Reconfiguration of respiratory-related population activity in a rostrally tilted transversal slice preparation following blockade of inhibitory neurotransmission in neonatal rats.
Recent studies showed that respiratory rhythm generation depends on oscillators located in the pre-Bötzinger complex (pre-BötC) and the parafacial respiratory group (pFRG). To study inhibitory synaptic interactions between these two oscillators, we developed a rostrally tilted transversal slice preparation, which preserves these regions. The onset of rhythmic mass activity in the retrotrapezoid nucleus (RTN)/pFRG preceded that of the pre-BötC. Blockade of glycinergic and gamma-aminobutyric acidic inhibition synchronized pre-BötC and RTN/pFRG activity and significantly increased pre-BötC burst frequency, amplitude, and duration. Population imaging revealed recruitment of inspiratory-like neurones, while expiratory-like neurones lost their phasic activity. The reconfiguration after disinhibition reveals: (1) synaptic inhibition of the pre-BötC arising from the RTN/pFRG, (2) excitatory drive from the RTN/pFRG that triggers the pre-BötC burst. Our findings support the view that these synaptic interactions in vitro relate to the initiation of the inspiratory phase or to the steering of the expiratory-inspiratory phase transition in vivo.
Funke
Frank
F
DFG Research Center Molecular Physiology of the Brain, Zentrum für Physiologie und Pathophysiologie, Georg-August-Universität Göttingen, Humboldtallee 23, 37073, Göttingen, Germany. ffunke1@gwdg.de
Müller
Michael
M
Dutschmann
Mathias
M
D000818:Animals; D000831:Animals, Newborn; D001640:Bicuculline / Q000494:pharmacology; D004558:Electric Stimulation; D004594:Electrophysiology; D005260:Female; D018756:GABA Antagonists / Q000494:pharmacology; D007091:Image Processing, Computer-Assisted; D066298:In Vitro Techniques; D008297:Male; D009434:Neural Pathways / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D011042:Poisons / Q000494:pharmacology; D051381:Rats; D015656:Respiratory Mechanics / Q000502:physiology*; D013331:Strychnine / Q000494:pharmacology; D009435:Synaptic Transmission / Q000187:drug effects* / Q000502:physiology*
D018756:GABA Antagonists; D011042:Poisons; D013331:Strychnine; D001640:Bicuculline