Antagonism of substance P and perception of breathlessness in patients with chronic obstructive pulmonary disease.

Highlights: [•] We investigated whether substance P modulates the perception of breathlessness in patients with chronic obstructive pulmonary disease. [•] Aprepitant, an antagonist that blocks neurokinin (NK)-1 receptor signaling, or placebo was administered prior to resistive load breathing. [•] Our results do not support a role for the substance P-NK-1 pathway in the perception of breathlessness in patients with COPD. [•] With aprepitant, but not with placebo, blood levels of substance P (+54%) and beta-endorphin (+27%) increased. [•] The co-transmission of substance P (excitatory) and beta-endorphin (inhibitory) neuropeptides presumably reflects an integrated response. [ABSTRACT FROM AUTHOR]