Intracellular neuronal recordings form the ventral respiratory group (VRG) and region of the pontine Kölliker‐Fuse nucleus (KF) during vagal entrainment of breathing in rat.

Abstract

Medullary parts of the respiratory network were associated with respiratory rhythm generation, while pontine parts play a role in secondary modulations of breathing. Recently we identified the KF as key structure that synchronise afferent and network mediated inspiratory off-switch mechanisms (IOS) in response to vagal stimulations (X-stim.). However, potential changes or reconfiguration of the activity patterns of respiratory neurones during synchronisation of IOS are unknown. We performed intracellular recordings to identify changes in neuronal activities during the synchronisation in the perfused brainstem preparation of rats. In the VRG we recorded from 33 respiratory neurones before, during and after repetitive trails of X-stim. Only postinspiratory (PI) and late-I neurones had a clear excitatory response to rhythmic X-stim., while the remaining sub-types of neurones were in summary inhibited. PI and late-I neurones were rhythmically activated by X inputs, but maintained bursting patterns independent of the X-stim. This independent bursting was related to the respiratory rhythm before X-stim. In contrast, recordings of KF neurones (n=12) never showed such stimulus independent bursting. We suggest that the independent bursting of VRG neurones is related to the pontine inputs illustrating the potential interference of the two IOS mechanisms on the cellular level. Funded by BCCN Göttingen