[Effects of 4-aminopyridine on calcium currents and sodium currents in guinea pig ventricular myocytes].
OBJECTIVE
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.


CONCLUSIONS
4-AP blocked L-type calcium channel and sodium channels in guinea-pig ventricular myocytes concentration-dependently.
Fu
L Y
LY
Department of Pharmacology, School of Basic Medical Science, Tongji Medical University, Wuhan 430030, China. liyingfu@hotmail.com
Li
Y
Y
Xia
G J
GJ
Yao
W X
WX
Jiang
M X
MX
D015761:4-Aminopyridine / Q000494:pharmacology*; D000818:Animals; D015220:Calcium Channels / Q000187:drug effects*; D002469:Cell Separation; D005260:Female; D006168:Guinea Pigs; D006352:Heart Ventricles / Q000187:drug effects; D008297:Male; D032383:Myocytes, Cardiac / Q000187:drug effects*; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers / Q000494:pharmacology*; D015222:Sodium Channels / Q000187:drug effects*
D015220:Calcium Channels; D026902:Potassium Channel Blockers; D015222:Sodium Channels; D015761:4-Aminopyridine