Glycinergic interneurons are functionally integrated into the inspiratory network of mouse medullary slices.
Neuronal activity in the respiratory network is functionally dependent on inhibitory synaptic transmission. Using two-photon excitation microscopy, we analyzed the integration of glycinergic neurons in the isolated inspiratory pre-Bötzinger complex-driven network of the rhythmic slice preparation. Inspiratory (96%) and 'tonic' expiratory neurons (4%) were identified via an increase or decrease, respectively, of the cytosolic free calcium concentration during the inspiratory-related respiratory burst. Furthermore, in BAC-transgenic mice expressing EGFP under the control of the GlyT2-promoter, 50% of calcium-imaged inspiratory neurons were glycinergic. Inspiratory bursting of glycinergic neurons in the slice was confirmed by whole-cell recording. We also found glycinergic neurons that receive phasic inhibition from other glycinergic neurons. Our calcium imaging data show that glycinergic neurons comprise a large population of inspiratory neurons in the pre-Bötzinger complex-driven network of the rhythmic slice preparation.
Winter
Stefan M
SM
Abt Neuro- und Sinnesphysiologie, Zentrum Physiologie und Pathophysiologie, Georg-August-Universität, Göttingen, Germany.
Fresemann
Jens
J
Schnell
Christian
C
Oku
Yoshitaka
Y
Hirrlinger
Johannes
J
Hülsmann
Swen
S
D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D001683:Biological Clocks / Q000502:physiology*; D001933:Brain Stem / Q000502:physiology*; D002478:Cells, Cultured; D005998:Glycine / Q000378:metabolism*; D001239:Inhalation / Q000502:physiology*; D007395:Interneurons / Q000502:physiology*; D051379:Mice; D008822:Mice, Transgenic; D009415:Nerve Net / Q000502:physiology*; D009433:Neural Inhibition / Q000502:physiology
D005998:Glycine