1
|
L-arginine and Arginase Products Potentiate Dexmedetomidine-induced Contractions in the Rat Aorta. Anesthesiology 2019; 128:564-573. [PMID: 29251642 DOI: 10.1097/aln.0000000000002032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND The α2-adrenergic sedative/anesthetic agent dexmedetomidine exerts biphasic effects on isolated arteries, causing endothelium-dependent relaxations at concentrations at or below 30 nM, followed by contractions at higher concentrations. L-arginine is a common substrate of endothelial nitric oxide synthase and arginases. This study was designed to investigate the role of L-arginine in modulating the overall vascular response to dexmedetomidine. METHODS Isometric tension was measured in isolated aortic rings of Sprague Dawley rats. Cumulative concentrations of dexmedetomidine (10 nM to 10 μM) were added to quiescent rings (with and without endothelium) after previous incubation with vehicle, N-nitro-L-arginine methyl ester hydrochloride (L-NAME; nitric oxide synthase inhibitor), prazosin (α1-adrenergic antagonist), rauwolscine (α2-adrenergic antagonist), L-arginine, (S)-(2-boronethyl)-L-cysteine hydrochloride (arginase inhibitor), N-hydroxy-L-arginine (arginase inhibitor), urea and/or ornithine. In some preparations, immunofluorescent staining, immunoblotting, or measurement of urea content were performed. RESULTS Dexmedetomidine did not contract control rings with endothelium but evoked concentration-dependent increases in tension in such rings treated with L-NAME (Emax 50 ± 4%) or after endothelium-removal (Emax 74 ± 5%; N = 7 to 12). Exogenous L-arginine augmented the dexmedetomidine-induced contractions in the presence of L-NAME (Emax 75 ± 3%). This potentiation was abolished by (S)-(2-boronethyl)-L-cysteine hydrochloride (Emax 16 ± 4%) and N-hydroxy-L-arginine (Emax 18 ± 4%). Either urea or ornithine, the downstream arginase products, had a similar potentiating effect as L-arginine. Immunoassay measurements demonstrated an upregulation of arginase I by L-arginine treatment in the presence of L-NAME (N = 4). CONCLUSIONS These results suggest that when vascular nitric oxide homeostasis is impaired, the potentiation of the vasoconstrictor effect of dexmedetomidine by L-arginine depends on arginase activity and the production of urea and ornithine.
Collapse
|
2
|
Lervik A, Raszplewicz J, Ranheim B, Solbak S, Toverud SF, Haga HA. Dexmedetomidine or fentanyl? Cardiovascular stability and analgesia during propofol-ketamine total intravenous anaesthesia in experimental pigs. Vet Anaesth Analg 2018; 45:295-308. [DOI: 10.1016/j.vaa.2017.08.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 07/13/2017] [Accepted: 08/29/2017] [Indexed: 10/18/2022]
|
3
|
Zhou SZ, Li ZM, Liu XR, Zhou J, Tan XQ, Yang Y, Wei JC. Bidirectional Regulatory Effects of Dexmedetomidine on Porcine Coronary Tone In Vitro. Med Sci Monit 2017; 23:1621-1626. [PMID: 28369032 PMCID: PMC5388309 DOI: 10.12659/msm.903501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Background Studies in vivo have shown that dexmedetomidine (DEX) could protect the myocardium and modulate the coronary blood flow. This study aimed to investigate the direct and concentration-dependent effects of DEX on the tone of porcine coronary artery in vitro and the underlying mechanisms. Material/Methods Distal branches of the porcine anterior descending coronary arteries were dissected and cut into 3–5 mm rings. The tones of coronary rings in response to cumulative DEX were measured using the PowerLab system. Coronary rings were divided into three groups: 1) endothelium-intact coronary rings without drug pretreatment (control); 2) endothelium-intact coronary rings pretreated with either yohimbine, tetraethylamine (TEA) or NG-nitro-L-arginine methyl ester (L-NAME); and 3) endothelium-denuded coronary rings pretreated with either yohimbine or TEA. Results DEX induced coronary ring relaxation at lower concentrations (10−9 to 10−7 M) followed by constriction at higher concentrations (10−6 to 10−5 M). The coronary constrictive effect of higher DEX (10−5 M) was greater in the endothelium-denuded rings than in the endothelium-intact rings. Yohimbine reduced the coronary constrictive effect of DEX at higher concentrations (10−6 to 10−5 M). TEA and L-NAME significantly reduced the coronary relaxing effect of DEX at lower concentrations (10−9 to 10−7 M) in endothelium-intact rings. TEA attenuated the coronary relaxation induced by DEX in endothelium-denuded rings. Conclusions DEX exerts bidirectional effects on porcine coronary tone. The coronary relaxing effect of DEX at lower concentrations is likely associated with endothelium integrity, NO synthesis and BKCa channel activation, while the coronary constrictive effect of DEX at higher concentrations is mediated by α2 adrenoceptors in the coronary smooth muscle cells.
