Mechanism of bicarbonate secretion in rat (Rattus rattus) colon.
1. Colonic HCO3 secretion was measured as the residual flux in male Sprague-Dawley rats (Rattus rattus). 2. Basal HCO3 secretion was increased by 1 mM dibutyryl cyclic AMP (dbcAMP) and was reduced to baseline by 0.1 mM methazolamide (Mtz) but not by SITS (1 mM), DIDS (1 mM) or amiloride (1 mM). 3. In vivo, intravenous vasoactive intestinal peptide increased HCO3 secretion and prior perfusion with 1 mM Mtz prevented this increase. 4. These results suggest that the source of basal and cAMP-stimulated HCO3 secretion is, in part, intracellular and requires the action of carbonic anhydrase.
Dagher
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PC
Nephrology Section, Department of Veterans Affairs Medical Center, New York University School of Medicine, NY 10010.
Rho
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Charney
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D000818:Animals; D001639:Bicarbonates / Q000378:metabolism*; D001692:Biological Transport; D003994:Bucladesine / Q000494:pharmacology; D002256:Carbonic Anhydrases / Q000378:metabolism; D003106:Colon / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D008297:Male; D008704:Methazolamide / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley
D001639:Bicarbonates; D003994:Bucladesine; D000242:Cyclic AMP; D002256:Carbonic Anhydrases; D008704:Methazolamide