Laryngeal effects of serotonin in rabbits.

Changes in laryngeal resistance to airflow have been measured in rabbits during spontaneous breathing, while larynx was isolated "in situ". Intravenous injections of serotonin resulted in variable apnoea followed by rapid, shallow breathing, coupled with increases in laryngeal inspiratory and expiratory resistances. These laryngeal responses persisted after cutting vagi in the chest. The "central" actions of serotonin seem to be responsible for stimulatory laryngeal effects.