Innervation of pulmonary vessels in healthy state and in pulmonary hypertension

Abstract

The vascular bed of the lungs is innervated by three types of nerve fibers: sympathetic, parasympathetic and sensitive. Compared to other organs, the density of innervation and reactivity to vasoactive substances of neuronal origin is maximal in large vessels and decreases towards the periphery. Significant specific features of the innervation of the vessels of the pulmonary circulation are noted. Thus, in laboratory rodents (rats and mice), sympathetic and parasympathetic efferent perivascular axons barely reach the hilum of the lung, while in humans this innervation extends to small intrapulmonary vessels. The most distal arterioles, such as intraacinar arterioles, are devoid of innervation. A significant role in the realization of the effects of the autonomic nervous system on pulmonary vascular tone is attributed to the combined action of neurotransmitters. The main physiological role of the innervation of the pulmonary vessels by vegetative and sensory nerve fibers is expressed trophic activity. Changes in the autonomic innervation of the vessels of the lungs play an important role in the mechanisms of the formation of pulmonary hypertension of various origins, namely, pulmonary hypertension against the background of hypoxia, primary arterial pulmonary hypertension, chronic thromboembolic pulmonary hypertension. In recent years, data have appeared on the participation of the autonomic nervous system in the process of remodeling of the vessels of the pulmonary circulation in pathologies of various origins.