Serotonin Regulates the Firing of Principal Cells of the Subiculum by Inhibiting a T-type Ca2+Current.
The subiculum is the main output of the hippocampal formation. A high proportion of its principal neurons fire action potentials in bursts triggered by the activation of low threshold calcium currents. This firing pattern promotes synaptic release and regulates spike-timing-dependent plasticity. The subiculum receives a high density of fibers originating from the raphe nuclei, suggesting that serotonin (5-HT) modulates subicular neurons. Here we investigated if and how 5-HT modulates the firing pattern of bursting neurons. By combining electrophysiological analysis with pharmacology, optogenetics and calcium imaging, we demonstrate that 5-HT2Creceptors reduce bursting activity by inhibiting a low-threshold calcium current mediated by T-type Ca2+channels in principal cells of the subiculum. In addition, we show that the activation of this novel pathway decreases bursting activity and the occurrence of epileptiform discharges induced inin vitromodels for temporal lobe epilepsy (TLE).
Department of Neuroscience and Pharmacology, University of Copenhagen Copenhagen, Denmark.
Anders V
AV
Petersen
Department of Biomedical Sciences, University of Copenhagen Copenhagen, Denmark.
Camilla S
CS
Jensen
Institut de Neurobiologie de la Méditerranée (INMED), Institut National de la Santé et de la Recherche Médicale (INSERM) U901, Aix-Marseille Université Marseille, France.
Valérie
V
Crépel
Department of Neuroscience and Pharmacology, University of Copenhagen Copenhagen, Denmark.
Mathias
M
Falkerslev
Department of Neuroscience and Pharmacology, University of Copenhagen Copenhagen, Denmark.
Jean-François
JF
Perrier
burst firing; calcium channels; serotonin; subiculum; temporal lobe epilepsy (TLE)