Gum Arabic (GA) modifies paracellular water and electrolyte transport in the small intestine

• Published in: Digestive diseases and sciences 2003-04, Vol.48 (4), p.755-760
• Main Authors: REHMAN, Khalil U, WINGERTZAHN, Mark A, TEICHBERG, Saul, HARPER, Rita G, WAPNIR, Raul A
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Cell Membrane Permeability - drug effects; Cell Membrane Permeability - physiology; Chenodeoxycholic Acid - pharmacology; Gastroenterology. Liver. Pancreas. Abdomen; Gum Arabic - pharmacology; Intestinal Absorption - drug effects; Intestinal Absorption - physiology; Jejunum - drug effects; Jejunum - physiology; Male; Medical sciences; Other diseases. Semiology; Perfusion; Potassium - metabolism; Protamines - pharmacology; Pyrimidines - pharmacology; Rats; Sodium - metabolism; Stomach. Duodenum. Small intestine. Colon. Rectum. Anus; Water-Electrolyte Balance - drug effects; Water-Electrolyte Balance - physiology
• ISSN: 0163-2116; 1573-2568
• DOI: 10.1023/A:1022845011192

Previous experiments have shown that a soluble fiber, gum arabic (GA), enhances water, electrolyte, and glucose absorption in animal models of diarrhea. The mechanisms implicated in this effect have not been fully elucidated. This study examined the possibility that paracellular transport is modulated by luminal GA, resulting in an enhanced rate of absorption in the small intestine. This hypothesis was tested by 3-hr jejunal perfusions on anesthetized rats with solutions containing 140 mM NaCl, 5 mM KCl, and 2 microCi/liter (74 kBq) 3H2O, with either 2.5 g/liter GA [+GA] or in its absence [CTL], and one of the following agents, capable of altering paracellular transport: chenodeoxycholic acid at 0.5 mM (CDC), 2,4,6-triaminopyrimidine (TAP) at 20 mM, and protamine at 100 mg/liter (PTM). Sodium, potassium, net water, and unidirectional water movement were measured. The addition of GA increased sodium absorption in perfusions with CDC, TAP, or PTM only. Similar effects by GA on net water absorption rates were obtained in tissues permeabilized with CDC and PTM; however, GA added to TAP did not normalize the reduction caused by TAP. Although PTM did not alter net water absorption, addition of GA to perfusates with PTM enhanced absorption values above those of CTL. GA reversed the strong negative effects of CDC on potassium absorption but was ineffective in this regard with TAP and PTM. The data obtained with those reagents that affect paracellular transport and the histological evidence support the view that GA promotes net absorption by this route in the small intestine of normal rats.