Recent progress in pulmonary innervation.

Abstract

Recent additions to the understanding of the innervation of the lung have included a detailed description of the pattern in the canine airways, confirmation of the two pathways in the human, the demonstration of nonadrenergic inhibition in vivo, and studies that raise the question as to whether or not the distal airways are innervated. The inhibitory contribution of the nonadrenergic inhibitory system in the guinea pig has been shown to be less than that of the adrenergic system, and the role of the nonadrenergic system in airway smooth muscle control remains unclear. The ganglia of the human lung resemble those in the gastrointestinal tract, but their function in the lung remains speculative. Many features of the innervation in a variety of species are unexplained, and some features, such as the dominant inhibitory pattern in several birds, are completely opposite to that in mammals; the purpose of this is not understood.