Denise Kohmann Institute of Physiology I Robert-Koch-Str. 27a D-48149 Münster Phone: +49 (0) 251/83 52531 E-mail: kohmann@uni-muenster.de

Joined OCC in 2012

Research Project

In the thalamic reticular nucleus (TRN), neurons are coupled to each other by electrical synapses. These are believed to play a major role in regulating synchronous activity in the brain during sleep and epileptic seizures. This study aims to investigate the role of these electrical synapses in childhood absence epilepsy, an idiopathic, generalized, and non-convulsive form of epilepsy that is characterized by 2.5-4 Hz spike-and-wave discharges (SWD) in the EEG. We compared the properties of electrical synapses in Genetic Absence Epilepsy Rats from Strasbourg (GAERS) to those of Non Epileptic Control Rats (NEC) in order to determine the contribution of electrical coupling to pathophysiological rhythmogenesis.
Paired recordings using the whole-cell patch-clamp technique were performed in TRN neurons in acute brain slices from GAERS and NEC rats between age p12 and p15. Ca2+-imaging was done using two-photon laser-scanning-microscopy.
The probability of electrical coupling between GAERS and NEC was not significantly different and, in both strains, the coupling was blocked in the presence of carbenoxolone, a connexon blocker. The coupling coefficient decreased in the pre-synaptic cell in the course of eliciting 50 rebound bursts with 2 Hz. This could be due to the observed Ca2+-influx into the pre-synaptic cell or due to a pH increase, which is known to inhibit electrical coupling in neurons. Further experiments will be performed to test these hypotheses.

Promotion Committee

Prof. Dr. T. Budde
Prof. Dr. N Sachser
Dr. P. Coulon

CV