Vasoactive intestinal peptide stimulates tracheal submucosal gland secretion in ferret.

We studied the effect of vasoactive intestinal peptide (VIP) on the output of 35S-labeled macromolecules from ferret tracheal explants either placed in beakers or suspended in modified Ussing chambers. In Ussing chamber experiments, the radiolabel precursor, sodium [35S]sulfate, and all drugs were placed on the submucosal side of the tissue. Washings were collected at 30-min intervals from the luminal side and were dialyzed to remove unbound 35S, leaving radiolabeled macromolecules. Vasoactive intestinal peptide at 3 × 10−7 M stimulated bound 35S output by a mean of +252.6% (n = 14). The VIP response was dose-dependent with a near maximal response and a half maximal response at approximately 10−6 M and 10−8, M, respectively. The VIP effect was not inhibited by a mixture of tetrodotoxin, atropine, l-propranolol, and phentolamine. Vasoactive intestinal peptide had no effect on the electrical properties of the tissues. We conclude that VIP stimulates output of sulfated-macromolecules from ferret tracheal sub...