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Shimizu N, Shimizu T, Higashi Y, Zou S, Fukuhara H, Karashima T, Inoue K, Saito M. Possible involvement of brain hydrogen sulphide in the inhibition of the rat micturition reflex induced by activation of brain alpha7 nicotinic acetylcholine receptors. Eur J Pharmacol 2023:175839. [PMID: 37301318 DOI: 10.1016/j.ejphar.2023.175839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 05/24/2023] [Accepted: 06/08/2023] [Indexed: 06/12/2023]
Abstract
We previously reported that brain α7 nicotinic acetylcholine receptors inhibited the rat micturition reflex. To elucidate the mechanisms underlying this inhibition, we focused on the relationship between α7 nicotinic acetylcholine receptors and hydrogen sulphide (H2S) because we found that H2S also inhibits the rat micturition reflex in the brain. Therefore, we investigated whether H2S is involved in the inhibition of the micturition reflex induced by the activation of α7 nicotinic acetylcholine receptors in the brain. Cystometry was performed in male Wistar rats under urethane anesthesia (0.8 g/kg, ip) to examine the effects of icv pre-treated GYY4137 (H2S donor, 1 or 3 nmol/rat) or aminooxyacetic acid (AOAA; non-selective H2S synthesis inhibitor, 3 or 10 μg/rat) on PHA568487 (α7 nicotinic acetylcholine receptor agonist, icv)-induced prolongation of intercontraction intervals. PHA568487 administration at a lower dose (0.3 nmol/rat, icv) had no significant effect on intercontraction intervals, while under pre-treatment with GYY4137 (3 nmol/rat icv), PHA568487 (0.3 nmol/rat, icv) significantly prolonged intercontraction intervals. PHA568487 at a higher dose (1 nmol/rat, icv) induced intercontraction interval prolongation, and the PHA568487-induced prolongation was significantly suppressed by AOAA (10 μg/rat, icv). The AOAA-induced suppression of the PHA568487-induced intercontraction interval prolongation was negated by supplementing H2S via GYY4137 at a lower dose (1 nmol/rat, icv) in the brain. GYY4137 or AOAA alone showed no significant effect on intercontraction intervals at each dose used in this study. These findings suggest a possible involvement of brain H2S in inhibiting the rat micturition reflex induced by activation of brain alpha7 nicotinic acetylcholine receptors.
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Affiliation(s)
- Nobutaka Shimizu
- Pelvic Floor Center, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
| | - Takahiro Shimizu
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan.
| | - Youichirou Higashi
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
| | - Suo Zou
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
| | - Hideo Fukuhara
- Department of Urology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
| | - Takashi Karashima
- Department of Urology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
| | - Keiji Inoue
- Department of Urology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
| | - Motoaki Saito
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
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Rodríguez-Núñez I, Pontes RB, Romero F, Campos RR. Effects of physical exercise on baroreflex sensitivity and renal sympathetic nerve activity in chronic nicotine-treated rats. Can J Physiol Pharmacol 2021; 99:786-794. [PMID: 33290163 DOI: 10.1139/cjpp-2020-0381] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Chronic nicotine exposure may increase cardiovascular risk by impairing the cardiac autonomic function. Besides, physical exercise (PE) has shown to improve cardiovascular health. Thus, we aimed to investigate the effects of PE on baroreflex sensitivity (BRS), heart rate variability (HRV), and sympathetic nerve activity (SNA) in chronically nicotine-exposed rats. Male Wistar rats were assigned to four independent groups: Control (treated with saline solution), Control+Ex (treated with saline and submitted to treadmill training), Nicotine (treated with Nicotine), and Nicotine+Ex (treated with nicotine and submitted to treadmill training). Nicotine (1 mg·kg-1) was administered daily for 28 consecutive days. PE consisted of running exercise (60%-70% of maximal aerobic capacity) for 45 min, 5 days per week, for 4 weeks. At the end of the protocol, cardiac BRS, HRV, renal SNA (rSNA), and renal BRS were assessed. Nicotine treatment decreased absolute values of HRV indexes, increased low frequency/high frequency ratio of HRV, reduced the bradycardic and sympatho-inhibitory baroreceptor reflex responses, and reduced the rSNA. PE effectively restored time-domain HRV indexes, the bradycardic and sympatho-inhibitory reflex responses, and the rSNA in chronic nicotine-treated rats. PE was effective in preventing the deterioration of time-domain parameters of HRV, arterial baroreceptor dysfunction, and the rSNA after nicotine treatment.
