Single-channel activity correlated with medium-duration, Ca-dependent K current in cultured rat hippocampal neurones.
Whole-cell voltage- and patch-clamp techniques were used to record the calcium-dependent component of ImAHP and correlated single-channel activity in postnatal cultured rat hippocampal neurons. The Ca-dependent ImAHP was elicited by voltage steps to + 10 mV from a holding potential of -50 mV in the whole-cell mode. In cell-attached patches, single currents of approximately 2 pA were observed following spontaneous action currents. The duration of ensemble-averaged single-channel activity was very similar to that of the whole-cell ImAHP, approximately 100 ms. Both whole-cell current and single-channel activity could be blocked by bath-applied cadmium, 200 microM. Vigorous channel activity was evoked by bursts of action potentials that are known to elicit Ca-dependent AHPs. We conclude that this channel is a candidate for mediating ImAHP.
Alger
B E
BE
Department of Pharmacology, University College London, UK.
Sim
J A
JA
Brown
D A
DA
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D002104:Cadmium / Q000494:pharmacology; D002118:Calcium / Q000502:physiology*; D002478:Cells, Cultured; D006624:Hippocampus / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000494:pharmacology; D013997:Time Factors
D015221:Potassium Channels; D013757:Tetraethylammonium Compounds; D002104:Cadmium; D019789:Tetraethylammonium; D002118:Calcium