[Effects of nilvadipine on membrane potential in cultured neuroblastoma-glioma hybrid NG108-15 cells].
Examination was made of the effects of nilvadipine on membrane potential in cultured neuroblastoma-glioma hybrid NG108-15 cells using the current clamp method. The NG108-15 cells line differentiates into neuronal cells following the addition of 1mM dibutyryl cAMP to the culture medium. This agent (nilvadipine) was found to inhibit both sodium and calcium current on the cell membranes of differentiated NG108-15 cells. The inhibitory effect was reversible in a dose-dependent manner between 10 and 100 microM. A substantial washing-time with normal saline, over 20 minutes, was needed for complete recovery from inhibition. The higher the concentration of nilvadipine, the more suppressive was the action on the membrane potential. A higher dose of nilvadipine, 100 microM, caused the disappearance of the peak membrane potential. This effect appeared irreversible, when cells were incubated in the presence of 100 microM nilvadipine for a longer time. Nilvadipine may thus exert inhibitory effect on the electrophysiological activity of neuronal cells, especially the calcium current of the membrane.
Yamasaki
T
T
Department of Neurosurgery, Shimane Medical University, Izumo, Japan.
Akiyama
Y
Y
Kawahara
M
M
Nagao
S
S
Moritake
K
K
Enomoto
K
K
Maeno
T
T
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004594:Electrophysiology; D005910:Glioma / Q000503:physiopathology*; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D009447:Neuroblastoma / Q000503:physiopathology*; D009543:Nifedipine / Q000031:analogs & derivatives* / Q000494:pharmacology; D051381:Rats; D014407:Tumor Cells, Cultured / Q000187:drug effects
D002121:Calcium Channel Blockers; C035100:nilvadipine; D009543:Nifedipine