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Affiliation(s)
- Iván Rodríguez-Núñez
- Departamento de Fisiologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
- Departamento de Kinesiología, Facultad de Medicina, Universidad de Concepción, Chile
| | - Roberto B Pontes
- Departamento de Fisiologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - Fernando Romero
- Programa de Doctorado en Ciencias Médicas, Departamento de Cirugía, Facultad de Medicina, Universidad de La Frontera, Temuco. Chile
| | - Ruy R Campos
- Departamento de Fisiologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
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Chen HH, Li YD, Cheng PW, Fang YC, Lai CC, Tseng CJ, Pan JY, Yeh TC. Gabapentin Reduces Blood Pressure and Heart Rate through the Nucleus Tractus Solitarii. ACTA CARDIOLOGICA SINICA 2019; 35:627-633. [PMID: 31879515 DOI: 10.6515/acs.201911_35(6).20190429b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Background Oral and intravenous gabapentin can markedly attenuate blood pressure (BP) in hypertensive rats. The nucleus tractus solitarii (NTS) is the primary integrative center for cardiovascular control and other autonomic functions in the central nervous system. However, the signaling mechanisms involved in gabapentin-mediated cardiovascular effects in the NTS remain unclear. We investigated whether the nitric oxide synthase (NOS) signaling pathway was involved in gabapentin-mediated BP regulation in the NTS of spontaneously hypertensive (SHR) rats. Methods SHR rats were anesthetized with urethane at age 10-12 weeks. Arterial pressure and heart rate (HR) were monitored through a femoral artery catheter. For stereotaxic intra-NTS microinjection, the dorsal surface of the medulla was exposed by limited craniotomy. We observed that unilateral microinjection of gabapentin into the NTS whether to change dose-related BP and HR. Then, unilateral microinjection of gabapentin into the NTS before and after N(ω)-nitro-L-arginine methyl ester (L-NAME) treatment whether to change blood pressure and heart rate. Results Unilateral microinjection of gabapentin into the NTS produced prominent dose-related depressor and bradycardic effects in SHR rats. The cardiovascular effects of gabapentin were attenuated by the prior administration of the NOS inhibitor, L-NAME. Conclusions Gabapentin modulated central BP and HR control in the NTS of SHR rats in this study through NOS signaling.
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Affiliation(s)
- Hsin-Hung Chen
- Department of Medical Education and Research.,Yuh-Ing Junior College of Health Care & Management
| | - Yih-Do Li
- Department of Laboratory Medicine, Zuoying Branch of Kaohsiung Armed Forces General Hospital
| | - Pei-Wen Cheng
- Department of Medical Education and Research.,Yuh-Ing Junior College of Health Care & Management
| | - Yi-Chien Fang
- Department of Laboratory Medicine, Zuoying Branch of Kaohsiung Armed Forces General Hospital
| | | | | | - Jun-Yen Pan
- Division of Cardiovascular Surgery, Department of Surgery.,Department of Nursing, Shu-Zen Junior College of Medicine and Management, Kaohsiung
| | - Tung-Chen Yeh
- Department of Internal Medicine, Division of Cardiology, Kaohsiung Veterans General Hospital.,Department of Nursing, Chung Hwa University of Medical Technology, Tainan, Taiwan
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4
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Sallam MY, El-Gowilly SM, Fouda MA, Abd-Alhaseeb MM, El-Mas MM. Brainstem cholinergic pathways diminish cardiovascular and neuroinflammatory actions of endotoxemia in rats: Role of NFκB/α7/α4β2AChRs signaling. Neuropharmacology 2019; 157:107683. [DOI: 10.1016/j.neuropharm.2019.107683] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 06/16/2019] [Accepted: 06/23/2019] [Indexed: 12/20/2022]
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Liu HF, Zhao Z, Zhang J, Wu YY, Jiao Y, Wu T, Kim SC, Lee BH, Fan Y, Lee CW, Kim YW, Yang CH, Zhu XD, Zhao RJ. Acupuncture reduces nicotine-induced norepinephrine release in the hypothalamus via the solitary NMDA receptor/NOS pathway. Neurosci Lett 2019; 705:33-38. [DOI: 10.1016/j.neulet.2019.04.036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 04/12/2019] [Accepted: 04/16/2019] [Indexed: 10/27/2022]
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Wei J, Xu L, Du YN, Tang XF, Ye MQ, Wu YJ, Han WQ, Gao PJ. Membrane raft redox signalling contributes to endothelial dysfunction and vascular remodelling of thoracic aorta in angiotensin II-infused rats. Exp Physiol 2019; 104:946-956. [PMID: 30924217 DOI: 10.1113/ep087335] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 03/12/2019] [Indexed: 12/21/2022]
Abstract
NEW FINDINGS What is the central question of this study? Is the membrane raft redox signalling pathway involved in blood pressure increase, endothelial dysfunction and vascular remodelling in an angiotensin II-induced hypertensive animal model? What is the main finding and its importance? The membrane raft redox signalling pathway was involved in endothelial dysfunction and medial remodelling in angiotensin II-induced hypertension. ABSTRACT The membrane raft (MR) redox pathway is characterized by NADPH oxidase activation via the clustering of its subunits through lysosome fusion and the activation of acid sphingomyelinase (ASMase). Our previous study shows that the MR redox signalling pathway is associated with angiontensin II (AngII)-induced production of reactive oxygen species (ROS) and endothelial dysfunction in rat mesenteric arteries. In the present study, we hypothesized that this signalling pathway is involved in blood pressure increase, endothelial dysfunction and vascular remodelling in an AngII-induced hypertensive animal model. Sixteen-week-old male Sprague-Dawley rats were subjected to AngII infusion for 2 weeks with or without treatment with the lysosome fusion inhibitor bafilomycin A1 and ASMase inhibitor amitriptyline. After treatments, aortas were harvested for further study. The results showed that the MR redox signalling pathway was activated as indicated by the increase of MR formation, ASMase activity and ROS production in aorta from AngII-infused rats compared with that from control rats. MR formation and ROS production were significantly inhibited in thoracic aorta from AngII-induced rats treated with bafilomycin A1 and amitriptyline. Both treatments significantly attenuated blood pressure increase, endothelial dysfunction and vascular remodelling including medial hypertrophy, and increased collagen and fibronectin deposition in thoracic aortas from AngII-infused rats. Finally, both treatments significantly prevented the increase of inflammatory factors including monocyte chemotactic protein 1, intercellular adhesion molecule 1 and tumour necrosis factor α in thoracic aorta from AngII-infused rats. In conclusion, the present study demonstrates that the MR redox signalling pathway was involved in endothelial dysfunction and medial remodelling in AngII-induced hypertension.
