Possible involvement of serotonin in obstructive apnea of the newborn.

Experiments were conducted on newborn rats in order to study the serotonergic modulation of the central respiratory activity during the neonatal period. In vitro experiments performed on isolated brainstem spinal cord preparations demonstrated that serotonin exerts a permanent excitatory modulation on the central respiratory rhythm generator but depresses the inspiratory motor output to the genioglossus muscle. In vivo experiments confirmed that increasing endogenous serotonin levels decreases the inspiratory activity of the genioglossus and elicits drastic obstructive apneas.