51
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Ohanyan V, Yin L, Bardakjian R, Kolz C, Enrick M, Hakobyan T, Kmetz J, Bratz I, Luli J, Nagane M, Khan N, Hou H, Kuppusamy P, Graham J, Fu FK, Janota D, Oyewumi MO, Logan S, Lindner JR, Chilian WM. Requisite Role of Kv1.5 Channels in Coronary Metabolic Dilation. Circ Res 2015. [PMID: 26224794 DOI: 10.1161/circresaha.115.306642] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
RATIONALE In the working heart, coronary blood flow is linked to the production of metabolites, which modulate tone of smooth muscle in a redox-dependent manner. Voltage-gated potassium channels (Kv), which play a role in controlling membrane potential in vascular smooth muscle, have certain members that are redox-sensitive. OBJECTIVE To determine the role of redox-sensitive Kv1.5 channels in coronary metabolic flow regulation. METHODS AND RESULTS In mice (wild-type [WT], Kv1.5 null [Kv1.5(-/-)], and Kv1.5(-/-) and WT with inducible, smooth muscle-specific expression of Kv1.5 channels), we measured mean arterial pressure, myocardial blood flow, myocardial tissue oxygen tension, and ejection fraction before and after inducing cardiac stress with norepinephrine. Cardiac work was estimated as the product of mean arterial pressure and heart rate. Isolated arteries were studied to establish whether genetic alterations modified vascular reactivity. Despite higher levels of cardiac work in the Kv1.5(-/-) mice (versus WT mice at baseline and all doses of norepinephrine), myocardial blood flow was lower in Kv1.5(-/-) mice than in WT mice. At high levels of cardiac work, tissue oxygen tension dropped significantly along with ejection fraction. Expression of Kv1.5 channels in smooth muscle in the null background rescued this phenotype of impaired metabolic dilation. In isolated vessels from Kv1.5(-/-) mice, relaxation to H2O2 was impaired, but responses to adenosine and acetylcholine were normal compared with those from WT mice. CONCLUSIONS Kv1.5 channels in vascular smooth muscle play a critical role in coupling myocardial blood flow to cardiac metabolism. Absence of these channels disassociates metabolism from flow, resulting in cardiac pump dysfunction and tissue hypoxia.
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Affiliation(s)
| | - Liya Yin
- Department of Integrative Medical Sciences
| | - Raffi Bardakjian
- Departement Internal Medicine, Canton Medical Education Foundation
| | | | | | | | - John Kmetz
- Department of Integrative Medical Sciences
| | - Ian Bratz
- Department of Integrative Medical Sciences
| | | | - Masaki Nagane
- Department of Radiology and Medicine, Geisel School of Medicine at Dartmouth College
| | - Nadeem Khan
- Department of Radiology and Medicine, Geisel School of Medicine at Dartmouth College
| | - Huagang Hou
- Department of Radiology and Medicine, Geisel School of Medicine at Dartmouth College
| | - Periannan Kuppusamy
- Department of Radiology and Medicine, Geisel School of Medicine at Dartmouth College
| | | | | | | | - Moses O Oyewumi
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University
| | | | - Jonathan R Lindner
- Division of Cardiovascular Medicine, UHN62, Oregon Health and Science University
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52
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Li H, Hong DH, Son YK, Na SH, Jung WK, Bae YM, Seo EY, Kim SJ, Choi IW, Park WS. Cilostazol induces vasodilation through the activation of Ca2+-activated K+ channels in aortic smooth muscle. Vascul Pharmacol 2015; 70:15-22. [DOI: 10.1016/j.vph.2015.01.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 01/06/2015] [Accepted: 01/08/2015] [Indexed: 11/25/2022]
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53
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Zhang Q, Bai Y, Yang Z, Tian J, Meng Z. The molecular mechanism of the effect of sulfur dioxide inhalation on the potassium and calcium ion channels in rat aortas. Hum Exp Toxicol 2015; 35:418-27. [DOI: 10.1177/0960327115591375] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
This study investigated the molecular mechanism of the effect of sulfur dioxide (SO2) on the expression of adenosine triphosphate (ATP)-sensitive potassium ion (K+; KATP) channel, big-conductance calcium ion (Ca2+)-activated K+ (BKCa) channel, and L-type (L-Ca2+) channel subunits in rat aortas with quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot. The results showed that the messenger RNA and protein levels of the KATP channel subunits Kir6.1, Kir6.2, and sulfonylurea receptor 2B (SUR2B) of rat aortas were significantly increased by SO2 at 14 mg/m3, whereas the levels of SUR2A were not changed. SO2 at all the treated concentrations markedly raised the expression of the BKCa channel subunits α and β1. SO2 at 14 mg/m3 significantly decreased the expression of the L-Ca2+ channel Cav1.2 and Cav1.3. The histological examination of rat aorta tissues showed moderate injury of tunica media in the presence of SO2 at 14 mg/m3. These suggest that SO2 can activate the KATP and BKCa channels by upregulating the expression of Kir6.1, Kir6.2, SUR2B, BKCa α, and BKCa β1, while inhibit the L-Ca2+ channels by downregulating the expression of Cav1.2 and Cav1.3 in rat aortas. The molecular mechanism of SO2-induced vasorelaxant effect might be linked to the changes in expression of these channel subunits, which plays an important role in the pathogenesis of SO2-associated cardiovascular diseases.
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Affiliation(s)
- Q Zhang
- Institute of Environmental Medicine and Toxicology, Institute of Environmental Science, Shanxi University, Taiyuan, China
| | - Y Bai
- Institute of Environmental Medicine and Toxicology, Institute of Environmental Science, Shanxi University, Taiyuan, China
| | - Z Yang
- Institute of Environmental Medicine and Toxicology, Institute of Environmental Science, Shanxi University, Taiyuan, China
| | - J Tian
- Institute of Environmental Medicine and Toxicology, Institute of Environmental Science, Shanxi University, Taiyuan, China
| | - Z Meng
- Institute of Environmental Medicine and Toxicology, Institute of Environmental Science, Shanxi University, Taiyuan, China
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54
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The calmodulin inhibitor CGS 9343B inhibits voltage-dependent K + channels in rabbit coronary arterial smooth muscle cells. Toxicol Appl Pharmacol 2015; 285:207-13. [DOI: 10.1016/j.taap.2015.03.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 03/05/2015] [Accepted: 03/10/2015] [Indexed: 11/18/2022]
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55
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Li H, Choi IW, Hong DH, Son YK, Na SH, Jung WK, Firth AL, Jung ID, Park YM, Park WS. W-7 inhibits voltage-dependent K(+) channels independent of calmodulin activity in rabbit coronary arterial smooth muscle cells. Eur J Pharmacol 2015; 750:14-9. [PMID: 25617796 DOI: 10.1016/j.ejphar.2014.12.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 12/02/2014] [Accepted: 12/20/2014] [Indexed: 10/24/2022]
Abstract
We investigated the effect of W-7, a calmodulin inhibitor, on voltage-dependent K(+) (Kv) channels in freshly isolated coronary arterial smooth muscle cells using the whole-cell patch clamp technique. The amplitude of Kv currents was inhibited by W-7 in a concentration-dependent manner, with an IC50 value of 3.38±0.47μM and a Hill coefficient of 0.84±0.10. W-7 shifted the activation curve to a more positive potential but had no significant effect on the inactivation curve, which indicated that W-7 inhibited the Kv current in a closed state of the Kv channel. Another calmodulin inhibitor, W-13, had no significant effect on Kv currents and did not change the inhibitory effect of W-7 on Kv channels. From these results, we conclude that W-7 inhibited the Kv current in a dose-dependent manner, but this inhibition occurred independent of calmodulin activity and in a closed (inactivated) state of the Kv channels.
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Affiliation(s)
- Hongliang Li
- Institute of Medical Sciences, Department of Physiology, Kangwon National University School of Medicine, Chuncheon 200-701, South Korea
| | - Il-Whan Choi
- Department of Microbiology, Inje University College of Medicine, Busan 614-735, South Korea
| | - Da Hye Hong
- Institute of Medical Sciences, Department of Physiology, Kangwon National University School of Medicine, Chuncheon 200-701, South Korea
| | - Youn Kyoung Son
- Institute of Medical Sciences, Department of Physiology, Kangwon National University School of Medicine, Chuncheon 200-701, South Korea
| | - Sung Hun Na
- Institute of Medical Sciences, Department of Obstetrics and Gynecology, Kangwon National University Hospital, School of Medicine, Kangwon National University, Chuncheon 200-701, South Korea
| | - Won-Kyo Jung
- Department of Biomedical Engineering, and Center for Marine-Integrated Biomedical Technology (BK21 Plus) Pukyong National University, Busan 608-737, South Korea
| | - Amy L Firth
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - In Duk Jung
- Department of Immunology, Lab of Dendritic Cell Differentiation and Regulation, College of Medicine, Konkuk University, Chungju 380-701, South Korea
| | - Yeong-Min Park
- Department of Immunology, Lab of Dendritic Cell Differentiation and Regulation, College of Medicine, Konkuk University, Chungju 380-701, South Korea.
| | - Won Sun Park
- Institute of Medical Sciences, Department of Physiology, Kangwon National University School of Medicine, Chuncheon 200-701, South Korea.
