can also be delivered in a wide variety of different ways. After it has been heated, it can be smoked, consumed sublingually, or brought into touch with mucosal surfaces, with the buccal mucosa being the most popular one. These three methods of consumption account for the vast majority of its use. It has been demonstrated without a reasonable doubt that people who partake in nicotine do, in fact, experience an increase in their levels of alertness, wakefulness, attention, and focus. The half-life of the substance, in addition to its effects, is highly variable depending on the forms in which it is consumed, viz. cigarettes, tobacco, gums, lozenges, and the manner in which it is administered. This is the case regardless of whether the chemical is administered orally or intravenously. It is common for a person to require multiple "hits" of the chemical throughout the course of the day, though the frequency of these needs and the intervals between them can vary greatly. The time interval between each of these "hits" can range anywhere from a few hours to a few minutes. The user has the potential to develop a tolerance to the neurostimulatory and systemic effects of nicotine, as well as a heightened sensitivity to those effects, and even hereditary predispositions to specific adverse consequences. There is also a possibility that the user will develop an addiction to nicotine. This literature review aims to explore the relationship between nicotine consumption and its effects on the central nervous system, especially on sleep.
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Affiliation(s)
- Nihaal Singh
- Medicine, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Anil Wanjari
- Medicine, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Arya Harshyt Sinha
- Medicine, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
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2
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Alhowail A. Molecular insights into the benefits of nicotine on memory and cognition (Review). Mol Med Rep 2021; 23:398. [PMID: 33786606 PMCID: PMC8025477 DOI: 10.3892/mmr.2021.12037] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 10/13/2020] [Indexed: 01/19/2023] Open
Abstract
The health risks of nicotine are well known, but there is some evidence of its beneficial effects on cognitive function. The present review focused on the reported benefits of nicotine in the brain and summarizes the associated underlying mechanisms. Nicotine administration can improve cognitive impairment in Alzheimer's disease (AD), and dyskinesia and memory impairment in Parkinson's disease (PD). In terms of its mechanism of action, nicotine slows the progression of PD by inhibiting Sirtuin 6, a stress‑responsive protein deacetylase, thereby decreasing neuronal apoptosis and improving neuronal survival. In AD, nicotine improves cognitive impairment by enhancing protein kinase B (also referred to as Akt) activity and stimulating phosphoinositide 3‑kinase/Akt signaling, which regulates learning and memory processes. Nicotine may also activate thyroid receptor signaling pathways to improve memory impairment caused by hypothyroidism. In healthy individuals, nicotine improves memory impairment caused by sleep deprivation by enhancing the phosphorylation of calmodulin‑dependent protein kinase II, an essential regulator of cell proliferation and synaptic plasticity. Furthermore, nicotine may improve memory function through its effect on chromatin modification via the inhibition of histone deacetylases, which causes transcriptional changes in memory‑related genes. Finally, nicotine administration has been demonstrated to rescue long‑term potentiation in individuals with sleep deprivation, AD, chronic stress and hypothyroidism, primarily by desensitizing α7 nicotinic acetylcholine receptors. To conclude, nicotine has several cognitive benefits in healthy individuals, as well as in those with cognitive dysfunction associated with various diseases. However, further research is required to shed light on the effect of acute and chronic nicotine treatment on memory function.
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Affiliation(s)
- Ahmad Alhowail
- Department of Pharmacology and Toxicology, College of Pharmacy, Qassim University, Buraydah 52571, Qassim, Kingdom of Saudi Arabia
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3
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Lin SX, Curtis MA, Sperry J. Pyridine alkaloids with activity in the central nervous system. Bioorg Med Chem 2020; 28:115820. [PMID: 33120080 PMCID: PMC7561606 DOI: 10.1016/j.bmc.2020.115820] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/27/2020] [Accepted: 10/05/2020] [Indexed: 12/29/2022]
Abstract
This review discusses all pyridine alkaloids with CNS activity, their therapeutic potential, and the interesting array of sources whence they originate.
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Affiliation(s)
- Simon X Lin
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand
| | - Maurice A Curtis
- Centre for Brain Research, University of Auckland, Auckland, New Zealand; Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Jonathan Sperry
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand.
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Gilyarevskiy SR. Pharmacological Basis of the Clinical Efficacy of Varenicline Used to Facilitate Smoking Cessation. RATIONAL PHARMACOTHERAPY IN CARDIOLOGY 2019. [DOI: 10.20996/1819-6446-2019-15-1-95-104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Modern problems caused by the high prevalence of smoking, as well as pharmacological approaches that facilitate quitting smoking are discussed in the review. Data on the mechanisms of formation of nicotine addiction, which determine the choice of drug interventions aimed at increasing the probability of quitting smoking are presented. The pharmacological characteristics of the most commonly used drugs used to facilitate smoking cessation are given. Special attention is paid to data on the mechanisms of action of varenicline and evidence of its clinical efficacy and safety, including in patients with concomitant cardiovascular diseases, as well as in patients with a history of acute coronary syndrome. Evidence on the effectiveness of the combined use of varenicline and nicotine replacement therapy are presented.
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5
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Toxins as tools: Fingerprinting neuronal pharmacology. Neurosci Lett 2018; 679:4-14. [DOI: 10.1016/j.neulet.2018.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 01/09/2018] [Accepted: 02/02/2018] [Indexed: 12/30/2022]
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Chehab OM, Dakik HA. Interventions for smoking cessation in patients admitted with Acute Coronary Syndrome: a review. Postgrad Med J 2017; 94:116-120. [PMID: 28942430 DOI: 10.1136/postgradmedj-2017-135040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 08/20/2017] [Accepted: 09/09/2017] [Indexed: 11/03/2022]
Abstract
Tobacco smoking contributes to about six million deaths per year and is predicted to increase in the future. Several pharmacological interventions are used for smoking cessation. Trials using nicotine replacement therapy (NRT) in acute coronary syndrome (ACS) showed inconclusive results. Furthermore, three trials using bupropion in patients admitted with ACS failed to show improvement in smoking cessation compared with placebo. Interestingly, only one trial using varenicline was successful in achieving smoking abstinence in the acute setting. With regard to behavioural interventions, a meta-analysis found that telephone counselling was successful in both the acute and stable settings, with greater effect in the acute setting. The best results for smoking cessation were found in trials that used a combination of pharmacological and behavioural interventions. The objective of this report is to review the results of studies on interventions used for smoking cessation after an ACS.
