Chronic hypobaric hypoxia effects on rat colon in vitro sensitivity to acute hypoxia and amiloride

• Published in: Digestive diseases and sciences Vol. 47; no. 5; pp. 1086 - 1090
• Main Authors: SARAVI, Fernando D, CHIRINO, Daniel R, SALDENA, Teobaldo A, CINCUNEGUI, Liliana M, CARRA, Graciela E, ITUARTE, Leonor M. E
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01-05-2002; Springer Nature B.V
• Subjects: Amiloride - pharmacology; Animals; Atmospheric Pressure; Biological and medical sciences; Colon - drug effects; Colon - physiopathology; Diseases of the digestive system; Hypoxia - physiopathology; In Vitro Techniques; Intestinal Mucosa - drug effects; Intestinal Mucosa - physiopathology; Male; Medical sciences; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Rats; Rats, Wistar; Oxygen; Potassium sparing diuretic; Rat; Acute; Rodentia; In vitro; Colonic disease; Vertebrata; Chronic; Sensitivity; Mammalia; Amiloride; Animal; Digestive diseases; Hypoxia; Colon; Hypobarism
• ISSN: 0163-2116; 1573-2568
• DOI: 10.1023/A:1015094225062

Chronic hypoxia induces many physiological changes, but little is known about its effects on colonic epithelial function. Isolated distal colon mucosa from rats under normobaric conditions and rats submitted to hypobaric hypoxia for either 4 or 10 days was studied in an Ussing chamber. After 4 days of hypoxia, there was only a 15% increase in transepithelial resistivity. However, 10-day hypoxic rats showed higher short circuit current, potential difference, and resistivity. In this group, but not in normal or 4-day hypoxic animals, amiloride dose-dependently depressed short circuit current. The response to acute hypoxia in vitro was unchanged after chronic hypoxia and was not affected by amiloride. Although the amiloride-sensitive increase in short circuit current in 10-day hypoxic rats might resemble mineralocorticoid action, resistivity was increased and serum aldosterone was very low. It is suggested that chronic hypoxia may enhance electrogenic sodium transport by an aldosterone-independent mechanism.