Effects of sodium concentration and osmolality on water and electrolyte absorption from the intact human colon

Billich, Christian; Levitan, Ruven

doi:10.1172/jci106100

Cited by 116 publications

(54 citation statements)

References 29 publications

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“…3, bar a, the mean basal J-was 0.27+0.03 nl mn-* mm.inThese experiments demonstrate that, in the basal state, isolated The role of Na' in crypt fluid absorption was examined next. In both in vivo and in vitro studies of rat distal colon, water absorption has been found to be Na' dependent (2,23,24). In the present studies, choline was substituted for Na' in both the lumen and bath.…”

Section: Resultsmentioning

confidence: 61%

Fluid absorption in isolated perfused colonic crypts.

Singh¹,

Binder²,

Boron³

et al. 1995

J. Clin. Invest.

114

104

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A spatial segregation of ion transport processes between crypt and surface epithelial cells is well-accepted and integrated into physiological and pathophysiological paradigms of small and large intestinal function: Absorptive processes are believed to be located in surface (and villous) cells, whereas secretory processes are believed to be present in crypt cells. Validation of this model requires direct determination of fluid movement in intestinal crypts. This study describes the adaptation of techniques from renal tubule microperfusion to hand-dissect and perfuse single, isolated crypts from rat distal colon to measure directly fluid movement. Morphologic analyses of the isolated crypt preparation revealed no extraepithelial cellular elements derived from the lamina propria, including myofibroblasts. In the basal state, crypts exhibited net fluid absorption (mean net fluid movement = 0.34+0.01 nl mm-' -min-'), which was Na+ and partially HCO-dependent. Addition of 1 mM dibutyryl-cyclic AMP, 60 nM vasoactive intestinal peptide, or 0.1 mM acetylcholine to the bath (serosal) solution reversibly induced net fluid secretion (net fluid movement --0.35+0.01 nl mm-. min-'). These observations permit speculation that absorption is a constitutive transport function in crypt cells and that secretion by crypt cells is regulated by one or more neurohumoral agonists that are released in situ from lamina propria cells. The functional, intact polarized crypt described here that both absorbs and secretes will permit future studies that dissect the mechanisms that govern fluid and electrolyte movement in the colonic crypt. (J. Clin. Invest. 1995. 96:2373-2379

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Section: Resultsmentioning

confidence: 61%

Fluid absorption in isolated perfused colonic crypts.

Singh¹,

Binder²,

Boron³

et al. 1995

J. Clin. Invest.

114

104

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“…Differences in ion transport processes in the rat colon have been reported (6,9,10,13,42), and significant differences in function appear to exist in various colonic segments of several other species including humans (1,2,7,8,43,44). Thus, there may be more differences than similarities in the function ofvarious segments ofthe large intestine.…”

Section: Discussionmentioning

confidence: 95%

“…Many investigations of colonic function have assumed that electrolyte transport processes are uniform throughout the large intestine. Thus, in vivo luminal perfusion experiments, in humans and experimental animals, have frequently been performed without regard to the possibility that electrolyte movement may differ in one or more segments (1)(2)(3). Further, in vitro studies of ion transport have until recently been primarily performed in the distal portion of the colon (4,5).…”

Section: Introductionmentioning

confidence: 99%

Ion transport in proximal colon of the rat. Sodium depletion stimulates neutral sodium chloride absorption.

Foster¹,

Budinger²,

Hayslett³

et al. 1986

J. Clin. Invest.

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The model of sodium and chloride transport proposed for the colon is based on studies performed in the distal segment and tacitly assumes that ion transport is similar throughout the colon. In rat distal colon, neutral sodium-chloride absorption accounts for the major fraction of overall sodium absorption and aldosterone stimulates electrogenic, amiloride-sensitive sodium absorption. Since we have demonstrated qualitative differences in potassium transport in proximal and distal segments of rat colon, unidirectional 22Na and 'Cl fluxes were performed under shortcircuit conditions across isolated proximal colon of control and sodium-depleted rats with secondary hyperaldosteronism. In the control group, net sodium absorption (JN:) (7.4±0.5 Ateq/h * cm2) was greater than I,, (1.4±0.1 lueq/h cm2), and JPt was 0 in Ringer solution. Residual flux (J) was -5.2±0.5 teq/h cm2 consistent with hydrogen ion secretion suggesting that neutral sodium absorption may represent sodium-hydrogen exchange. 1 mM mucosal amiloride, which inhibits sodium-hydrogen exchange in other epithelia, produced comparable decreases in J" and JR (4.1±0.6 and 3.2±0.6 ;&eq/h * cm2, respectively) without a parallel fall in I,<. Sodium depletion stimulated JN, JA, and I., by 7.0±1.4, 6.3±1.9, and 0.8±0.2 ;eq/h cm2, respectively, and 1 mM amiloride markedly inhibited JN' and J by 6.0±1.1 and 4.0±1.6 ,ueq/h * cm2, respectively, with only a minimal reduction in I4.. Conclusions: the predominant neutral sodium-absorptive mechanism in proximal colon is sodium-hydrogen exchange. Sodium depletion stimulates electroneutral chloride-dependent sodium absorption (most likely as a result of increasing sodium-hydrogen and chloride-bicarbonate exchanges), not electrogenic chloride-independent sodium transport. The model of ion transport in the proximal colon is distinct from that of the distal colon.