Collapse
Affiliation(s)
- Shu-Zhi Zhou
- Department of Anesthesiology, Ya'an People's Hospital, Ya'an, Sichuan, China (mainland)
| | - Zhi-Ming Li
- Department of Anesthesiology, The 1st People's Hospital of Yibin, Yibin, Sichuan, China (mainland)
| | - Xue-Ru Liu
- Department of Anesthesiology, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China (mainland).,Key Laboratory of Medical Electrophysiology, Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease/Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China (mainland)
| | - Jun Zhou
- Department of Anesthesiology, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China (mainland)
| | - Xiao-Qiu Tan
- Key Laboratory of Medical Electrophysiology, Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease/Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China (mainland)
| | - Yan Yang
- Key Laboratory of Medical Electrophysiology, Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease/Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China (mainland)
| | - Ji-Cheng Wei
- Department of Anesthesiology, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China (mainland)
| |
Collapse
|
4
|
Byon HJ, Ok SH, Lee SH, Kang S, Cho Y, Han JY, Sohn JT. Dexmedetomidine Inhibits Phenylephrine-induced Contractions via Alpha-1 Adrenoceptor Blockade and Nitric Oxide Release in Isolated Rat Aortae. Int J Med Sci 2017; 14:143-149. [PMID: 28260990 PMCID: PMC5332843 DOI: 10.7150/ijms.17456] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Accepted: 12/21/2016] [Indexed: 12/16/2022] Open
Abstract
The goal of this in vitro study was to examine the effect of the alpha-2 adrenoceptor agonist dexmedetomidine on phenylephrine (alpha-1 adrenoceptor agonist)-induced contraction in isolated rat aortae and to elucidate the associated cellular mechanisms, with a particular focus on alpha-1 adrenoceptor antagonism. Dexmedetomidine dose-response curves were generated in isolated endothelium-intact and endothelium-denuded rat aortae precontracted with phenylephrine or 5-hydroxytryptamine. Endothelium-denuded aortic rings were pretreated with either dexmedetomidine or the reversible alpha-1 adrenoceptor antagonist phentolamine, followed by post-treatment with the irreversible alpha-1 adrenoceptor blocker phenoxybenzamine. Control rings were treated with phenoxybenzamine alone. All rings were repeatedly washed with Krebs solution to remove all pretreatment drugs, including phenoxybenzamine, phentolamine and dexmedetomidine. Phenylephrine dose-response curves were then generated. The effect of rauwolscine on the dexmedetomidine-mediated change in phenylephrine-induced endothelial nitric oxide synthase (eNOS) phosphorylation in human umbilical vein endothelial cells was examined using western blotting. The magnitude of the dexmedetomidine-mediated inhibition of phenylephrine-induced contraction was higher in endothelium-intact aortae than in endothelium-denuded aortae or endothelium-intact aortae treated with Nω-nitro-L-arginine methyl ester. However, dexmedetomidine did not significantly alter 5-hydroxytryptamine-induced contraction. In further experiments, prazosin attenuated dexmedetomidine-induced contraction. Additionally, pretreatment with either dexmedetomidine plus phenoxybenzamine or phentolamine plus phenoxybenzamine produced greater phenylephrine-induced contraction than phenoxybenzamine alone, suggesting that dexmedetomidine protects aortae from the alpha-1 adrenoceptor blockade induced by phenoxybenzamine. Rauwolscine attenuated the dexmedetomidine-mediated enhancement of phenylephrine-induced eNOS phosphorylation. Taken together, these results suggest that dexmedetomidine attenuates phenylephrine-induced contractions via alpha-1 adrenoceptor blockade and endothelial nitric oxide release in the isolated rat aorta.
