• G4805 SUBSTANCE P (SP)-INDUCED CHLORIDE SECRETION IN HUMAN COLON IS MEDIATED BY INTESTINAL NERVES AND MAST CELLS AND A TYROSINE KINASE-DEPENDENT PATHWAY. Riegler M*,~I I Castagliuolo*, PTC. So ~, M Lotz*, C Wang*, M Wlk~, T Sogukoglul, E Cosentinh, G Bischnfil, G Hamilton,, B Telekyl, E Wenzh, JB. Matthewst, C. Pothoulakis*. Gastroenterology* and Surgeryt, Beth Israel Deaconess Medical Center, Department of Mechanical Engineering 'r, MIT, Cambridge, MA, and Vienna General Hospitah, Vienna, Austria.