Effects of N-methyl berbamine on delayed outward potassium current in isolated rat hepatocytes.
OBJECTIVE
To study the effects of N-methyl berbamine (NMB) on the delayed outward potassium currents (Ik) in isolated rat hepatocytes.


METHODS
With patch-clamp techniques and whole-cell recording method, holding potential -50 mV, command potential +30 to +140 mV, duration 900 ms.


RESULTS
NMB reduced Ik in a concentration-dependent manner. When the concentrations of NMB were 20, 50, 400 nmol.L-1 and 50 mumol.L-1, the amplitude values of Ik were decreased to 3.6 +/- 0.4 (P > 0.05), 2.1 +/- 1.6 (P > 0.05), 3.7 +/- 1.6 (P < 0.05), 2.3 +/- 1.3 nA (P < 0.01) from 4.4 +/- 1.0 (n = 4), 2.5 +/- 1.8 (n = 4), 5.8 +/- 2.1 (n = 5), 4.6 +/- 1.3 (n = 6) nA of control, respectively. The inhibitory rates were 10%, 15%, 37%, and 51%, respectively.


CONCLUSIONS
NMB was a K+ channel inhibitor.
Li
J M
JM
Department of Pharmacology, China Medical University, Shenyang, China.
Cui
G Y
GY
Liu
D J
DJ
Cui
H
H
Chang
T H
TH
Wang
Y P
YP
Zhang
K Y
KY
D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D044182:Benzylisoquinolines; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D007546:Isoquinolines / Q000494:pharmacology*; D008099:Liver / Q000166:cytology*; D008297:Male; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar
D000470:Alkaloids; D044182:Benzylisoquinolines; D007546:Isoquinolines; C120236:N-methylberbamine; D026902:Potassium Channel Blockers; D015221:Potassium Channels