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Hong DH, Li H, Kim HS, Kim HW, Shin SE, Jung WK, Na SH, Choi IW, Firth AL, Park WS, Kim DJ. The Effects of the Selective Serotonin Reuptake Inhibitor Fluvoxamine on Voltage-Dependent K + Channels in Rabbit Coronary Arterial Smooth Muscle Cells. Biol Pharm Bull 2015; 38:1208-13. [DOI: 10.1248/bpb.b15-00207] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Da Hye Hong
- Department of Physiology, Kangwon National University School of Medicine
| | - Hongliang Li
- Department of Physiology, Kangwon National University School of Medicine
| | - Han Sol Kim
- Department of Physiology, Kangwon National University School of Medicine
| | - Hye Won Kim
- Department of Physiology, Kangwon National University School of Medicine
| | - Sung Eun Shin
- Department of Physiology, Kangwon National University School of Medicine
| | - Won-Kyo Jung
- Department of Biomedical Engineering, Center for Marine-Integrated Biomedical Technology (BK21 Plus) Pukyong National University
| | - Sung Hun Na
- Department of Obstetrics and Gynecology, Kangwon National University Hospital, School of Medicine, Kangwon National University
| | - Il-Whan Choi
- Department of Microbiology, Inje University College of Medicine
| | | | - Won Sun Park
- Department of Physiology, Kangwon National University School of Medicine
| | - Dae-Joong Kim
- Department of Anatomy and Cell Biology, Kangwon National University School of Medicine
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57
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Dias FMV, Ribeiro Júnior RF, Fernandes AA, Fiorim J, Travaglia TCF, Vassallo DV, Stefanon I. Na+K+-ATPase activity and K+ channels differently contribute to vascular relaxation in male and female rats. PLoS One 2014; 9:e106345. [PMID: 25187951 PMCID: PMC4154682 DOI: 10.1371/journal.pone.0106345] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 08/07/2014] [Indexed: 11/19/2022] Open
Abstract
Gender associated differences in vascular reactivity regulation might contribute to the low incidence of cardiovascular disease in women. Cardiovascular protection is suggested to depend on female sex hormones' effects on endothelial function and vascular tone regulation. We tested the hypothesis that potassium (K+) channels and Na+K+-ATPase may be involved in the gender-based vascular reactivity differences. Aortic rings from female and male rats were used to examine the involvement of K+ channels and Na+K+-ATPase in vascular reactivity. Acetylcholine (ACh)-induced relaxation was analyzed in the presence of L-NAME (100 µM) and the following K+ channels blockers: tetraethylammonium (TEA, 2 mM), 4-aminopyridine (4-AP, 5 mM), iberiotoxin (IbTX, 30 nM), apamin (0.5 µM) and charybdotoxin (ChTX, 0.1 µM). The ACh-induced relaxation sensitivity was greater in the female group. After incubation with 4-AP the ACh-dependent relaxation was reduced in both groups. However, the dAUC was greater in males, suggesting that the voltage-dependent K+ channel (Kv) participates more in males. Inhibition of the three types of Ca2+-activated K+ channels induced a greater reduction in Rmax in females than in males. The functional activity of the Na+K+-ATPase was evaluated by KCl-induced relaxation after L-NAME and OUA incubation. OUA reduced K+-induced relaxation in female and male groups, however, it was greater in males, suggesting a greater Na+K+-ATPase functional activity. L-NAME reduced K+-induced relaxation only in the female group, suggesting that nitric oxide (NO) participates more in their functional Na+K+-ATPase activity. These results suggest that the K+ channels involved in the gender-based vascular relaxation differences are the large conductance Ca2+-activated K+ channels (BKCa) in females and Kv in males and in the K+-induced relaxation and the Na+K+-ATPase vascular functional activity is greater in males.
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Affiliation(s)
- Fernanda Moura Vargas Dias
- Universidade Federal do Espírito Santo, Departamento de Ciências Fisiológicas, Vitória, Espírito Santo, Brasil
| | | | - Aurélia Araújo Fernandes
- Universidade Federal do Espírito Santo, Departamento de Ciências Fisiológicas, Vitória, Espírito Santo, Brasil
| | - Jonaina Fiorim
- Universidade Federal do Espírito Santo, Departamento de Ciências Fisiológicas, Vitória, Espírito Santo, Brasil
| | | | - Dalton Valentim Vassallo
- Universidade Federal do Espírito Santo, Departamento de Ciências Fisiológicas, Vitória, Espírito Santo, Brasil
| | - Ivanita Stefanon
- Universidade Federal do Espírito Santo, Departamento de Ciências Fisiológicas, Vitória, Espírito Santo, Brasil
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58
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Zhang Q, Tian J, Bai Y, Lei X, Li M, Yang Z, Meng Z. Effects of gaseous sulfur dioxide and its derivatives on the expression of KATP, BKCa and L-Ca(2+) channels in rat aortas in vitro. Eur J Pharmacol 2014; 742:31-41. [PMID: 25192964 DOI: 10.1016/j.ejphar.2014.08.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Revised: 08/24/2014] [Accepted: 08/25/2014] [Indexed: 01/04/2023]
Abstract
Epidemiological investigations have revealed that sulfur dioxide (SO2) exposure is linked to cardiovascular diseases. Our previous study indicated that the vasorelaxant effect of SO2 might be partly related to ATP-sensitive K(+) (KATP), big-conductance Ca(2+)-activated K(+) (BKCa) and L-type calcium (L-Ca(2+)) channels. The present study was designed to further investigate the effects of gaseous SO2 and its derivatives on the gene and protein expression of these channels in the rat aortas in vitro. The results showed that the mRNA and protein levels of the KATP channel subunits Kir6.1, Kir6.2 and SUR2B of the rat aortas in SO2 and its derivatives groups were higher than those in control group. Similarly, the expression of the BKCa channel subunits α and β1 was increased by SO2 and its derivatives. However, SO2 and its derivatives at 1500μM significantly decreased the expression of the L-Ca(2+) channel subunits Cav1.2 and Cav1.3. Histological examination of the rat aorta tissues showed moderate injury of tunica media induced by SO2 and its derivatives at 1500μM. These results suggest that SO2 and its derivatives can activate the KATP and BKCa channels by increasing the expression of Kir6.1, Kir6.2, SUR2B and α, β1, respectively, while also inhibiting the L-Ca(2+) channels by decreasing the expression of Cav1.2 and Cav1.3 of the rat aortas. The molecular mechanism of the vasorelaxant effect of SO2 and its derivatives might be related to the expression changes of KATP, BKCa and L-Ca(2+) channel subunits, which may play a role in the pathogenesis of SO2-associated cardiovascular diseases.
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Affiliation(s)
- Quanxi Zhang
- Institute of Environmental Medicine and Toxicology, Institute of Environmental Science, Shanxi University, Wucheng Road 92#, Shanxi Province, Taiyuan 030006, PR China.
| | - Jingjing Tian
- Institute of Environmental Medicine and Toxicology, Institute of Environmental Science, Shanxi University, Wucheng Road 92#, Shanxi Province, Taiyuan 030006, PR China
| | - Yunlong Bai
- Institute of Environmental Medicine and Toxicology, Institute of Environmental Science, Shanxi University, Wucheng Road 92#, Shanxi Province, Taiyuan 030006, PR China
| | - Xiaodong Lei
- Institute of Environmental Medicine and Toxicology, Institute of Environmental Science, Shanxi University, Wucheng Road 92#, Shanxi Province, Taiyuan 030006, PR China
| | - Mei Li
- Institute of Environmental Medicine and Toxicology, Institute of Environmental Science, Shanxi University, Wucheng Road 92#, Shanxi Province, Taiyuan 030006, PR China
| | - Zhenhua Yang
- Institute of Environmental Medicine and Toxicology, Institute of Environmental Science, Shanxi University, Wucheng Road 92#, Shanxi Province, Taiyuan 030006, PR China
| | - Ziqiang Meng
- Institute of Environmental Medicine and Toxicology, Institute of Environmental Science, Shanxi University, Wucheng Road 92#, Shanxi Province, Taiyuan 030006, PR China
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Fedele F, Severino P, Bruno N, Stio R, Caira C, D'Ambrosi A, Brasolin B, Ohanyan V, Mancone M. Role of ion channels in coronary microcirculation: a review of the literature. Future Cardiol 2014; 9:897-905. [PMID: 24180545 DOI: 10.2217/fca.13.65] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
In normal coronary arteries, several different mechanisms of blood flow regulation exist, acting at different levels of the coronary tree: endothelial, nervous, myogenic and metabolic regulation. In addition, physiologic blood flow regulation is also dependent on the activity of several coronary ion channels, including ATP-dependent K(+) channels, voltage-gated K(+) channels and others. In this context, ion channels contribute by matching demands for homeostatic maintenance. They play a primary role in rapid response of both endothelium and vascular smooth muscle cells of larger and smaller arterial vessels of the coronary bed, leading to coronary vasodilation. Consequently, an alteration in ion channel function or expression could be directly involved in coronary vasomotion dysfunction.
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Affiliation(s)
- Francesco Fedele
- Department of Cardiovascular, Respiratory, Nephrology, Anesthesiology & Geriatric Sciences, Sapienza University, Policlinico Umberto I, Rome, Italy
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60
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Son YK, Hong DH, Li H, Kim DJ, Na SH, Park H, Jung WK, Choi IW, Park WS. Ca2+ channel inhibitor NNC 55-0396 inhibits voltage-dependent K+ channels in rabbit coronary arterial smooth muscle cells. J Pharmacol Sci 2014; 125:312-9. [PMID: 24989838 DOI: 10.1254/jphs.14054fp] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
We demonstrated the inhibitory effect of NNC 55-0396, a T-type Ca(2+) channel inhibitor, on voltage-dependent K(+) (K(V)) channels in freshly isolated rabbit coronary arterial smooth muscle cells. NNC 55-0396 decreased the amplitude of K(V) currents in a concentration-dependent manner, with an IC(50) of 0.080 μM and a Hill coefficient of 0.76.NNC 55-0396 did not affect steady-state activation and inactivation curves, indicating that the compound does not affect the voltage sensitivity of K(V) channel gating. Both the K(V) currents and the inhibitory effect of NNC 55-0396 on K(V) channels were not altered by depletion of extracellular Ca(2+) or intracellular ATP, suggesting that the inhibitory effect of NNC 55-0396 is independent of Ca(2+)-channel activity and phosphorylation-dependent signaling cascades. From these results, we concluded that NNC 55-0396 dosedependently inhibits K(V) currents, independently of Ca(2+)-channel activity and intracellular signaling cascades.
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Affiliation(s)
- Youn Kyoung Son
- Institute of Medical Sciences, Department of Physiology, Kangwon National University School of Medicine, Korea
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61
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Penso J, Cordeiro KC, da Cunha CR, da Silva Castro PF, Martins DR, Lião LM, Rocha ML, de Oliveira V. Vasorelaxant activity of 7-β-O-glycosides biosynthesized from flavonoids. Eur J Pharmacol 2014; 733:75-80. [DOI: 10.1016/j.ejphar.2014.03.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 03/06/2014] [Accepted: 03/10/2014] [Indexed: 01/01/2023]
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62
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Koide M, Syed AU, Braas KM, May V, Wellman GC. Pituitary adenylate cyclase activating polypeptide (PACAP) dilates cerebellar arteries through activation of large-conductance Ca(2+)-activated (BK) and ATP-sensitive (K ATP) K (+) channels. J Mol Neurosci 2014; 54:443-50. [PMID: 24744252 DOI: 10.1007/s12031-014-0301-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 03/28/2014] [Indexed: 12/24/2022]
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) is a potent vasodilator of numerous vascular beds, including cerebral arteries. Although PACAP-induced cerebral artery dilation is suggested to be cyclic AMP (cAMP)-dependent, the downstream intracellular signaling pathways are still not fully understood. In this study, we examined the role of smooth muscle K(+) channels and hypothesized that PACAP-mediated increases in cAMP levels and protein kinase A (PKA) activity result in the coordinate activation of ATP-sensitive K(+) (KATP) and large-conductance Ca(2+)-activated K(+) (BK) channels for cerebral artery dilation. Using patch-clamp electrophysiology, we observed that PACAP enhanced whole-cell KATP channel activity and transient BK channel currents in freshly isolated rat cerebellar artery myocytes. The increased frequency of transient BK currents following PACAP treatment is indicative of increased intracellular Ca(2+) release events termed Ca(2+) sparks. Consistent with the electrophysiology data, the PACAP-induced vasodilations of cannulated cerebellar artery preparations were attenuated by approximately 50 % in the presence of glibenclamide (a KATP channel blocker) or paxilline (a BK channel blocker). Further, in the presence of both blockers, PACAP failed to cause vasodilation. In conclusion, our results indicate that PACAP causes cerebellar artery dilation through two mechanisms: (1) KATP channel activation and (2) enhanced BK channel activity, likely through increased Ca(2+) spark frequency.
