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Updated: Aug 18, 2026

Isolation of Human Atrial Myocytes for Simultaneous Measurements of Ca2+ Transients and Membrane Currents
Published on: July 3, 2013
[Effects of 4-aminopyridine on calcium currents and sodium currents in guinea pig ventricular myocytes]
1Department of Pharmacology, School of Basic Medical Science, Tongji Medical University, Wuhan 430030, China. liyingfu@hotmail.com
Aim:
To investigate the effect of 4-aminopyridine (4-AP) on ion channels of myocytes.
Methods:
L-type calcium channel and sodium channel currents were recorded in guinea pig single ventricular myocyte using whole-cell patch-clamp techniques.
Results:
4-AP, 0.1, 0.5 and 1.0 mmol.L-1 were shown to inhibit L-type calcium channel currents (ICa, L) and sodium channel currents (INa) concentration-dependently. The percentage of inhibition were (11.6 +/- 1.7)%, (37.5 +/- 8.3)% and (54.5 +/- 6.9)% (P < 0.01) respectively for ICa, L, and (22.1 +/- 14.3)% (P < 0.05), (39.4 +/- 8.8)% and (62.3 +/- 6.8)% (P < 0.01) respectively for INa. 4-AP 0.5 mmol.L-1 shifted the I-V curves of ICa, L and INa upwardly.
Conclusion:
4-AP blocked L-type calcium channel and sodium channels in guinea-pig ventricular myocytes concentration-dependently.

