Nasal autonomic innervation with special reference to peptidergic nerves.

Studies of the nasal autonomic innervation in cat, rat and man have demonstrated the presence of Substance P (SP), Vasoactive Intestinal Polypeptide (VIP) and Pancreatic Polypeptide (PP) immunoreactivity in the classical pathways. SP was principally confined to the sensory neurones with nerve endings in the spinal trigeminal nucleus, around sphenopalatine ganglion cells and around blood vessels as well as under or within the nasal epithelium. VIP was located to parasympathetic postganglionic cholinergic neurones innervating blood vessels and glands. PP was found in a population of nor-adrenergic ganglion cells in the superior sympathetic ganglia and innervating arteries in the mucosa selectively. The recent findings suggest a hypothesis of a local reflex arch involving antidromic vasodilation by afferent, capsaicin sensitive SP neurones and parasympathetic VIP-cholinergic neurones in the efferent response.