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Affiliation(s)
- Masayo Koide
- Department of Pharmacology, University of Vermont College of Medicine, 149 Beaumont Avenue, Burlington, VT, 05405-0068, USA
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63
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Hong DH, Son YK, Li H, Jung ID, Park YM, Jung WK, Kim HS, Choi IW, Park WS. The calmodulin inhibitor and antipsychotic drug trifluoperazine inhibits voltage-dependent K+ channels in rabbit coronary arterial smooth muscle cells. Biochem Biophys Res Commun 2014; 443:321-5. [DOI: 10.1016/j.bbrc.2013.11.115] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 11/26/2013] [Indexed: 10/25/2022]
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64
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Upadhyay Dhungel K, Kim TW, Sharma N, Bhattarai JP, Ah Park S, Han SK, Kim CJ. Magnesium increases iberiotoxin-sensitive large conductance calcium activated potassium currents on the basilar artery smooth muscle cells in rabbits. Neurol Res 2013; 34:11-6. [DOI: 10.1179/1743132811y.0000000049] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Kshitiz Upadhyay Dhungel
- Cerebrovascular Laboratory-Department of NeurosurgeryResearch Institute of Clinical Medicine, Chonbuk National University Medical School & Hospital, Jeonju, Korea
| | - Tae Woon Kim
- Cerebrovascular Laboratory-Department of NeurosurgeryResearch Institute of Clinical Medicine, Chonbuk National University Medical School & Hospital, Jeonju, Korea
| | - Naveen Sharma
- Cerebrovascular Laboratory-Department of NeurosurgeryResearch Institute of Clinical Medicine, Chonbuk National University Medical School & Hospital, Jeonju, Korea
| | - Janardhan Prasad Bhattarai
- Department of Oral Physiology & Institute of Oral BioscienceSchool of Dentistry, Chonbuk National University, Jeonju, Korea
| | - Seon Ah Park
- Department of Oral Physiology & Institute of Oral BioscienceSchool of Dentistry, Chonbuk National University, Jeonju, Korea
| | - Seong Kyu Han
- Department of Oral Physiology & Institute of Oral BioscienceSchool of Dentistry, Chonbuk National University, Jeonju, Korea
| | - Chul Jin Kim
- Cerebrovascular Laboratory-Department of NeurosurgeryResearch Institute of Clinical Medicine, Chonbuk National University Medical School & Hospital, Jeonju, Korea
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Laughlin MH, Davis MJ, Secher NH, van Lieshout JJ, Arce-Esquivel AA, Simmons GH, Bender SB, Padilla J, Bache RJ, Merkus D, Duncker DJ. Peripheral circulation. Compr Physiol 2013; 2:321-447. [PMID: 23728977 DOI: 10.1002/cphy.c100048] [Citation(s) in RCA: 174] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Blood flow (BF) increases with increasing exercise intensity in skeletal, respiratory, and cardiac muscle. In humans during maximal exercise intensities, 85% to 90% of total cardiac output is distributed to skeletal and cardiac muscle. During exercise BF increases modestly and heterogeneously to brain and decreases in gastrointestinal, reproductive, and renal tissues and shows little to no change in skin. If the duration of exercise is sufficient to increase body/core temperature, skin BF is also increased in humans. Because blood pressure changes little during exercise, changes in distribution of BF with incremental exercise result from changes in vascular conductance. These changes in distribution of BF throughout the body contribute to decreases in mixed venous oxygen content, serve to supply adequate oxygen to the active skeletal muscles, and support metabolism of other tissues while maintaining homeostasis. This review discusses the response of the peripheral circulation of humans to acute and chronic dynamic exercise and mechanisms responsible for these responses. This is accomplished in the context of leading the reader on a tour through the peripheral circulation during dynamic exercise. During this tour, we consider what is known about how each vascular bed controls BF during exercise and how these control mechanisms are modified by chronic physical activity/exercise training. The tour ends by comparing responses of the systemic circulation to those of the pulmonary circulation relative to the effects of exercise on the regional distribution of BF and mechanisms responsible for control of resistance/conductance in the systemic and pulmonary circulations.
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Affiliation(s)
- M Harold Laughlin
- Department of Medical Pharmacology and Physiology, and the Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, USA.
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Yeung PKK, Shen J, Chung SSM, Chung SK. Targeted over-expression of endothelin-1 in astrocytes leads to more severe brain damage and vasospasm after subarachnoid hemorrhage. BMC Neurosci 2013; 14:131. [PMID: 24156724 PMCID: PMC3815232 DOI: 10.1186/1471-2202-14-131] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 10/15/2013] [Indexed: 01/15/2023] Open
Abstract
Background Endothelin-1 (ET-1) is a potent vasoconstrictor, and astrocytic ET-1 is reported to play a role in the pathogenesis of cerebral ischemic injury and cytotoxic edema. However, it is still unknown whether astrocytic ET-1 also contributes to vasogenic edema and vasospasm during subarachnoid hemorrhage (SAH). In the present study, transgenic mice with astrocytic endothelin-1 over-expression (GET-1 mice) were used to investigate the pathophysiological role of ET-1 in SAH pathogenesis. Results The GET-1 mice experienced a higher mortality rate and significantly more severe neurological deficits, blood–brain barrier breakdown and vasogenic edema compared to the non-transgenic (Ntg) mice following SAH. Oral administration of vasopressin V1a receptor antagonist, SR 49059, significantly reduced the cerebral water content in the GET-1 mice. Furthermore, the GET-1 mice showed significantly more pronounced middle cerebral arterial (MCA) constriction after SAH. Immunocytochemical analysis showed that the calcium-activated potassium channels and the phospho-eNOS were significantly downregulated, whereas PKC-α expression was significantly upregulated in the MCA of the GET-1 mice when compared to Ntg mice after SAH. Administration of ABT-627 (ETA receptor antagonist) significantly down-regulated PKC-α expression in the MCA of the GET-1 mice following SAH. Conclusions The present study suggests that astrocytic ET-1 involves in SAH-induced cerebral injury, edema and vasospasm, through ETA receptor and PKC-mediated potassium channel dysfunction. Administration of ABT-627 (ETA receptor antagonist) and SR 49059 (vasopressin V1a receptor antagonist) resulted in amelioration of edema and vasospasm in mice following SAH. These data provide a strong rationale to investigate SR 49059 and ABT-627 as therapeutic drugs for the treatment of SAH patients.
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Affiliation(s)
| | | | | | - Sookja K Chung
- Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
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67
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Role of genetic polymorphisms of ion channels in the pathophysiology of coronary microvascular dysfunction and ischemic heart disease. Basic Res Cardiol 2013; 108:387. [PMID: 24068186 PMCID: PMC3898136 DOI: 10.1007/s00395-013-0387-4] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 08/13/2013] [Accepted: 09/11/2013] [Indexed: 01/14/2023]
Abstract
Conventionally, ischemic heart disease (IHD) is equated with large vessel coronary disease. However, recent evidence has suggested a role of compromised microvascular regulation in the etiology of IHD. Because regulation of coronary blood flow likely involves activity of specific ion channels, and key factors involved in endothelium-dependent dilation, we proposed that genetic anomalies of ion channels or specific endothelial regulators may underlie coronary microvascular disease. We aimed to evaluate the clinical impact of single-nucleotide polymorphisms in genes encoding for ion channels expressed in the coronary vasculature and the possible correlation with IHD resulting from microvascular dysfunction. 242 consecutive patients who were candidates for coronary angiography were enrolled. A prospective, observational, single-center study was conducted, analyzing genetic polymorphisms relative to (1) NOS3 encoding for endothelial nitric oxide synthase (eNOS); (2) ATP2A2 encoding for the Ca2+/H+-ATPase pump (SERCA); (3) SCN5A encoding for the voltage-dependent Na+ channel (Nav1.5); (4) KCNJ8 and KCNJ11 encoding for the Kir6.1 and Kir6.2 subunits of K-ATP channels, respectively; and (5) KCN5A encoding for the voltage-gated K+ channel (Kv1.5). No significant associations between clinical IHD manifestations and polymorphisms for SERCA, Kir6.1, and Kv1.5 were observed (p > 0.05), whereas specific polymorphisms detected in eNOS, as well as in Kir6.2 and Nav1.5 were found to be correlated with IHD and microvascular dysfunction. Interestingly, genetic polymorphisms for ion channels seem to have an important clinical impact influencing the susceptibility for microvascular dysfunction and IHD, independent of the presence of classic cardiovascular risk factors.
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68
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Park MH, Son YK, Hong DH, Choi IW, Kim DJ, Lee H, Bang H, Na SH, Li H, Jo SH, Park WS. The Ca2+ channel inhibitor efonidipine decreases voltage-dependent K+ channel activity in rabbit coronary arterial smooth muscle cells. Vascul Pharmacol 2013; 59:90-5. [DOI: 10.1016/j.vph.2013.07.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 07/12/2013] [Accepted: 07/12/2013] [Indexed: 12/22/2022]
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69
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Involvement of Potassium Channels in Vasorelaxant Effect Induced by Valeriana prionophylla Standl. in Rat Mesenteric Artery. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2013; 2013:147670. [PMID: 24023569 PMCID: PMC3759249 DOI: 10.1155/2013/147670] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Revised: 07/07/2013] [Accepted: 07/08/2013] [Indexed: 11/17/2022]
Abstract
Assays in vitro and in vivo were performed on extract from roots and leaves from the Valeriana prionophylla Standl. (VPR and VPF, resp.). In phenylephrine (1 μM) precontracted rings, VPR (0.01–300 μg/mL) induced a concentration-dependent relaxation (maximum response (MR) = 75.4 ± 4.0%, EC50 = 5.97 (3.8–9.3) μg/mL, n = 6]); this effect was significantly modified after removal of the endothelium (EC50 = 39.6 (27.2–57.6) μg/mL, P < 0.05). However, VPF-induced vasorelaxation was less effective compared to VPR. When rings were preincubated with L-NAME (100 μM) or indomethacin (10 μM), the endothelium-dependent relaxation induced by VPR was significantly attenuated (MR = 20.9 ± 2.3%, 34.2 ± 2.9%, resp., P < 0.001). In rings denuded endothelium, precontracted with KCl (80 mM), or in preparations pretreated with KCl (20 mM) or tetraethylammonium (1 or 3 mM), the vasorelaxant activity of VPR was significantly attenuated (MR = 40.0 ± 8.2, n = 5; 50.5 ± 6.0%; 49.3 ± 6.4%; 46.8 ± 6.2%; resp., P < 0.01). In contrast, neither glibenclamide (10 μM), barium chloride (30 μM), nor 4-aminopyridine (1 mM) affected VPR-induced relaxation. Taken together, these results demonstrate that hypotension induced by VPR seems to involve, at least in part, a vascular component. Furthermore, endothelium-independent relaxation induced by VPR involves K+ channels activation, most likely due to BKCa channels, in the rat superior mesenteric artery.