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Affiliation(s)
- Jian Wei
- Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China
| | - Lian Xu
- Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China
| | - Ya-Nan Du
- Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China
| | - Xiao-Feng Tang
- Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China
| | - Mao-Qing Ye
- Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China
| | - Yong-Jie Wu
- Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China
| | - Wei-Qing Han
- Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China.,Laboratory of Vascular Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Ping-Jin Gao
- Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China.,Laboratory of Vascular Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
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7
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Alkam T, Nabeshima T. Molecular mechanisms for nicotine intoxication. Neurochem Int 2019; 125:117-126. [PMID: 30779928 DOI: 10.1016/j.neuint.2019.02.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 01/28/2019] [Accepted: 02/12/2019] [Indexed: 01/25/2023]
Abstract
Nicotine, one of the more than 4700 ingredients in tobacco smoke, is a neurotoxin and once used as pesticides in agriculture. Although its use in agriculture is prohibited in many countries, nicotine intoxication is still a problem among the workers in tobacco farms, and young children as well as adults due to the accidental or suicidal ingestions of nicotine products. Understanding the mechanism of nicotine intoxication is important not only for the prevention and treatment but also for the appropriate regulatory approaches. Here, we review pharmacokinetics of nicotine and the molecular mechanisms for acute and chronic intoxication from nicotine that might be relevant to the central and the peripheral nervous system. We include green tobacco sickness, acute intoxication from popular nicotine products, circadian rhythm changes, chronic intoxication from nicotine through prenatal nicotine exposure, newborn behaviors, and sudden infant death syndrome.
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Affiliation(s)
- Tursun Alkam
- Japanese Drug Organization of Appropriate Use and Research, Nagoya, Japan; Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA, USA.
| | - Toshitaka Nabeshima
- Japanese Drug Organization of Appropriate Use and Research, Nagoya, Japan; Advanced Diagnostic System Research Laboratory, Graduate School of Health Sciences, Fujita Health University, Toyoake, Japan.
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Han WQ, Xu L, Tang XF, Chen WD, Wu YJ, Gao PJ. Membrane rafts-redox signalling pathway contributes to renal fibrosis via modulation of the renal tubular epithelial-mesenchymal transition. J Physiol 2018; 596:3603-3616. [PMID: 29863758 DOI: 10.1113/jp275952] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 05/25/2018] [Indexed: 01/27/2023] Open
Abstract
KEY POINTS Membrane rafts (MRs)-redox signalling pathway is activated in response to transforming growth factor-β1 (TGF-β1) stimulation in renal tubular cells. This pathway contributes to TGF-1β-induced epithelial-mesenchymal transition (EMT) in renal tubular cells. The the MRs-redox signalling pathway is activated in renal tubular cells isolated from angiotensin II (AngII)-induced hypertensive rats. Inhibition of this pathway attenuated renal inflammation and fibrosis in AngII-induced hypertension. ABSTRACT The membrane rafts (MRs)-redox pathway is characterized by NADPH oxidase subunit clustering and activation through lysosome fusion, V-type proton ATPase subunit E2 (encoded by the Atp6v1e2 gene) translocation and sphingomyelin phosphodiesterase 1 (SMPD1, encoded by the SMPD1 gene) activation. In the present study, we hypothesized that the MRs-redox-derived reactive oxygen species (ROS) are involved in renal inflammation and fibrosis by promoting renal tubular epithelial-mesenchymal transition (EMT). Results show that transforming growth factor-β1 (TGF-β1) acutely induced MR formation and ROS production in NRK-52E cells, a rat renal tubular cell line. In addition, transfection of Atp6v1e2 small hairpin RNAs (shRNA) and SMPD1 shRNA attenuated TGF-β1-induced changes in EMT markers, including E-cadherin, α-smooth muscle actin (α-SMA) and fibroblast-specific protein-1 (FSP-1) in NRK-52E cells. Moreover, Erk1/2 activation may be a downstream regulator of the MRs-redox-derived ROS, because both shRNAs significantly inhibited TGF-β1-induced Erk1/2 phosphorylation. Further in vivo study shows that the renal tubular the MRs-redox signalling pathway was activated in angiotensin II (AngII)-induced hypertension, as indicated by the increased NADPH oxidase subunit Nox4 fraction in the MR domain, SMPD1 activation and increased ROS content in isolated renal tubular cells. Finally, renal transfection of Atp6v1e2 shRNA and SMPD1 shRNA significantly prevented renal fibrosis and inflammation, as indicated by the decrease of α-SMA, fibronectin, collagen I, monocyte chemoattractant protein-1 (MCP-1), intercellular cell adhesion molecule-1 (ICAM-1) and tumour necrosis factor-α (TNF-α) in kidneys from AngII-infused rats. It was concluded that the the MRs-redox signalling pathway is involved in TGF-β1-induced renal tubular EMT and renal inflammation/fibrosis in AngII-induced hypertension.