Collapse
Affiliation(s)
- Hyo-Jin Byon
- Department of Anesthesiology and Pain Medicine, Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Seong-Ho Ok
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University School of Medicine, Gyeongsang National University Hospital, Jinju, 52727, Republic of Korea
| | - Soo Hee Lee
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University School of Medicine, Gyeongsang National University Hospital, Jinju, 52727, Republic of Korea
| | - Sebin Kang
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Jinju, 52727, Republic of Korea
| | - Youngil Cho
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Jinju, 52727, Republic of Korea
| | - Jeong Yeol Han
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Changwon Hospital, Changwon, 51427, Republic of Korea
| | - Ju-Tae Sohn
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University School of Medicine, Gyeongsang National University Hospital, Jinju, 52727, Republic of Korea;; Institute of Health Sciences, Gyeongsang National University, Jinju-si, Republic of Korea
| |
Collapse
|
5
|
Nong L, Ma J, Zhang G, Deng C, Mao S, Li H, Cui J. Dexmedetomidine inhibits vasoconstriction via activation of endothelial nitric oxide synthase. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2016; 20:441-7. [PMID: 27610030 PMCID: PMC5014990 DOI: 10.4196/kjpp.2016.20.5.441] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 02/04/2016] [Accepted: 02/29/2016] [Indexed: 01/18/2023]
Abstract
Despite the complex vascular effects of dexmedetomidine (DEX), its actions on human pulmonary resistance arteries remain unknown. The present study tested the hypothesis that DEX inhibits vascular tension in human pulmonary arteries through the endothelial nitric oxide synthase (eNOS) mediated production of nitric oxide (NO). Pulmonary artery segments were obtained from 62 patients who underwent lung resection. The direct effects of DEX on human pulmonary artery tension and changes in vascular tension were determined by isometric force measurements recorded on a myograph. Arterial contractions caused by increasing concentrations of serotonin with DEX in the presence or absence of L-NAME (endothelial nitric oxide synthase inhibitor), yohimbine (α2-adrenoceptor antagonist) and indomethacin (cyclooxygenase inhibitor) as antagonists were also measured. DEX had no effect on endothelium-intact pulmonary arteries, whereas at concentrations of 10–8~10–6 mol/L, it elicited contractions in endothelium-denuded pulmonary arteries. DEX (0.3, 1, or 3×10–9 mmol/L) inhibited serotonin-induced contraction in arteries with intact endothelium in a dose-dependent manner. L-NAME and yohimbine abolished DEX-induced inhibition, whereas indomethacin had no effect. No inhibitory effect was observed in endothelium-denuded pulmonary arteries. DEX-induced inhibition of vasoconstriction in human pulmonary arteries is mediated by NO production induced by the activation of endothelial α2-adrenoceptor and nitric oxide synthase.
Collapse
Affiliation(s)
- Lidan Nong
- Department of Anesthesiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, China
| | - Jue Ma
- Department of Anesthesiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, China
| | - Guangyan Zhang
- Department of Anesthesiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, China
| | - Chunyu Deng
- Medical Research Center of Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangdong Provincial Cardiovascular Institute, Guangzhou 510080, China
| | - Songsong Mao
- Department of Anesthesiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, China
| | - Haifeng Li
- Department of Anesthesiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, China
| | - Jianxiu Cui
- Department of Anesthesiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, China
| |
Collapse
|
6
|
Seyrek M, Halici Z, Yildiz O, Ulusoy HB. Interaction between dexmedetomidine and α-adrenergic receptors: emphasis on vascular actions. J Cardiothorac Vasc Anesth 2011; 25:856-62. [PMID: 21862350 DOI: 10.1053/j.jvca.2011.06.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Indexed: 11/11/2022]
Affiliation(s)
- Melik Seyrek
- Department of Pharmacology, Gulhane Military Medical Academy, Ankara, Turkey
| | | | | | | |
Collapse
|
7
|
Kim WS, Baek SH, Lee SK, Jeon TY, Kim HY, Shin SW. Dexmedetomidine does not produce vasocontraction on human isolated gastroepiploic artery. Korean J Anesthesiol 2011; 60:428-33. [PMID: 21738846 PMCID: PMC3121090 DOI: 10.4097/kjae.2011.60.6.428] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Revised: 12/13/2010] [Accepted: 12/15/2010] [Indexed: 11/10/2022] Open
