Hilar somatostatin interneurons contribute to synchronized GABA activity in an in vitro epilepsy model.
Epilepsy is a disorder characterized by excessive synchronized neural activity. The hippocampus and surrounding temporal lobe structures appear particularly sensitive to epileptiform activity. Somatostatin (SST)-positive interneurons within the hilar region have been suggested to gate hippocampal activity, and therefore may play a crucial role in the dysregulation of hippocampal activity. In this study, we examined SST interneuron activity in the in vitro 4-aminopyridine (4-AP) model of epilepsy. We employed a multi-disciplinary approach, combining extracellular multi-electrode array (MEA) recordings with patch-clamp recordings and optical imaging using a genetically encoded calcium sensor. We observed that hilar SST interneurons are strongly synchronized during 4-AP-induced local field potentials (LFPs), as assayed by Ca(2+) imaging as well as juxtacellular or intracellular recording. SST interneurons were particularly responsive to GABA-mediated LFPs that occurred in the absence of ionotropic glutamatergic transmission. Our results present evidence that the extensive synchronized activity of SST-expressing interneurons contribute to the generation of GABAergic LFPs in an in vitro model of temporal lobe seizures.
Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Germany ; Department of Psychiatry and Psychotherapy, Charité Universitätsmedizin Berlin, Germany.
Sabine
S
Grosser
Department of Pharmacology and Physiology, Georgetown University, Washington, District of Columbia, United States of America ; Interdisciplinary Program in Neuroscience, Georgetown University, Washington, District of Columbia, United States of America.
Bridget N
BN
Queenan
Graduate Program in Physiology and Biophysics, Georgetown University, Washington, District of Columbia, United States of America.
Rupa R
RR
Lalchandani
Department of Pharmacology and Physiology, Georgetown University, Washington, District of Columbia, United States of America ; Interdisciplinary Program in Neuroscience, Georgetown University, Washington, District of Columbia, United States of America.
Stefano
S
Vicini
D015761:4-Aminopyridine / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002118:Calcium / Q000378:metabolism; D004833:Epilepsy, Temporal Lobe / Q000378:metabolism; D007395:Interneurons / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D013004:Somatostatin / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D013004:Somatostatin; D005680:gamma-Aminobutyric Acid; D015761:4-Aminopyridine; D002118:Calcium