title: A New Approach of Modified Submerged Patch Clamp Recording Reveals Interneuronal Dynamics during Epileptiform Oscillations.
abstract: HighlightsSimultaneous epileptiform LFPs and single-cell activity can be recorded in the membrane chamber.Interneuron firing can be linked to epileptiform high frequency activity.Fast ripples, unique to chronic epilepsy, can be modeled inex vivotissue from TeNT-treated rats. Traditionally, visually-guided patch clamp in brain slices using submerged recording conditions has been required to characterize the activity of individual neurons. However, due to limited oxygen availability, submerged conditions truncate fast network oscillations including epileptiform activity. Thus, it is technically challenging to study the contribution of individual identified neurons to fast network activity. The membrane chamber is a submerged-style recording chamber, modified to enhance oxygen supply to the slice, which we use to demonstrate the ability to record single-cell activity duringin vitroepilepsy. We elicited epileptiform activity using 9 mM potassium and simultaneously recorded from fluorescently labeled interneurons. Epileptiform discharges were more reliable than in standard submerged conditions. During these synchronous discharges interneuron firing frequency increased and action potential amplitude progressively decreased. The firing of 15 interneurons was significantly correlated with epileptiform high frequency activity (HFA; ~100-500 Hz) cycles. We also recorded epileptiform activity in tissue prepared from chronically epileptic rats, treated with intrahippocampal tetanus neurotoxin. Four of these slices generated fast ripple activity, unique to chronic epilepsy. We showed the membrane chamber is a promising newin vitroenvironment facilitating patch clamp recordings in acute epilepsy models. Further, we showed that chronic epilepsy can be better modeled usingex vivobrain slices. These findings demonstrate that the membrane chamber facilitates previously challenging investigations into the neuronal correlates of epileptiform activityin vitro.
authors.affiliation: Neuronal Networks Group, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham Birmingham, UK.
authors.forename: Gareth
authors.initials: G
authors.lastname: Morris
authors.affiliation: Department of Developmental Epileptology, Institute of Physiology, Czech Academy of Sciences Prague, Czechia.
authors.forename: Premysl
authors.initials: P
authors.lastname: Jiruska
authors.affiliation: Neuronal Networks Group, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham Birmingham, UK.
authors.forename: John G R
authors.initials: JG
authors.lastname: Jefferys
authors.affiliation: Neuronal Networks Group, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham Birmingham, UK.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Powell
keywords: LFP; epilepsy; high frequency activity; in vitro; membrane chamber; patch clamp