Reversal properties of an EGTA-resistant late hyperpolarization that follows synaptic stimulation of hippocampal neurons.
A late hyperpolarization (LH) which follows low level to moderate synaptic stimulation of neurons in the hippocampal formation neurons was previously shown to consist primarily of a potassium conductance. The present experiments showed that when extracellular cesium was present in order to reduce anamolous rectification, the relation between LH amplitude and membrane potential was linear over a range of negative membrane potentials between approximately -60 and -120 millivolts. In addition, the LH was resistant to blockade by the calcium chelator EGTA. Each of these results differ with those expected if the underlying conductance of the LH were similar to several known potassium conductances of vertebrate neurons, including presently known potassium conductances that are activated by calcium.
D000818:Animals; D002118:Calcium / Q000502:physiology*; D002463:Cell Membrane Permeability; D004533:Egtazic Acid / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D018377:Neurotransmitter Agents / Q000502:physiology; D011188:Potassium / Q000502:physiology*; D051381:Rats; D013569:Synapses / Q000502:physiology; D009435:Synaptic Transmission
D018377:Neurotransmitter Agents; D004533:Egtazic Acid; D011188:Potassium; D002118:Calcium