DOI: /j.cnki.cjcpe APD RVOT I NCX tail RVOT RVOT RVOT RVOT APD RVOT RVOT RVOT RVOT APD RVOT

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1 DOI: /j.cnki.cjcpe * RVOT I NCX tail RVOT RV RVOT I NCX tail I NCX tail RVOT APD RV RVOT APD RVOT I NCX tail RV P < RVOT APD APD RVOT I NCX tail RVOT DOI CNKI /R http / /www. cnki. net /kcms /detail / R html R A The properties of action potential and sodium-calcium exchange tail current of rabbit right ventricular outflow tract myocytes. WANG Yan 1 LIN Chen-hui 1 LI Yuan 1 LIU Tai-peng 2 XIAO Guo-sheng 1 CHANG He 1 HUANG Wei-bin 1 YE Tao 1 GONG Yan 1. 1 Xiamen Heart Center Xiamen Zhongshan Hospital of Xiamen University Xiamen China 2 Department of Physiology and Biophysics College of Life Sciences Peking University Beijing China Corresponding author GONG Yan WY@ medmail. com. cn Abstract Objective To explore the electrophysiological basis of arrhythmogenesis in right ventricular outflow tract RVOT myocytes of rabbit heart. The properties of action potential and sodium-calcium exchange tail current I NCX tail in rabbit RVOT cells were observed. Methods Patch-clamp technique was used to measure I NCX tail and action potential in single myocytes obtained by enzymatic dispersion of rabbit ventricle. Results Marked variability of action potential repolarization was observed in rabbit RVOT cardiomyocytes. The events of early afterdepolarization EAD and marked action potential duration APD extension were recorded in RVOT cells. The peak of I NCX tail was delayed significantly in marked APD extension RVOT cells compared to RV free wall cells and the amplitude of I NCX tail in the former was larger than the latter ones P < Conclusion In rabbit RVOT cardiomyocytes prolonged APD might be the induction factor of delayed afterdeporization and EAD genesis. Under this precondition the late-peaking and larger amplitude of I NCX tail in RVOT cells might play pivotal role in the mechanism of RVOT arrhythmogenesis. Chinese Journal of Cardiac Pacing and Electrophysiology Key words Electrophysiology Right ventricular outflow tract Triggered activity Na + /Ca 2 + exchange current Action potential * No. A WY@ medmail. com. cn RVOT RVOT RVOT RVOT 1 RVOT

2 528 2 NaOH ph 7. 4 I NCX tail mmol /L K-ASP 120 KCl 30 RVOT Na 2 ATP 4 HEPES 5KOH ph 7. 2 KB mmol /L 50 KCl KH 2 PO 4 30 Na + /Ca 2 + HEPES 10 glucose 10 MgCl exchanger 2 1 EDTA 0. 5KOH ph NCX KB I NCX 2. 2 mmol /L L Ca 2 + Nikon Japan 10 ~ 15 min 1 ~ 2 ml /min APD Sutter American NCX NCX 2 ~ 5 MΩ - I NCX > GΩ RVOT EPC10 Heka E- NCX lectronic Co. Patch Master Heka Electronic 3 Co. RVOT 25 I NCX tail RV RVOT 15 ms 900 pa 1 Hz 69 RV 60 1 RVOT ~ 2. 5 kg APD RV 500 IU /kg RVOT 4 100% Langendorff I NCX tail I NCX tail RV RVOT 8 ~ 10 min 13 ~ mvna ~ 70 cm H 2 O 100% 50 ms 50 ms RV RV I 4 NCX tail 10 ms RVOT 3 mm RVOT 200 ms RV RVOT KB 1. 4 SPSS16. 0 x珋 ± s t P < KB 1 ~ 8 h n 1. 2 mmol /L 2 NaCl KCl 5. 4 NaHCO MgCl NaH 2 PO HEPES 5 glucose 10100% O 2 NaOH ph I collagenase Type I Worthington Co 0. 6 mg /ml taurine Sigma Co 2. 4 mg /ml bovine serum albumin Solarbio Co 1. 2 mg /ml pronase E Biodee Biotechology Co mg /ml mmol /L NaCl 150 KCl 5. 4 CaCl MgCl 2 1 HEPES 5 glucose % O mv 2. 1 RV RVOT RV APD % 38% 35% RV APD APD

3 RV APD a b c 3a 4 RVOT a b ± ms 95% ms RVOT ms ± mv 700 ms RVOT 22 RVOT 5% 36. 7% APD ms ms mv mv EAD APD 4 APD 5 RV 3b APD RVOT 5 RV RVOT APD 1Hz a RV b RVOT 2. 2 I NCX tail I NCX tail 6 APD RV APD RV RVOT-APD 700 ms RVOT-APD I NCX tail I NCX tail 7 RV n = 8 I NCX tail 500 ms RV OT-APD n = 4 I NCX tail

4 530 RM- VT camp camp camp A A NCX NCX - NCX NCX Ni 2 + NCX Na + Ca 2 + NCX 7 NCX Ca 2 + Ca 2 + I NCX tail NCX Hancox Levi 4 RVOT 1 RVOT 850 ms 500 ms ± Ito RVOT pa vs ± pa P > RVOT- Ito RV APD n = 7 I NCX tail RVOT 850 ms RVOT- RVOT APD n = ms RV ± pa vs ± pa P < RVOT I NCX RVOT RV- OT RVOT RVOT RV Ic RVOT RVOT RVOT RVOT RVOT RVOT APD APD RVOT I NCX tail Lerman 6 RVOT RV

5 I NCX tail RV OT RVOT APD 1 I NCX tail J RV OT I NCX tail J RV Ca 2 + NCX Ca 2 + diac triggered activity J. J Pharmacol Sci I NCX tail 4 Hancox JC RVOT Cardiovasc Electrophysiol NCX RVOT monophasic ventricular tachycardia J NCX NCX NCX NCX RV Homma N Amran MS Nagasawa Y et al. Topics on the Na + / Ca 2 + exchanger involvement of Na + /Ca 2 + exchange system in car Levi AJ. Na-Ca exchange tail current indicates voltage dependence of the Cai transient in rabbit ventricular myocytes J. J 5. J Lerman BB Stein K Engelstein ED et al. Mechanism of repetitive. Circulation Weber CR Piacentino V 3rd Ginsburg KS et al. Na + -Ca 2 + exchange current and submembrane Ca 2 + during the cardiac action potential J. Circulation Research PURE - PURE 35 ~ IQR 2. 0 ~ ~ % β % ACE-I ARBs 19. 5% 14. 6% 62. 0% β % ACE-I ARBs 49. 8% 66. 5% 8. 8% 9. 7% 5. 2% 3. 3% P < % 45. 1% % 80. 2% 28. 7% 21. 3% β % 15. 6% ACE-I ARBs 22. 8% 15. 5% 19. 9% 11. 6% P < P < Yusuf S et al. Lancet