cAMP promotes gap junctional coupling in T84 cells.
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.
Chanson
M
M
Department of Physiology, Medical College of Pennsylvania, Philadelphia 19129, USA.
White
M M
MM
Garber
S S
SS
D002460:Cell Line; D003106:Colon / Q000166:cytology / Q000502:physiology*; D017630:Connexins / Q000378:metabolism; D000242:Cyclic AMP / Q000502:physiology*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000819:agonists / Q000037:antagonists & inhibitors; D004553:Electric Conductivity; D004594:Electrophysiology; D005456:Fluorescent Dyes; D017629:Gap Junctions / Q000502:physiology*; D006801:Humans; D007473:Ion Channels / Q000502:physiology; D007546:Isoquinolines; D009994:Osmolar Concentration
D017630:Connexins; D005456:Fluorescent Dyes; D007473:Ion Channels; D007546:Isoquinolines; C017475:lucifer yellow; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases