1
|
Rajkovic J, Peric M, Stanisic J, Gostimirovic M, Novakovic R, Djokic V, Tepavcevic S, Rakocevic J, Labudovic-Borovic M, Gojkovic-Bukarica L. Effect of Type-2 Diabetes Mellitus on the Expression and Function of Smooth Muscle ATP-Sensitive Potassium Channels in Human Internal Mammary Artery Grafts. Pharmaceuticals (Basel) 2024; 17:857. [PMID: 39065708 PMCID: PMC11280115 DOI: 10.3390/ph17070857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2024] [Revised: 06/10/2024] [Accepted: 06/27/2024] [Indexed: 07/28/2024] Open
Abstract
Here we have shown for the first time altered expression of the vascular smooth muscle (VSM) KATP channel subunits in segments of the human internal mammary artery (HIMA) in patients with type-2 diabetes mellitus (T2DM). Functional properties of vascular KATP channels in the presence of T2DM, and the interaction between its subunits and endogenous ligands known to relax this vessel, were tested using the potassium (K) channels opener, pinacidil. HIMA is the most commonly used vascular graft in cardiac surgery. Previously it was shown that pinacidil relaxes HIMA segments through interaction with KATP (SUR2B/Kir6.1) vascular channels, but it is unknown whether pinacidil sensitivity is changed in the presence of T2DM, considering diabetes-induced vascular complications commonly seen in patients undergoing coronary artery bypass graft surgery (CABG). KATP subunits were detected in HIMA segments using Western blot and immunohistochemistry analyses. An organ bath system was used to interrogate endothelium-independent vasorelaxation caused by pinacidil. In pharmacological experiments, pinacidil was able to relax HIMA from patients with T2DM, with sensitivity comparable to our previous results. All three KATP subunits (SUR2B, Kir6.1 and Kir6.2) were observed in HIMA from patients with and without T2DM. There were no differences in the expression of the SUR2B subunit. The expression of the Kir6.1 subunit was lower in HIMA from T2DM patients. In the same group, the expression of the Kir6.2 subunit was higher. Therefore, KATP channels might not be the only method of pinacidil-induced dilatation of T2DM HIMA. T2DM may decrease the level of Kir6.1, a dominant subunit in VSM of HIMA, altering the interaction between pinacidil and those channels.
Collapse
Affiliation(s)
- Jovana Rajkovic
- Institute of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (M.G.); (L.G.-B.)
| | - Miodrag Peric
- Dedinje Cardiovascular Institute, 11000 Belgrade, Serbia;
| | - Jelena Stanisic
- Laboratory for Molecular Biology and Endocrinology, Vinca Institute of Nuclear Sciences, University of Belgrade, 11000 Belgrade, Serbia; (J.S.); (S.T.)
| | - Milos Gostimirovic
- Institute of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (M.G.); (L.G.-B.)
| | - Radmila Novakovic
- Center for Genome Sequencing and Bioinformatics, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, 11000 Belgrade, Serbia;
| | - Vladimir Djokic
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA;
| | - Snezana Tepavcevic
- Laboratory for Molecular Biology and Endocrinology, Vinca Institute of Nuclear Sciences, University of Belgrade, 11000 Belgrade, Serbia; (J.S.); (S.T.)
| | - Jelena Rakocevic
- Institute of Histology and Embryology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (J.R.); (M.L.-B.)
| | - Milica Labudovic-Borovic
- Institute of Histology and Embryology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (J.R.); (M.L.-B.)
| | - Ljiljana Gojkovic-Bukarica
- Institute of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (M.G.); (L.G.-B.)
