Solute diffusion through stripped mouse duodenum.
We measured villous cell intracellular pH (pH(i)) and solute diffusion between the bathing media and the epithelial cells in stripped, chambered mouse duodenum. Apical perfusion of a high CO2 solution rapidly acidified the upper villous cells with recovery after its removal. Apical zoniporide (ZP) enhanced CO(2)-induced acidification. Serosal ZP, dimethylamiloride (DMA) or stilbene anion transport inhibitors failed to alter CO(2)-induced acidification, whereas serosal high CO(2) buffer acidified the upper villous cells. Serosal 5-hydroxytryptamine rapidly acidified the upper villous cells. All serosally-perfused fluorescent compounds stained the crypt area, but not the villi or villous cells. In contrast, intravenous carboxyfluorescein quickly diffused into the interstitial space of the entire mucosa, and mucosally perfused fluorescent compound rapidly penetrated the epithelial cell layer. In muscle-stripped duodenum mounted in a small-aperture perfusion chamber, serosal solutes can readily diffuse only to the crypt cell region, whereas access to the villous epithelial cells is diffusion-limited. In contrast, rapid villous cell responses to serosally applied solutes are best explained by neural reflexes. Limited viability of the villous cells and impaired structural stability of the villi further limit long-term, villous cell functional studies of mucosal preparations mounted in small aperture diffusion chambers.
Takeuchi
T
T
Greater Los Angles Veterans Affairs Healthcare System, University of California Los Angeles, Los Angeles, CA 90073, USA.
Ham
M
M
Mizumori
M
M
Guth
P H
PH
Engel
E
E
Kaunitz
J D
JD
Akiba
Y
Y
D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D000838:Anions; D001692:Biological Transport / Q000187:drug effects; D002245:Carbon Dioxide / Q000378:metabolism; D004058:Diffusion; D004386:Duodenum / Q000378:metabolism*; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D005452:Fluoresceins / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D006146:Guanidines / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011720:Pyrazoles / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology; D027982:Sodium-Bicarbonate Symporters / Q000037:antagonists & inhibitors; D017923:Sodium-Hydrogen Exchangers / Q000037:antagonists & inhibitors; D012996:Solutions; D013267:Stilbenes / Q000378:metabolism
D000838:Anions; D005452:Fluoresceins; D005456:Fluorescent Dyes; D006146:Guanidines; D011720:Pyrazoles; C498899:Slc4a4 protein, mouse; D027982:Sodium-Bicarbonate Symporters; D017923:Sodium-Hydrogen Exchangers; D012996:Solutions; D013267:Stilbenes; C069139:growth factor-activatable Na-H exchanger NHE-1; D002245:Carbon Dioxide; C024098:6-carboxyfluorescein; D012701:Serotonin; C039465:5-dimethylamiloride; D000584:Amiloride; C424422:zoniporide