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70
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Hong DH, Choi IW, Son YK, Kim DJ, Na SH, Jung WK, Yoon YW, Park WS. The effect of PI3 kinase inhibitor LY294002 on voltage-dependent K+ channels in rabbit coronary arterial smooth muscle cells. Life Sci 2013; 92:916-22. [DOI: 10.1016/j.lfs.2013.03.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 02/21/2013] [Accepted: 03/15/2013] [Indexed: 10/27/2022]
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71
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Thorpe RB, Stockman SL, Williams JM, Lincoln TM, Pearce WJ. Hypoxic depression of PKG-mediated inhibition of serotonergic contraction in ovine carotid arteries. Am J Physiol Regul Integr Comp Physiol 2013; 304:R734-43. [PMID: 23447135 DOI: 10.1152/ajpregu.00212.2012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Chronic hypoxia attenuates soluble guanylate cyclase-induced vasorelaxation in serotonin (5-HT)-contracted ovine carotid arteries. Because protein kinase G (PKG) mediates many effects of soluble guanylate cyclase activation through phosphorylation of multiple kinase targets in vascular smooth muscle, we tested the hypothesis that chronic hypoxia reduces the ability of PKG to phosphorylate its target proteins, which attenuates the ability of PKG to induce vasorelaxation. We also tested the hypothesis that hypoxia attenuates PKG expression and/or activity. Arteries from normoxic and chronically hypoxic (altitude of 3,820 m for 110 days) fetal and adult sheep were denuded of endothelium and equilibrated with 95% O2-5% CO2 in the presence of nitro-l-arginine methyl ester (l-NAME) and N(G)-nitro-l-arginine (l-NNA) to inhibit residual endothelial nitric oxide synthase. Concentration-response relations for 5-HT were determined in the presence of prazosin to minimize activation of α-adrenergic receptors. The PKG activator 8-(p-chlorophenylthio)-guanosine 3',5'-cyclic monophosphate (8-pCTP-cGMP) reduced agonist binding affinity of the 5-HT receptor in a concentration-dependent manner that was attenuated by hypoxia. Expression and activity of PKG-I was not significantly affected by chronic hypoxia in either fetal or adult arteries, although PKG-I abundance was greater in fetal arteries. Pretreatment with the large conductance calcium-sensitive potassium channel (BK) inhibitor iberiotoxin attenuated the vasorelaxation induced by 8-pCPT-cGMP in normoxic but not chronically hypoxic arteries. These results support the hypothesis that hypoxia attenuates the vasorelaxant effects of PKG through suppression of the ability of PKG to activate large conductance calcium-sensitive potassium channels in arterial smooth muscle. The results also reveal that this hypoxic effect is greater in fetal than adult arteries and that chronic maternal hypoxia can profoundly affect fetal vascular function.
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Affiliation(s)
- Richard B Thorpe
- Divisions of Physiology, Pharmacology, and Biochemistry, Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA
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72
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Brereton MF, Wareing M, Jones RL, Greenwood SL. Characterisation of K+ channels in human fetoplacental vascular smooth muscle cells. PLoS One 2013; 8:e57451. [PMID: 23437391 PMCID: PMC3578819 DOI: 10.1371/journal.pone.0057451] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Accepted: 01/24/2013] [Indexed: 11/18/2022] Open
Abstract
Adequate blood flow through placental chorionic plate resistance arteries (CPAs) is necessary for oxygen and nutrient transfer to the fetus and a successful pregnancy. In non-placental vascular smooth muscle cells (SMCs), K(+) channels regulate contraction, vascular tone and blood flow. Previous studies showed that K(+) channel modulators alter CPA tone, but did not distinguish between effects on K(+) channels in endothelial cells and SMCs. In this study, we developed a preparation of freshly isolated CPASMCs of normal pregnancy and investigated K(+) channel expression and function. CPASMCs were isolated from normal human term placentas using enzymatic digestion. Purity and phenotype was confirmed with immunocytochemistry. Whole-cell patch clamp was used to assess K(+) channel currents, and mRNA and protein expression was determined in intact CPAs and isolated SMCs with RT-PCR and immunostaining. Isolated SMCs expressed α-actin but not CD31, a marker of endothelial cells. CPASMCs and intact CPAs expressed h-caldesmon and non-muscle myosin heavy chain-2; phenotypic markers of contractile and synthetic SMCs respectively. Whole-cell currents were inhibited by 4-AP, TEA, charybdotoxin and iberiotoxin implicating functional K(v) and BK(Ca) channels. 1-EBIO enhanced whole cell currents which were abolished by TRAM-34 and reduced by apamin indicating activation of IK(Ca) and SK(Ca) respectively. BK(Ca), IK(Ca) and SK(Ca)3 mRNA and/or protein were expressed in CPASMCs and intact CPAs. This study provides the first direct evidence for functional K(v), BK(Ca,) IK(Ca) and SK(Ca) channels in CPASMCs. These cells display a mixed phenotype implicating a dual role for CPASMCs in controlling both fetoplacental vascular resistance and vasculogenesis.
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MESH Headings
- Actins/genetics
- Actins/metabolism
- Calcium/metabolism
- Calmodulin-Binding Proteins/genetics
- Calmodulin-Binding Proteins/metabolism
- Chorion/blood supply
- Chorion/cytology
- Chorion/drug effects
- Chorion/metabolism
- Female
- Fetus
- Gene Expression/drug effects
- Humans
- Membrane Potentials/drug effects
- Membrane Potentials/physiology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/cytology
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Myosin Heavy Chains/genetics
- Myosin Heavy Chains/metabolism
- Patch-Clamp Techniques
- Placenta/blood supply
- Placenta/cytology
- Placenta/drug effects
- Placenta/metabolism
- Potassium/metabolism
- Potassium Channel Blockers/pharmacology
- Potassium Channels, Calcium-Activated/antagonists & inhibitors
- Potassium Channels, Calcium-Activated/classification
- Potassium Channels, Calcium-Activated/genetics
- Potassium Channels, Calcium-Activated/metabolism
- Potassium Channels, Voltage-Gated/antagonists & inhibitors
- Potassium Channels, Voltage-Gated/classification
- Potassium Channels, Voltage-Gated/genetics
- Potassium Channels, Voltage-Gated/metabolism
- Pregnancy
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Affiliation(s)
- Melissa F Brereton
- Maternal and Fetal Health Research Centre, Institute of Human Development, University of Manchester, St. Mary's Hospital, Manchester, United Kingdom.
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73
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Wang ZQ, Xu JF, Wang JP, Zhao WJ, Zeng M. Involvement of guanylate cyclase and K+ channels in relaxation evoked by ferulate nitrate in rat aorta artery. J Pharmacol Sci 2013; 118:521-30. [PMID: 22510967 DOI: 10.1254/jphs.11179fp] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
Vasorelaxant properties of N-2-(ferulamidoethyl)-nitrate (ferulate nitrate, FLNT), a newly synthesized nitrate, were compared with those of isosorbide dinitrate, nicorandil, nitroglycerin, and 8-bromoguanosine 3,5-cyclic monophosphate (8-Br-cGMP) in rat aorta pre-contracted by phenylephrine. FLNT produced vasorelaxation in a concentration-dependent manner (0.1 - 100 µM). The degree of relaxation induced by FLNT was similar to that induced by isosorbide dinitrate. In addition, removal of endothelium did not affect the relaxant effect of FLNT. FLNT caused a rightward shift of the cumulative concentration-response curves of phenylephrine and reduced the maximal efficacy of contraction. 1H-[1,2,4]Oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ, 10 µM) and K(+)-channel blockers charybdotoxin (CHT, 0.1 µM) and BaCl(2) (1 µM) reduced the relaxant effect of FLNT in the endothelium-denuded arteries, whereas glibenclamide (1 µM) and 4-aminopyridine (1 mM) failed to influence FLNT-induced vasorelaxation. Furthermore, in the presence of ODQ, both CHT (0.1 µM) and BaCl(2) (1 µM) still significantly reduced the relaxation evoked by FLNT. Pretreatment of vessels with hydroxocobalamin, a nitric oxide scavenger, abolished the FLNT effect. These findings demonstrate that FLNT induces relaxation of the rat aorta rings endothelium-independently. Furthermore, we demonstrated that FLNT-induced vasorelaxation is related to its stimulation of soluble guanylate cyclase and activation of K(+) channels.
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Affiliation(s)
- Zhan-Qing Wang
- Department of Pharmacology, General Hospital of Beijing Military Command, Beijing, China.
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74
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Wang Y, Han Y, Yang J, Wang Z, Liu L, Wang W, Zhou L, Wang D, Tan X, Fu C, Jose PA, Zeng C. Relaxant effect of all-trans-retinoic acid via NO-sGC-cGMP pathway and calcium-activated potassium channels in rat mesenteric artery. Am J Physiol Heart Circ Physiol 2013; 304:H51-7. [PMID: 23125214 PMCID: PMC3543680 DOI: 10.1152/ajpheart.00240.2012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 10/26/2012] [Indexed: 02/05/2023]
Abstract
Intraperitoneal injection of all-trans-retinoic acid (ATRA) results in a reduction of blood pressure in spontaneously hypertensive rats. However, the mechanisms involved in this effect are not clear. We hypothesized that ATRA may relax resistance arteries. In this study, we found that ATRA relaxed phenylephrine-preconstricted mesenteric arterial rings, which were abrogated by the removal of the endothelium. Pretreatment of endothelium-intact arterial rings with an inhibitor of endothelial nitric oxide (NO) synthase, N(G)-nitro-l-arginine methyl ester (l-NAME), or soluble guanylyl cyclase, 1H-[1,2,4]-oxadiazole-[4,3-α]-quinoxaline-1-one, reduced the vasorelaxant effect of ATRA. Incubation of mesenteric arterial rings with ATRA increased the production of NO and cGMP, which were blocked by N(G)-nitro-l-arginine methyl ester. The vasorelaxant effect of ATRA was markedly attenuated in the presence of an inhibitor of big conductance calcium-activated potassium channels (charybdotoxin), but not with an inhibitor of voltage-dependent potassium channel (4-aminopyridine) or ATP-sensitive potassium channel (glibenclamide). Activation of retinoic acid receptors (RARs) with CH55 or retinoic X receptors (RXRs) with LGD1069 induced the vasorelaxation of phenylephrine-preconstricted mesenteric arterial rings. The RAR (BMS493) and RXR (UVI3003) antagonists blocked the ATRA-induced vasorelaxation. The vasorelaxant effect ATRA is physiologically relevant because the intravenous infusion of ATRA decreased blood pressure in normotensive rats. We conclude that ATRA relaxes resistance vessels via both RARs and RXRs receptors that are mediated by the endothelium-dependent NO-cGMP pathway, which may participate in the control of blood pressure.