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Affiliation(s)
- Omar M Chehab
- Division of Cardiology, Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon.,National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, UK
| | - Habib A Dakik
- Division of Cardiology, Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon
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Microinjection of acetylcholine into cerebellar fastigial nucleus induces blood depressor response in anesthetized rats. Neurosci Lett 2016; 629:79-84. [PMID: 27373533 DOI: 10.1016/j.neulet.2016.06.063] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 05/25/2016] [Accepted: 06/28/2016] [Indexed: 11/21/2022]
Abstract
It is well known that the cerebellar fastigial nucleus (FN) is involved in cardiovascular modulation, and has direct evidence of cholinergic activity; however, whether and how acetylcholine (ACh) in the FN modulates blood pressure has not been investigated. In this study, we analyzed mean arterial pressure, maximal change in mean arterial pressure, and the reaction time of blood pressure changes after microinjection of cholinergic reagents into the FN in anesthetized rats. The results showed that ACh evoked a concentration-dependent (10, 30 and 100mM) effect on blood pressure down-regulation. The muscarinic ACh (mACh) receptor antagonist atropine, but not the nicotinic ACh (nACh) receptor antagonist mecamylamine, blocked the ACh-mediated depressor response. The mACh receptor agonist oxotremorine M, rather than nACh receptor agonist nicotine, mimicked the ACh-mediated blood pressure decrease in a dose-dependent manner (10, 30 and 100mM). These results indicate that cholinergic input in the cerebellar FN exerts a depressor effect on systemic blood pressure regulation, and such effects are substantially contributed by mACh rather than nACh receptors, although the precise mechanism concerning the role of mACh receptor in FN-mediated blood pressure modulation remains to be elucidated.
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Takemoto Y. Central cardiovascular actions of l-homocysteine microinjected into ventrolateral medullary autonomic areas of the rat. Amino Acids 2016; 48:2215-25. [DOI: 10.1007/s00726-016-2259-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 05/07/2016] [Indexed: 02/07/2023]
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Zhang C, Sun T, Zhou P, Zhu Q, Zhang L. Role of Muscarinic Acetylcholine Receptor-2 in the Cerebellar Cortex in Cardiovascular Modulation in Anaesthetized Rats. Neurochem Res 2015; 41:804-12. [PMID: 26526144 DOI: 10.1007/s11064-015-1755-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 10/28/2015] [Accepted: 10/29/2015] [Indexed: 02/05/2023]
Abstract
Our previous investigations have demonstrated that microinjection of acetylcholine (ACh) or muscarinic ACh receptor activation in the cerebellar cortex induces a systemic blood pressure depressor response. This study aimed to determine the role of muscarinic ACh receptor-2 (M2 receptor) in the cerebellar cortex in cardiovascular function regulation in rats. A nonselective muscarinic receptor agonist (oxotremorine M, OXO; 30 mM), a selective M2 receptor agonist (arecaidine but-2-ynyl ester tosylate, ABET; 3, 10, and 30 mM), 30 mM OXO mixed with a selective M2 receptor antagonist (methoctramine hydrate, MCT; 0.3, 1, and 3 mM), and normal saline (0.9 % NaCl) were separately microinjected (0.5 µl/5 s) into the cerebellar cortex (lobule VI) of anaesthetized rats. We measured the mean arterial pressure (MAP), maximum change in MAP, and reactive time (RT; the duration required for the blood pressure to return to basal levels), heart rate (HR) and the maximum change in HR during the RT in response to drug activation. The results demonstrated that ABET dose-dependently decreased MAP and HR, increased the maximum change in MAP and the maximum change in HR, and prolonged the RT. Furthermore, MCT dose-dependently blocked the OXO-mediated cardiovascular depressor response. This study provides the first evidence that M2 receptors in the cerebellar cortex are involved in cardiovascular regulation, the activation of which evokes significant depressor and bradycardic responses.
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Affiliation(s)
- Changzheng Zhang
- School of Life Sciences, Anqing Normal University, 128 South Linghu Road, Anqing, 246011, Anhui, People's Republic of China.
| | - Tingzhe Sun
- School of Life Sciences, Anqing Normal University, 128 South Linghu Road, Anqing, 246011, Anhui, People's Republic of China
| | - Peiling Zhou
- School of Life Sciences, Anhui Normal University, 1 East Beijing Road, Wuhu, 241000, Anhui, People's Republic of China
| | - Qingfeng Zhu
- School of Life Sciences, Anqing Normal University, 128 South Linghu Road, Anqing, 246011, Anhui, People's Republic of China
| | - Liefeng Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210046, Jiangsu, People's Republic of China.
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Rosenthal DG, Weitzman M, Benowitz NL. Nicotine Addiction: Mechanisms and Consequences. INTERNATIONAL JOURNAL OF MENTAL HEALTH 2014. [DOI: 10.2753/imh0020-7411400102] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
| | | | - Neal L. Benowitz
- b Departments of Medicine, Bioengineering, and Therapeutic Sciences, University of California San Francisco
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Poliacek I, Rose MJ, Pitts TE, Mortensen A, Corrie LW, Davenport PW, Bolser DC. Central administration of nicotine suppresses tracheobronchial cough in anesthetized cats. J Appl Physiol (1985) 2014; 118:265-72. [PMID: 25477349 DOI: 10.1152/japplphysiol.00075.2014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
We tested the hypothesis that nicotine, which acts peripherally to promote coughing, might inhibit reflex cough at a central site. Nicotine was administered via the vertebral artery [intra-arterial (ia)] to the brain stem circulation and by microinjections into a restricted area of the caudal ventral respiratory column in 33 pentobarbital anesthetized, spontaneously breathing cats. The number of coughs induced by mechanical stimulation of the tracheobronchial airways; amplitudes of the diaphragm, abdominal muscle, and laryngeal muscles EMGs; and several temporal characteristics of cough were analyzed after administration of nicotine and compared with those during control and recovery period. (-)Nicotine (ia) reduced cough number, cough expiratory efforts, blood pressure, and heart rate in a dose-dependent manner. (-)Nicotine did not alter temporal characteristics of the cough motor pattern. Pretreatment with mecamylamine prevented the effect of (-)nicotine on blood pressure and heart rate, but did not block the antitussive action of this drug. (+)Nicotine was less potent than (-)nicotine for inhibition of cough. Microinjections of (-)nicotine into the caudal ventral respiratory column produced similar inhibitory effects on cough as administration of this isomer by the ia route. Mecamylamine microinjected in the region just before nicotine did not significantly reduce the cough suppressant effect of nicotine. Nicotinic acetylcholine receptors significantly modulate functions of brain stem and in particular caudal ventral respiratory column neurons involved in expression of the tracheobronchial cough reflex by a mecamylamine-insensitive mechanism.
