NEUROPEPTIDE-Y AND NOREPINEPHRINE COOPERATIVELY INHIBIT HUMAN TRACHEAL GLAND CELL SECRETION

The effects of neuropeptide Y (NPY) and norepinephrine (NE) on the sec retion of human tracheal gland (HTG) cells in culture were examined us ing the bronchial inhibitor (BrI) as a secretory marker. NPY by itself provoked no change in secretion, neither in intracellular Ca2+ nor in adenosine 3',5'-cyclic monophosphate (cAMP) levels. NE induced transi ent intracellular Ca2+ mobilization and an increase of intracellular c AMP and also, as previously described, a short-time concentration-depe ndent decrease of BrI secreted by HTG cells. When applied together on HTG cells, NPY and NE induced an increase of intracellular cAMP, a dis crete sustained increase of basal intracellular Ca2+, and a long-lasti ng inhibition of secretion. Our data suggest that NPY acts for human t racheal gland cells as a NE neuromodulator rather than as a neurotrans mitter. Thus culture of HTG cells appears to be an interesting pharmac ological support for studying inhibition of bronchial secretion and co uld be applied in the study of pathologies where hypersecretion is obs erved, such as cystic fibrosis.