Influence of codeine on lobeline-induced respiratory reflexes and sensations and on ventilation with exercise in healthy subjects

This is the first report of an attenuation of lobeline-elicited respiratory reflexes and sensations that are attributable to J receptors (pulmonary C fibres) by a pharmacological entity. It also suggests that codeine decreased these receptors' known contribution to respiratory augmentation and motor inhibition during exercise, which was seen as a delay in the onset of, and a decrease in the magnitude of respiratory discomfort during treadmill walking and an increase in the duration walked by more than half the subjects.