- Dedinje Cardiovascular Institute, 11000 Belgrade, Serbia;
| |
Collapse
|
2
|
The Effects of Acidosis on eNOS in the Systemic Vasculature: A Focus on Early Postnatal Ontogenesis. Int J Mol Sci 2022; 23:ijms23115987. [PMID: 35682667 PMCID: PMC9180972 DOI: 10.3390/ijms23115987] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 05/16/2022] [Accepted: 05/23/2022] [Indexed: 01/27/2023] Open
Abstract
The activity of many vasomotor signaling pathways strongly depends on extracellular/intracellular pH. Nitric oxide (NO) is one of the most important vasodilators produced by the endothelium. In this review, we present evidence that in most vascular beds of mature mammalian organisms metabolic or respiratory acidosis increases functional endothelial NO-synthase (eNOS) activity, despite the observation that direct effects of low pH on eNOS enzymatic activity are inhibitory. This can be explained by the fact that acidosis increases the activity of signaling pathways that positively regulate eNOS activity. The role of NO in the regulation of vascular tone is greater in early postnatal ontogenesis compared to adulthood. Importantly, in early postnatal ontogenesis acidosis also augments functional eNOS activity and its contribution to the regulation of arterial contractility. Therefore, the effect of acidosis on total peripheral resistance in neonates may be stronger than in adults and can be one of the reasons for an undesirable decrease in blood pressure during neonatal asphyxia. The latter, however, should be proven in future studies.
Collapse
|
3
|
Zakaria ER, Patel AA, Li N, Matheson PJ, Garrison RN. Vasoactive Components of Dialysis Solution. Perit Dial Int 2020. [DOI: 10.1177/089686080802800316] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
BackgroundConventional peritoneal dialysis (PD) solutions elicit vasodilation, which is implicated in the variable rate of solute transport during the dwell. The components causing such vasoactivity are still controversial. This study was conducted to define the vasoactive components of conventional and new PD solutions.MethodsThree visceral peritoneal microvascular levels were visualized by intravital video microscopy of the terminal ileum of anesthetized rats. Anesthesia-free decerebrate conscious rats served as control. Microvascular diameter and blood flow by Doppler measurements were conducted after topical peritoneal exposure to 4 clinical PD solutions and 6 prepared solutions designed to isolate potential vasoactive components of the PD solution.ResultsAll clinically available PD solutions produced a rapid and generalized vasodilation at all intestinal microvascular levels, regardless of the osmotic solute. The pattern and magnitude of this dilation was not affected by anesthesia but was determined by arteriolar size, the osmotic solute, and the solution's buffer anion system. The greatest dilation occurred in the small precapillary arterioles and was elicited by conventional PD solution and heat re-sterilized solution containing low glucose degradation products (GDPs). Hypertonic mannitol solutions produced a dilation that was approximately 50% less than the dilation obtained with glucose solutions with identical osmolarity and buffer. Increasing a solution's osmolarity did not produce a parallel increase in the magnitude of dilation, suggesting a nonlinear relationship between the two variables. Lactate dissolved in an isotonic solution was completely non-vasoactive unless the solution's H+concentration was increased. At low pH, isotonic lactate produced a rapid but transient vasodilation. This vascular reactivity was similar in magnitude and pattern to that obtained with the isotonic 7.5% icodextrin solution (Extraneal; Baxter Healthcare, Deerfield, Illinois, USA).Conclusions( 1 ) Hyperosmolarity is the major vasoactive component of PD solution. ( 2 ) Hyperosmolarity and active intracellular glucose uptake account together for approximately 75% of PD solution-induced dilation, whereas GDPs contribute to approximately 25%. ( 3 ) Lactate is vasoactive only at low pH (high [H+]). ( 4 ) The magnitude of PD solution-mediated vasodilation is partially dependent on the nature of the osmotic solute, the GDP contents, and the [H+], which determine the vasoactivity of the lactate-buffer anion system. Studies are required to define the molecular mechanisms of PD-induced vasodilation and to determine the vasoactive properties of these solutions after chronic infusion.
