Chemical Control of Airway and Ventilatory Responses Mediated Via Dorsomedial Medullary 5-HT2 Receptors

The airway and ventilatory responses in mice elicited by the inhalation of hypercapnic or hypoxic gas mixtures were investigated by a microdialysis technique, 5-HT release analysis and double-chamber plethysmography with or without 5-HT2 receptor activity in the dorsomedial medulla oblongata (DMM). Hypercapnia elicited compensatory airway dilation and additive ventilatory augmentation to 5-HT2 receptor activity in the DMM. Hypoxia mediated immediate onset of hypoxic hyperventilation and airway dilation, and subsequent hypoxic ventilatory decline. Chemical control of the airway and ventilatory responses mediated via 5-HT2 receptors in the DMM are reviewed.