Blocking effect of 1389-S on the sodium current in isolated guinea-pig ventricular myocytes.
Under whole cell patch conditions, 1389-S blocked the INa in guinea-pig ventricular myocytes under steady state conditions (Kdrest = 30 microM, Kdi = 2.4 microM) with a shift of the inactivation curve to the hyperpolarizing direction. Both brief and long conditioning pulses could produce a use-dependent block of 1389-S. These results suggest that 1389-S had a higher affinity to the inactivated than to the rested state under steady state conditions and had a higher affinity to the activated state during train pulses as well as to the inactivated state, making channels unavailable for conduction upon activation.
Hisatome
I
I
1st Department of Internal Medicine, Tottori University School of Medicine, Yonago, Japan.
Matsuoka
S
S
Miyamoto
J
J
Sawaguchi
M
M
Omodani
H
H
Osaki
S
S
Kotake
H
H
Mashiba
H
H
Sato
R
R
D000818:Animals; D004558:Electric Stimulation; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D011412:Propanolamines / Q000494:pharmacology*; D015222:Sodium Channels / Q000187:drug effects*
D011412:Propanolamines; D015222:Sodium Channels; C044492:711389-S