Endogenous 5-HT(1/2) systems and the newborn rat respiratory control. A comparative in vivo and in vitro study.
Consequences of 5-HT(1/2) systems blockade by methysergide on newborn rats respiratory drive were evaluated in vivo with unrestrained animals and in vitro using brainstem-spinal cord preparations. A decrease in respiratory frequency until a plateau level was observed under both in vivo (82.8 +/- 0.6% of control values) and in vitro (76.8 +/- 0.8% of control values) conditions whereas an increase in inspiratory amplitude (135.1 +/- 2.1% of control values) was only retrieved in vivo. By the use of the c-fos expression analysis, we correlated these effects with neuronal activity changes, particularly, in vivo in two key structures between the respiratory ponto-medullary network and the peripheral or suprapontine afferences, namely the commissural subnucleus of the nucleus of the solitary tract and the lateral parabrachial nucleus. Thus, peripheral and suprapontine inputs seem to be of a primeval importance in the respiratory influence of endogenous 5-HT. Besides, as 5-HT is involved in the respiratory perturbations that occur in sudden infant death syndrome (SIDS), our results suggest a participation of peripheral and suprapontine inputs in these disorders.
Bodineau
Laurence
L
Dysrégulations métaboliques acquises et génétiques, EA 2088-2629, Faculté de Médecine, Université de Picardie Jules Verne, 3 rue des Louvels, 80036 Amiens cedex 1, France. laurence.bodineau@u-picardie.fr
Cayetanot
Florence
F
Marlot
Daniel
D
Collin
Thibault
T
Gros
Françoise
F
Frugière
Alain
A
D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001933:Brain Stem / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D008784:Methysergide / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D012123:Pulmonary Ventilation / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D044263:Receptors, Serotonin, 5-HT1 / Q000187:drug effects / Q000502:physiology*; D044348:Receptors, Serotonin, 5-HT2 / Q000187:drug effects / Q000502:physiology*; D015656:Respiratory Mechanics / Q000187:drug effects / Q000502:physiology*; D012702:Serotonin Antagonists / Q000494:pharmacology; D013116:Spinal Cord / Q000166:cytology / Q000187:drug effects / Q000502:physiology
D016760:Proto-Oncogene Proteins c-fos; D044263:Receptors, Serotonin, 5-HT1; D044348:Receptors, Serotonin, 5-HT2; D012702:Serotonin Antagonists; D008784:Methysergide