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Affiliation(s)
- Wei-Qing Han
- Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Laboratory of Vascular Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China
| | - Lian Xu
- Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Laboratory of Vascular Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Xiao-Feng Tang
- Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China
| | - Wen-Dong Chen
- Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China
| | - Yong-Jie Wu
- Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China
| | - Ping-Jin Gao
- Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Laboratory of Vascular Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China
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Higashi Y, Shimizu T, Yamamoto M, Tanaka K, Yawata T, Shimizu S, Zou S, Ueba T, Yuri K, Saito M. Stimulation of brain nicotinic acetylcholine receptors activates adrenomedullary outflow via brain inducible NO synthase-mediated S-nitrosylation. Br J Pharmacol 2018; 175:3758-3772. [PMID: 30007012 DOI: 10.1111/bph.14445] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 05/26/2018] [Accepted: 07/04/2018] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND PURPOSE We have demonstrated that i.c.v.-administered (±)-epibatidine, a nicotinic ACh receptor (nAChR) agonist, induced secretion of noradrenaline and adrenaline (catecholamines) from the rat adrenal medulla with dihydro-β-erythroidin (an α4β2 nAChR antagonist)-sensitive brain mechanisms. Here, we examined central mechanisms for the (±)-epibatidine-induced responses, focusing on brain NOS and NO-mediated mechanisms, soluble GC (sGC) and protein S-nitrosylation (a posttranslational modification of protein cysteine thiol groups), in urethane-anaesthetized (1.0 g·kg-1 , i.p.) male Wistar rats. EXPERIMENTAL APPROACH (±)-Epibatidine was i.c.v. treated after i.c.v. pretreatment with each inhibitor described below. Then, plasma catecholamines were measured electrochemically after HPLC. Immunoreactivity of S-nitrosylated cysteine (SNO-Cys) in α4 nAChR subunit (α4)-positive spinally projecting neurones in the rat hypothalamic paraventricular nucleus (PVN, a regulatory centre of adrenomedullary outflow) after i.c.v. (±)-epibatidine administration was also investigated. KEY RESULTS (±)-Epibatidine-induced elevation of plasma catecholamines was significantly attenuated by L-NAME (non-selective NOS inhibitor), carboxy-PTIO (NO scavenger), BYK191023 [selective inducible NOS (iNOS) inhibitor] and dithiothreitol (thiol-reducing reagent), but not by 3-bromo-7-nitroindazole (selective neuronal NOS inhibitor) or ODQ (sGC inhibitor). (±)-Epibatidine increased the number of spinally projecting PVN neurones with α4- and SNO-Cys-immunoreactivities, and this increment was reduced by BYK191023. CONCLUSIONS AND IMPLICATIONS Stimulation of brain nAChRs can induce elevation of plasma catecholamines through brain iNOS-derived NO-mediated protein S-nitrosylation in rats. Therefore, brain nAChRs (at least α4β2 subtype) and NO might be useful targets for alleviation of catecholamines overflow induced by smoking.
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Affiliation(s)
- Youichirou Higashi
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, Japan
| | - Takahiro Shimizu
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, Japan
| | - Masaki Yamamoto
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, Japan
| | - Kenjiro Tanaka
- Department of Neurobiology and Anatomy, Kochi Medical School, Kochi University, Nankoku, Kochi, Japan
| | - Toshio Yawata
- Department of Neurosurgery, Kochi Medical School, Kochi University, Nankoku, Kochi, Japan
| | - Shogo Shimizu
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, Japan
| | - Suo Zou
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, Japan
| | - Tetsuya Ueba
- Department of Neurosurgery, Kochi Medical School, Kochi University, Nankoku, Kochi, Japan
| | - Kazunari Yuri
- Department of Neurobiology and Anatomy, Kochi Medical School, Kochi University, Nankoku, Kochi, Japan
| | - Motoaki Saito
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, Japan
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Furuya WI, Colombari E, Ferguson AV, Colombari DSA. Effects of acetylcholine and cholinergic antagonists on the activity of nucleus of the solitary tract neurons. Brain Res 2017; 1659:136-141. [PMID: 28131721 DOI: 10.1016/j.brainres.2017.01.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 01/11/2017] [Accepted: 01/21/2017] [Indexed: 02/08/2023]
Abstract
Previously we have demonstrated that microinjection of acetylcholine (ACh) into the intermediate nucleus of the solitary tract (iNTS) induced sympatho-inhibition combined with a decrease in the phrenic nerve activity (PNA), whereas in the commissural NTS (cNTS), ACh did not change sympathetic nerve activity (SNA), but increased the PNA. In view of these demonstrated distinctive effects of ACh in different subnuclei of the NTS the current studies were undertaken to examine, using patch clamp techniques, the specific effects of ACh on the excitability of individual neurons in the NTS, as well as the neuropharmacology of these actions. Coronal slices of the brainstem containing either cNTS or iNTS subnuclei were used, and whole cell patch clamp recordings obtained from individual neurons in these two subnuclei. In cNTS, 58% of recorded neurons (n=12) demonstrated rapid reversible depolarizations in response to ACh (10mM), effects which were inhibited by the nicotinic antagonist mecamylamine (10μM), but unaffected by the muscarinic antagonist atropine (10μM). Similarly, bath application of ACh depolarized 76% of iNTS neurons (n=17), although in this case both atropine and mecamylamine reduced the ACh-induced depolarization. These data demonstrate that ACh depolarizes cNTS neurons through actions on nicotinic receptors, while depolarizing effects in iNTS are apparently mediated by both receptors.
