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The Vasoactive Effect of Perivascular Adipose Tissue and Hydrogen Sulfide in Thoracic Aortas of Normotensive and Spontaneously Hypertensive Rats. Biomolecules 2022; 12:biom12030457. [PMID: 35327649 PMCID: PMC8946625 DOI: 10.3390/biom12030457] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 02/28/2022] [Accepted: 03/09/2022] [Indexed: 02/05/2023] Open
Abstract
The objective of this study was to investigate the vasoregulatory role of perivascular adipose tissue (PVAT) and its mutual interaction with endogenous and exogenous H2S in the thoracic aorta (TA) of adult normotensive Wistar rats and spontaneously hypertensive rats (SHRs). In SHRs, hypertension was associated with cardiac hypertrophy and increased contractility. Regardless of the strain, PVAT revealed an anticontractile effect; however, PVAT worsened endothelial-dependent vasorelaxation. Since H2S produced by both the vascular wall and PVAT had a pro-contractile effect in SHRs, H2S decreased the sensitivity of adrenergic receptors to noradrenaline in Wistar rats. While H2S had no contribution to endothelium-dependent relaxation in Wistar rats, in SHRs, H2S produced by the vascular wall had a pro-relaxant effect. We observed a larger vasorelaxation induced by exogenous H2S donor in SHRs than in Wistar rats. Additionally, in the presence of PVAT, this effect was potentiated. We demonstrated that PVAT of the TA aggravated endothelial function in SHRs. However, H2S produced by the TA vascular wall had a pro-relaxation effect, and PVAT revealed anti-contractile activity mediated by the release of an unknown factor and potentiated the vasorelaxation induced by exogenous H2S. All these actions could represent a form of compensatory mechanism to balance impaired vascular tone regulation.
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Lezama-Martinez D, Elena Hernandez-Campos M, Flores-Monroy J, Valencia-Hernandez I, Martinez-Aguilar L. Time-Dependent Effects of Individual and Combined Treatments With Nebivolol, Lisinopril, and Valsartan on Blood Pressure and Vascular Reactivity to Angiotensin II and Norepinephrine. J Cardiovasc Pharmacol Ther 2021; 26:490-499. [PMID: 33779339 DOI: 10.1177/10742484211001861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Clinical guidelines suggest the combination of 2 drugs as a strategy to treat hypertension. However, some antihypertensive combinations have been shown to be ineffective. Therefore, it is necessary to determine whether differences exist between the results of monotherapy and combination therapy by temporal monitoring of the responses to angiotensin II and norepinephrine, which are vasoconstrictors involved in the development of hypertension. Thus, the purpose of this work was to determine the vascular reactivity to angiotensin II and norepinephrine in spontaneously hypertensive rat (SHR) aortic rings after treatment with valsartan, lisinopril, nebivolol, nebivolol-lisinopril, and nebivolol-valsartan for different periods of time. In this study, male SHR and Wistar Kyoto normotensive (WKY) rats were divided into 7 groups treated for 1, 2, and 4 weeks: (1) WKY + vehicle, (2) SHR + vehicle; (3) SHR + nebivolol; (4) SHR + lisinopril; (5) SHR + valsartan; (6) SHR + nebivolol-lisinopril; and (7) SHR + nebivolol-valsartan. Blood pressure was measured by the tail-cuff method, and vascular reactivity was determined from the concentration-response curve to angiotensin II and norepinephrine in aortic rings. The results showed that the combined and individual treatments reduced mean blood pressure at all times evaluated. All treatments decreased vascular reactivity to angiotensin II; however, in the case of lisinopril and nebivolol-lisinopril, the effect observed was significant up to 2 weeks. All treatments decreased the reactivity to norepinephrine up to week 4. These results show a time-dependent difference in vascular reactivity between the pharmacological treatments, with nebivolol-valsartan and nebivolol-lisinopril being both effective combinations. Additionally, the results suggest crosstalk between the renin-angiotensin and sympathetic nervous systems to reduce blood pressure and to improve treatment efficacy.
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Affiliation(s)
- Diego Lezama-Martinez
- Laboratory of Pharmacology, F.E.S.-Cuautitlan, 7180Universidad Nacional Autonoma de Mexico, Cuautitlan Izcalli, Mexico, Mexico
- Laboratory of Pharmacodynamics, Escuela Superior de Medicina, 27740Instituto Politecnico Nacional, D.F., Mexico, Mexico
| | - Maria Elena Hernandez-Campos
- Laboratory of Pharmacodynamics, Escuela Superior de Medicina, 27740Instituto Politecnico Nacional, D.F., Mexico, Mexico
| | - Jazmin Flores-Monroy
- Laboratory of Pharmacology, F.E.S.-Cuautitlan, 7180Universidad Nacional Autonoma de Mexico, Cuautitlan Izcalli, Mexico, Mexico
| | - Ignacio Valencia-Hernandez
- Laboratory of Pharmacodynamics, Escuela Superior de Medicina, 27740Instituto Politecnico Nacional, D.F., Mexico, Mexico
| | - Luisa Martinez-Aguilar
- Laboratory of Pharmacology, F.E.S.-Cuautitlan, 7180Universidad Nacional Autonoma de Mexico, Cuautitlan Izcalli, Mexico, Mexico
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Stultiens JJA, Guinand N, Van Rompaey V, Pérez Fornos A, Kunst HPM, Kingma H, van de Berg R. The resilience of the inner ear-vestibular and audiometric impact of transmastoid semicircular canal plugging. J Neurol 2021; 269:5229-5238. [PMID: 34374862 PMCID: PMC9467949 DOI: 10.1007/s00415-021-10693-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/18/2021] [Accepted: 06/28/2021] [Indexed: 11/30/2022]
Abstract
Background Certain cases of superior semicircular canal dehiscence or benign paroxysmal positional vertigo can be treated by plugging of the affected semicircular canal. However, the extent of the impact on vestibular function and hearing during postoperative follow-up is not known. Objective To evaluate the evolution of vestibular function and hearing after plugging of a semicircular canal. Methods Six patients underwent testing before and 1 week, 2 months, and 6 months after plugging of the superior or posterior semicircular canal. Testing included caloric irrigation test, video Head Impulse Test (vHIT), cervical and ocular Vestibular Evoked Myogenic Potentials (VEMPs) and audiometry. Results Initially, ipsilateral caloric response decreased in all patients and vHIT vestibulo-ocular reflex (VOR) gain of each ipsilateral semicircular canal decreased in 4/6 patients. In 4/6 patients, postoperative caloric response recovered to > 60% of the preoperative value. In 5/6 patients, vHIT VOR gain was restored to > 85% of the preoperative value for both ipsilateral non-plugged semicircular canals. In the plugged semicircular canal, this gain decreased in 4/5 patients and recovered to > 50% of the preoperative value. Four patients preserved cervical and ocular VEMP responses. Bone conduction hearing deteriorated in 3/6 patients, but recovered within 6 months postoperatively, although one patient had a persistent loss of 15 dB at 8 kHz. Conclusion Plugging of a semicircular canal can affect both vestibular function and hearing. After initial deterioration, most patients show recovery during follow-up. However, a vestibular function loss or high-frequency hearing loss can persist. This stresses the importance of adequate counseling of patients considering plugging of a semicircular canal. Supplementary Information The online version contains supplementary material available at 10.1007/s00415-021-10693-5.
