BOMBESIN STIMULATES HUMAN NASAL MUCOUS AND SEROUS CELL SECRETION INVIVO

Bombesin, gastrin-related peptide (GRP), and related peptides sharing the common carboxy-terminal sequence stimulate lactoferrin (serous cell marker) and glycoconjugate (mucous cell and goblet cell marker) release from human nasal mucosal explants in vitro. In vivo, GRP released from trigeminal sensory nerves may act upon GRP-bombesin binding sites on respiratory epithelial cells and submucosal glands. To determine whether GRP-bombesin can stimulate nasal secretion in vivo, bombesin was administered to eight normal subjects by unilateral, topical administration. Secretions from both nostrils were collected for measurement of total protein, lysozyme, hexose-containing glycoconjugates, and albumin (marker of vascular permeability). Baseline secretions contained 72.0 +/- 17.3-mu-g/ml of total protein, 14 +/- 2-mu-g/ml of lysozyme, 113 +/- 44-mu-g/ml of hexose-containing glycoconjugates, and 7.8 +/- 3.4-mu-g/ml of albumin. Hexose-containing glycoconjugate secretion was significantly increased after 1 nmol (385 +/- 63-mu-g/ml, P < 0.001 by analysis of variance), 10, 100, and 1,000 nmol of bombesin, but the secretion was not dose dependent. Significant lysozyme (24 +/- 3-mu-g/ml, P < 0.05) and total protein (155 +/- 23-mu-g/ml, P < 0.01) secretion occurred after 1,000 nmol. No statistically significant changes in albumin secretion occurred at any dose. Saline had no significant effects on secretion. Therefore, bombesin stimulated secretion from submucosal glands and possibly epithelial cells in the human nose without affecting vascular permeability.