Collapse
Affiliation(s)
| | - Anuj A. Patel
- Department of Physiology and Biophysics Louisville, Kentucky, USA
| | - Na Li
- Department of Physiology and Biophysics Louisville, Kentucky, USA
| | - Paul J. Matheson
- Department of Surgery, University of Louisville Louisville, Kentucky, USA
| | - Richard N. Garrison
- Department of Physiology and Biophysics Louisville, Kentucky, USA
- Department of Surgery, University of Louisville Louisville, Kentucky, USA
- Veterans Affairs Medical Center, Louisville, Kentucky, USA
| |
Collapse
|
4
|
Celotto AC, Ferreira LG, Capellini VK, Albuquerque AAS, Rodrigues AJ, Evora PRB. Acute but not chronic metabolic acidosis potentiates the acetylcholine-induced reduction in blood pressure: an endothelium-dependent effect. ACTA ACUST UNITED AC 2015; 49:e5007. [PMID: 26648089 PMCID: PMC4712485 DOI: 10.1590/1414-431x20155007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 09/08/2015] [Indexed: 11/22/2022]
Abstract
Metabolic acidosis has profound effects on vascular tone. This study investigated the in vivo effects of acute metabolic acidosis (AMA) and chronic metabolic acidosis (CMA) on hemodynamic parameters and endothelial function. CMA was induced by ad libitum intake of 1% NH4Cl for 7 days, and AMA was induced by a 3-h infusion of 6 M NH4Cl (1 mL/kg, diluted 1:10). Phenylephrine (Phe) and acetylcholine (Ach) dose-response curves were performed by venous infusion with simultaneous venous and arterial blood pressure monitoring. Plasma nitrite/nitrate (NOx) was measured by chemiluminescence. The CMA group had a blood pH of 7.15±0.03, which was associated with reduced bicarbonate (13.8±0.98 mmol/L) and no change in the partial pressure of arterial carbon dioxide (PaCO2). The AMA group had a pH of 7.20±0.01, which was associated with decreases in bicarbonate (10.8±0.54 mmol/L) and PaCO2 (47.8±2.54 to 23.2±0.74 mmHg) and accompanied by hyperventilation. Phe or ACh infusion did not affect arterial or venous blood pressure in the CMA group. However, the ACh infusion decreased the arterial blood pressure (ΔBP: -28.0±2.35 mm Hg [AMA] to -4.5±2.89 mmHg [control]) in the AMA group. Plasma NOx was normal after CMA but increased after AMA (25.3±0.88 to 31.3±0.54 μM). These results indicate that AMA, but not CMA, potentiated the Ach-induced decrease in blood pressure and led to an increase in plasma NOx, reinforcing the effect of pH imbalance on vascular tone and blood pressure control.
Collapse
Affiliation(s)
- A C Celotto
- Departamento de Cirurgia e Anatomia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
| | - L G Ferreira
- Departamento de Cirurgia e Anatomia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
| | - V K Capellini
- Departamento de Cirurgia e Anatomia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
| | - A A S Albuquerque
- Departamento de Cirurgia e Anatomia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
| | - A J Rodrigues
- Departamento de Cirurgia e Anatomia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
| | - P R B Evora
- Departamento de Cirurgia e Anatomia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
| |
Collapse
|
5
|
de Nadai TR, de Nadai MN, Cassiano Silveira AP, Celotto AC, Albuquerque AAS, de Carvalho MTR, Scarpelini S, Rodrigues AJ, Evora PRB. In vitro effects of extracellular hypercapnic acidification on the reactivity of rat aorta. Nitric Oxide 2015; 50:79-87. [DOI: 10.1016/j.niox.2015.09.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 06/18/2015] [Accepted: 09/02/2015] [Indexed: 11/28/2022]
|
6
|
Niu L, Liu Y, Hou X, Cui L, Li J, Zhang X, Zhang M. Extracellular acidosis contracts coronary but neither renal nor mesenteric artery via modulation of H+,K+-ATPase, voltage-gated K+channels and L-type Ca2+channels. Exp Physiol 2014; 99:995-1006. [DOI: 10.1113/expphysiol.2014.078634] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Longgang Niu