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Affiliation(s)
- Joost J A Stultiens
- Department of Otorhinolaryngology & Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands.
| | - Nils Guinand
- Division of Otorhinolaryngology and Head-and-Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Vincent Van Rompaey
- Department of Otorhinolaryngology and Head & Neck Surgery, Faculty of Medicine and Health Sciences, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium
| | - Angélica Pérez Fornos
- Division of Otorhinolaryngology and Head-and-Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Henricus P M Kunst
- Department of Otorhinolaryngology & Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Hermanus Kingma
- Department of Otorhinolaryngology & Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Raymond van de Berg
- Department of Otorhinolaryngology & Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands
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Hsu JCN, Sekizawa S, Tochinai R, Kuwahara M. Loss of Group II Metabotropic Glutamate Receptor Signaling Exacerbates Hypertension in Spontaneously Hypertensive Rats. Life (Basel) 2021; 11:life11070720. [PMID: 34357092 PMCID: PMC8307370 DOI: 10.3390/life11070720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/13/2021] [Accepted: 07/18/2021] [Indexed: 11/16/2022] Open
Abstract
High blood pressure is a major risk factor of cerebro-cardiovascular outcomes. Blood pressure is partly regulated by the autonomic nervous system and its reflex functions; therefore, we hypothesized that pharmacological intervention in the brainstem that can regulate blood pressure could be a novel therapeutic strategy to control hypertension. We infused a group II metabotropic glutamate receptor (mGluR) antagonist (LY341495, 0.40 μg/day), using a mini-osmotic pump, into the dorsal medulla oblongata in young spontaneously hypertensive rats (SHRs), as this area is adjacent to the nucleus tractus solitarius (NTS), of which the neurons are involved in baroreflex pathways with glutamatergic transmission. Blood pressure was recorded for conscious rats with the tail cuff method. A 6-week antagonist treatment from 6 to 12 weeks of age slightly but significantly increased systolic blood pressure by >30 mmHg, compared to that in SHRs without treatment. Moreover, the effect continued even 3 weeks after the treatment ended, and concurred with an increase in blood catecholamine concentration. However, heart rate variability analysis revealed that LY341495 treatment had little effect on autonomic activity. Meanwhile, mRNA expression level of mGluR subtype 2, but not subtype 3 in the brainstem was significantly enhanced by the antagonist treatment in SHRs, possibly compensating the lack of mGluR signaling. In conclusion, mGluR2 signaling in the dorsal brainstem is crucial for preventing the worsening of hypertension over a relatively long period in SHRs, through a mechanism of catecholamine secretion. This may be a specific drug target for hypertension therapy.
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El-Mahdy MA, Mahgoup EM, Ewees MG, Eid MS, Abdelghany TM, Zweier JL. Long-term electronic cigarette exposure induces cardiovascular dysfunction similar to tobacco cigarettes: role of nicotine and exposure duration. Am J Physiol Heart Circ Physiol 2021; 320:H2112-H2129. [PMID: 33606584 DOI: 10.1152/ajpheart.00997.2020] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Electronic cigarette (e-cig) vaping (ECV) has been proposed as a safer alternative to tobacco cigarette smoking (TCS); however, this remains controversial due to a lack of long-term comparative studies. Therefore, we developed a chronic mouse exposure model that mimics human vaping and allows comparison with TCS. Longitudinal studies were performed to evaluate alterations in cardiovascular function with TCS and ECV exposure durations of up to 60 wk. For ECV, e-cig liquid with box-mod were used and for TCS, 3R4F-cigarettes. C57/BL6 male mice were exposed 2 h/day, 5 days/wk to TCS, ECV, or air control. The role of vape nicotine levels was evaluated using e-cig-liquids with 0, 6, or 24 mg/mL nicotine. Following 16-wk exposure, increased constriction to phenylephrine and impaired endothelium-dependent and endothelium-independent vasodilation were observed in aortic segents, paralleling the onset of systemic hypertension, with elevations in systemic vascular resistance. Following 32 wk, TCS and ECV induced cardiac hypertrophy. All of these abnormalities further increased out to 60 wk of exposure, with elevated heart weight and aortic thickness along with increased superoxide production in vessels and cardiac tissues of both ECV and TCS mice. While ECV-induced abnormalities were seen in the absence of nicotine, these occurred earlier and were more severe with higher nicotine exposure. Thus, long-term vaping of e-cig can induce cardiovascular disease similar to TCS, and the severity of this toxicity increases with exposure duration and vape nicotine content.NEW & NOTEWORTHY A chronic mouse exposure model that mimics human e-cigarette vaping and allows comparison with tobacco cigarette smoking was developed and utilized to perform longitudinal studies of alterations in cardiovascular function. E-cigarette exposure led to the onset of cardiovascular disease similar to that with tobacco cigarette smoking. Impaired endothelium-dependent and endothelium-independent vasodilation with increased adrenergic vasoconstriction were observed, paralleling the onset of systemic hypertension and subsequent cardiac hypertrophy. This cardiovascular toxicity was dependent on exposure duration and nicotine dose.
