Hypothermia masks most of the effects of rapid cycling VNS on rat hippocampal electrophysiology

AIM. Vagus nerve stimulation (VNS) modulates hippocampal dentate gyrus (DG) electrophysiology and induces hypothermia in freely moving rats. This study evaluated whether hippocampal (CA1) electrophysiology is similarly modulated and to what extent this is associated with VNS-induced hypothermia. METHODS. Six freely moving rats received a first 4 h session of rapid cycling VNS (7 s on/18 s off), while CA1 evoked potentials, EEG and core temperature were recorded. In a second 4 h session, external heating was applied during the 3rd and 4th h of VNS counteracting VNS-induced hypothermia. RESULTS. VNS decreased the slope of the field excitatory postsynaptic potential (fEPSP), increased the population spike (PS) amplitude and latency, decreased theta (4-12 Hz) and gamma (30-100 Hz) band power and theta peak frequency. Normalizing body temperature during VNS through external heating abolished the effects completely for fEPSP slope, PS latency and gamma band power, partially for theta band power and theta peak frequency and inverted the effect on PS amplitude. CONCLUSIONS. Rapid cycle VNS modulates CA1 electrophysiology similarly to DG, suggesting a wide-spread VNS-induced effect on hippocampal electrophysiology. Normalizing core temperature elucidated that VNS-induced hypothermia directly influences several electrophysiological parameters but also masks a VNS-induced reduction in neuronal excitability.

Jaar van publicatie:2019

BOF-keylabel:ja

IOF-keylabel:ja

BOF-publication weight:10

Auteurs:National

Authors from:Higher Education

Toegankelijkheid:Open