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Affiliation(s)
- I Poliacek
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida; and Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Martin, Slovak Republic
| | - M J Rose
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida; and
| | - T E Pitts
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida; and
| | - A Mortensen
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida; and
| | - L W Corrie
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida; and
| | - P W Davenport
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida; and
| | - D C Bolser
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida; and
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Takemoto Y. l-Cysteine and l-AP4 microinjections in the rat caudal ventrolateral medulla decrease arterial blood pressure. Auton Neurosci 2014; 186:45-53. [DOI: 10.1016/j.autneu.2014.09.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 09/12/2014] [Accepted: 09/21/2014] [Indexed: 02/07/2023]
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13
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Rollema H, Russ C, Lee TC, Hurst RS, Bertrand D. Functional interactions of varenicline and nicotine with nAChR subtypes implicated in cardiovascular control. Nicotine Tob Res 2014; 16:733-42. [PMID: 24406270 DOI: 10.1093/ntr/ntt208] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION It has been suggested that varenicline-induced activation of nicotinic acetylcholine receptors (nAChRs) could play a role in the cardiovascular (CV) safety of varenicline. However, since preclinical studies showed that therapeutic varenicline concentrations have no effect in models of CV function, this study examined in vitro profiles of varenicline and nicotine at nAChR subtypes possibly involved in CV control. METHODS Concentration-dependent functional effects of varenicline and nicotine at human α3β4, α3α5β4, α7, and α4β2 nAChRs expressed in oocytes were determined by electrophysiology. The proportion of nAChRs predicted to be activated and inhibited by concentrations of varenicline (1mg b.i.d.) and of nicotine in smokers was derived from activation-inhibition curves for each nAChR subtype. RESULTS Human varenicline and nicotine concentrations can desensitize and inhibit nAChRs but cause only low-level activation of α3β4, α4β2 (<2%), α7 (<0.05%), and α3α5β4 (<0.01%) nAChRs, which is consistent with literature data. Nicotine concentrations in smokers are predicted to inhibit larger fractions of α3β4 (48%) and α3α5β4 (10%) nAChRs than therapeutic varenicline concentrations (11% and 0.6%, respectively) and to inhibit comparable fractions of α4β2 nAChRs (42%-56%) and α7 nAChRs (16%) as varenicline. CONCLUSIONS Nicotine and varenicline concentrations in patients and smokers are predicted to cause minimal activation of ganglionic α3β4* nAChRs, while their functional profiles at α3β4, α3α5β4, α7, and α4β2 nAChRs cannot explain that substituting nicotine from tobacco with varenicline would cause CV adverse events in smokers who try to quit. Other pharmacological properties that could mediate varenicline-induced CV effects have not been identified.
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14
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Hu N, Ren J. Nicotine, cigarette smoking and cardiac function: an update. Toxicol Res (Camb) 2014. [DOI: 10.1039/c3tx50044f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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Jutkiewicz EM, Rice KC, Carroll FI, Woods JH. Patterns of nicotinic receptor antagonism II: cardiovascular effects in rats. Drug Alcohol Depend 2013; 131:284-97. [PMID: 23333294 PMCID: PMC4174279 DOI: 10.1016/j.drugalcdep.2012.12.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 12/17/2012] [Accepted: 12/18/2012] [Indexed: 11/18/2022]
Abstract
BACKGROUND Tobacco cessation pharmacotherapies currently are limited to nicotine itself, the partial nicotine agonists varenicline and cytisine, and the antidepressant bupropion. Compared with agonists, nicotinic antagonists such as the noncompetitive, nonselective compound mecamylamine, and the competitive, α4β2-preferring antagonist dihydro-β-erythroidine (DHβE) may be a novel approach to the treatment of tobacco smoking as both are effective antagonists of nicotine's central effects. Considering nicotinic acetylcholine receptors mediate critical peripheral effects of acetylcholine, such as cardiovascular effects, it is important to study how nicotinic antagonists would alter the cardiovascular system and the cardiovascular changes induced by nicotine. METHODS The effects of several nicotinic agonists and antagonists on blood pressure and heart rate were measured in conscious, unrestrained rats following parenteral administration using a telemetry system. RESULTS Nicotine and other nicotinic receptor agonists (epibatidine, varenicline, and cytisine) produced similar increases in blood pressure, whereas their effects on heart rate were biphasic. The cardiovascular changes were attenuated by the nonselective nicotine antagonist, mecamylamine, but the peripherally restricted antagonist hexamethonium blocked only the agonist-induced changes in blood pressure. The α7-preferring antagonist, MLA, and the α4β2-preferring antagonist, DHβE, were much less effective in blocking the agonist-induced cardiovascular changes, indicating that nicotine's cardiovascular effects, are due to activation at autonomic ganglia involving nicotinic receptor subtypes other than α4, α7, or β2. CONCLUSIONS The data indicate that the cardiovascular effects of nicotine and nicotine-like agents are mediated through receptor mechanisms that are distinct from those that mediate the central effects of nicotine.
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Affiliation(s)
- Emily M Jutkiewicz
- Department of Pharmacology, University of Michigan, 1150 W Medical Center Drive, Ann Arbor, MI 48109-5632, USA
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Martínez de Morentin PB, Whittle AJ, Fernø J, Nogueiras R, Diéguez C, Vidal-Puig A, López M. Nicotine induces negative energy balance through hypothalamic AMP-activated protein kinase. Diabetes 2012; 61:807-17. [PMID: 22315316 PMCID: PMC3314364 DOI: 10.2337/db11-1079] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 12/08/2011] [Indexed: 02/05/2023]
Abstract
Smokers around the world commonly report increased body weight after smoking cessation as a major factor that interferes with their attempts to quit. Numerous controlled studies in both humans and rodents have reported that nicotine exerts a marked anorectic action. The effects of nicotine on energy homeostasis have been mostly pinpointed in the central nervous system, but the molecular mechanisms controlling its action are still not fully understood. The aim of this study was to investigate the effect of nicotine on hypothalamic AMP-activated protein kinase (AMPK) and its effect on energy balance. Here we demonstrate that nicotine-induced weight loss is associated with inactivation of hypothalamic AMPK, decreased orexigenic signaling in the hypothalamus, increased energy expenditure as a result of increased locomotor activity, increased thermogenesis in brown adipose tissue (BAT), and alterations in fuel substrate utilization. Conversely, nicotine withdrawal or genetic activation of hypothalamic AMPK in the ventromedial nucleus of the hypothalamus reversed nicotine-induced negative energy balance. Overall these data demonstrate that the effects of nicotine on energy balance involve specific modulation of the hypothalamic AMPK-BAT axis. These targets may be relevant for the development of new therapies for human obesity.