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Affiliation(s)
- Mohamed A El-Mahdy
- Center for Environmental and Smoking Induced Disease and Department of Internal Medicine, Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio
| | - Elsayed M Mahgoup
- Center for Environmental and Smoking Induced Disease and Department of Internal Medicine, Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio.,Department of Pharmacology and Toxicology, College of Pharmacy, Al-Azhar University, Cairo, Egypt
| | - Mohamed G Ewees
- Center for Environmental and Smoking Induced Disease and Department of Internal Medicine, Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio
| | - Mahmoud S Eid
- Center for Environmental and Smoking Induced Disease and Department of Internal Medicine, Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio
| | - Tamer M Abdelghany
- Center for Environmental and Smoking Induced Disease and Department of Internal Medicine, Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio
| | - Jay L Zweier
- Center for Environmental and Smoking Induced Disease and Department of Internal Medicine, Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio
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Ferreira Miranda MT, Lemos MP, Sasaki JE, Mota GR, Marocolo M, Sordi CCD, Almeida TR, Dias da Silva VJ, Neto OB. Exercise training ameliorates adrenergic control in spontaneously hypertensive rats. Clin Exp Hypertens 2021; 43:101-111. [PMID: 32924628 DOI: 10.1080/10641963.2020.1817474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The goal of this study was to examine vascular control after sympathetic stimulation by tyramine infusion in hypertensive rats submitted to swimming training. To this end, male rats were assigned to the following groups: sedentary (SN) and trained normotensive (TN), sedentary (SH) and trained hypertensive (TH). Arterial pressure (AP), heart rate (HR), HR variability (HRV), AP variability (APV), and cardiac autonomic function were recorded. Following, infusion of tyramine was administrated. The TN and TH showed a lower resting HR compared with their respective sedentary groups (p < .05). Pressure levels were less in TH than SH (p < .05). The TH showed a higher HRV together with a lower APV in comparison to SH (p < .05). The sympathetic modulation of HRV and APV was lower in TH than in SH (p < .05). Both trained groups presented an increased parasympathetic modulation of HRV compared with their respective sedentary groups (p < .05). The TN and TH groups had a higher vagal effect in comparison with their respective sedentary groups (p < .001). The sympathetic effect was lower in TH than in SH (p < .001). Pressor and HR responses to tyramine in different doses were attenuated in TH (p < .001). Further analysis showed a significant association between infusion of tyramine and normalized LF component of HRV (r = 0.84, p < .001), systolic APV (r = 0.58, p < .001) and diastolic APV (r = 0.49, p < .001). In conclusion, exercise training provokes less pressor response variation by tyramine infusion in hypertensive animals suggesting sympathetic nerve endings adjustments and decrease of the vasoconstrictor effect attenuates injury caused by hypertension improving cardiovascular autonomic dysfunction, which can be associated with sympathetic attenuation.
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Affiliation(s)
- Munique Tostes Ferreira Miranda
- Exercise Science, Health and Human Performance Research Group, Department of Sport Sciences, Federal University of Triângulo Mineiro , Uberaba, Brazil.,Department of Medicine, Federal University of São Paulo , São Paulo, Brazil
| | - Marina Paiva Lemos
- Exercise Science, Health and Human Performance Research Group, Department of Sport Sciences, Federal University of Triângulo Mineiro , Uberaba, Brazil
| | - Jeffer Eidi Sasaki
- Exercise Science, Health and Human Performance Research Group, Department of Sport Sciences, Federal University of Triângulo Mineiro , Uberaba, Brazil
| | - Gustavo R Mota
- Exercise Science, Health and Human Performance Research Group, Department of Sport Sciences, Federal University of Triângulo Mineiro , Uberaba, Brazil
| | - Moacir Marocolo
- Department of Physiology, Federal University of Juiz de Fora , Juiz de Fora, Brazil
| | - Carla Cristina de Sordi
- Department of Endocrinology and Metabolism, Postgraduate Course on Health Science, Federal University of Triângulo Mineiro , Uberaba, Brazil
| | | | | | - Octávio Barbosa Neto
- Exercise Science, Health and Human Performance Research Group, Department of Sport Sciences, Federal University of Triângulo Mineiro , Uberaba, Brazil.,Department of Physiology, Federal University of Triângulo Mineiro , Uberaba, Brazil
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Nisimura LM, Bousquet P, Muccillo F, Tibirica E, Garzoni LR. Tyrosine hydroxylase and β2-adrenergic receptor expression in leukocytes of spontaneously hypertensive rats: putative peripheral markers of central sympathetic activity. ACTA ACUST UNITED AC 2020; 53:e9615. [PMID: 33146287 PMCID: PMC7643929 DOI: 10.1590/1414-431x20209615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 08/27/2020] [Indexed: 11/21/2022]
Abstract
The sympathetic nervous system (SNS) plays a fundamental role in the pathophysiology of cardiovascular diseases, including primary arterial hypertension. In this study, we aimed to investigate whether the expression of the rate-limiting enzyme in catecholamine synthesis, tyrosine hydroxylase (TH), and the β2-adrenergic receptor (β2-AR) in immune cells from peripheral blood, reflect central SNS activity in spontaneously hypertensive rats (SHR). TH expression in the lower brainstem and adrenal glands and β2-AR expression in the lower brainstem were analyzed by western blot analyses. In the leukocytes, TH and β2-AR expression was evaluated by flow cytometry before and after chronic treatment with the centrally-acting sympathoinhibitory drug clonidine. Western blot analyses showed increased TH and β2-AR expression in the lower brainstem and increased TH in adrenal glands from SHR compared to normotensive Wistar Kyoto rats (WKY). Lower brainstem from SHR treated with clonidine presented reduced TH and β2-AR levels, and adrenal glands had decreased TH expression compared to SHR treated with vehicle. Flow cytometry showed that the percentage of leukocytes that express β2-AR is higher in SHR than in WKY. However, the percentage of leukocytes that expressed TH was higher in WKY than in SHR. Moreover, chronic treatment with clonidine normalized the levels of TH and β2-AR in leukocytes from SHR to similar levels of those of WKY. Our study demonstrated that the percentage of leukocytes expressing TH and β2-AR was altered in arterial hypertension and can be modulated by central sympathetic inhibition with clonidine treatment.