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Affiliation(s)
- Werner I Furuya
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, Araraquara, SP, Brazil
| | - Eduardo Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, Araraquara, SP, Brazil
| | - Alastair V Ferguson
- Department of Biomedical and Molecular Sciences, School of Medicine, Queen's University, Kingston, ON, Canada
| | - Débora S A Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, Araraquara, SP, Brazil.
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Saeedi Saravi SS, Amirkhanloo R, Arefidoust A, Yaftian R, Saeedi Saravi SS, Shokrzadeh M, Dehpour AR. On the effect of minocycline on the depressive-like behavior of mice repeatedly exposed to malathion: interaction between nitric oxide and cholinergic system. Metab Brain Dis 2016; 31:549-61. [PMID: 26581675 DOI: 10.1007/s11011-015-9764-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 11/09/2015] [Indexed: 01/06/2023]
Abstract
This study was performed to investigate the antidepressant-like effect of minocycline in mice exposed to organophosphate pesticide malathion and possible involvement of nitric oxide/cGMP pathway in this paradigm. Mice were administered specific doses of malathion once daily for 7 consecutive days. After induction of depression, different doses of minocycline were daily injected alone or combined with non-specific NOS inhibitor, L-NAME, specific inducible NOS inhibitor, AG, NO precursor, L-arginine, and PDE5I, sildenafil. After locomotion assessment in open-field test, immobility times were recorded in the FST and TST. Moreover, hippocampal nitrite concentrations and acetylcholinesterase activity were measured. The results showed that repeated exposure to malathion induces depressive-like behavior at dose of 250 mg/kg. Minocycline (160 mg/kg) significantly reduced immobility times in FST and TST (P < 0.001). Combination of sub-effective doses of minocycline (80 mg/kg) with either L-NAME (3 mg/kg) or AG (25 mg/kg) significantly exerted a robust antidepressant-like effect in FST and TST (P < 0.001). Furthermore, minocycline at the same dose which has antidepressant-like effect, significantly reduced hippocampal nitrite concentration. The investigation indicates the essential role for NO/cGMP pathway in malathion-induced depressive-like behavior and antidepressant-like effect of minocycline. Moreover, the interaction between nitrergic and cholinergic systems are suggested to be involved in malathion-induced depression.
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Affiliation(s)
- Seyed Soheil Saeedi Saravi
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, P.O. Box: 13145-784, Tehran, Iran
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
- Department of Toxicology-Pharmacology, Faculty of Pharmacy, Guilan University of Medical Sciences, Rasht, Iran
| | - Roya Amirkhanloo
- Department of Toxicology-Pharmacology, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Alireza Arefidoust
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, P.O. Box: 13145-784, Tehran, Iran
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Rahele Yaftian
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, P.O. Box: 13145-784, Tehran, Iran
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Seyed Sobhan Saeedi Saravi
- Department of Toxicology-Pharmacology, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Mohammad Shokrzadeh
- Department of Toxicology-Pharmacology, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran.
| | - Ahmad Reza Dehpour
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, P.O. Box: 13145-784, Tehran, Iran.
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran.
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12
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Cheng PW, Kang BH, Lu PJ, Lin SS, Ho WY, Chen HH, Hong LZ, Wu YS, Hsiao M, Tseng CJ. Involvement of two distinct signalling pathways in IGF-1-mediated central control of hypotensive effects in normotensive and hypertensive rats. Acta Physiol (Oxf) 2014; 212:28-38. [PMID: 24995704 DOI: 10.1111/apha.12340] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 02/14/2014] [Accepted: 07/01/2014] [Indexed: 01/04/2023]
Abstract
AIMS Insulin-like growth factor-1 (IGF-1) is abundantly expressed in the nucleus tractus solitarii (NTS). In a previous study, we revealed that the induction of nitric oxide (NO) production in the NTS reduces blood pressure (BP). It is well known that both acute administration and chronic administration of IGF-I reduce BP. The aim of this study was to evaluate the short-term hypotensive effect of IGF-1 in the NTS and to delineate the underlying molecular mechanisms of IGF-1 in the NTS of normotensive WKY rats and spontaneously hypertensive rats (SHRs). METHOD Microinjections of the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 and the MAP kinase-ERK kinase (MEK) inhibitor PD98059 into the NTS in WKY rats and SHRs were used to study the involvement of IGF-1-induced depressor effects. RESULT An IGF-1 (7.7 pmol) injection into the NTS resulted in a significant decrease in BP and HR in WKY rats and SHRs. Immunoblotting and immunohistochemical analysis showed that the microinjection of LY294002 (0.6 pmol) or PD98059 (3.0 pmol) into the NTS attenuated the IGF-1-induced depressor effects and Akt or ERK phosphorylation in WKY rats. An attenuation effect of LY294002, but not PD98059, was found in the SHRs. However, the mRNA and protein expression levels of the IGF-1R showed no significant differences in the NTS of the WKY rats and the SHRs. CONCLUSION These results suggest that distinct Akt and ERK signalling pathways mediated the IGF-1 control of the central depressor effects in WKY rats and SHRs. ERK signalling defects may be associated with the development of hypertension.
