Sustained hyperexcitability elicited by repetitive electric stimulation of organotypic hippocampal explants.
Sustained or complex evoked extracellular slow-wave field potentials were recorded in the CA3/2 areas of organotypic hippocampal explants following stimulation of the dentate area. After repetitive electric stimulation, these discharges became more complex and/or self-sustaining. Self-sustaining discharges continued to occur for the duration of the experiment (15 min-10 h). These slow-wave discharges were evoked (or occurred spontaneously) over a wide range of extracellular K+ concentrations (3-9 mM) without addition of pharmacologic inhibitory antagonists, whereas in some explants raising extracellular K+ from 5.9 to 8-9 mM resulted in spontaneous discharges. The observation that epileptiform discharges in hippocampal explants often occurred spontaneously, were elicited by repetitive electric stimulation, and were recorded at K+ levels which are generally ineffective in acute adult hippocampal slices, indicates that excitability of these CNS explants may be significantly increased following altered neuronal and synaptic development (and/or reorganization) under isolated conditions in culture.
D000818:Animals; D046508:Culture Techniques; D004558:Electric Stimulation; D005071:Evoked Potentials; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D007696:Kindling, Neurologic; D051379:Mice; D009928:Organ Specificity; D011188:Potassium / Q000494:pharmacology
D011188:Potassium