Abstract
Background Recently, the addition of dexmedetomidine to sedation regimens after cardiac surgery had been reported and there is a possibility that dexmedetomidine can cause vasoconstriction. Vasopressin has been used as a prophylactic treatment for refractory vasodilatory shock during coronary artery bypass graft (CABG). Also, vasopressin may play an important role in initiating spasms at the graft artery. Here we evaluate the direct effect of dexmedetomidine on isolated human gastroepiploic arteries and the synergistic effect of dexmedetomidine and vasopressin. Methods Discarded gastroepiploic arteries from elective subtotal gastrectomy (n = 10) were used in this study. We measured the level of contraction in isolated human gastroepiploic arteries induced by increasing concentrations of dexmedetomidine (10-10 to 10-6 M) with or without vasopressin (10-10, 10-9 M). Arterial contractions caused by increasing concentrations of vasopressin (10-10 to 10-7.5 M) with or without dexmedetomidine (10-9, 10-7 M) were also measured in the tissue samples. Results Supraclinical concentrations of dexmedetomidine elicited contractions at concentrations of 10-7 M and 10-6 M (P < 0.05 versus resting tension). The same concentrations of dexmedetomidine (10-7, 10-6 M) significantly enhanced vasopressin-induced contractions (P < 0.05 versus vasopressin-induced contraction). Vasopressin produced concentration-dependent contractions and vasopressin (10-10, 10-9.5, 10-9 M) also increased the intensity of dexmedetomidine (10-7 M) induced contractions. Conclusions There was a synergistic effect between supraclinical doses of dexmedetomidine and vasopressin on the degree of contraction in isolated human gastroepiploic arteries. However, a sedative dose of dexmedetomidine (clinical dose: 0.2-0.7 µg/kg/hr, plasma concentration: 0.36-1.25 ng/ml) did not enhance vasopressin induced-contraction in isolated human gastroepiploic arteries.
Collapse
Affiliation(s)
- Won-Sung Kim
- Department of Anesthesia and Pain Medicine, Pusan National University School of Medicine, Yangsan, Korea
| | | | | | | | | | | |
Collapse
|
8
|
Ok SH, Jeong YS, Kim JG, Lee SM, Sung HJ, Kim HJ, Chang KC, Kwon SC, Sohn JT. c-Jun NH₂-terminal kinase contributes to dexmedetomidine-induced contraction in isolated rat aortic smooth muscle. Yonsei Med J 2011; 52:420-8. [PMID: 21488184 PMCID: PMC3101051 DOI: 10.3349/ymj.2011.52.3.420] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
PURPOSE Dexmedetomidine, a full agonist of α2B-adrenoceptors, is used for analgesia and sedation in the intensive care units. Dexmedetomidine produces an initial transient hypertension due to the activation of post-junctional α2B-adrenoceptors on vascular smooth muscle cells (SMCs). The aims of this in vitro study were to identify mitogen-activated protein kinase (MAPK) isoforms that are primarily involved in full, α2B-adrenoceptor agonist, dexmedetomidine-induced contraction of isolated rat aortic SMCs. MATERIALS AND METHODS Rat thoracic aortic rings without endothelium were isolated and suspended for isometric tension recording. Cumulative dexmedetomidine (10⁻⁹ to 10⁻⁶ M) dose-response curves were generated in the presence or absence of extracellular signal-regulated kinase (ERK) inhibitor PD 98059, p38 MAPK inhibitor SB 203580, c-Jun NH₂-terminal kinase (JNK) inhibitor SP 600125, L-type calcium channel blocker (verapamil and nifedipine), and α₂-adrenoceptor inhibitor atipamezole. Dexmedetomidine-induced phosphorylation of ERK, JNK, and p38 MAPK in rat aortic SMCs was detected using Western blotting. RESULTS SP 600125 (10⁻⁶ to 10⁻⁵ M) attenuated dexmedetomidine-evoked contraction in a concentration- dependent manner, whereas PD 98059 had no effect on dexmedetomidine- induced contraction. SB 203580 (10⁻⁵ M) attenuated dexmedetomidine-induced contraction. Dexmedetomidine-evoked contractions were both abolished by atipamezole and attenuated by verapamil and nifedipine. Dexmedetomidine induced phosphorylation of JNK and p38 MAPK in rat aortic SMCs, but did not induce phosphorylation of ERK. CONCLUSION Dexmedetomidine-induced contraction involves a JNK- and p38 MAPK-mediated pathway downstream of α₂-adrenoceptor stimulation in rat aortic SMCs. In addition, dexmedetomidine-induced contractions are primarily dependent on calcium influx via L-type calcium channels.