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Affiliation(s)
- Pablo B. Martínez de Morentin
- Department of Physiology, School of Medicine-CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, A Coruña, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, Spain
| | - Andrew J. Whittle
- Institute of Metabolic Science, Metabolic Research Laboratories, NIHR Cambridge Biomedical Research Centre Addenbrooke's Hospital, University of Cambridge, Cambridge, U.K
| | - Johan Fernø
- Dr. Einar Martens’ Research Group for Biological Psychiatry, Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Rubén Nogueiras
- Department of Physiology, School of Medicine-CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, A Coruña, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, Spain
| | - Carlos Diéguez
- Department of Physiology, School of Medicine-CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, A Coruña, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, Spain
| | - Antonio Vidal-Puig
- Institute of Metabolic Science, Metabolic Research Laboratories, NIHR Cambridge Biomedical Research Centre Addenbrooke's Hospital, University of Cambridge, Cambridge, U.K
| | - Miguel López
- Department of Physiology, School of Medicine-CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, A Coruña, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, Spain
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Gaede AH, Pilowsky PM. Catestatin, a chromogranin A-derived peptide, is sympathoinhibitory and attenuates sympathetic barosensitivity and the chemoreflex in rat CVLM. Am J Physiol Regul Integr Comp Physiol 2011; 302:R365-72. [PMID: 22129620 DOI: 10.1152/ajpregu.00409.2011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Hypertension is a major cause of morbidity. The neuropeptide catestatin [human chromogranin A-(352-372)] is a peptide product of the vesicular protein chromogranin A. Studies in the periphery and in vitro studies show that catestatin blocks nicotine-stimulated catecholamine release and interacts with β-adrenoceptors and histamine receptors. Catestatin immunoreactivity is present in the rostral ventrolateral medulla (RVLM), a key site for blood pressure control in the brain stem. Recently, we reported that microinjection of catestatin into the RVLM is sympathoexcitatory and increases barosensitivity. Here, we report the effects of microinjection of catestatin (1 mM, 50 nl) into the caudal ventrolateral medulla (CVLM) in urethane-anesthetized, bilaterally vagotomized, artificially ventilated Sprague-Dawley rats (n = 8). We recorded resting arterial pressure, splanchnic sympathetic nerve activity, phrenic nerve activity, heart rate, and measured cardiovascular homeostatic reflexes. Homeostatic reflexes were evaluated by measuring cardiovascular responses to carotid baroreceptor and peripheral chemoreceptor activation. Catestatin decreased basal levels of arterial pressure (-23 ± 4 mmHg), sympathetic nerve activity (-26.6 ± 5.7%), heart rate (-19 ± 5 bpm), and phrenic nerve amplitude (-16.8 ± 3.3%). Catestatin caused a 15% decrease in phrenic inspiratory period (T(i)) and a 16% increase in phrenic expiratory period (T(e)) but had no net effect on the phrenic interburst interval (T(tot)). Catestatin decreased sympathetic barosensitivity by 63.6% and attenuated the peripheral chemoreflex (sympathetic nerve response to brief hypoxia; range decreased 39.9%; slope decreased 30.1%). The results suggest that catestatin plays an important role in central cardiorespiratory control.
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Affiliation(s)
- Andrea H Gaede
- Australian School of Advanced Medicine, Macquarie University, North Ryde, NSW, Australia
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Identification of a cholinergic modulatory and rhythmogenic mechanism within the lamprey respiratory network. J Neurosci 2011; 31:13323-32. [PMID: 21917815 DOI: 10.1523/jneurosci.2764-11.2011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Acetylcholine (ACh) is well known to be involved in the control of breathing. However, no information is available on the role of ACh receptors (AChRs) within the lamprey respiratory network. The present study was performed on in vitro brainstem preparations of adult lampreys to investigate whether ACh affects respiratory activity possibly through an action on the paratrigeminal respiratory group (pTRG) that has been identified as an essential component of the respiratory network. Respiratory activity was monitored as vagal motor output. Bath application of 100 μM physostigmine or 1 μM nicotine increased respiratory frequency, while bath application of 100 μM D-tubocurarine or 0.25 μM α-bungarotoxin reduced respiratory frequency and increased the duration of vagal bursts. Since these effects were mimicked by microinjections of the same drugs into the pTRG, ACh proved to influence respiratory activity by acting on α7 nicotinic AChRs located within the pTRG. During apnea caused by partial blockade of ionotropic glutamate receptors at the level of the pTRG, bath application of bicuculline and strychnine restored the respiratory rhythm, although at reduced frequency. Similar results were obtained by the concurrent removal of both fast synaptic excitatory and inhibitory transmission. Blockade of pTRG α7 nicotinic AChRs suppressed this respiratory activity, thus indicating that pTRG neurons expressing these receptors contribute to respiratory rhythm generation. Together, these findings identify a novel cholinergic modulatory and possibly subsidiary rhythmogenic mechanism within the respiratory network of the adult lamprey and encourage further studies on the respiratory role of cholinergic receptors in different animal species.