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Affiliation(s)
- L M Nisimura
- Laboratório de Inovações em Terapias, Ensino e Bioprodutos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil.,Laboratório de Investigação Cardiovascular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil
| | - P Bousquet
- Department of Pharmacology, Faculty of Medicine, University of Strasbourg, Strasbourg, France
| | - F Muccillo
- Instituto Nacional de Cardiologia, Ministério da Saúde, Rio de Janeiro, RJ, Brasil
| | - E Tibirica
- Laboratório de Investigação Cardiovascular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil.,Instituto Nacional de Cardiologia, Ministério da Saúde, Rio de Janeiro, RJ, Brasil
| | - L R Garzoni
- Laboratório de Inovações em Terapias, Ensino e Bioprodutos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil
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Fornos AP, van de Berg R, Armand S, Cavuscens S, Ranieri M, Crétallaz C, Kingma H, Guyot JP, Guinand N. Cervical myogenic potentials and controlled postural responses elicited by a prototype vestibular implant. J Neurol 2019; 266:33-41. [PMID: 31396689 PMCID: PMC6722147 DOI: 10.1007/s00415-019-09491-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 07/28/2019] [Accepted: 07/29/2019] [Indexed: 02/04/2023]
Abstract
Gaze stabilization and postural control are two key functions of the vestibular system. In consequence, oscillopsia and chronic imbalance are the two main complaints of patients presenting with a severe bilateral vestibular function loss. The vestibular implant is emerging as a promising treatment for this group of patients whose quality of life is significantly impaired. Although the final aim of the vestibular implant should be to restore vestibular function as a whole, until now the research has focused mainly on the restoration of the vestibulo-ocular reflex to improve gaze stabilization. In this study, we aimed to explore whether the vestibulo-collic and vestibulo-spinal pathways could be activated and controlled with the electrical stimuli provided by our vestibular implant prototype. This was first explored and demonstrated with recordings of electrically elicited cervical vestibular evoked myogenic potentials (ecVEMPs). ecVEMPs with characteristics similar to the classical acoustically elicited cervical vestibular evoked myogenic potentials (cVEMPs) were successfully evoked in five out of the eight tested patients. Amplitudes of the electrically elicited N–P complex varied, ranging from 44 to 120 µV. Mean latencies of the N and P waves were of 9.71(± 1.17) ms and 17.24 ms (± 1.74), respectively. We also evaluated the possibility of generating controlled postural responses using a stepping test. Here, we showed that controlled and consistent whole-body postural responses can be effectively obtained with rapid changes in the “baseline” (constant rate and amplitude) electrical activity delivered by the vestibular implant in two out of the three tested subjects. Furthermore, obtained amplitude of body rotations was significantly correlated with the intensity of stimulation and direction of body rotations correlated with the side of the delivered stimulus (implanted side). Altogether, these data suggest that the vestibular implant could also be used to improve postural control in patients with bilateral vestibulopathy.
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Affiliation(s)
- Angelica Perez Fornos
- Division of Otorhinolaryngology Head and Neck Surgery, Geneva University Hospitals and University of Geneva, Rue Gabrielle-Perret-Gentil 4, 1205, Geneva, Switzerland
| | - Raymond van de Berg
- Division of Balance Disorders, Department of ENT, Maastricht University Medical Centre, Maastricht, The Netherlands
- Faculty of Physics, Tomsk State University, Tomsk, Russia
| | - Stéphane Armand
- Willy Taillard Laboratory of Kinesiology, Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Samuel Cavuscens
- Division of Otorhinolaryngology Head and Neck Surgery, Geneva University Hospitals and University of Geneva, Rue Gabrielle-Perret-Gentil 4, 1205, Geneva, Switzerland
| | - Maurizio Ranieri
- Division of Otorhinolaryngology Head and Neck Surgery, Geneva University Hospitals and University of Geneva, Rue Gabrielle-Perret-Gentil 4, 1205, Geneva, Switzerland
| | - Céline Crétallaz
- Division of Otorhinolaryngology Head and Neck Surgery, Geneva University Hospitals and University of Geneva, Rue Gabrielle-Perret-Gentil 4, 1205, Geneva, Switzerland
| | - Herman Kingma
- Division of Balance Disorders, Department of ENT, Maastricht University Medical Centre, Maastricht, The Netherlands
- Faculty of Physics, Tomsk State University, Tomsk, Russia
| | - Jean-Philippe Guyot
- Division of Otorhinolaryngology Head and Neck Surgery, Geneva University Hospitals and University of Geneva, Rue Gabrielle-Perret-Gentil 4, 1205, Geneva, Switzerland
| | - Nils Guinand
- Division of Otorhinolaryngology Head and Neck Surgery, Geneva University Hospitals and University of Geneva, Rue Gabrielle-Perret-Gentil 4, 1205, Geneva, Switzerland.
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Segiet A, Smykiewicz P, Kwiatkowski P, Żera T. Tumour necrosis factor and interleukin 10 in blood pressure regulation in spontaneously hypertensive and normotensive rats. Cytokine 2019; 113:185-194. [DOI: 10.1016/j.cyto.2018.07.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 04/30/2018] [Accepted: 07/02/2018] [Indexed: 02/07/2023]
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10
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Hitier M, Sato G, Zhang YF, Zheng Y, Besnard S, Smith PF. Vestibular-related eye movements in the rat following selective electrical stimulation of the vestibular sensors. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2018; 204:835-847. [DOI: 10.1007/s00359-018-1286-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 08/29/2018] [Accepted: 09/04/2018] [Indexed: 01/26/2023]
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Jiang W, Rajguru SM. Eye Movements Evoked by Pulsed Infrared Radiation of the Rat Vestibular System. Ann Biomed Eng 2018; 46:1406-1418. [PMID: 29845411 PMCID: PMC6095805 DOI: 10.1007/s10439-018-2059-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 05/24/2018] [Indexed: 10/16/2022]
Abstract
Light at infrared wavelengths has been demonstrated to modulate the pattern of neural signals transmitted from the angular motion sensing semicircular canals of the vestibular system to the brain. In the present study, we have characterized physiological eye movements evoked by focused, pulsed infrared radiation (IR) stimuli directed at an individual semicircular canal in a mammalian model. Pulsed IR (1863 nm) trains were directed at the posterior semicircular canal in a rat using 200-400 µm optical fibers. Evoked bilateral eye movements were measured using a custom-modified video-oculography system. The activation of vestibulo-ocular motor pathways by frequency modulated pulsed IR directed at single posterior semicircular canals evoked significant, characteristic bilateral eye movements. In this case, the resulting eye movements were disconjugate with ipsilateral eye moving upwards with a rotation towards the stimulated ear and the contralateral eye moving downwards. The eye movements were stable through several hours of repeated stimulation and could be maintained with 30 + minutes of continuous, frequency-modulated IR stimulation. Following the measurements, the distance of the fiber from target structures and orientation of the beam relative to vestibular structures were determined using micro-computed tomography. Results highlight the spatial selectivity of optical stimulation. Our results demonstrate a novel strategy for direct optical stimulation of the vestibular pathway in rodents and lays the groundwork for future applications of optical neural stimulation in inner ear research and therapeutic applications.
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Affiliation(s)
- Weitao Jiang
- Department of Biomedical Engineering, University of Miami, 1251 Memorial Drive, MEA 204, Coral Gables, FL, 33146, USA
| | - Suhrud M Rajguru
- Department of Biomedical Engineering, University of Miami, 1251 Memorial Drive, MEA 204, Coral Gables, FL, 33146, USA.