- Department of Pharmacology; Shanxi Medical University; Xinjiannanlu 56 Taiyuan 030001 Shanxi Province China
- Medical Functional Experimental Center; Shanxi Medical University; Xinjiannanlu 56 Taiyuan 030001 Shanxi Province China
| | - Yu Liu
- Department of Pharmacology; Shanxi Medical University; Xinjiannanlu 56 Taiyuan 030001 Shanxi Province China
| | - Xiaomin Hou
- Department of Pharmacology; Shanxi Medical University; Xinjiannanlu 56 Taiyuan 030001 Shanxi Province China
| | - Lijuan Cui
- Medical Functional Experimental Center; Shanxi Medical University; Xinjiannanlu 56 Taiyuan 030001 Shanxi Province China
| | - Jiangtao Li
- Department of Pharmacology; Shanxi Medical University; Xinjiannanlu 56 Taiyuan 030001 Shanxi Province China
| | - Xuanping Zhang
- Department of Pharmacology; Shanxi Medical University; Xinjiannanlu 56 Taiyuan 030001 Shanxi Province China
| | - Mingsheng Zhang
- Department of Pharmacology; Shanxi Medical University; Xinjiannanlu 56 Taiyuan 030001 Shanxi Province China
- Medical Functional Experimental Center; Shanxi Medical University; Xinjiannanlu 56 Taiyuan 030001 Shanxi Province China
- Cardiovascular Division of Physiology Department; Shanxi Medical University; Xinjiannanlu 56 Taiyuan 030001 Shanxi Province China
| |
Collapse
|
7
|
Effect of severe acidosis on vasoactive effects of epinephrine and norepinephrine in human distal mammary artery. J Thorac Cardiovasc Surg 2014; 147:1698-705. [DOI: 10.1016/j.jtcvs.2013.11.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 10/17/2013] [Accepted: 11/08/2013] [Indexed: 11/21/2022]
|
8
|
Seto SW, Au ALS, Poon CCW, Zhang Q, Li RWS, Yeung JHK, Kong SK, Ngai SM, Wan S, Ho HP, Lee SMY, Hoi MPM, Chan SW, Leung GPH, Kwan YW. Acute simvastatin inhibits K ATP channels of porcine coronary artery myocytes. PLoS One 2013; 8:e66404. [PMID: 23799098 PMCID: PMC3684588 DOI: 10.1371/journal.pone.0066404] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 05/06/2013] [Indexed: 01/19/2023] Open
Abstract
Background Statins (3-hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase inhibitors) consumption provides beneficial effects on cardiovascular systems. However, effects of statins on vascular KATP channel gatings are unknown. Methods Pig left anterior descending coronary artery and human left internal mammary artery were isolated and endothelium-denuded for tension measurements and Western immunoblots. Enzymatically-dissociated/cultured arterial myocytes were used for patch-clamp electrophysiological studies and for [Ca2+]i, [ATP]i and [glucose]o uptake measurements. Results The cromakalim (10 nM to 10 µM)- and pinacidil (10 nM to 10 µM)-induced concentration-dependent relaxation of porcine coronary artery was inhibited by simvastatin (3 and 10 µM). Simvastatin (1, 3 and 10 µM) suppressed (in okadaic acid (10 nM)-sensitive manner) cromakalim (10 µM)- and pinacidil (10 µM)-mediated opening of whole-cell KATP channels of arterial myocytes. Simvastatin (10 µM) and AICAR (1 mM) elicited a time-dependent, compound C (1 µM)-sensitive [3H]-2-deoxy-glucose uptake and an increase in [ATP]i levels. A time (2–30 min)- and concentration (0.1–10 µM)-dependent increase by simvastatin of p-AMPKα-Thr172 and p-PP2A-Tyr307 expression was observed. The enhanced p-AMPKα-Thr172 expression was inhibited by compound C, ryanodine (100 µM) and KN93 (10 µM). Simvastatin-induced p-PP2A-Tyr307 expression was suppressed by okadaic acid, compound C, ryanodine, KN93, phloridzin (1 mM), ouabain (10 µM), and in [glucose]o-free or [Na+]o-free conditions. Conclusions Simvastatin causes ryanodine-sensitive Ca2+ release which is important for AMPKα-Thr172 phosphorylation via Ca2+/CaMK II. AMPKα-Thr172 phosphorylation causes [glucose]o uptake (and an [ATP]i increase), closure of KATP channels, and phosphorylation of AMPKα-Thr172 and PP2A-Tyr307 resulted. Phosphorylation of PP2A-Tyr307 occurs at a site downstream of AMPKα-Thr172 phosphorylation.
