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Changes of action potential and L-type calcium channel current of Sprague-Dawley rat ventricular myocytes by different amlodipine isomers.
Can J Physiol Pharmacol. 2008 Sep; 86(9):620-5.CJ

Abstract

To investigate the effects of S- and R-amlodipine (Aml) on action potential (AP) and L-type calcium channel current (ICa-L), the whole-cell patch-clamp technique was used on rat ventricular myocytes to record AP, ICa-L, peak currents, steady-state activation currents, steady-state inactivation currents, and recovery currents from inactivation with S-Aml and R-Aml at various concentrations. Increasing concentrations of S-Aml gradually shortened AP durations (APDs). At concentrations of 0.1, 0.5, 1, 5, and 10 micromol/L, S-Aml blocked 1.5% +/- 0.2%, 25.4% +/- 5.3%, 65.2% +/- 7.3%, 78.4% +/- 8.1%, and 94.2% +/- 5.0% of ICa-L, respectively (p < 0.05), and the half-inhibited concentration was 0.62 +/- 0.12 micromol/L. Current-voltage curves were shifted upward; steady-state activation and inactivation curves were shifted to the left. At these concentrations of S-Aml, the half-activation voltages were -16.01 +/- 1.65, -17.61 +/- 1.60, -20.17 +/- 1.46, -21.87 +/- 1.69, and -24.09 +/- 1.87 mV, respectively, and the slope factors were increased (p < 0.05). The half-inactivation voltages were -27.16 +/- 4.48, -28.69 +/- 4.52, -31.19 +/- 4.17, -32.63 +/- 4.34, and -35.16 +/- 4.46 mV, respectively, and the slope factors were increased (p < 0.05). The recovery times from inactivation of S-Aml were prolonged (p < 0.05). In contrast, R-Aml had no effect on AP and ICa-L (p > 0.05) at the concentrations tested. Thus, only S-Aml has calcium channel blockade activity, whereas R-Aml has none of the pharmacologic actions associated with calcium channel blockers.

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Authors+Show Affiliations

Wang RX
Department of Cardiology, First Affiliated People's Hospital of Nanjing Medical University in Wuxi, Wuxi, China. ruxingw@sina.com.cn
Jiang WP
No affiliation info available

MeSH

Action PotentialsAmlodipineAnimalsCalcium Channel BlockersCalcium Channels, L-TypeCell SeparationFemaleHeart VentriclesIsomerismMaleMyocytes, CardiacPatch-Clamp TechniquesRatsRats, Sprague-Dawley

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

18758511

Citation

Wang, Ru-Xing, and Wen-Ping Jiang. "Changes of Action Potential and L-type Calcium Channel Current of Sprague-Dawley Rat Ventricular Myocytes By Different Amlodipine Isomers." Canadian Journal of Physiology and Pharmacology, vol. 86, no. 9, 2008, pp. 620-5.
Wang RX, Jiang WP. Changes of action potential and L-type calcium channel current of Sprague-Dawley rat ventricular myocytes by different amlodipine isomers. Can J Physiol Pharmacol. 2008;86(9):620-5.
Wang, R. X., & Jiang, W. P. (2008). Changes of action potential and L-type calcium channel current of Sprague-Dawley rat ventricular myocytes by different amlodipine isomers. Canadian Journal of Physiology and Pharmacology, 86(9), 620-5. https://doi.org/10.1139/y08-065
Wang RX, Jiang WP. Changes of Action Potential and L-type Calcium Channel Current of Sprague-Dawley Rat Ventricular Myocytes By Different Amlodipine Isomers. Can J Physiol Pharmacol. 2008;86(9):620-5. PubMed PMID: 18758511.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Changes of action potential and L-type calcium channel current of Sprague-Dawley rat ventricular myocytes by different amlodipine isomers. AU - Wang,Ru-Xing, AU - Jiang,Wen-Ping, PY - 2008/9/2/pubmed PY - 2008/11/15/medline PY - 2008/9/2/entrez SP - 620 EP - 5 JF - Canadian journal of physiology and pharmacology JO - Can J Physiol Pharmacol VL - 86 IS - 9 N2 - To investigate the effects of S- and R-amlodipine (Aml) on action potential (AP) and L-type calcium channel current (ICa-L), the whole-cell patch-clamp technique was used on rat ventricular myocytes to record AP, ICa-L, peak currents, steady-state activation currents, steady-state inactivation currents, and recovery currents from inactivation with S-Aml and R-Aml at various concentrations. Increasing concentrations of S-Aml gradually shortened AP durations (APDs). At concentrations of 0.1, 0.5, 1, 5, and 10 micromol/L, S-Aml blocked 1.5% +/- 0.2%, 25.4% +/- 5.3%, 65.2% +/- 7.3%, 78.4% +/- 8.1%, and 94.2% +/- 5.0% of ICa-L, respectively (p < 0.05), and the half-inhibited concentration was 0.62 +/- 0.12 micromol/L. Current-voltage curves were shifted upward; steady-state activation and inactivation curves were shifted to the left. At these concentrations of S-Aml, the half-activation voltages were -16.01 +/- 1.65, -17.61 +/- 1.60, -20.17 +/- 1.46, -21.87 +/- 1.69, and -24.09 +/- 1.87 mV, respectively, and the slope factors were increased (p < 0.05). The half-inactivation voltages were -27.16 +/- 4.48, -28.69 +/- 4.52, -31.19 +/- 4.17, -32.63 +/- 4.34, and -35.16 +/- 4.46 mV, respectively, and the slope factors were increased (p < 0.05). The recovery times from inactivation of S-Aml were prolonged (p < 0.05). In contrast, R-Aml had no effect on AP and ICa-L (p > 0.05) at the concentrations tested. Thus, only S-Aml has calcium channel blockade activity, whereas R-Aml has none of the pharmacologic actions associated with calcium channel blockers. SN - 0008-4212 UR - https://www.unboundmedicine.com/medline/citation/18758511/Changes_of_action_potential_and_L_type_calcium_channel_current_of_Sprague_Dawley_rat_ventricular_myocytes_by_different_amlodipine_isomers_ L2 - https://cdnsciencepub.com/doi/10.1139/y08-065?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -