Presence and distribution of 5HT-, VIP-, NPY-, and SP-immunoreactive structures in adult mouse lung

C. Verástegui, J. Fernández-Vivero, A. Prada, F. Rodríguez, A. Romero, M. González-Moreno and J.M. de Castro

Department of Morphological Sciences, Faculty of Medicine. University of Cadiz, Spain

Offprint requests to: Cristina Verastegui, Departamento de Ciencias Morfol6gicas, Facultad de Medicina, Plaza Fragela sIn 11003 Cadiz, Spain

Summary. A large number of biologically active substances have been identified and characterised in the respiratory tract of several mammals. These substances (amines and peptides) exert important regulatory influences on respiratory functions, and they act as neurotransmitters/neuromodulators, both being released from nerve terminals as neuroendocrine cells. However, these substances can also have other effects which suggest a paracrine action. Thus, to understand the role of amines and peptides in the lung, it is important to explore their localisation in different species. By using immunocytochemical staining methods we have studied the morphology and distribution of serotonin-, Substance P-, neuropeptide Y- and VIP-like immunoreactivity in the adult mouse lung. Moreover a pretreatment with colchicine, pargyline and 5-hydroxytryptophan as staining enlargement method was made. A widespread distribution of isolated endocrine cells and neuroepithelial bodies containing 5HT-like immunoreactivity was recorded within the lung. NPY-like immunoreactive nerve fibres were localised in the airway smooth muscle and surrounding the blood vessels. VIP-like immunoreactivity was revealed in single cells as well as in some nerve fibres and ganglia around the blood vessels and in the bronchial smooth muscle. SP-like IR was observed in nerve fibres located in the smooth muscle of the airways, surrounding bronchi and bronchioli but not next to the intrapulmonary blood vessels. Their localisation both in cells and nerve fibres of the respiratory system suggests that they playa role in the regulatory function of the mouse respiratory tract, exerting their influence by endocrine, paracrine, neurosecretory pathways or a combination of all of these. Histol Histopathol 12, 909-918 (1997)

Key words: Serotonin, Substance P, Neuropeptide Y, Vasoactive intestinal peptide, Lung

DOI: 10.14670/HH-12.909