Osmotic concentration of the gastric juice of dogs

Altamirano, M.; Izaguirre, Elizabeth Pérez; Milgram, E.

doi:10.1113/jphysiol.1969.sp008811

Cited by 4 publications

(3 citation statements)

References 15 publications

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“…Once again it has to be reported that less interest has been taken in the movements of water across the gastric mucosa than in the ion fluxes. It is generally stated that the gastric secretion is isotonic with the blood plasma, but according to Altamirano et al (1969) it is more usually slightly hypotonic in the dog. Durbin, Frank & Solomon (1956) measured the spontaneous net flow from serosa to mucosa in summer frogs when there was no osmotic gradient, and obtained a mean value of 11 -3 /d/cm 2 .…”

Section: Water Movementsmentioning

confidence: 99%

From frog skin to sheep rumen: a survey of transport of salts and water across multicellular structures

Keynes¹

1969

Quart. Rev. Biophys.

136

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All higher animals, whether they live in water or on dry land, are faced with the necessity of regulating rather closely their intake and excretion of salts and water in order to maintain the constancy of their internal ionic environment. The kidney is in general the most important organ of the body as far as the excretion of sodium, potassium, chloride and water is concerned, but there are other tissues which also play a part in controlling the ionic balance between the internal and external environments, such as the intestinal mucosa, the skin and urinary bladder in amphibia, the gill epithelium in fishes, the salt gland in marine birds, and the epithelium of the rumen in ruminants. In addition to excretory and absorptive organs of this type, there are others which are secretory and whose function involves the production of fluids differing in ionic composition from the blood plasma. Examples include the glands which secrete saliva and sweat, the oxyntic acid-producing cells of the gastric mucosa, and the epithelium of the stria vascularis which generates the potassium-rich endolymph of the mammalian cochlea. The purpose of this article is to consider briefly what is known about the active transport of salts and water across some typical multicellular secretory tissues, and to attempt in the process to discern what properties they have in common and in what respects they are specialized.

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Section: Water Movementsmentioning

confidence: 99%

From frog skin to sheep rumen: a survey of transport of salts and water across multicellular structures

Keynes¹

1969

Quart. Rev. Biophys.

136

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“…The metabolism of digestive glands leads to increases in the number of osmotically active particles in venous blood as Barcroft and Kato [1916] found with the dog's submaxillary gland. Altamirano, Izaguirre and Milgram [1969] considered that metabolic activity was of secondary importance to the 'clearance of free water by the mucosa' in leading to an increased osmolality of venous blood of the stomach when it was stimulated to secrete acid. Their observations, made in anaesthetized dogs, showed the osmolality of gastric venous blood increased by up to 10 mosmoles.kg-1 and arterial blood by 2-5 mosmoles.kgwhen histamine was used to stimulate secretion.…”

Section: Nervous Pathways For Inhibitory Responsesmentioning

confidence: 99%

Post Prandial Changes in Parotid Salivary Secretion and Plasma Osmolality and the Effects of Intravenous Infusions of Saline Solutions

Carr

Titchen

1978

Exp Physiol

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Parotid salivary secretion, reticular (gastric) contractions and blood osmolality were examined in conscious sheep prepared with re-entrant parotid duct cannulae and given 1000 g of lucerne chaff daily. Osmolality of blood (portal, carotid and jugular) rose by 2-4 mosmoles.kg' within 5 min of fresh food being given, continued to rise (up to 12-30 mosmoles.kg-1) over the next 3 h and remained above levels detected before fresh food was given for up to 10 h. The greatest changes were in portal blood which was characteristically hyperosmolal to jugular and carotid blood; a difference which disappeared on fasting for 36 h. Parotid saliva which was 5-20 mosmoles.kg' I hyposmolal to jugular blood, increased to up to 6 ml. min-1 within 30 sec of the sheep starting to eat and although they continued to do so for some hours remained at these high levels for only about 30 min.Attempts were made to see whether parotid salivary secretion was affected by changing the osmolality of the blood. Reductions in the rate of parotid salivary secretions and sometimes in the rate of reticular contractions were produced in conscious, anaesthetized and decerebrate preparations by making intravenous infusions of hyperosmolal solutions. The effects were stronger, and the latency shorter, when the infusions were made into the portal vein than when made into the posterior vena cava or a jugular vein. They were reduced by vagotomy and splanchnotomy although not abolished by both.Increases in parotid salivary secretion and frequently, but not invariably, in the rate of reticular contractions followed intravenous infusions of isosmolal and hyposmolal solutions. In 6 experiments (of a total of 12) increases in parotid salivary secretion followed the intravenous injection of arginine vasopressin (0-06 mU.kg-1), in none was saliva reduced by antidiuretic hormone.The possible involvement of peripheral osmoreceptors in the inhibitory effects, and of receptors sensitive to changes in blood volume in the excitatory effects, is raised in relation to post-prandial changes which occur in blood composition.Salivary secretions increase markedly when sheep first eat freshly provided food but although eating continues salivation declines and may fall to levels below those observed immediately before food was made available. Explanations advanced for the reductions in salivary secretion and apparent failure for buccal, oesophageal and gastric stimulation to remain effective as eating continues have included inhibitory effects of gastric distention as digesta and

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“…There has been speculation about the causes of hyposmolality in general (47, 64, 65, 155) and about the cause of the hyposmolality of gastric luminal contents in particular (6,37,120,139,146). 'Hyposmolality' in the context of 'exchange-diffusion' has been explained by assuming that during 'exchange' of hydrogen for sodium ions across the gastric mucosa, some degree of hyposmo lality of the luminal contents may result from the greater rate of diffusion of hydrogen ions out of the lumen than sodium ions into the lumen (120,146).…”

Section: Mechanisms O F Hyposmolalitymentioning

confidence: 99%

Back-Diffusion – Fact or Fiction?

Þjóðleifsson

Wormsley

1977

Digestion

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Alterations in the concentration of acid in gastric juice secreted at different flow rates and disappearance of acid from the gastric lumen, when the gastric mucosa is exposed to acid luminal contents, have been interpreted as indicating ‘back-diffusion’ of acid into the gastric mucosa from the luminal contents. The loss of acid from the gastric contents increases when the mucosa is exposed to certain drugs or is diseased, giving rise to the suggestion that the increased degree of ‘back-diffusion’ of acid indicates mucosal damage, reflecting a breakdown of the gastric mucosal ‘barrier’ to back-diffusion of acid from the gastric lumen. The change in the ‘barrier’ properties of the gastric mucosa has been found to be associated with change in the electrical properties of the mucosa, so that alterations of the transmucosal potential difference has been considered to denote gastric mucosal damage. The case for every one of these hypotheses and for their underlying assumptions is discussed and found wanting for lack of direct evidence.

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Osmotic concentration of the gastric juice of dogs

Cited by 4 publications

References 15 publications

From frog skin to sheep rumen: a survey of transport of salts and water across multicellular structures

From frog skin to sheep rumen: a survey of transport of salts and water across multicellular structures

Post Prandial Changes in Parotid Salivary Secretion and Plasma Osmolality and the Effects of Intravenous Infusions of Saline Solutions

Back-Diffusion – Fact or Fiction?

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