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Affiliation(s)
- P.-W. Cheng
- Department of Medical Education and Research; Kaohsiung Veterans General Hospital; Kaohsiung Taiwan
| | - B.-H. Kang
- Department of Diving Medicine; Zouying Branch of Kaohsiung Armed Forces General Hospital Kaohsiung; Kaohsiung Taiwan
| | - P.-J. Lu
- Institute of Clinical Medicine; National Cheng-Kung University; Tainan Taiwan
| | - S.-S. Lin
- Institute of Biomedical Sciences; National Sun Yat-Sen University; Kaohsiung Taiwan
| | - W.-Y. Ho
- Division of General Internal Medicine; Department of Internal Medicine; Kaohsiung Medical University Hospital; Kaohsiung Medical University; Kaohsiung Taiwan
| | - H.-H. Chen
- Institute of Clinical Medicine; National Yang-Ming University; Taipei Taiwan
| | - L.-Z. Hong
- Department of Medical Education and Research; Taichung Veterans General Hospital; Taichung Taiwan
| | - Y.-S. Wu
- Department of Medical Education and Research; Kaohsiung Veterans General Hospital; Kaohsiung Taiwan
| | - M. Hsiao
- Genomics Research Center; Academia Sinica; Taipei Taiwan
| | - C.-J. Tseng
- Department of Medical Education and Research; Kaohsiung Veterans General Hospital; Kaohsiung Taiwan
- Institute of Clinical Medicine; National Cheng-Kung University; Tainan Taiwan
- Division of General Internal Medicine; Department of Internal Medicine; Kaohsiung Medical University Hospital; Kaohsiung Medical University; Kaohsiung Taiwan
- Department of Medical Research; China Medical University Hospital; China Medical University; Taichung Taiwan
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13
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Feng L, Uteshev VV. Projection target-specific action of nicotine in the caudal nucleus of the solitary tract. J Neurosci Res 2014; 92:1560-72. [PMID: 24975270 DOI: 10.1002/jnr.23436] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 05/11/2014] [Accepted: 05/20/2014] [Indexed: 01/26/2023]
Abstract
The brainstem nucleus of the solitary tract (NTS) is the key integrating relay in the central processing of sensory information from the thoracic and from most subdiaphragmatic viscera. Modulation of neuronal excitability and synaptic activity in the NTS by nicotinic agents can have potent effects on vital physiological functions, such as feeding, digestion, respiration, and blood circulation. Caudal NTS neurons demonstrate considerable heterogeneity in projection targets, synaptic properties, and expression of nicotinic acetylcholine receptors (nAChRs). However, despite its heterogeneity, the caudal NTS may contain discrete subsets of neurons with unique projection target-specific properties. To test this hypothesis, we used in vivo fluorescent tracing and ex vivo patch-clamp electrophysiology to evaluate responsiveness to nicotine of anatomically identified caudal NTS neurons that project to the hypothalamic paraventricular nucleus (PVN) and the brainstem caudal ventrolateral medulla (CVLM). The results of this study demonstrate that responsiveness to nicotine correlates with where the neurons project. Specifically, PVN-projecting caudal NTS neurons respond to nicotine only presynaptically (i.e., via activation of presynaptic nAChRs and potentiation of synaptic release of glutamate), suggesting indirect, glutamate-dependent effects of nicotine on the PVN-projecting NTS circuitry. By contrast, CVLM-projecting caudal NTS neurons exhibit only limited presynaptic, but dominant somatodendritic, responsiveness to nicotine, suggesting that the effects of nicotine on the CVLM-projecting NTS circuitry are direct and largely glutamate independent. Understanding the relationships among function-specific brainstem/hypothalamic neuronal networks, nuclei, and individual neurons could help develop therapies targeting identifiable neuronal circuits to offset impaired autonomic homeostasis.