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The effect of varenicline on heart rate variability in healthy smokers and nonsmokers. Auton Neurosci 2011; 164:82-6. [DOI: 10.1016/j.autneu.2011.05.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2011] [Revised: 05/07/2011] [Accepted: 05/19/2011] [Indexed: 11/17/2022]
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20
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Moore C, Wang Y, Ramage AG. Nicotine's central cardiovascular actions: Receptor subtypes involved and their possible physiological role in anaesthetized rats. Eur J Pharmacol 2011; 668:177-83. [DOI: 10.1016/j.ejphar.2011.06.055] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 06/20/2011] [Accepted: 06/27/2011] [Indexed: 10/18/2022]
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Cardiac-specific overexpression of metallothionein rescues nicotine-induced cardiac contractile dysfunction and interstitial fibrosis. Toxicol Lett 2011; 202:8-14. [PMID: 21238558 DOI: 10.1016/j.toxlet.2011.01.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 01/07/2011] [Accepted: 01/07/2011] [Indexed: 11/22/2022]
Abstract
Cigarette smoking is a devastating risk factor for cardiovascular diseases and nicotine is believed the main toxin component responsible for the toxic myocardial effects of smoking. Nonetheless, neither the precise mechanism of nicotine-induced cardiac dysfunction nor effective treatment is elucidated. The aim of this study was to evaluate the impact of cardiac-specific overexpression of heavy metal scavenger metallothionein on myocardial geometry and mechanical function following nicotine exposure. Adult male friend virus B (FVB) wild-type and metallothionein mice were injected with nicotine (2 mg/kg/d) intraperitoneally for 10 days. Mechanical and intracellular Ca²+ properties were examined. Myocardial histology (cross-sectional area and fibrosis) was evaluated by hematoxylin and eosin (H&E) and Masson trichrome staining, respectively. Oxidative stress and apoptosis were measured by fluoroprobe 5-(6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate (CM-H₂DCFDA) fluorescence and caspase-3 activity, respectively. Nicotine exposure failed to affect the protein abundance of metallothionein. Our data revealed reduced echocardiographic contractile capacity (fractional shortening), altered cardiomyocyte contractile and intracellular Ca²+ properties including depressed peak shortening amplitude, maximal velocity of shortening/relengthening, resting and electrically-stimulated rise in intracellular Ca²+, as well as prolonged duration of relengthening and intracellular Ca²+ clearance in hearts from nicotine-treated FVB mice, the effect of which was ameliorated by metallothionein. Biochemical and histological findings depicted overt accumulation of reactive oxygen species (ROS), apoptosis and myocardial fibrosis without any change in myocardial cross-sectional area following nicotine treatment, which was mitigated by metallothionein. Taken together, our findings suggest the antioxidant metallothionein may reconcile short-term nicotine exposure-induced myocardial contractile dysfunction and fibrosis possibly through inhibition of ROS accumulation and apoptosis.
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22
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Abstract
Tobacco use became common all over the world after discovery of Americas. Tobacco, a plant carries in its leaves an alkaloid called nicotine, which is responsible not only for several pathophysiological changes in the body but also develops tolerance to its own action with repeated use. Studies suggest that the alpha-4 beta-2 nicotine acetylcholine receptor subtype is the main receptor that mediates nicotine dependence. Nicotine acts on these receptors to facilitate neurotransmitter release (dopamine and others), producing pleasure and mood modulation. Repeated exposure to nicotine develops neuroadaptation of the receptors, resulting in tolerance to many of the effects of nicotine. Withdrawal symptoms appear on stoppage of tobacco use, which are characterized by irritability, anxiety, increased eating, dysphoria, and hedonic dysregulation, among others. Smoking is also reinforced by conditioning. Pharmacotherapies for smoking cessation should reduce withdrawal symptoms and block the reinforcing effects of nicotine obtained from smoking without causing excessive adverse effects.
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Affiliation(s)
- R C Jiloha
- Department of Psychiatry, G. B. Pant Hospital, Maulana Azad Medical College and University of Delhi, India
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23
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Affiliation(s)
- Neal L Benowitz
- Division of Clinical Pharmacology and Experimental Therapeutics, Medical Service, San Francisco General Hospital Medical Center, and the Department of Medicine, University of California, San Francisco, San Francisco, CA 94143-1220, USA.
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Sofuoglu M, Herman AI, Mooney M, Waters AJ. Varenicline attenuates some of the subjective and physiological effects of intravenous nicotine in humans. Psychopharmacology (Berl) 2009; 207:153-62. [PMID: 19693492 PMCID: PMC2796376 DOI: 10.1007/s00213-009-1643-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2009] [Accepted: 08/07/2009] [Indexed: 10/20/2022]
Abstract
RATIONALE Varenicline, a partial nicotinic acetylcholine receptor (nAChR) agonist, is approved for smoking cessation. A few preclinical studies examined the pharmacological effects of varenicline, alone or in combination with nicotine. How varenicline affects the pharmacological effects of pure nicotine has not been examined in humans. The goal of this study was to characterize varenicline's actions on nicotine's dose-dependent effects in abstinent smokers. METHODS Six male and six female smokers participated in a double-blind, placebo-controlled, crossover study. Smokers had two 4-day treatment periods, assigned in random sequence, to varenicline (1 mg/day) or placebo treatment. On day 4 of each treatment phase, smokers had an experimental session, where they received three escalating doses of intravenous (IV) nicotine (0.1, 0.4, and 0.7 mg/70 kg), in 30-min intervals. Varenicline's effects were assessed through subjective, physiological, and cognitive performance outcomes to nicotine administered via IV route. RESULTS In response to IV nicotine, varenicline treatment attenuated the rating of drug strength, high, head rush, and stimulated. Varenicline also attenuated nicotine-induced increases in heart rate. Varenicline had mixed effects on cognitive performance. Smokers under varenicline treatment, compared with placebo, reported enhanced positive mood measured with the Positive and Negative Affect Schedule. CONCLUSIONS These findings provide new insights into the mechanisms of action of varenicline in smoking cessation.
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Affiliation(s)
- Mehmet Sofuoglu
- Department of Psychiatry and VA Connecticut Healthcare System, Yale University School of Medicine, 950 Campbell Ave., Bldg. 36/116A4, West Haven, CT 06516, USA.
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25
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Abstract
Nicotine sustains tobacco addiction, a major cause of disability and premature death. Nicotine binds to nicotinic cholinergic receptors, facilitating neurotransmitter release and thereby mediating the complex actions of nicotine in tobacco users. Dopamine, glutamate, and gamma aminobutyric acid release are particularly important in the development of nicotine dependence, and corticotropin-releasing factor appears to contribute to nicotine withdrawal. Nicotine dependence is highly heritable. Genetic studies indicate roles for nicotinic receptor subtypes, as well as genes involved in neuroplasticity and learning, in development of dependence. Nicotine is primarily metabolized by CYP 2A6, and variability in rate of metabolism contributes to vulnerability to tobacco dependence, response to smoking cessation treatment, and lung cancer risk. Tobacco addiction is much more common in persons with mental illness and substance abuse disorders, representing a high proportion of current smokers. Pharmacotherapeutic approaches to tobacco addiction include nicotine replacement, bupropion, and varenicline, the latter a selective nicotine receptor partial agonist.
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Affiliation(s)
- Neal L Benowitz
- Department of Medicine, Division of Clinical Pharmacology and Experimental Therapeutics, Medical Service, San Francisco General Hospital Medical Center, University of California, San Francisco, California 94143-1220, USA.
