AJP - Cell Physiology, Vol 262, Issue 1 C67-C74, Copyright © 1992 by American Physiological Society

ARTICLES

Purinergic receptor activation of Cl- secretion in T84 cells

S. Dho, K. Stewart and J. K. Foskett
Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada.

The regulation by ATP of Cl- secretion in T84 cells grown on filters was investigated by measuring short-circuit current (Isc = net Cl- secretion). ATP (greater than or equal to 10 microM) added to the basolateral side markedly stimulated Isc both in the presence and absence of forskolin-activated Isc. Fluorescence microscopy of cells loaded with the Ca2+ indicator fura-2 showed that ATP stimulated a transient increase in intracellular free Ca2+ concentration [Ca2+]i. The augmentation of forskolin-stimulated Isc by ATP was at least partly caused by mobilization of Ca2+ from an internal store because prior depletion of the store using ionomycin prevented the response. The activity sequence for stimulation of Isc in the presence of forskolin was adenosine 5'-O-(3-thiotriphosphate) = 5'-adenylylimidodiphosphate (AMP-PNP) greater than ATP greater than ADP greater than AMP, suggesting the presence of a P2 purinergic receptor. Neither beta, gamma-methyleneadenosine 5'-triphosphate nor alpha, beta-methyleneadenosine 5'-triphosphate increased the Isc. Stimulation of Isc by ATP in the absence of forskolin was at least partly due to the breakdown of ATP to AMP and adenosine, which act at P1 receptors to stimulate Isc, since 1) inhibition of the ecto-phosphohydrolase 5'-nucleotidase by alpha, beta-methylene-ADP partially inhibited stimulation of Isc by ATP, 2) the adenosine receptor antagonists caffeine and 8-phenyltheophylline markedly inhibited the ATP-stimulated Isc, and 3) AMP-PNP, a weakly hydrolyzable analogue of ATP, caused a much smaller increase in Isc compared with ATP. Adenosine had no effect on [Ca2+]i.(ABSTRACT TRUNCATED AT 250 WORDS)

This article has been cited by other articles:

				K. R. Hallows, G. P. Kobinger, J. M. Wilson, L. A. Witters, and J. K. Foskett Physiological modulation of CFTR activity by AMP-activated protein kinase in polarized T84 cells Am J Physiol Cell Physiol, May 1, 2003; 284(5): C1297 - C1308. [Abstract] [Full Text] [PDF]

				T. Yamamoto and Y. Suzuki Role of luminal ATP in regulating electrogenic Na+ absorption in guinea pig distal colon Am J Physiol Gastrointest Liver Physiol, August 1, 2002; 283(2): G300 - G308. [Abstract] [Full Text] [PDF]

				J. K. Crane, R. A. Olson, H. M. Jones, and M. E. Duffey Release of ATP during host cell killing by enteropathogenic E. coli and its role as a secretory mediator Am J Physiol Gastrointest Liver Physiol, July 1, 2002; 283(1): G74 - G86. [Abstract] [Full Text] [PDF]

				J. E. Smitham and K. E. Barrett Differential effects of apical and basolateral uridine triphosphate on intestinal epithelial chloride secretion Am J Physiol Cell Physiol, June 1, 2001; 280(6): C1431 - C1439. [Abstract] [Full Text] [PDF]

				T. D. Nguyen, S. Meichle, U. S. Kim, T. Wong, and M. W. Moody P2Y11, a purinergic receptor acting via cAMP, mediates secretion by pancreatic duct epithelial cells Am J Physiol Gastrointest Liver Physiol, May 1, 2001; 280(5): G795 - G804. [Abstract] [Full Text] [PDF]

				I. Rubera, M. Tauc, M. Bidet, C. Verheecke-Mauze, G. De Renzis, C. Poujeol, B. Cuiller, and P. Poujeol Extracellular ATP increases [Ca2+]i in distal tubule cells. II. Activation of a Ca2+-dependent Cl- conductance Am J Physiol Renal Physiol, July 1, 2000; 279(1): F102 - F111. [Abstract] [Full Text] [PDF]

				J. T. Turner, R. S. Redman, J. M. Camden, L. A. Landon, and D. O. Quissell A rat parotid gland cell line, Par-C10, exhibits neurotransmitter-regulated transepithelial anion secretion Am J Physiol Cell Physiol, August 1, 1998; 275(2): C367 - C374. [Abstract] [Full Text] [PDF]

				T. D. Nguyen, M. W. Moody, C. E. Savard, and S. P. Lee Secretory effects of ATP on nontransformed dog pancreatic duct epithelial cells Am J Physiol Gastrointest Liver Physiol, July 1, 1998; 275(1): G104 - G113. [Abstract] [Full Text] [PDF]

				J. S. Woo, C. N. Inoue, K. Hanaoka, E. M. Schwiebert, S. E. Guggino, and W. B. Guggino Adenylyl cyclase is involved in desensitization and recovery of ATP-stimulated Cl- secretion in MDCK cells Am J Physiol Cell Physiol, February 1, 1998; 274(2): C371 - C378. [Abstract] [Full Text] [PDF]

				D. C. Devor and R. A. Frizzell Modulation of K+ channels by arachidonic acid in T84 cells. II. Activation of a Ca2+-independent K+ channel Am J Physiol Cell Physiol, January 1, 1998; 274(1): C149 - C160. [Abstract] [Full Text] [PDF]