Functional morphology and neurochemical characterization of diverse sensory receptors in mouse lungs

Abstract

Because of the importance of genetically modified mice for functional studies, and the present lack of data, aim of this study was the identification and neurochemical coding of sensory nerve terminals related to neuroepithelial bodies (NEBs) and other sensory receptors in mouse lungs. Antibodies against known selective markers for sensory nerve terminals in rat lungs were used in control and vagotomized mouse lungs. Mouse pulmonary NEBs were found to receive at least two populations of myelinated vagal afferents with intraepithelial terminals: immunoreactive (IR) for vesicular glutamate transporters (VGLUTs) and calbindin D28k; expressing P2X3 ATP receptors. CGRP IR was seen in thin vagal nerve fibers and in delicate non-vagal fibers, both in close proximity to NEBs. VGLUT 1 and P2X3 IR were further found both in receptor complexes reminiscent of the visceral pleura receptors (VPRs) and the smooth muscle-associated airway receptors (SMARs) that we characterized in rat lungs. The presented data revealed that mouse lungs harbor VPRs, SMARs and several populations of sensory nerve terminals that selectively contact NEBs. The neurochemical information on diverse sensory receptors in mouse lungs will be essential for the interpretation of functional data obtained from our recently developed in situ mouse lung slice model. Support: FWO grant G.0085.04 (D.A.); UA grants NOI-BOF 2003 (D.A.) and KP-BOF 2006 (I.B.)