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MESH Headings
- Animals
- Blood Pressure/drug effects
- Cyclic GMP/metabolism
- Dose-Response Relationship, Drug
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/enzymology
- Enzyme Inhibitors/pharmacology
- Guanylate Cyclase/metabolism
- Infusions, Intravenous
- Male
- Mesenteric Artery, Superior/drug effects
- Mesenteric Artery, Superior/enzymology
- Myography
- Nitric Oxide/metabolism
- Nitric Oxide Synthase/antagonists & inhibitors
- Nitric Oxide Synthase/metabolism
- Potassium Channel Blockers/pharmacology
- Potassium Channels, Calcium-Activated/drug effects
- Potassium Channels, Calcium-Activated/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, Cytoplasmic and Nuclear/metabolism
- Receptors, Retinoic Acid/drug effects
- Receptors, Retinoic Acid/metabolism
- Retinoid X Receptors/drug effects
- Retinoid X Receptors/metabolism
- Second Messenger Systems/drug effects
- Soluble Guanylyl Cyclase
- Time Factors
- Tretinoin/administration & dosage
- Tretinoin/pharmacology
- Vasodilation/drug effects
- Vasodilator Agents/administration & dosage
- Vasodilator Agents/pharmacology
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Affiliation(s)
- Yusheng Wang
- Department of Cardiology, The First Affiliated Hospital of Shantou University Medical College, Chongqing, China
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75
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Kamp MA, Dibué M, Schneider T, Steiger HJ, Hänggi D. Calcium and potassium channels in experimental subarachnoid hemorrhage and transient global ischemia. Stroke Res Treat 2012; 2012:382146. [PMID: 23251831 PMCID: PMC3518967 DOI: 10.1155/2012/382146] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 10/27/2012] [Indexed: 11/23/2022] Open
Abstract
Healthy cerebrovascular myocytes express members of several different ion channel families which regulate resting membrane potential, vascular diameter, and vascular tone and are involved in cerebral autoregulation. In animal models, in response to subarachnoid blood, a dynamic transition of ion channel expression and function is initiated, with acute and long-term effects differing from each other. Initial hypoperfusion after exposure of cerebral vessels to oxyhemoglobin correlates with a suppression of voltage-gated potassium channel activity, whereas delayed cerebral vasospasm involves changes in other potassium channel and voltage-gated calcium channels expression and function. Furthermore, expression patterns and function of ion channels appear to differ between main and small peripheral vessels, which may be key in understanding mechanisms behind subarachnoid hemorrhage-induced vasospasm. Here, changes in calcium and potassium channel expression and function in animal models of subarachnoid hemorrhage and transient global ischemia are systematically reviewed and their clinical significance discussed.
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Affiliation(s)
- Marcel A. Kamp
- Department for Neurosurgery, Medical Faculty, Heinrich Heine University, Moorenstraße 5, 40225 Düsseldorf, Germany
- Institute for Neurophysiology, University of Cologne, Robert-Koch-Straße 39, 50931 Cologne, Germany
| | - Maxine Dibué
- Department for Neurosurgery, Medical Faculty, Heinrich Heine University, Moorenstraße 5, 40225 Düsseldorf, Germany
- Institute for Neurophysiology, University of Cologne, Robert-Koch-Straße 39, 50931 Cologne, Germany
- Center of Molecular Medicine, Cologne, Germany
| | - Toni Schneider
- Institute for Neurophysiology, University of Cologne, Robert-Koch-Straße 39, 50931 Cologne, Germany
- Center of Molecular Medicine, Cologne, Germany
| | - Hans-Jakob Steiger
- Department for Neurosurgery, Medical Faculty, Heinrich Heine University, Moorenstraße 5, 40225 Düsseldorf, Germany
| | - Daniel Hänggi
- Department for Neurosurgery, Medical Faculty, Heinrich Heine University, Moorenstraße 5, 40225 Düsseldorf, Germany
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76
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Fiorim J, Ribeiro Júnior RF, Azevedo BF, Simões MR, Padilha AS, Stefanon I, Alonso MJ, Salaices M, Vassallo DV. Activation of K+ channels and Na+/K+ ATPase prevents aortic endothelial dysfunction in 7-day lead-treated rats. Toxicol Appl Pharmacol 2012; 262:22-31. [DOI: 10.1016/j.taap.2012.04.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 04/10/2012] [Accepted: 04/12/2012] [Indexed: 11/15/2022]
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77
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Nitric Oxide Signaling Pathways Involved in the Inhibition of Spontaneous Activity in the Guinea Pig Prostate. J Urol 2012; 187:2254-60. [DOI: 10.1016/j.juro.2012.01.072] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Indexed: 11/24/2022]
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78
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Park WS, Hong DH, Son YK, Kim MH, Jeong SH, Kim HK, Kim N, Han J. Alteration of ATP-sensitive K+ channels in rabbit aortic smooth muscle during left ventricular hypertrophy. Am J Physiol Cell Physiol 2012; 303:C170-8. [PMID: 22572849 DOI: 10.1152/ajpcell.00041.2012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated the impairment of ATP-sensitive K(+) (K(ATP)) channels in aortic smooth muscle cells (ASMCs) from isoproterenol-induced hypertrophied rabbits. The amplitude of K(ATP) channels induced by the K(ATP) channel opener pinacidil (10 μM) was greater in ASMCs from control than from hypertrophied animals. In phenylephrine-preconstricted aortic rings, pinacidil induced relaxation in a dose-dependent manner. The dose-dependent curve was shifted to the right in the hypertrophied (EC(50): 17.80 ± 3.28 μM) compared with the control model (EC(50): 6.69 ± 2.40 μM). Although the level of Kir6.2 subtype expression did not differ between ASMCs from the control and hypertrophied models, those of the Kir6.1 and SUR2B subtypes were decreased in the hypertrophied model. Application of the calcitonin-gene related peptide (100 nM) and adenylyl cyclase activator forskolin (10 μM), which activates protein kinase A (PKA) and consequently K(ATP) channels, induced a K(ATP) current in both control and hypertrophied animals; however, the K(ATP) current amplitude did not differ between the two groups. Furthermore, PKA expression was not altered between the control and hypertrophied animals. These results suggests that the decreased K(ATP) current amplitude and K(ATP) channel-induced vasorelaxation in the hypertrophied animals were attributable to the reduction in K(ATP) channel expression but not to changes in the intracellular signaling mechanism that activates the K(ATP) current.
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Affiliation(s)
- Won Sun Park
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, Korea
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79
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Yılmaz B, Usta C. Ellagic Acid-Induced Endothelium-Dependent and Endothelium-Independent Vasorelaxation in Rat Thoracic Aortic Rings and the Underlying Mechanism. Phytother Res 2012; 27:285-9. [DOI: 10.1002/ptr.4716] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 04/10/2012] [Indexed: 11/10/2022]
Affiliation(s)
- Bedriniam Yılmaz
- Pharmacology Department, Medical School; University of Mediterranean; Antalya Turkey
| | - Coskun Usta
- Pharmacology Department, Medical School; University of Mediterranean; Antalya Turkey
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80
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Jeong I, Yoon SH, Hahn SJ. Effects of dapoxetine on cloned Kv1.5 channels expressed in CHO cells. Naunyn Schmiedebergs Arch Pharmacol 2012; 385:707-16. [PMID: 22538641 DOI: 10.1007/s00210-012-0754-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Accepted: 04/10/2012] [Indexed: 11/25/2022]
Abstract
The effects of dapoxetine were examined on cloned Kv1.5 channels stably expressed in Chinese hamster ovary cells using the whole-cell patch clamp technique. Dapoxetine decreased the peak amplitude of Kv1.5 currents and accelerated the decay rate of current inactivation in a concentration-dependent manner with an IC ( 50 ) of 11.6 μM. Kinetic analysis of the time-dependent effects of dapoxetine on Kv1.5 current decay yielded the apparent association (k (+1 )) and dissociation (k (-1 )) rate constants of 2.8 μM(-1) s(-1) and 34.2 s(-1), respectively. The theoretical K ( D ) value, derived by k (-1 )/k (+1 ), yielded 12.3 μM, which was reasonably similar to the IC ( 50 ) value obtained from the concentration-response curve. Dapoxetine decreased the tail current amplitude and slowed the deactivation process of Kv1.5, which resulted in a tail crossover phenomenon. The block by dapoxetine is voltage-dependent and steeply increased at potentials between -10 and +10 mV, which correspond to the voltage range of channel activation. At more depolarized potentials, a weaker voltage dependence was observed (δ=0.31). Dapoxetine had no effect on the steady-state activation of Kv1.5 but shifted the steady-state inactivation curves in a hyperpolarizing direction. Dapoxetine produced a use-dependent block of Kv1.5 at frequencies of 1 and 2 Hz and slowed the time course for recovery of inactivation. These effects were reversible after washout of the drug. Our results indicate that dapoxetine blocks Kv1.5 currents by interacting with the channel in both the open and inactivated states of the channel.
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Affiliation(s)
- Imju Jeong
- Department of Physiology, Medical Research Center, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Socho-gu, Seoul 137-701, South Korea
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81
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Arai H, Zaima K, Mitsuta E, Tamamoto H, Saito A, Hirasawa Y, Rahman A, Kusumawati I, Zaini NC, Morita H. Alstiphyllanines I-O, ajmaline type alkaloids from Alstonia macrophylla showing vasorelaxant activity. Bioorg Med Chem 2012; 20:3454-9. [PMID: 22560833 DOI: 10.1016/j.bmc.2012.04.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2012] [Revised: 04/04/2012] [Accepted: 04/06/2012] [Indexed: 10/28/2022]
Abstract
Seven new ajmaline type alkaloids, alstiphyllanines I-O (1-7) were isolated from the leaves of Alstonia macrophylla together with six related alkaloids (8-13). Structures and stereochemistry of 1-7 were fully elucidated and characterized by 2D NMR analysis. A series of alstiphyllanines I-O (1-7) as well as the known ajmaline type alkaloids (8-13) showed that they relaxed phenylephrine (PE)-induced contractions against rat aortic ring. Among them, vincamedine (10) showed potent vasorelaxant activity, which may be mediated through inhibition of Ca(2+) influx through voltage-dependent Ca(2+) channels (VDCs) and/or receptor-operated Ca(2+) channels (ROCs) as well as partially mediated the NO release from endothelial cells. The presence of substituents at both N-1 and C-17 may be important to show vasorelaxation activity.
