Monoamine oxidase A-deficiency and noradrenergic respiratory regulations in neonatal mice.
In vitro experiments were performed on brainstem-spinal cord preparations from mouse neonates to compare the noradrenergic regulations of the respiratory network in the control C3H/HeJ strain and the transgenic Tg8 strain which has been created from the C3H/HeJ strain by deletion of the gene encoding monoamine oxidase A (MAOA), the main enzyme for serotonin degradation. In both control and MAOA-deficient strains, we show: (i). that the pontine A5 area exerts a potent inhibitory modulation on the respiratory rhythm generator; (ii). that noradrenaline application induces a tonic phrenic activity; and (iii). that noradrenaline increases the respiratory rhythm. The latter effect is however delayed and weak in the Tg8 strain. Therefore, MAOA-deficiency has only slightly altered the noradrenergic regulations of the respiratory network.
Viemari
Jean Charles
JC
Biology of Rhythm and Development, GERM - CNRS - Université de la Méditerranée, 280 Boulevard Sainte Marguerite, 13009 Marseille, France.
Hilaire
Gérard
G
D000818:Animals; D000831:Animals, Newborn; D008526:Medulla Oblongata / Q000187:drug effects / Q000201:enzymology; D051379:Mice; D008809:Mice, Inbred C3H; D008822:Mice, Transgenic; D008995:Monoamine Oxidase / Q000172:deficiency* / Q000235:genetics; D009415:Nerve Net / Q000187:drug effects / Q000201:enzymology; D009638:Norepinephrine / Q000494:pharmacology* / Q000502:physiology; D015656:Respiratory Mechanics / Q000187:drug effects / Q000502:physiology*; D013116:Spinal Cord / Q000187:drug effects / Q000201:enzymology
D008995:Monoamine Oxidase; D009638:Norepinephrine