AJP - Cell Physiology, Vol 262, Issue 5 C1313-C1323, Copyright © 1992 by American Physiological Society
Goblet cell degranulation in isolated canine tracheal epithelium: response to exogenous ATP, ADP, and adenosine
C. W. Davis, M. L. Dowell, M. Lethem and M. Van Scott
Department of Physiology, University of North Carolina, Chapel Hill 27599.
Mucin secretion by goblet cells was determined by quantifying degranulation
events (DE) in isolated, superficial epithelium from canine trachea. The
epithelium was isolated and explanted to a novel transparent, permeable
support, and the goblet cells were visualized by video microscopy. Baseline
degranulation events were quantified at 0.05 DE/min. Luminal ATP (10(-4) M,
n = 10) stimulated a biphasic secretory response; a burst, maximum rate =
87.9 +/- 25.3, was followed by a plateau, rate = 1.9 +/- 0.3 DE/min.
Serosal ATP elicited a complex set of responses: 9 cells failed to respond,
13 exhibited a trivial response, and 31 responded vigorously but with
highly variable patterns of degranulation. Nonhydrolyzable
5'-adenylylimidodiphosphate caused degranulation from both sides of the
epithelium. Luminal ADP and adenosine were ineffective. Serosal ADP and
adenosine elicited a range of responses that was similar in diversity and
magnitude to the ATP response. Our conclusions were as follows: 1) goblet
cells in the superficial epithelium of the airway can be studied at the
single-cell level in explants; 2) nucleotides stimulate goblet cells to
secrete mucin; and 3) the goblet cell expresses different nucleotide
receptors on its apical and basolateral membranes.