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Affiliation(s)
- Hiroko Arai
- Faculty of Pharmaceutical Sciences, Hoshi University, Shinagawa, Tokyo 142-8501, Japan
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82
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Goto K, Kansui Y, Oniki H, Ohtsubo T, Matsumura K, Kitazono T. Upregulation of endothelium-derived hyperpolarizing factor compensates for the loss of nitric oxide in mesenteric arteries of dahl salt-sensitive hypertensive rats. Hypertens Res 2012; 35:849-54. [DOI: 10.1038/hr.2012.36] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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83
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Fernández-Mariño AI, Porras-González C, González-Rodríguez P, Selent J, Pastor M, Ureña J, Castellano A, Valverde MA, Fernández-Fernández JM. Tungstate activates BK channels in a β subunit- and Mg2+-dependent manner: relevance for arterial vasodilatation. Cardiovasc Res 2012; 95:29-38. [PMID: 22473360 DOI: 10.1093/cvr/cvs139] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
AIMS Tungstate reduces blood pressure in experimental animal models of both hypertension and metabolic syndrome, although the underlying mechanisms are not fully understood. Given that the large-conductance voltage- and Ca(2+)-dependent K(+) (BK) channel is a key element in the control of arterial tone, our aim was to evaluate whether BK channel modulation by tungstate can contribute to its antihypertensive effect. METHODS AND RESULTS Patch-clamp studies of heterologously expressed human BK channels (α + β(1-4) subunits) revealed that cytosolic tungstate (1 mM) induced a significant left shift (∼20 mV) in the voltage-dependent activation curve only in BK channels containing αβ(1) or αβ(4) subunits, but reduced the amplitude of K(+) currents through all BK channels tested. The β(1)-dependent activation of BK channels by tungstate was enhanced at cytosolic Ca(2+) levels reached during myocyte contraction, and prevented either by removal of cytosolic Mg(2+) or by mutations rendering the channel insensitive to Mg(2+). A lower concentration of tungstate (0.1 mM) induced voltage-dependent activation of the vascular BKαβ(1) channel without reducing current amplitude, and consistently exerted a vasodilatory action on wild-type but not on β(1)-knockout mouse arteries pre-contracted with endothelin-1. CONCLUSION Tungstate activates BK channels in a β subunit- and Mg(2+)-dependent manner and induces vasodilatation only in mouse arteries that express the BK β(1) subunit.
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Affiliation(s)
- Ana I Fernández-Mariño
- Laboratori de Fisiologia Molecular i Canalopaties, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, C/Dr. Aiguader 88, Barcelona, Spain
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84
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Sorensen CM, Braunstein TH, Holstein-Rathlou NH, Salomonsson M. Role of vascular potassium channels in the regulation of renal hemodynamics. Am J Physiol Renal Physiol 2012; 302:F505-18. [DOI: 10.1152/ajprenal.00052.2011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
K+ conductance is a major determinant of membrane potential ( Vm) in vascular smooth muscle (VSMC) and endothelial cells (EC). The vascular tone is controlled by Vm through the action of voltage-operated Ca2+ channels (VOCC) in VSMC. Increased K+ conductance leads to hyperpolarization and vasodilation, while inactivation of K+ channels causes depolarization and vasoconstriction. K+ channels in EC indirectly participate in the control of vascular tone by several mechanisms, e.g., release of nitric oxide and endothelium-derived hyperpolarizing factor. In the kidney, a change in the activity of one or more classes of K+ channels will lead to a change in hemodynamic resistance and therefore of renal blood flow and glomerular filtration pressure. Through these effects, the activity of renal vascular K+ channels influences renal salt and water excretion, fluid homeostasis, and ultimately blood pressure. Four main classes of K+ channels [calcium activated (KCa), inward rectifier (Kir), voltage activated (KV), and ATP sensitive (KATP)] are found in the renal vasculature. Several in vitro experiments have suggested a role for individual classes of K+ channels in the regulation of renal vascular function. Results from in vivo experiments are sparse. We discuss the role of the different classes of renal vascular K+ channels and their possible role in the integrated function of the renal microvasculature. Since several pathological conditions, among them hypertension, are associated with alterations in K+ channel function, the role of renal vascular K+ channels in the control of salt and water excretion deserves attention.
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Affiliation(s)
- Charlotte Mehlin Sorensen
- Institute of Biomedical Sciences, Division of Renal and Vascuar Physiology, The Panum Institute, and
| | - Thomas Hartig Braunstein
- Danish National Research Foundation Center for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark
| | | | - Max Salomonsson
- Institute of Biomedical Sciences, Division of Renal and Vascuar Physiology, The Panum Institute, and
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85
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Perinatal hypoxia enhances cyclic adenosine monophosphate-mediated BKCa channel activation in adult murine pulmonary artery. J Cardiovasc Pharmacol 2012; 57:154-65. [PMID: 21289495 DOI: 10.1097/fjc.0b013e3182016adf] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Exposure to perinatal hypoxia results in alteration of the adult pulmonary circulation, which is linked among others to alterations in K(+) channels in pulmonary artery (PA) smooth muscle cells. In particular, large conductance Ca(2+)-activated K(+) (BK(Ca)) channels protein expression and activity were increased in adult PA from mice born in hypoxia compared with controls. We evaluated long-term effects of perinatal hypoxia on the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) pathway-mediated activation of BK(Ca) channels, using isoproterenol, forskolin, and dibutyryl-cAMP. Whole-cell outward current was higher in pulmonary artery smooth muscle cells from mice born in hypoxia compared with controls. Spontaneous transient outward currents, representative of BK(Ca) activity, were present in a greater proportion in pulmonary artery smooth muscle cells of mice born in hypoxia than in controls. Agonists induced a greater relaxation in PA of mice born in hypoxia compared with controls, and BK(Ca) channels contributed more to the cAMP/PKA-mediated relaxation in case of perinatal hypoxia. In summary, perinatal hypoxia enhanced cAMP-mediated BK(Ca) channels activation in adult murine PA, suggesting that this pathway could be a potential target for modulating adult pulmonary vascular tone after perinatal hypoxia.
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86
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Morgado M, Cairrão E, Santos-Silva AJ, Verde I. Cyclic nucleotide-dependent relaxation pathways in vascular smooth muscle. Cell Mol Life Sci 2012; 69:247-66. [PMID: 21947498 PMCID: PMC11115151 DOI: 10.1007/s00018-011-0815-2] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 08/21/2011] [Accepted: 08/23/2011] [Indexed: 02/07/2023]
Abstract
Vascular smooth muscle tone is controlled by a balance between the cellular signaling pathways that mediate the generation of force (vasoconstriction) and release of force (vasodilation). The initiation of force is associated with increases in intracellular calcium concentrations, activation of myosin light-chain kinase, increases in the phosphorylation of the regulatory myosin light chains, and actin-myosin crossbridge cycling. There are, however, several signaling pathways modulating Ca(2+) mobilization and Ca(2+) sensitivity of the contractile machinery that secondarily regulate the contractile response of vascular smooth muscle to receptor agonists. Among these regulatory mechanisms involved in the physiological regulation of vascular tone are the cyclic nucleotides (cAMP and cGMP), which are considered the main messengers that mediate vasodilation under physiological conditions. At least four distinct mechanisms are currently thought to be involved in the vasodilator effect of cyclic nucleotides and their dependent protein kinases: (1) the decrease in cytosolic calcium concentration ([Ca(2+)]c), (2) the hyperpolarization of the smooth muscle cell membrane potential, (3) the reduction in the sensitivity of the contractile machinery by decreasing the [Ca(2+)]c sensitivity of myosin light-chain phosphorylation, and (4) the reduction in the sensitivity of the contractile machinery by uncoupling contraction from myosin light-chain phosphorylation. This review focuses on each of these mechanisms involved in cyclic nucleotide-dependent relaxation of vascular smooth muscle under physiological conditions.
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Affiliation(s)
- Manuel Morgado
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal
| | - Elisa Cairrão
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal
| | - António José Santos-Silva
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal
| | - Ignacio Verde
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal
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87
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Niwa S, Ohya S, Kojima Y, Sasaki S, Yamamura H, Sakuragi M, Kohri K, Imaizumi Y. Down-Regulation of the Large-Conductance Ca 2+-Activated K + Channel, K Ca1.1 in the Prostatic Stromal Cells of Benign Prostate Hyperplasia. Biol Pharm Bull 2012; 35:737-44. [DOI: 10.1248/bpb.35.737] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Satomi Niwa
- Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University
| | - Susumu Ohya
- Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University
| | - Yoshiyuki Kojima
- Department of Nephro-urology, Graduate School of Medical Sciences, Nagoya City University
| | - Shoichi Sasaki
- Department of Nephro-urology, Graduate School of Medical Sciences, Nagoya City University
| | - Hisao Yamamura
- Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University
| | | | - Kenjiro Kohri
- Department of Nephro-urology, Graduate School of Medical Sciences, Nagoya City University
| | - Yuji Imaizumi
- Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University
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88
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Hong DH, Yang D, Choi IW, Son YK, Jung WK, Kim DJ, Han J, Na SH, Park WS. The T-type Ca2+ Channel Inhibitor Mibefradil Inhibits Voltage-Dependent K+ Channels in Rabbit Coronary Arterial Smooth Muscle Cells. J Pharmacol Sci 2012; 120:196-205. [DOI: 10.1254/jphs.12104fp] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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89
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Picchi A, Limbruno U, Focardi M, Cortese B, Micheli A, Boschi L, Severi S, De Caterina R. Increased basal coronary blood flow as a cause of reduced coronary flow reserve in diabetic patients. Am J Physiol Heart Circ Physiol 2011; 301:H2279-84. [DOI: 10.1152/ajpheart.00615.2011] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A reduced coronary flow reserve (CFR) has been demonstrated in diabetes, but the underlying mechanisms are unknown. We assessed thermodilution-derived CFR after 5-min intravenous adenosine infusion through a pressure-temperature sensor-tipped wire in 30 coronary arteries without significant lumen reduction in 30 patients: 13 with and 17 without a history of diabetes. We determined CFR as the ratio of basal and hyperemic mean transit times (Tmn); fractional flow reserve (FFR) as the ratio of distal and proximal pressures at maximal hyperemia to exclude local macrovascular disease; and an index of microvascular resistance (IMR) as the distal coronary pressure at maximal hyperemia divided by the inverse of the hyperemic Tmn. We also assessed insulin resistance by the homeostasis model assessment (HOMA) index. FFR was normal in all investigated arteries. CFR was significantly lower in diabetic vs. nondiabetic patients [median (interquartile range): 2.2 (1.4–3.2) vs. 4.1 (2.7–4.4); P = 0.02]. Basal Tmn was lower in diabetic vs. nondiabetic subjects [median (interquartile range): 0.53 (0.25–0.71) vs. 0.64 (0.50–1.17); P = 0.04], while hyperemic Tmn and IMR were similar. We found significant correlations at linear regression analysis between logCFR and the HOMA index ( r2 = 0.35; P = 0.0005) and between basal Tmn and the HOMA index ( r2 = 0.44; P < 0.0001). In conclusion, compared with nondiabetic subjects, CFR is lower in patients with diabetes and epicardial coronary arteries free of severe stenosis, because of increased basal coronary flow, while hyperemic coronary flow is similar. Basal coronary flow relates to insulin resistance, suggesting a key role of cellular metabolism in the regulation of coronary blood flow.