Collapse
Affiliation(s)
- Sai Wang Seto
- The Vascular Biology Unit, Queensland Research Centre for Peripheral Vascular Disease, School of Medicine and Dentistry, James Cook University, Townsville, Queensland, Australia
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, PR of China
| | - Alice Lai Shan Au
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, PR of China
| | - Christina Chui Wa Poon
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, PR of China
| | - Qian Zhang
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, PR of China
| | - Rachel Wai Sum Li
- Department of Pharmacology and Pharmacy, Faculty of Medicine, The University of Hong Kong, Hong Kong, PR of China
| | - John Hok Keung Yeung
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, PR of China
| | - Siu Kai Kong
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Shatin, Hong Kong, PR of China
| | - Sai Ming Ngai
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Shatin, Hong Kong, PR of China
| | - Song Wan
- Department of Surgery, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, PR of China
| | - Ho Pui Ho
- Department of Electronic Engineering, Faculty of Engineering, The Chinese University of Hong Kong, Shatin, Hong Kong, PR of China
| | - Simon Ming Yuen Lee
- Institute of Chinese Medical Sciences, the University of Macau, Macau, PR of China
| | - Maggie Pui Man Hoi
- Institute of Chinese Medical Sciences, the University of Macau, Macau, PR of China
| | - Shun Wan Chan
- State Key Laboratory of Chinese Medicine and Molecular Pharmacology, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong, PR of China
- * E-mail: (YWK); (GPHL); (SWC)
| | - George Pak Heng Leung
- Department of Pharmacology and Pharmacy, Faculty of Medicine, The University of Hong Kong, Hong Kong, PR of China
- * E-mail: (YWK); (GPHL); (SWC)
| | - Yiu Wa Kwan
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, PR of China
- * E-mail: (YWK); (GPHL); (SWC)
| |
Collapse
|
9
|
Capellini VK, Restini CBA, Bendhack LM, Evora PRB, Celotto AC. The effect of extracellular pH changes on intracellular pH and nitric oxide concentration in endothelial and smooth muscle cells from rat aorta. PLoS One 2013; 8:e62887. [PMID: 23690964 PMCID: PMC3656859 DOI: 10.1371/journal.pone.0062887] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 03/26/2013] [Indexed: 11/29/2022] Open
Abstract
Aims It has been known for more than a century that pH changes can alter vascular tone. However, there is no consensus about the effects of pH changes on vascular response. In this study, we investigated the effects of extracellular pH (pHo) changes on intracellular pH (pHi) and intracellular nitric oxide concentration ([NO]i) in freshly isolated endothelial cells and cross sections from rat aorta. Main Methods The HCl was used to reduce the pHo from 7.4 to 7.0 and from 7.4 to 6.5; the NaOH was used to increase the pHo from 7.4 to 8.0 and from 7.4 to 8.5. The fluorescent dyes 5-(and-6)-carboxy SNARF-1, acetoxymethyl ester, acetate (SNARF-1) and diaminofluorescein-FM diacetate (DAF-FM DA) were employed to measure the pHi and [NO]i, respectively. The fluorescence intensity was measured in freshly isolated endothelial cells by flow cytometry and in freshly obtained aorta cross sections by confocal microscopy. Key Findings The endothelial and vascular smooth muscle pHi was increased at pHo 8.5. The extracellular acidification did not change the endothelial pHi, but the smooth muscle pHi was reduced at pHo 7.0. At pHo 8.5 and pHo 6.5, the endothelial [NO]i was increased. Both extracellular alkalinization and acidification increased the vascular smooth muscle [NO]i. Significance Not all changes in pHo did result in pHi changes, but disruption of acid-base balance in both directions induced NO synthesis in the endothelium and/or vascular smooth muscle.
