Effects of carbamazepine on nerve activity and transmitter release in neuroblastoma-glioma hybrid cells and the frog neuromuscular junction.
Effects of the antiepileptic drug carbamazepine on nerve action potential and transmitter release in mouse neuroblastoma-glioma hybrid cells (NG108-15) and the frog neuromuscular junction were studied. Carbamazepine within a concentration range of 0.1-0.5 mmol/L reduced the peak height of the action potential of the NG108-15 cells, whereas the membrane potential and membrane resistance were unaffected. Voltage clamp revealed that the decrease in the action was due to the blockage of the Na+, delayed K+ and transient Ca2+ currents. Carbamazepine did not affect Ca(2+)-activated and A type K+ currents and long-lasting Ca2+ current. In the frog neuromuscular junction, carbamazepine decreased the mean quantal content by a parallel shift in the frequency augmentation-potentiation (FAP) relation. It is concluded that carbamazepine blocks the voltage-dependent Na+, delayed K+, and transient Ca2+ currents and quantal transmitter release through a decrease of nerve excitation.
Department of Neurosurgery, Shimane Medical University, Japan.
Y
Y
Matsumoto
K
K
Enomoto
K
K
Moritake
T
T
Maeno
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002220:Carbamazepine / Q000494:pharmacology*; D005910:Glioma; D051379:Mice; D009447:Neuroblastoma; D009466:Neuromuscular Blocking Agents / Q000494:pharmacology*; D009469:Neuromuscular Junction / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D011188:Potassium / Q000378:metabolism; D011898:Ranidae; D012964:Sodium / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects* / Q000502:physiology; D014407:Tumor Cells, Cultured
D009466:Neuromuscular Blocking Agents; D002220:Carbamazepine; D012964:Sodium; D011188:Potassium; D002118:Calcium