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Affiliation(s)
- Andrea Picchi
- Department of Cardiology, Misericordia Hospital, Grosseto
| | - Ugo Limbruno
- Department of Cardiology, Misericordia Hospital, Grosseto
| | - Marta Focardi
- Department of Cardiology, Misericordia Hospital, Grosseto
| | | | - Andrea Micheli
- Department of Cardiology, Misericordia Hospital, Grosseto
| | - Letizia Boschi
- Department of Physiology, University of Siena, Siena; and
| | - Silva Severi
- Department of Cardiology, Misericordia Hospital, Grosseto
| | - Raffaele De Caterina
- Institute of Cardiology and Center of Excellence on Aging, “G. d'Annunzio” University-Chieti, Chieti, Italy
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90
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Kim EY, Lee YJ, Rhyu MR. Black cohosh (Cimicifuga racemosa) relaxes the isolated rat thoracic aorta through endothelium-dependent and -independent mechanisms. JOURNAL OF ETHNOPHARMACOLOGY 2011; 138:537-542. [PMID: 22001858 DOI: 10.1016/j.jep.2011.09.048] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 09/21/2011] [Accepted: 09/25/2011] [Indexed: 05/31/2023]
Abstract
AIM OF THE STUDY The rhizome of the Cimicifuga racemosa (commonly known as black cohosh) has been used in treatment of climacteric complaints for decades in North America and Europe. A number of studies investigated the estrogenic potential of black cohosh, but its effectiveness is still controversial. Recently, it was reported that the extract of black cohosh acted as an agonist at the serotonin (5-HT) receptor and 5-HT derivative was isolated out of the black cohosh extract. Because it is well known that the 5-HT elicited the various cardiovascular effects including vasorelaxation, we investigated the vasorelaxant effects of the extract of black cohosh and its possible mechanisms of action. MATERIALS AND METHODS The extract of black cohosh (BcEx) was examined for its vasorelaxant effects in isolated rat aorta. The aortic rings were equilibrated under resting tension and induced reproducible contraction in organ bath. The control contraction was produced by 300 nM NE, and then BcEx were added. In experiments where specific inhibitors were used, they were added 20 min before NE contraction. RESULTS BcEx elicited two phases of relaxation in rat aorta pre-contracted with norepinephrine. The first, a rapid relaxation, which occurred within seconds of BcEx administration, was eliminated by pretreatment with N(G)-nitro-l-arginine (l-NNA) or methylene blue. The endogenous NO synthase substrate l-Arg markedly reversed the action of l-NNA, indicating that BcEx elicited the vasorelaxant effect via the NO/cGMP pathway. The second, slowly developing relaxation was not affected by the endothelium denudation. BcEx-induced endothelium-independent vasorelaxation appears to involve the inhibition of calcium influx mediated by the opening of inward rectifier potassium channels. CONCLUSIONS BcEx elicits the vasorelaxant effect via endothelium-dependent and -independent mechanisms and may contribute to a better understanding of a potential link between the use of black cohosh and its beneficial effects on vascular health.
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Affiliation(s)
- Eun-Young Kim
- Functional Food Technology Research Group, Korea Food Research Institute, Gyeonggi-do, Republic of Korea
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91
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Silva-Filho JC, Oliveira NNPM, Arcanjo DDR, Quintans-Júnior LJ, Cavalcanti SCH, Santos MRV, Oliveira RDCM, Oliveira AP. Investigation of mechanisms involved in (-)-borneol-induced vasorelaxant response on rat thoracic aorta. Basic Clin Pharmacol Toxicol 2011; 110:171-7. [PMID: 21883938 DOI: 10.1111/j.1742-7843.2011.00784.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The monoterpene (-)-borneol is present in essential oils of several medicinal plants. The aim of this study was to evaluate (-)-borneol effects on rat thoracic aorta artery rings. The cumulative addition of (-)-borneol (10(-9) -3 × 10(-4) M) on a phenylephrine-induced pre-contraction (10(-6) M) promoted a vasorelaxant effect in a concentration-dependent manner and independent of vascular endothelium. A similar effect was obtained on KCl-induced pre-contractions (80 mM). (-)-Borneol (10(-5) -3 × 10(-4 ) M) inhibited contractions induced by cumulative addition of CaCl2 (10(-6) -3 × 10(-2) M) in depolarizing medium without Ca(2+) in a concentration-dependent manner. On S-(-) Bay K 8644-induced pre-contractions (10(-7) M), (-)-borneol did not induce significant changes compared with KCl-induced pre-contractions. In a Ca(2+) -free medium, (-)-borneol (10(-5) , 10(-4) or 10(-3) M) interfered in calcium mobilization from phenylephrine (10(-6) M)- or caffeine (20 mM)-sensitive intracellular stores. The involvement of K(+) channels was evaluated by tetraethylammonium (3 mM), 4-aminopyridine (1 mM) and glibenclamide (10(-5) M) pre-treatment, and (-)-borneol-induced vasorelaxation was markedly attenuated. Thus, this vasorelaxant effect can probably be attributed to calcium influx blockade through voltage-operated calcium channels (CaV L), calcium mobilization from intracellular stores and potassium channels activation.
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Affiliation(s)
- José Couras Silva-Filho
- Medicinal Plants Research Center, Federal University of Piauí, BrazilDepartament of Physiology, Federal University of Sergipe, Brazil
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92
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Morita H, Zaima K, Koga I, Saito A, Tamamoto H, Okazaki H, Kaneda T, Hashimoto T, Asakawa Y. Vasorelaxant effects of macrocyclic bis(bibenzyls) from liverworts. Bioorg Med Chem 2011; 19:4051-6. [DOI: 10.1016/j.bmc.2011.05.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 05/13/2011] [Accepted: 05/13/2011] [Indexed: 11/25/2022]
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93
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Rainbow RD, Parker AM, Davies NW. Protein kinase C-independent inhibition of arterial smooth muscle K(+) channels by a diacylglycerol analogue. Br J Pharmacol 2011; 163:845-56. [PMID: 21323899 PMCID: PMC3111686 DOI: 10.1111/j.1476-5381.2011.01268.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND AND PURPOSE Analogues of the endogenous diacylglycerols have been used extensively as pharmacological activators of protein kinase C (PKC). Several reports show that some of these compounds have additional effects that are independent of PKC activation, including direct block of K(+) and Ca(2+) channels. We investigated whether dioctanoyl-sn-glycerol (DiC8), a commonly used diacylglycerol analogue, blocks K(+) currents of rat mesenteric arterial smooth muscle in a PKC-independent manner. EXPERIMENTAL APPROACH Conventional whole-cell and inside-out patch clamp was used to measure the inhibition of K(+) currents of rat isolated mesenteric smooth muscle cells by DiC8 in the absence and presence of PKC inhibitor peptide. KEY RESULTS Mesenteric artery smooth muscle K(v) currents inactivated very slowly with a time constant of about 2 s following pulses from -65 to +40 mV. Application of 1 µM DiC8 produced an approximate 40-fold increase in the apparent rate of inactivation. Pretreatment of the cells with PKC inhibitor peptide had a minimal effect on the action of DiC8, and substantial inactivation still occurred, indicating that this effect was mainly independent of PKC. We also found that DiC8 blocked BK and K(ATP) currents, and again a significant proportion of these blocks occurred independently of PKC activation. CONCLUSIONS AND IMPLICATIONS These results show that DiC8 has a direct effect on arterial smooth muscle K(+) channels, and this precludes its use as a PKC activator when investigating PKC-mediated effects on vascular K(+) channels.
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Affiliation(s)
- RD Rainbow
- Department of Cardiovascular Sciences, University of LeicesterLeicester, UK
| | - AM Parker
- Department of Cell Physiology and Pharmacology, University of LeicesterLeicester, UK
| | - NW Davies
- Department of Cell Physiology and Pharmacology, University of LeicesterLeicester, UK
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94
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A new nitrosyl ruthenium complex nitric oxide donor presents higher efficacy than sodium nitroprusside on relaxation of airway smooth muscle. Eur J Pharm Sci 2011; 43:370-7. [PMID: 21605670 DOI: 10.1016/j.ejps.2011.05.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 05/02/2011] [Accepted: 05/08/2011] [Indexed: 11/21/2022]
Abstract
Nitric oxide (NO) has been demonstrated to be the primary agent in relaxing airways in humans and animals. We investigated the mechanisms involved in the relaxation induced by NO-donors, ruthenium complex [Ru(terpy)(bdq)NO(+)](3+) (TERPY) and sodium nitroprusside (SNP) in isolated trachea of rats contracted with carbachol in an isolated organs chamber. For instance, we verified the contribution of K(+) channels, the importance of sGC/cGMP pathway, the influence of the extra and intracellular Ca(2+) sources and the contribution of the epithelium on the relaxing response. Additionally, we have used confocal microscopy in order to analyze the action of the NO-donors on cytosolic Ca(2+) concentration. The results demonstrated that both compounds led to the relaxation of trachea in a dependent-concentration way. However, the maximum effect (E(max)) of TERPY is higher than the SNP. The relaxation induced by SNP (but not TERPY) was significantly reduced by pretreatment with ODQ (sGC inhibitor). Only TERPY-induced relaxation was reduced by tetraethylammonium (K(+) channels blocker) and by pre-contraction with 75mM KCl (membrane depolarization). The response to both NO-donors was not altered by the presence of thapsigargin (sarcoplasmic reticulum Ca(2+)-ATPase inhibitor). The epithelium removal has reduced the relaxation only to SNP, and it has no effect on TERPY. The both NO-donors reduced the contraction evoked by Ca(2+) influx, while TERPY have shown a higher inhibitory effect on contraction. Moreover, the TERPY was more effective than SNP in reducing the cytosolic Ca(2+) concentration measured by confocal microscopy. In conclusion, these results show that TERPY induces airway smooth muscle relaxation by cGMP-independent mechanisms, it involves the fluxes of Ca(2+) and K(+) across the membrane, it is more effective in reducing cytosolic Ca(2+) concentration and inducing relaxation in the rat trachea than the standard drug, SNP.