Collapse
Affiliation(s)
- Seong-Ho Ok
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Jinju, Korea
| | - Young Seok Jeong
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Jinju, Korea
| | - Jae-Gak Kim
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Jinju, Korea
| | - Seung-Min Lee
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Jinju, Korea
| | - Hui-Jin Sung
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Jinju, Korea
| | - Hye Jung Kim
- Department of Pharmacology, Gyeongsang National University School of Medicine, Jinju, Korea
| | - Ki Churl Chang
- Department of Pharmacology, Gyeongsang National University School of Medicine, Jinju, Korea
| | - Seong-Chun Kwon
- Department of Physiology, Kwandong University College of Medicine, Kangneung, Korea
| | - Ju-Tae Sohn
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University School of Medicine, Jinju, Korea
- Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, Korea
| |
Collapse
|
9
|
Mimuro S, Katoh T, Suzuki A, Yu S, Adachi YU, Uraoka M, Sano H, Sato S. Deterioration of myocardial injury due to dexmedetomidine administration after myocardial ischaemia. Resuscitation 2010; 81:1714-7. [DOI: 10.1016/j.resuscitation.2010.07.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Revised: 07/13/2010] [Accepted: 07/29/2010] [Indexed: 12/27/2022]
|
10
|
Wong ESW, Man RYK, Vanhoutte PM, Ng KFJ. Dexmedetomidine Induces Both Relaxations and Contractions, via Different α2-Adrenoceptor Subtypes, in the Isolated Mesenteric Artery and Aorta of the Rat. J Pharmacol Exp Ther 2010; 335:659-64. [DOI: 10.1124/jpet.110.170688] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
11
|
Dexmedetomidine suppresses the decrease in blood pressure during anesthetic induction and blunts the cardiovascular response to tracheal intubation. J Clin Anesth 2009; 21:194-9. [DOI: 10.1016/j.jclinane.2008.08.015] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2007] [Revised: 07/30/2008] [Accepted: 08/02/2008] [Indexed: 11/15/2022]
|
12
|
Kim HJ, Sohn JT, Jeong YS, Cho MS, Kim HJ, Chang KC, Shin MK, Park CS, Chung YK. Direct effect of dexmedetomidine on rat isolated aorta involves endothelial nitric oxide synthesis and activation of the lipoxygenase pathway. Clin Exp Pharmacol Physiol 2008; 36:406-12. [PMID: 19018801 DOI: 10.1111/j.1440-1681.2008.05082.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
1. The aims of the present in vitro study were to examine the roles of pathways associated with arachidonic acid metabolism in dexmedetomidine-induced contraction and to determine which endothelium-derived vasodilators are involved in the endothelium-dependent attenuation of vasoconstriction elicited by dexmedetomidine. 2. Dexmedetomidine (10(-9)-10(-6) mol/L) concentration-response curves were constructed in: (i) aortic rings with no drug pretreatment; (ii) endothelium-denuded aortic rings pretreated with either 2 x 10(-5) mol/L quinacrine dihydrochloride, 10(-5) mol/L nordihydroguaiaretic acid (NDGA), 3 x 10(-5) mol/L indomethacin or 10(-5) mol/L fluconazole; and (iii) endothelium-intact aortic rings pretreated with either 5 x 10(-5) mol/L N(G)-nitro-l-arginine methyl ester (l-NAME), 10(-5) mol/L fluconazole, 10(-5) mol/L indomethacin, 10(-5) mol/L glibenclamide, 5 x 10(-3) mol/L tetraethylammonium or 5 x 10(-5) mol/L l-NAME plus rauwolscine (10(-5), 10(-6) mol/L). The production of nitric oxide (NO) metabolites was determined in human umbilical vein endothelial cells treated with dexmedetomidine. 3. Quinacrine dihydrochloride, NDGA and indomethacin attenuated the dexmedetomidine-induced contraction of endothelium-denuded rings. Dexmedetomidine (10(-7)-10(-6) mol/L)-induced contractions of endothelium-denuded rings were enhanced compared with those of endothelium-intact rings, as were dexmedetomidine-induced contractions of endothelium-intact rings pretreated with l-NAME or tetraethylammonium. Rauwolscine attenuated dexmedetomidine-induced contractions in endothelium-intact rings pretreated with l-NAME. Dexmedetomidine (10(-6) mol/L) was found to activate NO production. 4. Taken together, the results indicate that dexmedetomidine-induced contraction of aortic rings involves activation of the lipoxygenase and cyclo-oxygenase pathways and is attenuated by increased NO production following stimulation of endothelial alpha(2)-adrenoceptors by dexmedetomidine.
Collapse
Affiliation(s)
- Hee-Jin Kim
- Department of Anaesthesiology and Pain Medicine, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea
| | | | | | | | | | | | | | | | | |
Collapse
|