Venue: Centre Broca Nouvelle Aquitaine
Dr. Stefan Hallermann
Carl-Ludwig-Institute for Physiology
University Leipzig – Germany
http://physiologie.medizin.uni-leipzig.de/?de,id49
Invited by Christophe Mulle
Abstract
The presynaptic action potential critically controls synaptic transmission. At experimentally- accessible large nerve terminals, sodium and potassium channels control the amplitude and duration of action potentials, respectively. Recently, potassium channels were found to dynamically regulate action potential amplitude in small nerve terminals and this effect was proposed as a novel mechanism for synaptic plasticity. To investigate this apparent difference between large and small terminals, we established high-resolution current-clamp recordings from small nerve terminals of cultured neocortical neurons. Using an electrical equivalent circuit and quartz glass pipettes, we systematically investigated errors related to pipette capacitance and the performance of current-clamp amplifiers. We found rapid action potentials with an amplitude of ~120 mV. Blocking potassium channels prolonged action potentials but did not affect their amplitude. Furthermore, the spike amplitude was unaffected during short-term and homeostatic plasticity. Thus, our data indicate large and stable action potential amplitude at small neocortical nerve terminals.
Selected publications
Haselmann H, Mannara F, Werner C, Planagumà J, Miguez-Cabello F, Schmidl L, Grünewald B, Petit-Pedrol M, Kirmse K, Classen J, Demir F, Klöcker N, Soto D, Doose S, Dalmau J, Hallermann S, Geis C (2018) Human Autoantibodies against the AMPA Receptor Subunit GluA2 Induce Receptor Reorganization and Memory Dysfunction. Neuron 100:91-105
Ritzau-Jost A, Jablonski L, Viotti J, Lipstein N, Eilers J, and Hallermann S. (2018) Apparent calcium dependence of vesicle recruitment. J Physiol 596:4693-707
Delvendahl I, Vyleta NP, von Gersdorff H, and Hallermann S. (2016) Fast, temperature-sensitive and clathrin-independent endocytosis at central synapses. Neuron 90:492-8
Delvendahl I, Jablonski L, Baade C, Matveev V, Neher E, and Hallermann S. (2015) Reduced endogenous Ca2+ buffering speeds active zone Ca2+ signaling. Proc Natl Acad Sci U S A 112:E3075-84
Ritzau-Jost A, Delvendahl I, Rings A, Byczkowicz N, Harada H, Shigemoto R, Hirrlinger J, Eilers J, and Hallermann S. (2014) Ultrafast action potentials mediate kilohertz signaling at a central synapse. Neuron 84:152-63