The absorption of chloride ions from the reticulo‐rumen sac

Dobson, A.; Phillipson, A. T.

doi:10.1113/jphysiol.1958.sp005918

Cited by 55 publications

(36 citation statements)

References 8 publications

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“…The interaction between bicarbonate and acetate movements The linear relation between the appearance of total CO2 in the rumen and the absorption of short-chain fatty acids (Masson & Phillipson, 1951) was confirmed for acetate during the course of experiments published elsewhere (Dobson & Phillipson, 1958;Dobson, 1959). Eighteen observations of acetate uptake and bicarbonate appearance in the rumen of six sheep are summarized in Fig.…”

Section: Gaseou8 C02 Exchangementioning

confidence: 86%

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The effect of absorption on the acidity of rumen contents

Ash¹,

Dobson²

1963

The Journal of Physiology

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The role of the saliva in neutralizing the large quantities of fatty acid which are produced by the fermentations in the rumen of the sheep is well known. However, there is evidence that the absorptive properties of the reticulo-rumen epithelium also play a part in maintaining a relatively stable acidity of the rumen contents. Danielli, Hitchcock, Marshall & Phillipson (1945) observed that when fatty acid was absorbed from solutions introduced into the isolated reticulo-rumen, continual additions of acid were necessary in order to keep the pH below 6. It was suggested by Danielli et al. that at a low pH, un-ionized fatty acid was leaving the rumen more rapidly than the corresponding anion.Another mechanism involved in the neutralization of fatty acid was discovered by Masson & Phillipson (1951). These workers observed that when alkaline solutions of fatty acid were introduced into the isolated reticulo-rumen the pH drifted towards 7-3-7-8 and sometimes passed through a minimal value. Further, the appearance of total C02, mainly as bicarbonate, was closely related to the disappearance of fatty acid.The way in which the apparent interaction between fatty acid uptake and bicarbonate appearance occurs is difficult to investigate, since there are changes in seven known species of particles which may affect the pH. These are hydrogen and hydroxyl ions, carbon dioxide, bicarbonate and carbonate, ionized and un-ionized fatty acid; in addition there are unknown contributions of metabolites by the epithelium.The aim of the present work was to determine the forms in which fatty acid and bicarbonate enter and leave the solutions in the rumen. Observations were made by means of a comparatively simple system in which fatty acid was omitted from the solutions in the rumen so that information might be obtained concerning the movements of C02 and bicarbonate and thus the changes as a result of including fatty acid could be assessed. Subsequently the observations were extended to the plasma side of the epithelium. Throughout this paper the term C02 is used to describe dissolved C02 + undissociated carbonic acid; total C02 refers to C02 + bicarbonate.

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Section: Gaseou8 C02 Exchangementioning

confidence: 86%

“…The electrical potential between jugular blood and rumen contents was measured by a procedure described previously (Dobson & Phillipson, 1958). TABLE 2.…”

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confidence: 99%

The effect of absorption on the acidity of rumen contents

Ash¹,

Dobson²

1963

The Journal of Physiology

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“…Thus, chloride entering the rumen with saliva (10-40mmoll -1 ) under in vivo conditions is absorbed into blood against a considerable electrochemical gradient (Sperber and Hyden, 1952;Dobson and Phillipson, 1958;Martens et al, 1991), requiring that the paracellular pathway effectively prevents a reflux.…”

Section: The Barrier Function Of Forestomach Epitheliamentioning

confidence: 99%

Sheep rumen and omasum primary cultures and source epithelia: barrier function aligns with expression of tight junction proteins

Stumpff

Georgi

Mundhenk

et al. 2011

Journal of Experimental Biology

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SUMMARYThe forestomachs of cows and sheep have historically served as important models for the study of epithelial transport. Thus, the ruminal epithelium was among the first tissues in which absorption of chloride against an electrochemical gradient was observed, requiring a tight paracellular barrier to prevent back-leakage. However, little is known about ruminal barrier function, despite the considerable implications for ruminant health. The tight junction proteins of the omasum have never been investigated, and no cell culture model exists. We present a new method for the isolation of cells from forestomach epithelia. Protein expression of cells and source tissues of sheep were studied using western blot, PCR and confocal laser scanning microscopy. Supplementary material available online at

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“…The method used was that of Dobson & Phillipson (1958) PEG (4000) was measured by the turbidimetric method of Hyden (1955). Osmotic pressure was measured by depression of the freezing point (Osmette, Precision System Inc, Newton, MA, U.S.A.).…”

Section: Measurements Of Mg Absorptionmentioning

confidence: 99%

Magnesium Absorption From the Digestive Tract of Sheep

Care¹,

Brown²,

Farrar³

et al. 1984

Exp Physiol

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SUMMARYFactors affecting absorption of Mg from the ovine rumen have been studied using either a pouch constructed from part of the dorsal rumen or by an isolated washed rumen technique in vivo. Net absorption of Mg against the prevailing electrochemical gradient was observed. An increase in the K/Na ratio within the rumen led to an increase in the potential difference across the rumen wall, blood positive, and to a decrease in the net efflux of Mg from the rumen. This decrease was due to an increase in Mg influx into the rumen. The addition of ammonium chloride (30 mmol/l) to the rumen contents also led to a reduction in net Mg absorption but to no significant change in potential difference. The effects of high K/Na ratio and high ammonium ion concentration within the rumen were additive in causing decreases in net effluxes of both Mg and Na. An inverse relationship was demonstrated between the Ca concentration in the rumen and the net absorption rate of Mg. It was concluded that the efflux of Mg across the rumen wall depends at least in part on a functional system for Na transport.

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The absorption of chloride ions from the reticulo‐rumen sac

Cited by 55 publications

References 8 publications

The effect of absorption on the acidity of rumen contents

The effect of absorption on the acidity of rumen contents

Sheep rumen and omasum primary cultures and source epithelia: barrier function aligns with expression of tight junction proteins

Magnesium Absorption From the Digestive Tract of Sheep

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