The effect of cAMP on electrogenic Na(+) absorption in the rat distal colon.
Cyclic AMP is a ubiquitous second messenger produced in cells in response to extracellular stimulants. The aim of this study was to examine its role in the regulation of amiloride-sensitive electrogenic Na(+) absorption in the rat distal colon by measuring the short-circuit current (I(sc)) and (22)Na(+) fluxes in a chamber-mounted mucosal sheet. Forskolin stimulated the amiloride-inhibitable I(sc) and amiloride-inhibitable (22)Na(+) absorption. 8Br-cAMP also stimulated the amiloride-inhibitable I(sc). Furthermore, isoproterenol, acting via beta-adrenergic activation, stimulated the amiloride-inhibitable I(sc). The isoproterenol-induced increase in the amiloride-sensitive I(sc) was largely suppressed by H89, a protein kinase A inhibitor. In conclusion, cAMP can upregulate amiloride-sensitive electrogenic Na(+) absorption in the rat distal colon.
Tsuchiya
Y
Y
Laboratory of Physiology, School of Food and Nutritional Sciences, University of Shizuoka, Shizuoka, 422-8526, Japan.
Suzuki
Y
Y
D000042:Absorption; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D005576:Colforsin / Q000494:pharmacology; D003106:Colon / Q000502:physiology*; D000242:Cyclic AMP / Q000494:pharmacology*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004232:Diuretics; D004594:Electrophysiology; D007408:Intestinal Absorption / Q000502:physiology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012964:Sodium / Q000493:pharmacokinetics*; D015854:Up-Regulation
D004232:Diuretics; D005576:Colforsin; D000584:Amiloride; D012964:Sodium; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases