AJP - Cell Physiology, Vol 271, Issue 2 C533-C539, Copyright © 1996 by American Physiological Society

ARTICLES

cAMP promotes gap junctional coupling in T84 cells

M. Chanson, M. M. White and S. S. Garber
Department of Physiology, Medical College of Pennsylvania, Philadelphia 19129, USA.

The effect of intracellular adenosine 3',5'-cyclic monophosphate (cAMP) on dye and electrical coupling was studied in T84 cells, a cell line often used as a model for epithelial cell fluid secretion. Injections of lucifer yellow (LY) into single cells within a cluster of control cells resulted in LY localization to 1.3 +/- 0.2 (mean +/- SE) cells within a cluster. Twenty-six percent of control T84 cell pairs were electrically coupled as assayed by the dual patch-clamp technique. Treatment of cells with agents that either increase intracellular cAMP and/or activate protein kinase A (PKA) increased dye localization to 3.8 +/- 0.6 cells and the proportion of electrically coupled cell pairs to 65%. No electrical coupling was observed in the presence of the Rp diastereomer of adenosine-3',5'-cyclic monophosphothioate (Rp-cAMPS), a PKA antagonist. Excess of Rp-cAMPS prevented cell coupling elicited by 20 microM of the Sp diastereomer of adenosine-3',5'-cyclic monophosphothioate. Expression of connexin 32 mRNA, but not of connexins 26, 43, or 45, was detected by reverse transcription-polymerase chain reaction. These results suggest that communication between T84 cells is modulated by PKA, providing a mechanism for regulating multicellular activity, such as fluid secretion.

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