Collapse
Affiliation(s)
- Verena K. Capellini
- Laboratory of Endothelial Function, Department of Surgery and Anatomy, School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Carolina B. A. Restini
- Laboratory of Pharmacology, Department of Physics and Chemistry, School of Pharmaceutical Science, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Lusiane M. Bendhack
- Laboratory of Pharmacology, Department of Physics and Chemistry, School of Pharmaceutical Science, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Paulo R. B. Evora
- Laboratory of Endothelial Function, Department of Surgery and Anatomy, School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Andréa C. Celotto
- Laboratory of Endothelial Function, Department of Surgery and Anatomy, School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil
- * E-mail:
| |
Collapse
|
10
|
Ives SJ, Andtbacka RHI, Noyes RD, Morgan RG, Gifford JR, Park SY, Symons JD, Richardson RS. α1-Adrenergic responsiveness in human skeletal muscle feed arteries: the impact of reducing extracellular pH. Exp Physiol 2012; 98:256-67. [PMID: 22798402 DOI: 10.1113/expphysiol.2012.066613] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Graded exercise results not only in the modulation of adrenergic mediated smooth muscle tone and a preferential increase in blood flow to the active skeletal muscle termed 'functional sympatholysis', but is also paralleled by metabolically induced reductions in pH. We therefore sought to determine whether pH attenuates α(1)-adrenergic receptor sensitivity in human feed arteries. Feed arteries (560 ± 31 μm i.d.) were harvested from 24 humans (55 ± 4 years old) and studied using the isometric tension technique. Vessel function was assessed using KCl, phenylephrine (PE), ACh and sodium nitroprusside (SNP) concentration-response curves to characterize non-receptor-mediated and receptor-mediated vasocontraction, as well as endothelium-dependent and -independent vasorelaxation, respectively. All concentration-response curves were obtained from (originally contiguous) vessel rings in separate baths with a pH of 7.4, 7.1, 6.8 or 6.5. Reduction of the pH, via HCl, reduced maximal PE-induced vasocontraction (pH 7.4 = 85 ± 19, pH 7.1 = 57 ± 16, pH 6.8 = 34 ± 15 and pH 6.5 = 16 ± 5% KCl(max)), which was partly due to reduced smooth muscle function, as assessed by KCl (pH 7.4 = 88 ± 13, pH 7.1 = 67 ± 8, pH 6.8 = 67 ± 9 and pH 6.5 = 58 ± 8% KCl(max)). Graded acidosis had no effect on maximal vasorelaxation. In summary, these data reveal that reductions in extracellular pH attenuate α(1)-mediated vasocontraction, which is partly explained by reduced smooth muscle function, although vasorelaxation in response to ACh and SNP remained intact. These findings support the concept that local acidosis is likely to contribute to functional sympatholysis and exercise hyperaemia by opposing sympathetically mediated vasoconstriction while not impacting vasodilatation.
Collapse
Affiliation(s)
- Stephen J Ives
- Geriatric Research, Education and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT, USA.
| | | | | | | | | | | | | | | |
Collapse
|
11
|
|
12
|
Exploring the mechanism of endothelial involvement in acidosis-induced vasodilatation of aortic tissues from normal and diabetic rats. Eur J Pharmacol 2010; 642:99-106. [DOI: 10.1016/j.ejphar.2010.05.040] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Revised: 05/06/2010] [Accepted: 05/28/2010] [Indexed: 12/19/2022]
|
13
|
Celotto A, Capellini V, Baldo C, Dalio M, Rodrigues A, Evora P. Effects of acid-base imbalance on vascular reactivity. Braz J Med Biol Res 2008; 41:439-45. [DOI: 10.1590/s0100-879x2008005000026] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Accepted: 05/29/2008] [Indexed: 11/22/2022] Open
|
14
|
Jawaid A, ur Rehman T, Rohra DK. Regulation of Human Coronary Vascular Tone: Further Evidence Must Be Sought Before Ruling Out the Direct Role of ATP-Sensitive Potassium Channels in Regulation of Coronary Vasculature. Circ Res 2006; 98:e73. [PMID: 16728664 DOI: 10.1161/01.res.0000225256.68436.66] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|