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“…In calves that were induced to be born at 277 days of gestation (approximately 2 weeks premature), heart rate and respiration rate remained high through neonatal life, while other measures within normal ranges included rectal temperature, blood gases and metabolic traits, although these calves only grew 2.2±0.3 kg in this period (Bittrich et al, 2002). Given the relatively low growth, underdeveloped calves may not have survived under more stressful circumstances, even if apparently vigorous at birth.…”

Section: Calf Ability To Sucklementioning

confidence: 99%

“…In rats, urea was secreted into the proximal and distal colon at respective rates of approximately ~ 8.5 µL and ~5.5 µL (per minute-gram wet weight of intestinal tissue; Fihn and Jodal, 2001). Urea absorption into the colon might be minimal at best (Billich and Levitan, 1969) compared to that of the small intestine (Fordtran et al, 1965).…”

Section: Urea Molecule Distributionmentioning

confidence: 99%

Dehydration as a risk factor for calf mortality in northern Australia

Muller¹

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It is estimated that approximately one million calves die in Australia every year, with the majority unexplained. This thesis reviews losses associated with dehydration-mediated mortality during neonatal life, when there is highest risk of mortality, and reports three studies of neonatal calf dehydration.For 12 neonatal Brahman calves at Spyglass research site (northern forest land type, Queensland), variation in hydration status was investigated (Experiment 1). Change in live-weight from birth was used as the primary measure of hydration. Half of this cohort had low live weight gain between birth and day 3 of life (p = 0.01) compared to calves growing at 0.95±0.24 kg/day from birth. Low growth and associated reduced plasma protein (p = 0.04) in 6 calves indicated reduced colostrum, milk uptake and therefore reduced body fluid replenishment compared to other calves. This positions them at high risk of mortality under adverse environmental conditions. Urea space was tested as a measure of body water; however, percentage body water estimates were unrealistically elevated (> 80% of live weight) and therefore not representative of actual calf percentage body water.Descriptive analysis of risk factors for calf mortality was conducted for 478 and 378 tropically adapted newborn calves, respectively at Spyglass and Brian Pastures (southern forest land type, central Queensland) research sites (Experiment 2). The incidence risk of neonatal mortality in the southern forest of Queensland and northern forest of Queensland was 3.1% and 4.7%, respectively. Some risk factors and the percentage of calves exposed to high mortality risk included: dam body condition score ≤2 (8%), birth weight ≤28 kg (18%), low birth vigour (2%), large udder size (1%), at least two large teats (2%) and poor maternal protectiveness (5%). The low proportion of cows in poor body condition and good nutritional management limited the opportunity for dehydration-mediated neonatal mortality. There were no cases of prolonged heat stress around calving at the level previously associated with foetal and calf mortality. Experiment 2 indicates that low calf mortality may be achieved in any country type, provided that a low proportion of calves are exposed to high risk of mortality. A simple mechanistic model was developed to describe milk uptake volumes and ambient temperature (heat stress) impacts on neonatal hydration. This model provided clarification for the possible risk of dehydration mediated mortality across breeding herds of northern Australia.This thesis demonstrated variation in milk delivery, modelled that low milk delivery is associated with dehydration-mediated mortality and demonstrated that risk of mortality is low at a herd level when the risk factors associated with reduced milk delivery have low frequency.3

show abstract

Effects of sodium concentration and osmolality on water and electrolyte absorption from the intact human colon

Cited by 116 publications

References 29 publications

Fluid absorption in isolated perfused colonic crypts.

Fluid absorption in isolated perfused colonic crypts.

Ion transport in proximal colon of the rat. Sodium depletion stimulates neutral sodium chloride absorption.

Dehydration as a risk factor for calf mortality in northern Australia

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