- Department of Otolaryngology, University of Miami, 1600 NW 10th Ave, RMSB 3160, Miami, FL, 33136, USA.
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Berg T. Kv7(KCNQ)-K +-Channels Influence Total Peripheral Resistance in Female but Not Male Rats, and Hamper Catecholamine Release in Hypertensive Rats of Both Sexes. Front Physiol 2018. [PMID: 29515459 PMCID: PMC5826282 DOI: 10.3389/fphys.2018.00117] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
K+-channels of the Kv7/KCNQ-family hyperpolarize and stabilize excitable cells such as autonomic neurons and vascular smooth muscle cells (VSMC). Kv7 may therefore play a role in blood pressure (BP) homeostasis, and prevent a high total peripheral vascular resistance (TPR), a hallmark of hypertensive disease. The present study analyzed if Kv7 channels influence catecholamine release and TPR in normotensive (WKY) and spontaneously hypertensive rats (SHR), and if they may contribute to the antihypertensive protection seen in young, female SHR. Tyramine-stimulated norepinephrine release evokes an adrenergic cardiovascular response, and also allows modulation of release to be reflected in the overflow to plasma. The experiment itself activated some secretion of epinephrine. The results show: (1) XE-991 (Kv7.1-7.4-inhibitor), but not chromanol 293B (Kv7.1-inhibitor), increased tyramine-stimulated norepinephrine overflow and epinephrine secretion in both sexes in SHR, but not WKY. (2) Surprisingly, the Kv7-openers retigabine (Kv7.2-7.5) and ICA-27243 (Kv7.2-7.3-preferring) increased catecholamine release in female SHR. (3) The rise in TPR following tyramine-stimulated norepinephrine release was increased by XE-991 but not chromanol in the female WKY only. (4) Retigabine and ICA-27243 reduced the TPR-response to tyramine in the female SHR only. These results suggested: (1) Up-regulation of Kv7.2-7.3 function in sympathetic neurons and chromaffin cells hampered catecholamine release in SHR of both sexes. (2) The increase catecholamine release observed after channel openers in the female SHR may possibly involve reduced transmission in cholinergic neurons which hamper catecholamine release. These two mechanisms may serve to counter-act the hyperadrenergic state in SHR. (3) Kv7.4, most likely in the vasculature, opposed the tension-response to norepinephrine in the female WKY. (4) Vascular Kv7.4-7.5 could be stimulated and then opposed norepinephrine-induced vasoconstriction in the female SHR. (5) Vascular Kv7 channels did not counter-act norepinephrine induced vasoconstriction in male rats, possibly due to different Kv7 channel regulation. Kv7 channels may represent a novel target for antihypertensive therapy.
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Affiliation(s)
- Torill Berg
- Division of Physiology, Department of Molecular Medicine, Institute for Basic Medical Sciences, University of Oslo, Oslo, Norway
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Berg T. β- and α 2-Adrenoceptor Control of Vascular Tension and Catecholamine Release in Female Normotensive and Spontaneously Hypertensive Rats. Front Neurol 2017; 8:130. [PMID: 28424658 PMCID: PMC5380753 DOI: 10.3389/fneur.2017.00130] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 03/20/2017] [Indexed: 11/26/2022] Open
Abstract
As in humans, young, female, spontaneously hypertensive rats (SHR) have a lower blood pressure than male SHR. In male, normotensive rats (WKY), α2- and β1+2-adrenoceptors (AR) reciprocally controlled catecholamine release and vascular smooth muscle tension. This interaction was malfunctioning in male SHR. The present study analyzed if a favorable shift in the α2/β1+2AR interaction may represent an antihypertensive protection in females. Female SHR (early hypertension, 12–14 weeks) and age-matched WKY were infused with tyramine (15 min) to stimulate norepinephrine (NE) release through the reuptake transporter, consequently preventing reuptake. Presynaptic control of vesicular release was therefore reflected as differences in overflow to plasma. The released NE increased total peripheral vascular resistance (TPR). The results showed that β1>2AR facilitated tyramine-stimulated NE release in both strains, also in the presence of α2AR-antagonist (L-659,066). βAR-antagonist (atenolol-β1, ICI-118551-β2, nadolol-β1+2) had no effect on the increased secretion of epinephrine after L-659,066 in WKY, but β1>2AR-antagonist augmented the L-659,066-induced increase in the secretion of epinephrine in SHR. Nadolol increased the TPR response to tyramine with a greater effect in WKY than SHR, whereas β1or2-selective antagonists did not. One βAR-subtype may therefore substitute for the other. When both β1+2AR were blocked, α2AR-antagonist still reduced the TPR response in WKY but not SHR. Thus, α2/β1+2AR reciprocally controlled catecholamine release, with a particular negative β1AR-influence on α2AR-auto-inhibition of epinephrine secretion in SHR. Moreover, in these female rats, β1/2AR-independent α2AR-mediated vasoconstriction was seen in WKY but not SHR, but β1/2AR-mediated vasodilation downregulated adrenergic vasoconstriction, not only in WKY but also in SHR.
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Affiliation(s)
- Torill Berg
- Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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Berg T. M-currents (Kv7.2-7.3/KCNQ2-KCNQ3) Are Responsible for Dysfunctional Autonomic Control in Hypertensive Rats. Front Physiol 2016; 7:584. [PMID: 27965589 PMCID: PMC5126116 DOI: 10.3389/fphys.2016.00584] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 11/14/2016] [Indexed: 01/19/2023] Open
Abstract
Autonomic dysfunctions play important roles in hypertension, heart failure and arrhythmia, often with a detrimental and fatal effect. The present study analyzed if these dysfunctions involved M-channels (members of the Kv7/KNCQ family) in spontaneously hypertensive rats (SHR). Cardiac output and heart rate (HR) were recorded by a flow probe on the ascending aorta in anesthetized SHR and normotensive rats (WKY), and blood pressure (BP) by a femoral artery catheter. Total peripheral vascular resistance (TPR) was calculated. XE-991 (Kv7.1-7.4-inhibitor) reduced resting HR in WKY but only after reserpine in SHR. XE-991 increased TPR and BP baseline in both strains. Retigabine (Kv7.2-7.5-opener) reduced HR, TPR and BP, also after reserpine. Depolarization induced by 3,4-diaminopyridine (3,4-DAP), a voltage-sensitive K+ channel (Kv) inhibitor, activated release of both acetylcholine and norepinephrine, thus activating an initial, cholinergic bradycardia in SHR, followed by sustained, norepinephrine-dependant tachycardia in both strains. XE-991 augmented the initial 3,4-DAP-induced bradycardia and eliminated the late tachycardia in SHR, but not in WKY. The increased bradycardia was eliminated by hexamethonium and methoctramine (M2muscarinic receptor antagonist) but not reserpine. Retigabine eliminated the increased bradycardia observed in reserpinized SHR. XE-991 also increased 3,4-DAP-stimulated catecholamine release, but not after hexamethonium or reserpine. Conclusions: M-currents hampered parasympathetic ganglion excitation and, through that, vagal control of HR, in SHR but not WKY. M-currents also opposed catecholamine release in SHR but not in WKY. M-currents represented a vasodilatory component in resting TPR-control, with no strain-related difference detected. Excessive M-currents may represent the underlying cause of autonomic dysfunctions in hypertension.
