Rhein stimulates active chloride secretion in the short-circuited rat colonic mucosa.
In a short-circuited mucosa-submucosa preparation of the rat descending colon with preserved Meissner's plexus mounted as an everted sac rhein transiently increased the potential difference and short-circuit current (Isc) when administered serosally and mucosally, but serosal application was more effective. Maximal effects were obtained at rhein concentrations of 1.6 X 10(-4) and 3 X 10(-4) mol/l. Net chloride absorption was decreased. Indomethacin (5 X 10(-6) mol/l) did not inhibit the increase of Isc, but omission of calcium from the serosal side as well as tetrodoxin (2 X 10(-7) mol/l) decreased it by 50 and 60%. Mechanical removal of Meissner's plexus partly blocked the effect of rhein, too. It is concluded that rhein stimulates colonic secretion by a direct action on the epithelial cells together with an indirect action via neurohumoral mechanisms.
Goerg
K J
KJ
1st Medical Clinic, Johannes Gutenberg University, Mainz, FRG.
Wanitschke
R
R
Schwarz
M
M
Meyer zum Büschenfelde
K H
KH
D000818:Animals; D000880:Anthraquinones / Q000008:administration & dosage / Q000494:pharmacology*; D002118:Calcium / Q000494:pharmacology; D002400:Cathartics / Q000494:pharmacology; D002712:Chlorides / Q000378:metabolism*; D003106:Colon / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D007213:Indomethacin / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D013368:Submucous Plexus / Q000378:metabolism; D013779:Tetrodotoxin / Q000494:pharmacology
D000880:Anthraquinones; D002400:Cathartics; D002712:Chlorides; D013779:Tetrodotoxin; D002118:Calcium; D007213:Indomethacin; C020491:rhein