LAUSR

Pulmonary vagal nociceptors defend the airways. Cardiopulmonary vagal nociceptors synapse in the nucleus tractus solitarius (NTS). Evidence has demonstrated convergence of cardiopulmonary nociceptors with afferents from carotid chemoreceptors. Whether sensory convergence occurs in motor nuclei and how sensory convergence affects reflexive efferent motor output directed towards the airways are critical knowledge gaps. Here we show that distinct tracer injection into the pulmonary nociceptors and carotid chemoreceptors lead to co-labelled neurons in the nucleus tractus solitarius and nucleus ambiguus. Precise simultaneous stimulation delivered to pulmonary nociceptors and carotid chemoreceptors doubled efferent vagal output, enhanced phrenic pause and subsequently augmented phrenic motor activity. These results suggest that multiple afferents are involved in protecting the airways and concurrent stimulation enhances airway defensive reflex output.