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Affiliation(s)
- Torill Berg
- Division of Physiology, Department of Molecular Medicine, Institute for Basic Medical Sciences, University of Oslo Oslo, Norway
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15
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Berg T. α2-Adrenoreceptor Constraint of Catecholamine Release and Blood Pressure Is Enhanced in Female Spontaneously Hypertensive Rats. Front Neurosci 2016; 10:130. [PMID: 27065790 PMCID: PMC4812064 DOI: 10.3389/fnins.2016.00130] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Accepted: 03/15/2016] [Indexed: 12/30/2022] Open
Abstract
UNLABELLED α2-adrenoceptors (α2AR) lower central sympathetic output and peripheral catecholamine release, and may therefore prevent sympathetic hyperactivity and hypertension. The α2AR are dysfunctional in male spontaneously hypertensive rats (SHR). Premenopausal females are less hypertensive than males. The purpose of this study was to test if this difference could be explained by functional α2AR in the female SHR. A 15-min tyramine-infusion was used to stimulate norepinephrine release through the re-uptake transporter, consequently preventing re-uptake. Presynaptic control of vesicular release will therefore be reflected as differences in overflow to plasma. The surgical trauma activates secretion of epinephrine, also subjected to α2AR auto-inhibition. Blood pressure was monitored through a femoral artery catheter and cardiac output by ascending aorta flow in 12-14 weeks-old (early hypertension) SHR and normotensive rats (WKY). Total peripheral vascular resistance (TPR) was calculated. Female SHR, unlike male, were close to normotensive. Pre-treatment with none-selective (clonidine) or non-A-selective (ST-91) α2AR agonist reduced, and none-selective α2AR antagonist (L-659,066) increased tyramine-induced norepinephrine overflow in female WKY and SHR. L-659,066 also increased secretion of epinephrine. The L-659,066-induced increase in catecholamine release was further enhanced by additional pre-treatment with ST-91 or angiotensin AT1 receptor antagonist (losartan) in SHR only. L-659,066 eliminated the tyramine-induced rise in TPR in both strains in female rats. CONCLUSION α2AR-mediated control of catecholamine release and vascular tension was therefore functional in female SHR, unlike that previously observed in male SHR. Functional α2AR is likely to have a protective function and may explain the lack of hypertension in the young female SHR.
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Affiliation(s)
- Torill Berg
- Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo Oslo, Norway
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16
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Berg T. Voltage-Sensitive K(+) Channels Inhibit Parasympathetic Ganglion Transmission and Vagal Control of Heart Rate in Hypertensive Rats. Front Neurol 2015; 6:260. [PMID: 26696959 PMCID: PMC4672051 DOI: 10.3389/fneur.2015.00260] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Accepted: 11/25/2015] [Indexed: 01/19/2023] Open
Abstract
Parasympathetic withdrawal plays an important role in the autonomic dysfunctions in hypertension. Since hyperpolarizing, voltage-sensitive K+ channels (KV) hamper transmitter release, elevated KV-activity may explain the disturbed vagal control of heart rate (HR) in hypertension. Here, the KV inhibitor 3,4-diaminopyridine was used to demonstrate the impact of KV on autonomic HR control. Cardiac output and HR were recorded by a flow probe on the ascending aorta in anesthetized, normotensive (WKY), and spontaneously hypertensive rats (SHR), and blood pressure by a femoral artery catheter. 3,4-diaminopyridine induced an initial bradycardia, which was greater in SHR than in WKY, followed by sustained tachycardia in both strains. The initial bradycardia was eliminated by acetylcholine synthesis inhibitor (hemicholinium-3) and nicotinic receptor antagonist/ganglion blocker (hexamethonium), and reversed to tachycardia by muscarinic receptor (mAchR) antagonist (atropine). The latter was abolished by sympatho-inhibition (reserpine). Reserpine also eliminated the late, 3,4-diaminopyridine-induced tachycardia in WKY, but induced a sustained atropine-sensitive bradycardia in SHR. Inhibition of the parasympathetic component with hemicholinium-3, hexamethonium, or atropine enhanced the late tachycardia in SHR, whereas hexamethonium reduced the tachycardia in WKY. In conclusion, 3,4-diaminopyridine-induced acetylcholine release, and thus enhanced parasympathetic ganglion transmission, with subsequent mAchR activation and bradycardia. 3,4-diaminopyridine also activated tachycardia, initially by enhancing sympathetic ganglion transmission, subsequently by activation of norepinephrine release from sympathetic nerve terminals. The 3,4-diaminopyridine-induced parasympathetic activation was stronger and more sustained in SHR, demonstrating an enhanced inhibitory control of KV on parasympathetic ganglion transmission. This enhanced KV activity may explain the dysfunctional vagal HR control in SHR.