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26
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O'Leary KT, Loughlin SE, Chen Y, Leslie FM. Nicotinic acetylcholine receptor subunit mRNA expression in adult and developing rat medullary catecholamine neurons. J Comp Neurol 2008; 510:655-72. [PMID: 18698592 DOI: 10.1002/cne.21833] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) mediate numerous visceral functions via medullary catecholamine (CA) neurons found in the nucleus tractus solitarius (NTS), dorsal motor nucleus of the vagus (DMV), and ventrolateral medulla (VLM). However, the nAChR subtypes involved are not known. We have therefore characterized expression of nine nAChR subunit mRNAs in adult and developing rat medullary CA nuclei using combined isotopic/nonisotopic in situ hybridization. Tyrosine hydroxylase (TH) mRNA, the CA-synthesizing enzyme, was used as a marker for CA neurons, because these nuclei consist of heterogeneous populations of cells. Subunit mRNA expression varied within and between nuclei, along the rostrocaudal axis, between cell types, and across development. All CA neurons expressed beta2 mRNA, whereas alpha2 mRNA was completely absent. alpha6 And beta3 mRNA expression were restricted mainly to the VLM. alpha4, alpha5, And alpha7 mRNA expression was significantly greater in the rostral than in the caudal VLM. alpha3 And beta4 mRNAs were highly expressed in the dorsal region of the NTS, whereas dense alpha7 mRNA expression was restricted to the DMV and ventral NTS. The remaining subunit mRNAs were detected to some degree in both DMV and NTS. Except for alpha4 mRNA, which peaked prenatally, expression levels of subunit transcripts in the NTS and DMV were lower during development compared with adults. In the VLM, alpha3, alpha4, and alpha5 mRNAs expression peaked perinatally, whereas alpha6 and beta3 levels increased with age. These variations in nAChR subunit mRNA expression suggest that different receptor subtypes may produce function-specific regulation of medullary CA systems.
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Affiliation(s)
- Kathryn T O'Leary
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, California 92697, USA
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27
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Abstract
Nicotine sustains addictive tobacco use, which in turn causes much premature disability and death. The essence of drug addiction is loss of control of drug use. Molecular biology studies suggest that the alpha(4)beta(2) nicotinic acetylcholine receptor subtype is the main receptor mediating nicotine dependence. Nicotine acts on these brain nicotinic cholinergic receptors to facilitate neurotransmitter release (dopamine and others), producing pleasure, stimulation, and mood modulation. Neuroadaptation develops with repeated exposure to nicotine, resulting in tolerance to many of the effects of nicotine. When a smoker stops smoking, a nicotine withdrawal syndrome ensues, characterized by irritability, anxiety, increased eating, dysphoria, and hedonic dysregulation, among other symptoms. Smoking is also reinforced by conditioning, such that specific stimuli that are psychologically associated with smoking become cues for an urge to smoke. These include the taste and smell of tobacco, as well as particular moods, situations, and environmental cues. Pharmacotherapies to aid smoking cessation should ideally reduce nicotine withdrawal symptoms and block the reinforcing effects of nicotine obtained from smoking without causing excessive adverse effects. Further, given the important role of sensory effects of smoking and psychoactive effects of nicotine, counseling and behavioral therapies are important adjuncts to and substantially augment the benefits of pharmacotherapy.
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Affiliation(s)
- Neal L Benowitz
- Division of Clinical Pharmacology and Experimental Therapeutics, Medical Service, San Francisco General Hospital Medical Center, San Francisco, California, USA.
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28
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Moore C, Wang Y, Ramage AG. Cardiovascular effects of activation of central alpha7 and alpha4beta2 nAChRs: a role for vasopressin in anaesthetized rats. Br J Pharmacol 2008; 153:1728-38. [PMID: 18297099 PMCID: PMC2438263 DOI: 10.1038/bjp.2008.47] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Revised: 01/10/2008] [Accepted: 01/22/2008] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE Central application of nicotine causes the release of vasopressin and affects blood pressure. Involvement of the 5 neuronal nicotinic receptor groups, alpha2(*)-alpha7(*) in these effects is unknown. The availability of selective agonists for alpha7 (PSAB-OFP) and alpha4beta2 (TC-2559) nACh receptors allowed their role to be investigated. EXPERIMENTAL APPROACH Recordings were made of arterial blood pressure, heart rate and renal sympathetic nerve activity in anaesthetized male rats with neuromuscular blockade and artificial respiration. Effects of the agonists, PSAB-OFP (1-10 micromol kg(-1)) and TC-2559 (1-10 micromol kg(-1)) on these variables given intracerebroventricularly (i.c.v.) and intracisternally (i.c.) in the presence or absence of the antagonists, DhbetaE (10 micromol kg(-1)) and MLA (0.5 micromol kg(-1)), for the appropriate nicotinic receptor subtypes, respectively, and a V(1) receptor antagonist, given i.v. or centrally, were investigated. KEY RESULTS Both agonists given i.c.v. caused a delayed rise in blood pressure and renal nerve activity which could be blocked only with the appropriate antagonist. The agonists had an earlier onset of action when given i.c., favouring the brainstem as the major site of action. The effects of these agonists were also attenuated by the V(1) receptor antagonist given i.v. and blocked when this antagonist was given centrally. Antagonists had no effect on baseline variables. CONCLUSIONS AND IMPLICATIONS Activation of alpha4beta2 and alpha7 receptors in the brainstem is mainly responsible for the cardiovascular effects of activating these receptors, which have a similar profile of action. These actions, although independent, are mediated by the central release of vasopressin.