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Affiliation(s)
- Lin Feng
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois
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14
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de Lartigue G. Putative roles of neuropeptides in vagal afferent signaling. Physiol Behav 2014; 136:155-69. [PMID: 24650553 DOI: 10.1016/j.physbeh.2014.03.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 02/23/2014] [Accepted: 03/10/2014] [Indexed: 02/06/2023]
Abstract
The vagus nerve is a major pathway by which information is communicated between the brain and peripheral organs. Sensory neurons of the vagus are located in the nodose ganglia. These vagal afferent neurons innervate the heart, the lung and the gastrointestinal tract, and convey information about peripheral signals to the brain important in the control of cardiovascular tone, respiratory tone, and satiation, respectively. Glutamate is thought to be the primary neurotransmitter involved in conveying all of this information to the brain. It remains unclear how a single neurotransmitter can regulate such an extensive list of physiological functions from a wide range of visceral sites. Many neurotransmitters have been identified in vagal afferent neurons and have been suggested to modulate the physiological functions of glutamate. Specifically, the anorectic peptide transmitters, cocaine and amphetamine regulated transcript (CART) and the orexigenic peptide transmitters, melanin concentrating hormone (MCH) are differentially regulated in vagal afferent neurons and have opposing effects on food intake. Using these two peptides as a model, this review will discuss the potential role of peptide transmitters in providing a more precise and refined modulatory control of the broad physiological functions of glutamate, especially in relation to the control of feeding.
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Affiliation(s)
- Guillaume de Lartigue
- Dept Anatomy, Physiology and Cell Biology, UC Davis School of Veterinary Medicine, Davis, CA 95616, USA.
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15
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Pigott B, Bartus K, Garthwaite J. On the selectivity of neuronal NOS inhibitors. Br J Pharmacol 2013; 168:1255-65. [PMID: 23072468 PMCID: PMC3594681 DOI: 10.1111/bph.12016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 09/07/2012] [Accepted: 09/30/2012] [Indexed: 12/16/2022] Open
Abstract
Background and Purpose Isoform-selective inhibitors of NOS enzymes are desirable as research tools and for potential therapeutic purposes. Vinyl-l-N-5-(1-imino-3-butenyl)-l-ornithine (l-VNIO) and Nω-propyl-l-arginine (NPA) purportedly have good selectivity for neuronal over endothelial NOS under cell-free conditions, as does N-[(3-aminomethyl)benzyl]acetamidine (1400W), which is primarily an inducible NOS inhibitor. Although used in numerous investigations in vitro and in vivo, there have been surprisingly few tests of the potency and selectivity of these compounds in cells. This study addresses this deficiency and evaluates the activity of new and potentially better pyrrolidine-based compounds. Experimental Approach The inhibitors were evaluated by measuring their effect on NMDA-evoked cGMP accumulation in rodent hippocampal slices, a response dependent on neuronal NOS, and ACh-evoked cGMP synthesis in aortic rings of the same animals, an endothelial NOS-dependent phenomenon. Key Results l-VNIO, NPA and 1400W inhibited responses in both tissues but all showed less than fivefold higher potency in the hippocampus than in the aorta, implying useless selectivity for neuronal over endothelial NOS at the tissue level. In addition, the inhibitors had a 25-fold lower potency in the hippocampus than reported previously, the IC50 values being approximately 1 μM for l-VNIO and NPA, and 150 μM for 1400W. Pyrrolidine-based inhibitors were similarly weak and nonselective. Conclusion and Implications The results suggest that l-VNIO, NPA and 1400W, as well as the newer pyrrolidine-type inhibitors, cannot be used as neuronal NOS inhibitors in cells without stringent verification. The identification of inhibitors with useable selectivity in cells and tissues remains an important goal.
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Affiliation(s)
- B Pigott
- Wolfson Institute for Biomedical Research, University College London, London, UK
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16
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Cheng PW, Wu ATH, Lu PJ, Yang YC, Ho WY, Lin HC, Hsiao M, Tseng CJ. Central hypotensive effects of neuropeptide Y are modulated by endothelial nitric oxide synthase after activation by ribosomal protein S6 kinase. Br J Pharmacol 2013; 167:1148-60. [PMID: 22708658 DOI: 10.1111/j.1476-5381.2012.02077.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND AND PURPOSE Neuropeptide Y (NPY) is a 36-amino acid polypeptide found abundantly in the central and peripheral nervous systems. NPY exerts a potent depressor effect via the activation of both Y(1) and Y(2) receptors in the nucleus tractus solitarii (NTS) of rats. However, the precise mechanisms involved in this NPY-mediated action remained unclear. EXPERIMENTAL APPROACH Effects of a selective antagonist of Y(1) receptors, a PKC inhibitor, a PI3 kinase inhibitor, a NOS inhibitor, an endothelial NOS (eNOS)-selective inhibitor, a neuronal NOS (nNOS)-specific inhibitor or a MAPK inhibitor, on responses to microinjection of NPY into the NTS of Wistar-Kyoto rats were studied to determine the underlying mechanisms. Blood pressure and heart rate were measured and, in NTS, protein phosphorylation assessed by immunohistochemical techniques. KEY RESULTS Unilateral microinjection of exogenous NPY (4.65pmol/60nL) into the NTS of urethane-anesthetized Wistar-Kyoto rats markedly decreased blood pressure and heart rate. Microinjection of the Y(1) receptor antagonist BIBP3226 or the G(i) /G(o) -protein inhibitor, Pertussis toxin, into the NTS attenuated these NPY-induced hypotensive effects. A selective Y(1) receptor agonist increased expression of ERK1/2, ribosomal protein S6 kinase (RSK) and the phosphorylation of eNOS. RSK also bound directly to eNOS and induced its phosphorylation at Ser(1177) . Pretreatment of the NTS with an eNOS inhibitor, but not a nNOS inhibitor, attenuated the NPY-induced hypotensive effects. CONCLUSIONS AND IMPLICATIONS Together, these results suggested that NPY-induced depressor effects were mediated by activating NPY Y(1) receptor-PKC-ERK-RSK-eNOS and Ca(2+) -eNOS signalling pathways, which are involved in regulation of blood pressure in the NTS.