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Affiliation(s)
- Torill Berg
- Division of Physiology, Department of Molecular Medicine, Institute for Basic Medical Sciences, University of Oslo , Oslo , Norway
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Berg T. Altered β1-3-adrenoceptor influence on α2-adrenoceptor-mediated control of catecholamine release and vascular tension in hypertensive rats. Front Physiol 2015; 6:120. [PMID: 25941491 PMCID: PMC4403294 DOI: 10.3389/fphys.2015.00120] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 03/31/2015] [Indexed: 11/29/2022] Open
Abstract
α2- and β-adrenoceptors (AR) reciprocally control catecholamine release and vascular tension. Disorders in these functions are present in spontaneously hypertensive rats (SHR). The present study tested if α2AR dysfunctions resulted from altered α2AR/βAR interaction. Blood pressure (BP) was recorded through a femoral artery catheter and cardiac output by an ascending aorta flow probe. Total peripheral vascular resistance (TPR) was calculated. Norepinephrine release was stimulated by a 15-min tyramine-infusion, which allows presynaptic release-control to be reflected as differences in overflow to plasma. Surgical stress activated some secretion of epinephrine. L-659,066 (α2AR-antagonist) enhanced norepinephrine overflow in normotensive controls (WKY) but not SHR. Nadolol (β1+2) and ICI-118551 (β2), but not atenolol (β1) or SR59230A [β(3)/1L] prevented this increase. All βAR antagonists allowed L-659,066 to augment tyramine-induced norepinephrine overflow in SHR and epinephrine secretion in both strains. Inhibition of cAMP-degradation with milrinone and β3AR agonist (BRL37344) enhanced the effect of L-659,066 on release of both catecholamines in SHR and epinephrine in WKY. β1/2AR antagonists and BRL37344 opposed the L-659,066-dependent elimination of the TPR-response to tyramine in WKY. α2AR/βAR antagonists had little influence on the TPR-response in SHR. Milrinone potentiated the L-659,066-dependent reduction of the TPR-response to tyramine. Conclusions: β2AR activity was a required substrate for α2AR auto inhibition of norepinephrine release in WKY. β1+2AR opposed α2AR inhibition of norepinephrine release in SHR and epinephrine secretion in both strains. βAR-α2AR reciprocal control of vascular tension was absent in SHR. Selective agonist provoked β3AR-Gi signaling and influenced the tyramine-induced TPR-response in WKY and catecholamine release in SHR.
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Affiliation(s)
- Torill Berg
- Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo Oslo, Norway
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18
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Berg T. β3-adrenoceptors inhibit stimulated norepinephrine release in spontaneously hypertensive rats. Front Physiol 2014; 5:499. [PMID: 25566095 PMCID: PMC4271585 DOI: 10.3389/fphys.2014.00499] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2014] [Accepted: 12/02/2014] [Indexed: 01/27/2023] Open
Abstract
Here, the influence of β3-adrenoceptors on catecholamine release in normotensive and spontaneously hypertensive rats was analyzed. Blood pressure was recorded through a femoral artery catheter, and cardiac output by ascending aorta flow. Time from onset of flow to maximum rise in flow indicated inotropy. Total peripheral vascular resistance (TPR) was calculated. Norepinephrine release was stimulated with tyramine, which allowed presynaptic release-control to be reflected as changes in the plasma norepinephrine concentration. β3-adrenoceptor agonist (BRL37344) reduced baseline vascular resistance, the tyramine-stimulated norepinephrine overflow and the positive inotropic response to tyramine in hypertensive but not normotensive rats. β3-adrenoceptor antagonist (SR59230A) reduced tyramine-stimulated norepinephrine release in both strains and the secretion of epinephrine in hypertensive rats. SR59230A reduced tyramine-induced tachycardia in normotensive rats, and prevented down-regulation of the tyramine-induced rise in resistance in hypertensive rats. It was concluded that the contradicting results obtained by agonist vs. antagonist, could be explained by their interaction with two different β-adrenoceptors: The BRL37344-dependent inhibition of stimulated norepinephrine release and positive inotropic response to tyramine was compatible with stimulation of β3-adrenoceptor coupling to inhibitory G-protein. This was observed only in hypertensive rats during stimulated, high levels of circulating catecholamines. The effect of BRL37344 on baseline vascular resistance was compatible with activation of β3-adrenoceptor coupling to endothelial nitric oxide synthase. The inhibitory effect of SR59230A on tyramine-stimulated norepinephrine release in both strains, the increased TPR-response to tyramine in hypertensive rats and tachycardia in normotensive rats may result from inhibition of the low-affinity-state β1-adrenoceptor, also known as the putative β4-adrenoceptor.
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Affiliation(s)
- Torill Berg
- Department of Physiology, Institute of Basic Medical Sciences, University of Oslo Oslo, Norway
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Liu J. Ethanol and liver: Recent insights into the mechanisms of ethanol-induced fatty liver. World J Gastroenterol 2014; 20:14672-14685. [PMID: 25356030 PMCID: PMC4209533 DOI: 10.3748/wjg.v20.i40.14672] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 03/18/2014] [Accepted: 06/13/2014] [Indexed: 02/06/2023] Open
Abstract
Alcoholic fatty liver disease (AFLD), a potentially pathologic condition, can progress to steatohepatitis, fibrosis, and cirrhosis, leading to an increased probability of hepatic failure and death. Alcohol induces fatty liver by increasing the ratio of reduced form of nicotinamide adenine dinucleotide to oxidized form of nicotinamide adenine dinucleotide in hepatocytes; increasing hepatic sterol regulatory element-binding protein (SREBP)-1, plasminogen activator inhibitor (PAI)-1, and early growth response-1 activity; and decreasing hepatic peroxisome proliferator-activated receptor-α activity. Alcohol activates the innate immune system and induces an imbalance of the immune response, which is followed by activated Kupffer cell-derived tumor necrosis factor (TNF)-α overproduction, which is in turn responsible for the changes in the hepatic SREBP-1 and PAI-1 activity. Alcohol abuse promotes the migration of bone marrow-derived cells (BMDCs) to the liver and then reprograms TNF-α expression from BMDCs. Chronic alcohol intake triggers the sympathetic hyperactivity-activated hepatic stellate cell (HSC) feedback loop that in turn activates the HSCs, resulting in HSC-derived TNF-α overproduction. Carvedilol may block this feedback loop by suppressing sympathetic activity, which attenuates the progression of AFLD. Clinical studies evaluating combination therapy of carvedilol with a TNF-α inhibitor to treat patients with AFLD are warranted to prevent the development of alcoholic liver disease.
