Differential contribution of pacemaker properties to the generation of respiratory rhythms during normoxia and hypoxia.
Pacemaker neurons have been described in most neural networks. However, whether such neurons are essential for generating an activity pattern in a given preparation remains mostly unknown. Here, we show that in the mammalian respiratory network two types of pacemaker neurons exist. Differential blockade of these neurons indicates that their relative contribution to respiratory rhythm generation changes during the transition from normoxia to hypoxia. During hypoxia, blockade of neurons with sodium-dependent bursting properties abolishes respiratory rhythm generation, while in normoxia respiratory rhythm generation only ceases upon pharmacological blockade of neurons with heterogeneous bursting properties. We propose that respiratory rhythm generation in normoxia depends on a heterogeneous population of pacemaker neurons, while during hypoxia the respiratory rhythm is driven by only one type of pacemaker.
Peña
Fernando
F
Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, IL 60637, USA. jfpena@mail.cinvestav.mx
Parkis
Marjorie A
MA
Tryba
Andrew K
AK
Ramirez
Jan-Marino
JM
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D001683:Biological Clocks / Q000187:drug effects / Q000502:physiology*; D002104:Cadmium / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D005260:Female; D005439:Flufenamic Acid / Q000494:pharmacology; D058787:GABA-A Receptor Antagonists; D002534:Hypoxia, Brain / Q000503:physiopathology*; D066298:In Vitro Techniques; D007811:Lanthanum / Q000494:pharmacology; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D009415:Nerve Net / Q000187:drug effects / Q000502:physiology*; D010507:Periodicity; D011963:Receptors, GABA-A / Q000378:metabolism; D018009:Receptors, Glycine / Q000037:antagonists & inhibitors / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000378:metabolism; D012119:Respiration / Q000187:drug effects*; D012125:Respiratory Center / Q000187:drug effects / Q000502:physiology*; D019782:Riluzole / Q000494:pharmacology; D026941:Sodium Channel Blockers / Q000494:pharmacology; D015222:Sodium Channels / Q000187:drug effects / Q000502:physiology; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
D058787:GABA-A Receptor Antagonists; D011963:Receptors, GABA-A; D018009:Receptors, Glycine; D016194:Receptors, N-Methyl-D-Aspartate; D026941:Sodium Channel Blockers; D015222:Sodium Channels; D002104:Cadmium; D005439:Flufenamic Acid; D007811:Lanthanum; D019782:Riluzole