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Affiliation(s)
- C Moore
- Department of Pharmacology, University College London, London, UK
| | - Y Wang
- Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Fudan University, Shanghai, China
| | - A G Ramage
- Department of Pharmacology, University College London, London, UK
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Yalcin M, Cavun S, Yilmaz MS, Savci V. Activation of the central cholinergic system mediates the reversal of hypotension by centrally administrated U-46619, a thromboxane A2 analog, in hemorrhaged rats. Brain Res 2006; 1118:43-51. [PMID: 16962568 DOI: 10.1016/j.brainres.2006.08.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2006] [Revised: 07/31/2006] [Accepted: 08/04/2006] [Indexed: 11/25/2022]
Abstract
In the present study, we investigated the role of the central cholinergic system in mediating the pressor effect of intracerebroventricularly administrated U-46619, a thromboxane A2 (TxA2) analog, in hemorrhaged hypotensive rats. Hemorrhage was performed by withdrawing a total volume of 2.1 ml of blood per 100 g body weight over a period of 10 min. Intracerebroventricular (i.c.v.) injection of U-46619 (0.5, 1, 2 micro g) produced a dose- and time-dependent increase in arterial pressure and reversed the hypotension of this condition. Hemorrhage caused small increases in extracellular hypothalamic acetylcholine and choline levels. Intracerebroventricular administration of U-46619 (1 micro g) further increased the levels of extracellular acetylcholine and choline by 57% and 41%, respectively. Pretreatment with SQ-29548 (8 mug; i.c.v.), a selective TxA2 receptor antagonist, completely abrogated the effects of subsequent injection of U-46619 (1 mug; i.c.v.) on arterial pressure and extracellular acetylcholine and choline levels. Pretreatment with mecamylamine (50 micro g; i.c.v.), a cholinergic nonselective nicotinic receptor antagonist, attenuated the pressor effect of U-46619 (1 micro g, i.c.v.) in hemorrhaged rats whereas pretreatment with atropine (10 micro g; i.c.v.), a cholinergic nonselective muscarinic receptor antagonist, had no effect. Interestingly, pretreatment of rats with methyllycaconitine (10 micro g; i.c.v.) or alpha-bungarotoxin (10 micro g; i.c.v.), selective antagonists of alpha-7 subtype nicotinic acetylcholine receptors (alpha7nAChRs), partially abolished the pressor effect of U-46619 (1 micro g; i.c.v.) in the hypotensive condition. Pretreatment with a combination of mecamylamine plus methyllycaconitine or mecamylamine plus alpha-bungarotoxin attenuated the reversal effect of U-46619, but only to the same extent as pretreatment with either antagonist alone. In conclusion, i.c.v. administration of U-46619 restores arterial pressure and increases posterior hypothalamic acetylcholine and choline levels by activating central TxA2 receptors in hemorrhaged hypotensive rats. The activation of central nicotinic cholinergic receptors, predominantly alpha7nAChRs, partially acts as a mediator in the pressor responses to i.c.v. injection of U-46619 under these conditions.
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MESH Headings
- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid/pharmacology
- Acetylcholine/metabolism
- Animals
- Blood Pressure/drug effects
- Blood Pressure/physiology
- Bridged Bicyclo Compounds, Heterocyclic
- Cholinergic Fibers/drug effects
- Cholinergic Fibers/metabolism
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Extracellular Fluid/drug effects
- Extracellular Fluid/metabolism
- Fatty Acids, Unsaturated
- Hemorrhage/complications
- Hemorrhage/physiopathology
- Hydrazines/pharmacology
- Hypotension/drug therapy
- Hypotension/etiology
- Hypotension/physiopathology
- Hypothalamus, Posterior/drug effects
- Hypothalamus, Posterior/metabolism
- Injections, Intraventricular
- Male
- Neural Pathways/drug effects
- Neural Pathways/metabolism
- Nicotinic Antagonists/pharmacology
- Rats
- Rats, Sprague-Dawley
- Receptors, Nicotinic/drug effects
- Receptors, Nicotinic/metabolism
- Receptors, Thromboxane A2, Prostaglandin H2/antagonists & inhibitors
- Receptors, Thromboxane A2, Prostaglandin H2/metabolism
- Thromboxane A2/analogs & derivatives
- Time Factors
- Vasoconstrictor Agents/pharmacology
- alpha7 Nicotinic Acetylcholine Receptor
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Affiliation(s)
- Murat Yalcin
- Uludag University Veterinary Faculty, Department of Physiology, 16059, Görükle, Bursa, Turkey
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30
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Gong CL, Chiu YT, Lin NN, Cheng CC, Lin SZ, Lee TJF, Kuo JS. Regulation of the common carotid arterial blood flow by nicotinic receptors in the medulla of cats. Br J Pharmacol 2006; 149:206-14. [PMID: 16894347 PMCID: PMC2013800 DOI: 10.1038/sj.bjp.0706844] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE Actions of glutamate and serotonin on their respective receptors in the dorsal facial area (DFA) of the medulla are known to regulate common carotid arterial (CCA) blood flow in cats. Less is known about acetylcholine action on its nicotinic receptor (nAChR) subtypes in the DFA for regulation of CCA blood flow and this aspect was investigated. EXPERIMENTAL APPROACH Nicotinic and muscarinic agonists and antagonists were microinjected into the DFA through a three-barrel tubing in anesthetized cats. RESULTS CCA blood flow was dose-dependently increased by nicotine (a non-selective nAChR agonist) and choline (a selective alpha7-nAChR agonist). These effects of nicotine were attenuated by alpha-bungarotoxin (an alpha7-nAChR antagonist), methyllycaconitine (an alpha7-nAChR antagonist), mecamylamine (a relatively selective alpha3beta4-nAChR antagonist) and dihydro-beta-erythroidine (a relatively selective alpha4beta2-nAChR antagonist). The choline-induced flow increase was attenuated by alpha-bungarotoxin and mecamylamine, but not by dihydro-beta-erythroidine. Muscarinic agonists (muscarine and methacholine) and antagonist (atropine) affected neither the basal nor the nicotine-induced increase in the CCA blood flow. CONCLUSIONS AND IMPLICATIONS Functional alpha7, alpha4beta2, and alpha3beta4 subunits of the nAChR appear to be present on the DFA neurons. Activations of these receptors increase the CCA blood flow. The present findings do not preclude the presence of other nAChRs subunits. Muscarinic receptors, if any, on the DFA are not involved in regulation of the CCA blood flow. Various subtypes of nAChRs in the DFA may mediate regulation of the CCA and cerebral blood flows.
