Differential modulation of neural network and pacemaker activity underlying eupnea and sigh-breathing activities.
Many networks generate distinct rhythms with multiple frequency and amplitude characteristics. The respiratory network in the pre-Bötzinger complex (pre-Böt) generates both the low-frequency, large-amplitude sigh rhythm and a faster, smaller-amplitude eupneic rhythm. Could the same set of pacemakers generate both rhythms? Here we used an in vitro respiratory brainslice preparation. We describe a subset of synaptically isolated pacemakers that spontaneously generate two distinct bursting patterns. These two patterns resemble network activity including sigh-like bursts that occur at low frequencies and have large amplitudes and eupneic-like bursts with higher frequency and smaller amplitudes. Cholinergic neuromodulation altered the network and pacemaker bursting: fictive sigh frequency is increased dramatically, whereas fictive eupneic frequency is drastically lowered. The data suggest that timing and amplitude characteristics of fictive eupneic and sigh rhythms are set by the same set of pacemakers that are tuned by changes in the neuromodulatory state.
Tryba
Andrew K
AK
Medical College of Wisconsin, Department of Physiology, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA. atryba@mcw.edu
Peña
Fernando
F
Lieske
Steven P
SP
Viemari
Jean-Charles
JC
Thoby-Brisson
Muriel
M
Ramirez
Jan-Marino
JM
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D001683:Biological Clocks / Q000187:drug effects / Q000502:physiology*; D001933:Brain Stem / Q000502:physiology; D004594:Electrophysiology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D018684:Glycine Agents / Q000494:pharmacology; D006321:Heart / Q000294:innervation / Q000502:physiology; D066298:In Vitro Techniques; D051379:Mice; D018721:Muscarinic Agonists / Q000494:pharmacology; D009415:Nerve Net / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D010095:Oxotremorine / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D015656:Respiratory Mechanics / Q000187:drug effects / Q000502:physiology*; D013331:Strychnine / Q000494:pharmacology; D013569:Synapses / Q000187:drug effects / Q000502:physiology
D018691:Excitatory Amino Acid Antagonists; D018756:GABA Antagonists; D018684:Glycine Agents; D018721:Muscarinic Agonists; D010095:Oxotremorine; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D013331:Strychnine; D001640:Bicuculline