Inhibition of slow TTX-insensitive inward current by the anticonvulsant carbamazepine in an identified neuron of Lymnaea stagnalis.
1. Pentylenetetrazol (PTZ), induces tonic depolarization and bursting activity in an identified neuron, B1, of Lymnaea stagnalis. This is due in part to activation of a slow, tetrodotoxin-insensitive inward sodium current. 2. Carbamazepine (CBZ) reversed the effect of PTZ on both membrane potential and inward current, after a delay of up to 5 min. CBZ alone had no effect on voltage or current responses. 3. These results suggest that CBZ blocks the slow sodium current, possibly via a decrease in intracellularly stored calcium ions.
Department of Physiological Sciences, University of Manchester, U.K.
A M
AM
Brown
C R
CR
McCrohan
P
P
Pamplin
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002220:Carbamazepine / Q000494:pharmacology*; D008195:Lymnaea; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D010433:Pentylenetetrazole / Q000494:pharmacology; D015222:Sodium Channels / Q000187:drug effects* / Q000502:physiology; D013779:Tetrodotoxin / Q000494:pharmacology*
D015222:Sodium Channels; D002220:Carbamazepine; D013779:Tetrodotoxin; D010433:Pentylenetetrazole