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Affiliation(s)
- Pei-Wen Cheng
- Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
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Cheng WH, Lu PJ, Hsiao M, Hsiao CH, Ho WY, Cheng PW, Lin CT, Hong LZ, Tseng CJ. Renin activates PI3K-Akt-eNOS signalling through the angiotensin AT₁ and Mas receptors to modulate central blood pressure control in the nucleus tractus solitarii. Br J Pharmacol 2012; 166:2024-35. [PMID: 22224457 DOI: 10.1111/j.1476-5381.2012.01832.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE The renin-angiotensin system (RAS) is critical for the control of blood pressure by the CNS. Recently, direct renin inhibitors were approved as antihypertensive agents. However, the signalling mechanism of renin, which regulates blood pressure in the nucleus tractus solitarii (NTS) remains unclear. Here we have investigated the signalling pathways involved in renin-mediated blood pressure regulation, at the NTS. EXPERIMENTAL APPROACH Depressor responses to renin microinjected into the NTS of Wistar-Kyoto rats were elicited in the absence and presence of the endothelial nitric oxide synthase (eNOS)-specific inhibitor, N(5)-(-iminoethyl)-L-ornithine, Akt inhibitor IV and LY294002, a PI3K inhibitor and GP antagonist-2A [G(q) inhibitor]. Lisinopril (angiotensin converting enzyme inhibitor), losartan, valsartan (angiotensin AT(1) receptor antagonists), D-Ala7-Ang-(1-7) (angiotensin-(1-7) receptor antagonist) were used to study the involvement of RAS on renin-induced depressor effects. KEY RESULTS Microinjection of renin into the NTS produced a prominent depressor effect and increased NO production. Pretreatment with G(q) -PI3K-Akt-eNOS pathway-specific inhibitors significantly attenuated the depressor response evoked by renin. Immunoblotting and immunohistochemical studies further showed that inhibition of PI3K significantly blocked renin-induced eNOS-Ser ¹¹⁷ and Akt-Ser⁴⁷³ phosphorylation in situ. In addition, pre-treatment of the NTS with RAS inhibitors attenuated the vasodepressor effects evoked by renin. Microinjection of renin also increased Ras activation in the NTS. CONCLUSIONS AND IMPLICATIONS Taken together, these results suggest renin modulated blood pressure at the NTS by AT₁ and Mas receptor-mediated activation of G(q) and Ras to evoke PI3K-Akt-eNOS signalling.
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Affiliation(s)
- Wen-Han Cheng
- Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
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Kaakinen M, Ducci F, Sillanpää MJ, Läärä E, Järvelin MR. Associations between variation in CHRNA5-CHRNA3-CHRNB4, body mass index and blood pressure in the Northern Finland Birth Cohort 1966. PLoS One 2012; 7:e46557. [PMID: 23029550 PMCID: PMC3459914 DOI: 10.1371/journal.pone.0046557] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 09/01/2012] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND The CHRNA5-CHRNA3-CHRNB4 gene cluster on 15q25 has consistently been associated with smoking quantity, nicotine dependence and lung cancer. Recent research also points towards its involvement in cardiovascular homeostasis, but studies in large human samples are lacking, especially on the role of the gene cluster in blood pressure regulation. METHODOLOGY/PRINCIPAL FINDINGS We studied the associations between 18 single nucleotide polymorphisms (SNPs) in CHRNA5-CHRNA3-CHRNB4 and systolic blood pressure (SBP), diastolic blood pressure (DBP), and body mass index (BMI) in 5402 young adults from the Northern Finland Birth Cohort 1966. We observed some evidence for associations between two SNPs and SBP and between six SNPs and BMI; the evidence for associations with DBP was weaker. The associations with the three phenotypes were driven by different loci with low linkage disequilibrium with each other. The associations appeared more pronounced in smokers, such that the smoking-increasing alleles would predict lower SBP and BMI. Each additional copy of the rs1948 G-allele and the rs950776 A-allele reduced SBP on average by -1.21 (95% CI -2.01, -0.40) mmHg in smokers. The variants associated with BMI included rs2036534, rs6495309, rs1996371, rs6495314, rs4887077 and rs11638372 and had an average effect size of -0.38 (-0.68, -0.08) kg/m(2) per an additional copy of the risk allele in smokers. Formal assessments of interactions provided weaker support for these findings, especially after adjustment for multiple testing. CONCLUSIONS Variation at 15q25 appears to interact with smoking status in influencing SBP and BMI. The genetic loci associated with SBP were in low linkage disequilibrium with those associated with BMI suggesting that the gene cluster might regulate SBP through biological mechanisms that partly differ from those regulating BMI. Further studies in larger samples are needed for more precise evaluation of the possible interactions, and to understand the mechanisms behind.
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Affiliation(s)
- Marika Kaakinen
- Institute of Health Sciences, University of Oulu, Oulu, Finland.
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