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95
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Liang GH, Adebiyi A, Leo MD, McNally EM, Leffler CW, Jaggar JH. Hydrogen sulfide dilates cerebral arterioles by activating smooth muscle cell plasma membrane KATP channels. Am J Physiol Heart Circ Physiol 2011; 300:H2088-95. [PMID: 21421823 DOI: 10.1152/ajpheart.01290.2010] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Hydrogen sulfide (H(2)S) is a gaseous signaling molecule that appears to contribute to the regulation of vascular tone and blood pressure. Multiple potential mechanisms of vascular regulation by H(2)S exist. Here, we tested the hypothesis that piglet cerebral arteriole smooth muscle cells generate ATP-sensitive K(+) (K(ATP)) currents and that H(2)S induces vasodilation by activating K(ATP) currents. Gas chromatography/mass spectrometry data demonstrated that after placing Na(2)S, an H(2)S donor, in solution, it rapidly (1 min) converts to H(2)S. Patch-clamp electrophysiology indicated that pinacidil (a K(ATP) channel activator), Na(2)S, and NaHS (another H(2)S donor) activated K(+) currents at physiological steady-state voltage (-50 mV) in isolated cerebral arteriole smooth muscle cells. Glibenclamide, a selective K(ATP) channel inhibitor, fully reversed pinacidil-induced K(+) currents and partially reversed (∼58%) H(2)S-induced K(+) currents. Western blot analysis indicated that piglet arterioles expressed inwardly rectifying K(+) 6.1 (K(ir)6.1) channel and sulfonylurea receptor 2B (SUR2B) K(ATP) channel subunits. Pinacidil dilated pressurized (40 mmHg) piglet arterioles, and glibenclamide fully reversed this effect. Na(2)S also induced reversible and repeatable vasodilation with an EC(50) of ∼30 μM, and this effect was partially reversed (∼55%) by glibenclamide. Vasoregulation by H(2)S was also studied in pressurized resistance-size cerebral arteries of mice with a genetic deletion in the gene encoding SUR2 (SUR2 null). Pinacidil- and H(2)S-induced vasodilations were smaller in arterioles of SUR2 null mice than in wild-type controls. These data indicate that smooth muscle cell K(ATP) currents control newborn cerebral arteriole contractility and that H(2)S dilates cerebral arterioles by activating smooth muscle cell K(ATP) channels containing SUR2 subunits.
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Affiliation(s)
- Guo Hua Liang
- Dept. of Physiology, Univ. of Tennessee Health Science Ctr., Memphis, TN 38163, USA
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96
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Celotto AC, Restini CBA, Capellini VK, Bendhack LM, Evora PRB. Acidosis induces relaxation mediated by nitric oxide and potassium channels in rat thoracic aorta. Eur J Pharmacol 2011; 656:88-93. [PMID: 21300058 DOI: 10.1016/j.ejphar.2011.01.053] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 01/05/2011] [Accepted: 01/25/2011] [Indexed: 10/18/2022]
Abstract
We investigated the mechanism by which extracellular acidification promotes relaxation in rat thoracic aorta. The relaxation response to HCl-induced extracellular acidification (7.4 to 6.5) was measured in aortic rings pre-contracted with phenylephrine (Phe, 10(-6) M) or KCl (45mM). The vascular reactivity experiments were performed in endothelium-intact and denuded rings, in the presence or absence of indomethacin (10(-5) M), L-NAME (10(-4) M), apamin (10(-6) M), and glibenclamide (10(-5) M). The effect of extracellular acidosis (pH 7.0 and 6.5) on nitric oxide (NO) production was evaluated in isolated endothelial cells loaded with diaminofluorescein-FM diacetate (DAF-FM DA, 5μM). The extracellular acidosis failed to induce any changes in the vascular tone of aortic rings pre-contracted with KCl, however, it caused endothelium-dependent and independent relaxation in rings pre-contracted with Phe. This acidosis induced-relaxation was inhibited by L-NAME, apamin, and glibenclamide, but not by indomethacin. The acidosis (pH 7.0 and 6.5) also promoted a time-dependent increase in the NO production by the isolated endothelial cells. These results suggest that extracellular acidosis promotes vasodilation mediated by NO, K(ATP) and SK(Ca), and maybe other K(+) channels in isolated rat thoracic aorta.
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Affiliation(s)
- Andréa C Celotto
- Laboratory of Endothelial Function, Department of Surgery and Anatomy, School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil.
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97
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Chan P, Liu IM, Li YX, Yu WJ, Cheng JT. Antihypertension Induced by Tanshinone IIA Isolated from the Roots of Salvia miltiorrhiza. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2011; 2011:392627. [PMID: 19542183 PMCID: PMC3135424 DOI: 10.1093/ecam/nep056] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Accepted: 05/07/2009] [Indexed: 12/15/2022]
Abstract
Tanshinone IIA is one of the active principles in danshen (Salvia miltiorrhiza Bge) widely used in treatment of cardiovascular disorders. We investigated the effect of danshen or tanshinone IIA on blood pressure and its possible mechanisms. An i.p. injection of danshen at 10 mg kg(-1) significantly lowered systolic blood pressure (SBP) of spontaneously hypertensive rats (SHRs) but failed to modify the SBP in normotensive Wistar-Kyoto rats (WKY). Oral administration of tanshinone IIA also decreased SBP in SHR but not in WKY. Tanshinone IIA produced a concentration-dependent relaxation in isolated SHR aortic rings precontracted with phenylephrine (10 nmol l(-1)) or potassium chloride (KCl) (40 mmol l(-1)). The relaxing effect of tanshinone IIA on tonic contraction of phenylephrine in isolated aortic rings without endothelium remained produced. Glibenclamide at concentration sufficient to block adenosine triphosphatase (ATP)-sensitive potassium (K(+)) channel attenuated this tanshinone IIA-induced relaxation that was not influenced by other inhibitors. We further investigated the effect of tanshinone IIA on the changes of intracellular calcium concentration ([Ca(2+)](i)) in cultured aortic smooth muscle (A7r5) cells using fura-2 as indicator. Tanshinone IIA decreased [Ca(2+)](i) elicited by phenylephrine (10 nmol l(-1)) or KCl (40 mmol l(-1)) in a concentration-dependent manner; glibenclamide, but not other inhibitors for K(+) channel, abated this effect. Our results suggest that tanshinone IIA acts as an active principle of danshen showing vasodilation through ATP-sensitive K(+) channel to lower [Ca(2+)](i).
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Affiliation(s)
- Paul Chan
- Division of Cardiovascular Medicine, Taipei Medical University-Wan Fang Hospital, Taipei City 11601, Taiwan
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98
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Kim EY, Kim JH, Rhyu MR. Endothelium-independent vasorelaxation by Ligusticum wallichii in isolated rat aorta: comparison of a butanolic fraction and tetramethylpyrazine, the main active component of Ligusticum wallichii. Biol Pharm Bull 2010; 33:1360-3. [PMID: 20686232 DOI: 10.1248/bpb.33.1360] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ligusticum wallichii is an herb widely used to treat vascular disorders in Asian countries, and tetramethylpyrazine (TMP) has been identified as one of its vasorelaxant active components. This study was performed to examine the endothelium-independent relaxation produced by the butanol-soluble fraction of L. wallichii extract (LwBt) and its possible mechanisms of action in isolated rat aortic rings. The effects were compared with those of TMP. LwBt produced vasorelaxation that increased gradually after 2-3 min of LwBt administration and reached a maximum within 30 min. LwBt-induced relaxation was significantly attenuated by pretreatment with 4-aminopyridine and apamin. Additionally, LwBt attenuated CaCl(2)-induced vasoconstriction in high-potassium depolarized medium. Thus, LwBt-induced vasorelaxation apparently involved inhibition of calcium influx, mediated by the opening of voltage-dependent and/or Ca(2+)-activated potassium channels. On the other hand, the effect of TMP was significantly attenuated by pretreatment with glibenclamide, and 4-aminopyridine had no effect. In conclusion, LwBt-induced endothelium-independent vasorelaxation was mediated by the opening of voltage-dependent potassium channels, while TMP-induced relaxation was mediated by the opening of ATP-dependent potassium channels. These effects of LwBt may be due to a substance other than TMP.
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Affiliation(s)
- Eun-Young Kim
- Food Function Research Division, Korea Food Research Institute, Gyeonggido 463-746, Korea
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99
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Seok YM, Choi YW, Kim GD, Kim HY, Takuwa Y, Kim IK. Effects of gomisin A on vascular contraction in rat aortic rings. Naunyn Schmiedebergs Arch Pharmacol 2010; 383:45-56. [DOI: 10.1007/s00210-010-0571-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 09/08/2010] [Indexed: 01/06/2023]
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100
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Long X, Mokelke EA, Neeb ZP, Alloosh M, Edwards JM, Sturek M. Adenosine receptor regulation of coronary blood flow in Ossabaw miniature swine. J Pharmacol Exp Ther 2010; 335:781-7. [PMID: 20855445 DOI: 10.1124/jpet.110.170803] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Adenosine clearly regulates coronary blood flow (CBF); however, contributions of specific adenosine receptor (AR) subtypes (A(1), A(2A), A(2B), A(3)) to CBF in swine have not been determined. ARs generally decrease (A(1), A(3)) or increase (A(2A), A(2B)) cyclic adenosine monophosphate, a major mediator of vasodilation. We hypothesized that A(1) antagonism potentiates coronary vasodilation and coronary stent deployment in dyslipidemic Ossabaw swine elicits impaired vasodilation to adenosine that is associated with increased A(1)/A(2A) expression. The left main coronary artery was accessed with a guiding catheter allowing intracoronary infusions. After placement of a flow wire into the left circumflex coronary artery the responses to bolus infusions of adenosine were obtained. Steady-state infusion of AR-specific agents was achieved by using a small catheter fed over the flow wire in control pigs. CBF was increased by the A(2)-nonselective agonist 2-phenylaminoadenosine (CV1808) in a dose-dependent manner. Baseline CBF was increased by the highly A(1)-selective antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), but not changed by other AR-specific agents. The nonselective A(2) antagonist 3,7-dimethyl-1-propargylxanthine and A(2A)-selective antagonist 4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol (ZM241385) abolished adenosine-induced CBF, whereas A(2B) and A(3) antagonism had no effect. Dyslipidemia and stenting decreased adenosine-induced CBF ∼70%, whereas A(1), A(2A), and A(2B) mRNA were up-regulated in dyslipidemic versus control >5-fold and there was no change in the ratio of A(1)/A(2A) protein in microvessels distal to the stent. In control Ossabaw swine A(1) antagonism by DPCPX positively regulated basal CBF. Impaired adenosine-induced CBF after stenting in dyslipidemia is most likely caused by the altered balance between A(1) and A(2A) signaling, not receptor expression.
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Affiliation(s)
- Xin Long
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana 46202-5120, USA
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