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Affiliation(s)
- C-L Gong
- Department of Physiology, School of Medicine, China Medical University Taichung, Taiwan
| | - Y-T Chiu
- Department of Education and Research, Taichung Veterans General Hospital Taichung, Taiwan
| | - N-N Lin
- Department of Education and Research, Taichung Veterans General Hospital Taichung, Taiwan
- Department of Veterinary Medicine, National Chung Hsing University Taichung, Taiwan
| | - C-C Cheng
- Department of Education and Research, Taichung Veterans General Hospital Taichung, Taiwan
- Department of Veterinary Medicine, National Chung Hsing University Taichung, Taiwan
| | - S-Z Lin
- Neuro-Medical Scientific Center and Center for Vascular Medicine, Buddhist Tzu Chi General Hospital and Tzu Chi University Hualien, Taiwan
| | - T J-F Lee
- Neuro-Medical Scientific Center and Center for Vascular Medicine, Buddhist Tzu Chi General Hospital and Tzu Chi University Hualien, Taiwan
- Institute of Pharmacology and Toxicology, Tzu Chi University Hualien, Taiwan
- Department of Pharmacology, Southern Illinois University, School of Medicine Springfield, IL, USA
| | - J-S Kuo
- Neuro-Medical Scientific Center and Center for Vascular Medicine, Buddhist Tzu Chi General Hospital and Tzu Chi University Hualien, Taiwan
- Institute of Pharmacology and Toxicology, Tzu Chi University Hualien, Taiwan
- Author for correspondence:
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Yalcin M, Cavun S, Yilmaz MS, Savci V. The involvement of central cholinergic system in the pressor effect of intracerebroventricularly injected U-46619, a thromboxane A2 analog, in conscious normotensive rats. Naunyn Schmiedebergs Arch Pharmacol 2005; 372:31-40. [PMID: 16133489 DOI: 10.1007/s00210-005-1087-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2005] [Accepted: 07/18/2005] [Indexed: 10/25/2022]
Abstract
The aim of this study was to determine the involvement of the central cholinergic system in the rise in blood pressure evoked by the thromboxane A2 (TxA2) analog, U-46619, given centrally. Intracerebroventricular (i.c.v.) injections of U-46619 (0.5, 1.0 and 2.0 microg) caused dose- and time-related increases in blood pressure and decreased heart rate in awake rats. U-46619 (1 microg; i.c.v.) also produced an approximately 65% increase in posterior hypothalamic extracellular acetylcholine and choline levels. Pretreatment with SQ-29548 (8 microg; i.c.v.), selective TxA2 receptor antagonist, completely inhibited both the cardiovascular responses and the increase in acetylcholine and choline levels to subsequent injection of U-46619 (1 microg; i.c.v.). Atropine (10 microg; i.c.v.), nonselective muscarinic receptor antagonist, pretreatment did not affect the cardiovascular responses observed after U-46619 (1 microg; i.c.v.). Pretreatment with the nonselective nicotinic receptor antagonist, mecamylamine (50 microg; i.c.v.) attenuated the pressor effect of U-46619 (1 microg; i.c.v.). Higher doses of mecamylamine (75 and 100 microg; i.c.v.) pretreatments did not change the magnitude of the blockade of pressor response to U-46619; however, they abolished the bradycardic effect of U-46619 dose-dependently. Interestingly, pretreatment of rats with methyllycaconitine (10 microg; i.c.v.) or alpha-bungarotoxin (10 microg; i.c.v.), selective antagonists of alpha7 subtype of nicotinic acetylcholine receptors (alpha7nAChRs), partially abolished the pressor response to i.c.v. injection of U-46619 (1 microg). Similar to the mecamylamine data, the use of higher doses of methyllycaconitine (25 and 50 microg; i.c.v.) produced the same magnitude of blockade that was observed after the 10 microg methyllycaconitine pretreatment, but it completely abolished the bradycardic effect of U-46619 (1 microg; i.c.v.) at the dose of 25 microg. The present results show that central administration of U-46619 produces pressor and bradycardic effect and increase in hypothalamic acetylcholine and choline levels by activating central TxA2 receptors. The activation of central nicotinic receptors, predominantly alpha7nAChRs, partially mediates the cardiovascular responses to i.c.v. injection of U-46619.
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MESH Headings
- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid/administration & dosage
- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid/pharmacology
- Acetylcholine/metabolism
- Aconitine/administration & dosage
- Aconitine/analogs & derivatives
- Animals
- Blood Pressure/drug effects
- Bridged Bicyclo Compounds, Heterocyclic
- Bungarotoxins/administration & dosage
- Central Nervous System/drug effects
- Central Nervous System/metabolism
- Choline/metabolism
- Fatty Acids, Unsaturated
- Heart Rate/drug effects
- Hydrazines/administration & dosage
- Hypothalamus, Posterior/drug effects
- Hypothalamus, Posterior/metabolism
- Injections, Intraventricular
- Male
- Mecamylamine/administration & dosage
- Nicotinic Antagonists/administration & dosage
- Rats
- Rats, Sprague-Dawley
- Receptors, Nicotinic/drug effects
- Receptors, Thromboxane A2, Prostaglandin H2/antagonists & inhibitors
- Time Factors
- Vasoconstrictor Agents/administration & dosage
- Vasoconstrictor Agents/pharmacology
- alpha7 Nicotinic Acetylcholine Receptor
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Affiliation(s)
- Murat Yalcin
- Department of Physiology, Uludag University Veterinary Faculty, 16059, Gorukle, Bursa, Turkey
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32
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Cucchiaro G, Commons KG. Alpha 4 nicotinic acetylcholine receptor subunit links cholinergic to brainstem monoaminergic neurotransmission. Synapse 2003; 49:195-205. [PMID: 12774304 DOI: 10.1002/syn.10218] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Agonists of nicotinic receptors containing the alpha4-subunit produce antinociception accompanied by several adverse side effects. The purpose of this study was to determine the distribution of the alpha4-subunit of nicotinic acetylcholine receptors (nAChR) in brainstem monoaminergic nuclei that may contribute to these effects using dual labeling immunofluorescence methods. The alpha4-subunit immunoreactivity was enriched in serotonergic (nucleus raphe magnus, pallidus, obscurus, and dorsalis) and noradrenergic (A5, locus coeruleus (LC), A7) areas associated with antinociception, where it was commonly colocalized with serotonin (5-HT) or tyrosine hydroxylase (TH) immunoreactivity. However, it was also noted that alpha4 was present in all other brainstem monoaminergic nuclei examined (adrenergic C1-C3, noradrenergic A1-alpha4, dopamine A9 and A10, nucleus raphe medianus). To determine if alpha4 agonists could impact neural activity in brainstem, monoaminergic nuclei that are associated with antinociception, the expression of c-Fos in response to the systemic administration of epibatidine (2.5, 5, or 10 microg/kg) was examined. Epibatidine produced a robust (2-5-fold) increase in c-Fos expression, which was not dose dependent, in all of these areas examined except the nucleus raphe magnus. These results suggest that the alpha4 subunit is positioned to mediate the effects of acetylcholine widely across many, if not all, monoaminergic neurons in the brainstem. These observations emphasize the potential involvement of noradrenergic, as well as serotonergic mechanisms in epibatidine's analgesic effects, and they also suggest that even selective alpha4 ligand may have widespread effects on brain monoamine neurotransmission.
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Affiliation(s)
- Giovanni Cucchiaro
- Department of Anesthesiology and Critical Care Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.
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