Isotonic volume reduction associated with cAMP stimulation of 36Cl efflux from jejunal crypt epithelial cells.
To determine the effect of 8-bromoadenosine 3',5'-cyclic monophosphate (8-BrcAMP) on the isotonic volume of jejunal crypt epithelial cells, we isolated these cells by sequential perfusion using a hyperosmolar Ca(2+)-free solution and measured cell volume electronically. 8-BrcAMP caused rapid shrinkage to a reduced but stable cell volume; this isotonic volume reduction was prevented by either a Cl(-)-channel blocker, anthracene-9-carboxylate (A-9C), or Ba2+, a K(+)-channel blocker. 8-BrcAMP substantially increased the rate of A-9C-sensitive 36Cl efflux from crypt cells; this increased rate of efflux was not influenced by Ba2+ but was abolished by alterations in membrane potential. Following 8-BrcAMP-stimulated isotonic volume reduction, addition of either Ba2+ or A-9C caused the crypt cells to reswell. In contrast, 8-BrcAMP added to enterocytes isolated from the villus compartment did not result in A-9C-sensitive volume reduction or in an increased rate of 36Cl efflux. Our data demonstrate that epithelial cells isolated from jejunal crypt compartments respond directly to cAMP with a rapid volume reduction that is paralleled by an increase in 36Cl efflux through a conductive pathway. Unlike other Cl- secretory epithelial cells, the intestinal crypt cell does not appear to regulate its volume in an isotonic medium after cAMP-induced shrinkage.
MacLeod
R J
RJ
McGill University-Montreal Children's Hospital Research Institute, Quebec, Canada.
Lembessis
P
P
Hamilton
J R
JR
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D000873:Anthracenes / Q000494:pharmacology; D001464:Barium / Q000494:pharmacology; D002712:Chlorides / Q000378:metabolism*; D000242:Cyclic AMP / Q000494:pharmacology*; D006168:Guinea Pigs; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism*; D007583:Jejunum / Q000166:cytology / Q000378:metabolism*; D008297:Male; D011868:Radioisotopes; D013267:Stilbenes / Q000494:pharmacology
D000873:Anthracenes; D002712:Chlorides; D011868:Radioisotopes; D013267:Stilbenes; D015124:8-Bromo Cyclic Adenosine Monophosphate; D001464:Barium; C022306:4,4'-dinitro-2,2'-stilbenedisulfonic acid; C010030:9-anthroic acid; D000242:Cyclic AMP