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Berg T. β1-Blockers Lower Norepinephrine Release by Inhibiting Presynaptic, Facilitating β1-Adrenoceptors in Normotensive and Hypertensive Rats. Front Neurol 2014; 5:51. [PMID: 24795691 PMCID: PMC3997042 DOI: 10.3389/fneur.2014.00051] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 03/28/2014] [Indexed: 01/23/2023] Open
Abstract
Peripheral norepinephrine release is facilitated by presynaptic β-adrenoceptors, believed to involve the β2-subtype exclusively. However, β1-selective blockers are the most commonly used β-blockers in hypertension. Here the author tested the hypothesis that β1AR may function as presynaptic, release-facilitating auto-receptors. Since β1AR-blockers are injected during myocardial infarction, their influence on the cardiovascular response to acute norepinephrine release was also studied. By a newly established method, using tyramine-stimulated release through the norepinephrine transporter (NET), presynaptic control of catecholamine release was studied in normotensive and spontaneously hypertensive rats. β1AR-selective antagonists (CGP20712A, atenolol, metoprolol) reduced norepinephrine overflow to plasma equally efficient as β2AR-selective (ICI-118551) and β1+2AR (nadolol) antagonists in both strains. Neither antagonist lowered epinephrine secretion. Atenolol, which does not cross the blood–brain barrier, reduced norepinephrine overflow after adrenalectomy (AdrX), AdrX + ganglion blockade, losartan, or nephrectomy. Atenolol and metoprolol reduced resting cardiac work load. During tyramine-stimulated norepinephrine release, they had little effect on work load, and increased the transient rise in total peripheral vascular resistance, particularly atenolol when combined with losartan. In conclusion, β1AR, like β2AR, stimulated norepinephrine but not epinephrine release, independent of adrenal catecholamines, ganglion transmission, or renal renin release/angiotensin AT1 receptor activation. β1AR therefore functioned as a peripheral, presynaptic, facilitating auto-receptor. Like tyramine, hypoxia may induce NET-mediated release. Augmented tyramine-induced vasoconstriction, as observed after injection of β1AR-blocker, particularly atenolol combined with losartan, may hamper organ perfusion, and may have clinical relevance in hypoxic conditions such as myocardial infarction.
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Affiliation(s)
- Torill Berg
- Department of Physiology, Institute of Basic Medical Sciences, University of Oslo , Oslo , Norway
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21
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Berg T. Angiotensin AT1 - α2C-Adrenoceptor Interaction Disturbs α2A-auto-Inhibition of Catecholamine Release in Hypertensive Rats. Front Neurol 2013; 4:70. [PMID: 23772221 PMCID: PMC3677154 DOI: 10.3389/fneur.2013.00070] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 05/26/2013] [Indexed: 11/13/2022] Open
Abstract
α2-Adrenoceptors lower central sympathetic output and peripheral catecholamine release, and thus may prevent sympathetic hyperactivity and hypertension. α2AR also influence vascular tension. These α2AR are malfunctioning in spontaneously hypertensive rats (SHR). Here I tested if an interaction between α2AR subtypes and the angiotensin AT1 receptor (AT1R) precipitated these disorders. Blood pressure was monitored through a femoral artery catheter and cardiac output by ascending aorta flow in anesthetized rats. Catecholamine concentrations were determined in plasma collected at the end of a 15-min tyramine-infusion. Tyramine stimulates norepinephrine release through the re-uptake transporter, thus preventing re-uptake. Presynaptic control of vesicular release is therefore reflected as differences in overflow to plasma. Previous experiments showed surgical stress to activate some secretion of epinephrine, also subjected to α2AR-auto-inhibition. Normotensive rats (WKY) and SHR were pre-treated with (1) vehicle or α2AR-antagonist (L-659,066), followed by fadolmidine (α2C>B>A + α1AR-agonist), ST-91 (α2non-A-selective agonist), or m-nitrobiphenyline (α2CAR-agonist + α2A+B-antagonist), or (2) AT1R-antagonist losartan, losartan + L-659,066, or losartan + clonidine. In WKY, L-659,066 alone, L-659,066 + agonist or losartan + L-659,066 increased catecholamine overflow to plasma after tyramine and eliminated the norepinephrine-induced rise in total peripheral vascular resistance (TPR). In SHR, L-659,066 + fadolmidine/ST-91/m-nitrobiphenyline and losartan + L-659,066 greatly increased, and losartan + clonidine reduced, catecholamine concentrations, and L-659,066 + ST-91, losartan + L-659,066 and losartan + clonidine eliminated the tyramine-induced rise in TPR. Separately, these drugs had no effect in SHR. In conclusion, peripheral α2CAR-stimulation or AT1R-inhibition restored failing α2AAR-mediated auto-inhibition of norepinephrine and epinephrine release and control of TPR in SHR.
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Affiliation(s)
- Torill Berg
- Department of Physiology, Institute of Basic Medical Sciences, University of Oslo , Oslo , Norway
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Berg T, Jensen J. Tyramine Reveals Failing α2-Adrenoceptor Control of Catecholamine Release and Total Peripheral Vascular Resistance in Hypertensive Rats. Front Neurol 2013; 4:19. [PMID: 23450822 PMCID: PMC3584258 DOI: 10.3389/fneur.2013.00019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 02/11/2013] [Indexed: 11/13/2022] Open
Abstract
α2-Adrenoceptor-activation lowers central sympathetic output, peripheral, vesicular norepinephrine release, epinephrine secretion, and modulates vascular tension. We previously demonstrated that α2-adrenoceptor-mediated inhibition of basal norepinephrine release was not reflected in plasma unless re-uptake through the norepinephrine transporter (NET) was blocked. Tyramine activates reverse norepinephrine transport through NET. Here we tested the hypothesis that tyramine, by engaging NET in release, also blocks re-uptake, and therefore allows manipulation of pre-junctional α2-adrenoceptors to directly regulate norepinephrine overflow to plasma. We compared in anesthetized spontaneously hypertensive rats (SHRs) and normotensive controls (WKYs), the effect of α2-adrenoreceptor antagonist (L-659,066) and/or agonist (clonidine) on norepinephrine overflow and increase in total peripheral vascular resistance (TPR) evoked by tyramine-infusion (1.26 μmol/min/kg, 15 min) and epinephrine secretion activated by the surgical stress. TPR was computed as blood pressure divided by cardiac output, recorded as ascending aortic flow. Plasma catecholamine concentrations after tyramine were higher in SHRs than WKYs. Pre-treatment with L-659,066 increased the catecholamine concentrations in WKYs, but only if combined with clonidine in SHRs. Clonidine alone reduced tyramine-induced norepinephrine overflow in SHRs, and epinephrine in both strains. Tyramine-induced increase in TPR was not different after clonidine, eliminated after L-659,066 and L-659,066 + clonidine in WKYs, but only after L-659,066 + clonidine in SHRs. We conclude that tyramine-infusion does allow presynaptic regulation of vesicular release to be accurately assessed by measuring differences in plasma norepinephrine concentration. Our results indicate that presynaptic α2-adrenoceptor regulation of norepinephrine release from nerve vesicles and epinephrine secretion is dysfunctional in SHRs, but can be restored by clonidine.
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Affiliation(s)
- Torill Berg
- Department of Physiology, Institute of Basic Medical Sciences, University of Oslo Oslo, Norway
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