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Titolo:
Lumen-to-surface pH gradients in opossum and rabbit esophagi: role of submucosal glands
Autore:
Abdulnour-Nakhoul, S; Nakhoul, NL; Orlando, RC;
Indirizzi:
Tulane Univ, Sch Med, Dept Med, Gastroenterol Sect, New Orleans, LA 70112 USA Tulane Univ New Orleans LA USA 70112 erol Sect, New Orleans, LA 70112 USA Tulane Univ, Sch Med, Dept Physiol, New Orleans, LA 70112 USA Tulane UnivNew Orleans LA USA 70112 t Physiol, New Orleans, LA 70112 USA Vet Adm Med Ctr, New Orleans, LA 70112 USA Vet Adm Med Ctr New Orleans LAUSA 70112 d Ctr, New Orleans, LA 70112 USA
Titolo Testata:
AMERICAN JOURNAL OF PHYSIOLOGY-GASTROINTESTINAL AND LIVER PHYSIOLOGY
fascicolo: 1, volume: 278, anno: 2000,
pagine: G113 - G120
SICI:
0193-1857(200001)278:1<G113:LPGIOA>2.0.ZU;2-K
Fonte:
ISI
Lingua:
ENG
Soggetto:
BICARBONATE SECRETION; MUCOSAL PROTECTION; ALKALINE SECRETION; GASTRIC MUCUS; INVIVO; ACID;
Keywords:
carbachol; alkaline secretion; microelectrodes; acid reflux;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
20
Recensione:
Indirizzi per estratti:
Indirizzo: Abdulnour-Nakhoul, S Tulane Univ, Sch Med, Dept Med, Gastroenterol Sect, SL 35,1430 Tulane Ave,New Orleans, LA 70112 USA Tulane Univ SL 35,1430 Tulane Ave New Orleans LA USA 70112
Citazione:
S. Abdulnour-Nakhoul et al., "Lumen-to-surface pH gradients in opossum and rabbit esophagi: role of submucosal glands", AM J P-GAST, 278(1), 2000, pp. G113-G120

Abstract

The opossum esophagus, like that of humans, contains a network of submucosal glands with the capacity to secrete bicarbonate ions into the esophageallumen. To evaluate the role of these glands in protecting the epithelial surface from acid insult, we measured the lumen-to-surface pH gradient in opossum esophagus at different luminal pH and compared it to that of rabbit esophagus, an organ devoid of submucosal glands. Sections of opossum and rabbit esophageal epithelium were mounted luminal side up in a modified Ussingchamber. pH-sensitive microelectrodes, positioned within 5 mu m of the epithelial cell surface, were used to monitor surface pH during perfusion withsolutions of different pH. At luminal pH 7.5, the pH(s) of both opossum and rabbit were similar (pH(s) = 7.5). Lowering luminal pH from 7.5 to 3.5 inopossum decreased pH, to 4.2 +/- 0.16, a value significantly higher than pH of perfusate, whereas in rabbit this maneuver decreased pH, to 3.69 +/- 0.08, a value not significantly different from pH of perfusate. In opossum but not, in rabbit, addition of carbachol to the serosal solution increased basal pH(s) to 7.8 +/- 0.1 and significantly blunted the decline in pH, on perfusion with acidic Ringer solution (pH 3.5), with pH(s) falling to 5.6 +/- 0.45. The effect of carbachol on surface buffering was inhibited by prior treatment with atropine. Luminal acidification to pH 2.0 in opossum (as in rabbit) abolished the lumen-to-surface pH gradient even after addition ofserosal carbachol. We conclude that the presence of submucosal glands in esophagus contributes through bicarbonate secretion to creation of a lumen-to-surface pH gradient. Although this gradient can be modulated by carbachol, its capacity to buffer (and therefore to protect) the epithelial surface against back-diffusing H+ is limited and dissipated at pH 2.0.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/07/20 alle ore 17:41:23