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Inhibitory effects of dauricine on potassium currents in guinea pig ventricular myocytes.
Acta Pharmacol Sin. 2000 Jan; 21(1):60-4.AP

Abstract

AIM

To study the effects of dauricine(Dau) on the rapidly activating component (IKr), the slowly activating component (IKs) of the delayed rectifier potassium current, and the inward rectifier potassium current (IKl) in guinea pig ventricular myocytes.

METHODS

Single myocytes were dissociated by enzymatic dissociation method. The currents were recorded with the whole-cell configuration of the patch-clamp technique.

RESULTS

(1) Dau 1, 3, 10, 30, and 100 mumol.L-1 blocked IKr and tail current (IKr-tail) in a concentration-dependent manner. The IC50 for block of IKr-tail was 16 (95% confidence limits: 13-22) mumol.L-1. The time constant of IKr-tail deactivation was (140 +/- 38) ms in the control and (130 +/- 26) ms in the presence of Dau 30 mumol.L-1 (n = 6 cells from 3 animals, P > 0.05). (2) Dau 1-100 mumol.L-1 produced concentration-dependent blocks of IKs and tail current (IKs-tail). The IC50 value for block of IKs-tail was 33 (95% confidence limits: 24-46) mumol.L-1. The time constant of IKs-tail deactivation was (92 +/- 18) ms in the control and (84 +/- 16) ms in the presence of Dau 30 mumol.L-1 (n = 8 cells from 4 animals, P > 0.05). (3) Addition of Dau 30 mumol.L-1 induced block of IKs and IKs-tail (n = 7 cells from 3 animals). The degree of block of IKs and IKs-tail depended on test potentials, increasing with more positive depolarizations. (4) Dau 20 mumol.L-1 blocked mainly inward component of IKl and reduced the reversal potential from -72 mV (control) to -78 mV (n = 6 cells from 3 animals).

CONCLUSION

(1) Dau inhibited IKs, but not the process of IKs deactivation. (2) Dau blocked IKr, but not the process of deactivation. (3) Dau had a blocking effect on IKl.

Authors+Show Affiliations

Department of Clinical Pharmacology, Tongji Medical University, Wuhan 430030, China. xiajs@hotmail.comNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

11263249

Citation

Xia, J S., et al. "Inhibitory Effects of Dauricine On Potassium Currents in Guinea Pig Ventricular Myocytes." Acta Pharmacologica Sinica, vol. 21, no. 1, 2000, pp. 60-4.
Xia JS, Guo DL, Zhang Y, et al. Inhibitory effects of dauricine on potassium currents in guinea pig ventricular myocytes. Acta Pharmacol Sin. 2000;21(1):60-4.
Xia, J. S., Guo, D. L., Zhang, Y., Zhou, Z. N., Zeng, F. D., & Hu, C. J. (2000). Inhibitory effects of dauricine on potassium currents in guinea pig ventricular myocytes. Acta Pharmacologica Sinica, 21(1), 60-4.
Xia JS, et al. Inhibitory Effects of Dauricine On Potassium Currents in Guinea Pig Ventricular Myocytes. Acta Pharmacol Sin. 2000;21(1):60-4. PubMed PMID: 11263249.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Inhibitory effects of dauricine on potassium currents in guinea pig ventricular myocytes. AU - Xia,J S, AU - Guo,D L, AU - Zhang,Y, AU - Zhou,Z N, AU - Zeng,F D, AU - Hu,C J, PY - 2001/3/27/pubmed PY - 2001/5/5/medline PY - 2001/3/27/entrez SP - 60 EP - 4 JF - Acta pharmacologica Sinica JO - Acta Pharmacol Sin VL - 21 IS - 1 N2 - AIM: To study the effects of dauricine(Dau) on the rapidly activating component (IKr), the slowly activating component (IKs) of the delayed rectifier potassium current, and the inward rectifier potassium current (IKl) in guinea pig ventricular myocytes. METHODS: Single myocytes were dissociated by enzymatic dissociation method. The currents were recorded with the whole-cell configuration of the patch-clamp technique. RESULTS: (1) Dau 1, 3, 10, 30, and 100 mumol.L-1 blocked IKr and tail current (IKr-tail) in a concentration-dependent manner. The IC50 for block of IKr-tail was 16 (95% confidence limits: 13-22) mumol.L-1. The time constant of IKr-tail deactivation was (140 +/- 38) ms in the control and (130 +/- 26) ms in the presence of Dau 30 mumol.L-1 (n = 6 cells from 3 animals, P > 0.05). (2) Dau 1-100 mumol.L-1 produced concentration-dependent blocks of IKs and tail current (IKs-tail). The IC50 value for block of IKs-tail was 33 (95% confidence limits: 24-46) mumol.L-1. The time constant of IKs-tail deactivation was (92 +/- 18) ms in the control and (84 +/- 16) ms in the presence of Dau 30 mumol.L-1 (n = 8 cells from 4 animals, P > 0.05). (3) Addition of Dau 30 mumol.L-1 induced block of IKs and IKs-tail (n = 7 cells from 3 animals). The degree of block of IKs and IKs-tail depended on test potentials, increasing with more positive depolarizations. (4) Dau 20 mumol.L-1 blocked mainly inward component of IKl and reduced the reversal potential from -72 mV (control) to -78 mV (n = 6 cells from 3 animals). CONCLUSION: (1) Dau inhibited IKs, but not the process of IKs deactivation. (2) Dau blocked IKr, but not the process of deactivation. (3) Dau had a blocking effect on IKl. SN - 1671-4083 UR - https://www.unboundmedicine.com/medline/citation/11263249/Inhibitory_effects_of_dauricine_on_potassium_currents_in_guinea_pig_ventricular_myocytes_ L2 - http://www.chinaphar.com/1671-4083/21/60.pdf DB - PRIME DP - Unbound Medicine ER -