Neurogenesis of gasping does not require inhibitory transmission using GABA(A) or glycine receptors.
We evaluated the hypothesis that the neurogenesis of gasping is not dependent upon inhibitory synaptic transmission involving GABA(A) or glycine receptors. Activity of the phrenic nerve was recorded in a perfused juvenile rat preparation. The pattern of phrenic activity was altered from eupnea to gasping in severe hypoxia or ischaemia. To block GABA(A) receptors, bicuculline or picrotoxin was administered. Strychnine was used to block transmission by glycine. Following administrations of bicuculline, picrotoxin or strychnine, the eupneic rhythm was greatly distorted whereas the decrementing pattern of the gasp was maintained. At high concentrations of these antagonists, the frequency of gasps was increased and the peak height of gasps fell. We conclude that the neurogenesis of gasping is not dependent upon fast, chloride-mediated inhibitory synaptic transmission.
Department of Physiology, Dartmouth Medical School, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03755, USA. walter.m.stjohn@dartmouth.edu
Walter M
WM
St-John
Julian F R
JF
Paton
D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D018755:GABA Agonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D058785:GABA-A Receptor Agonists; D058787:GABA-A Receptor Antagonists; D018684:Glycine Agents / Q000494:pharmacology; D000860:Hypoxia / Q000503:physiopathology; D066298:In Vitro Techniques; D009118:Muscimol / Q000494:pharmacology; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology*; D010477:Perfusion / Q000379:methods; D010791:Phrenic Nerve / Q000187:drug effects / Q000502:physiology; D010852:Picrotoxin / Q000494:pharmacology; D051381:Rats; D011963:Receptors, GABA-A / Q000502:physiology*; D018009:Receptors, Glycine / Q000502:physiology*; D012119:Respiration; D018709:Statistics, Nonparametric; D013331:Strychnine / Q000494:pharmacology
D001640:Bicuculline; D018755:GABA Agonists; D018756:GABA Antagonists; D058785:GABA-A Receptor Agonists; D058787:GABA-A Receptor Antagonists; D018684:Glycine Agents; D009118:Muscimol; D010852:Picrotoxin; D011963:Receptors, GABA-A; D018009:Receptors, Glycine; D013331:Strychnine