The effect of some molecules and ions on gastric function in the milk‐fed calf

Self Cite

SUMMARY1. Gastric emptying, gastric acid and pepsinogen secretion were assessed simultaneously in the conscious calf using the test meal and duodenal perfusion technique (Bell & Mostaghni, 1975).2. Duodenal infusion of NaCl at a constant osmolality of 300 m-osmole/kg, but with pH ranging from 2-0 to 12-0, did not alter the high level of gastric emptying and secretion already reported for isotonic NaCl or NaHCO3 alone (Bell & Mostaghni, 1975;Bell & Webber, 1979). Gastric function, therefore, is either unaffected by gastric chyme at pH 2-0-12-0 entering the duodenum, or else isotonicity is dominant over pH in activating duodenal receptors which increase motor activity.3. When the pH of the isotonic NaCl was reduced by the addition of HC1 to below pH 2-0, inhibition of gastric function occurred in direct proportion to the amount of titratable acid present in the infusate. The H+ moiety of isotonic duodenal infusates of pH < 2-0 dominates activation of osmoreceptors and so inhibits motor activity.4. When the same amount of acid but at differing concentrations and infusion rates was introduced into the duodenum uniform inhibition of gastric function occurred. This result indicates that duodenal acid receptors respond to acid concentration and flow rate to produce an integrated response in proportion to the amount (concentration x volume) of acid present.5. Isotonic NaHCO3 solutions adjusted to pH 8-1-12-0 by the addition of NaOH, like isotonic NaCl infusions, did not affect gastric function until pH 11 0-12-0, when significant inhibition occurred. This inhibitory effect of isotonic NaHCO3 at high pH is probably due to C032, since Na2CO3 and Li2CO3, but not LiCl, produce a similar inhibitory effect on gastric function.6. The inhibitory effect of carbonate gives some support to the existence of a C02-sensor as suggested by Hunt & Knox (1972)

Section: Discussionsupporting

confidence: 83%

“…In man (Hunt & Knox, 1969) and the calf (Bell & Razig, 1973b), as the concentration of HCl in a meal increases so emptying of the stomach decreases. In contrast to the inhibitory effect of duodenal acidification, alkalinization by isotonic NaHCO3 is an effective stimulant of gastric emptying and secretion (Bell & Webber, 1979).…”

Section: Introductionmentioning

confidence: 99%

The interplay between hydrogen ions, bicarbonate ions and osmolarity in the anterior duodenum modulating gastric function in the conscious calf

Bell

Nouri

Webber

1981

Self Cite

“…Hunt (1956) had suggested that this feed-back control mechanism from the duodenum to the gastric musculature was initiated by the action of components of the gastric chyme on an osmoreceptor situated in the duodenum. Bell & Razig (1973b) corroborated this suggestion by showing experimentally that a similar mechanism probably operated between the duodenum and stomach of the milk-fed calf.…”

Section: Introductionsupporting

confidence: 53%

“…), since this molecule is known to activate abomasal emptying at this concentration, and HCl (60 m-equivfl. ), which is strongly inhibitory, together with distilled water as control infusate (Bell & Razig, 1973b).…”

Section: Methodsmentioning

confidence: 99%

The effect of duodenal infusion on the electromyogram of gastric muscle during activation and inhibition of gastric emptying.

Bell¹,

Ml²

1975

SUMMARY1. When the abomasum of the conscious calf is partially distended, rhythmic motility can readily be recorded from the e.m.g. of the smooth muscle of the fundus (body) and antrum.2. In gastric evacuation rhythmic contractions of the antrum are reinforced by both rhythmic and tonic fundic contractions.3. The output volume of the stomach can be directly correlated with e.m.g. activity.4. Intragastric fluid is usually emptied in gushes coinciding with a strong contraction of the antrum but fluid may be evacuated, when the antrum is inactive, through the force generated by persisting rhythmic fundic contractions.5. Using re-entrant cannulae so that the duodenum can be infused separately from the gastric effluent, isotonic sodium bicarbonate produced almost 100 % gastric evacuation with greatly enhanced e.m.g. activity of fundus and antrum. Infusion of the duodenum with a solution of HC1, 60 m-equiv/L., produced the opposite effect, the gastric muscle becoming quiescent and 100 % of the gastric test meal being retained.6. These results show that the activating or inhibitory effects of a duodenal infusate are produced through an activating or inhibitory effect on the smooth muscle of the stomach.7. The mechanism of the interrelation between duodenal receptor and gastric effector has not yet been elucidated but the connexion is not intramural since it continues when the duodenum is transacted near to the pylorus.

“…In addition two calves (nos. 9 and 10) were provided with antral-duodenal re-entrant cannulae (Bell & Mostaghni, 1975 NaHCO3 (300 m-osmole/kg) was added to the majority of meals to stimulate abomasal emptying and on four occasions HCl (0-06 M) (Bell & Razig, 1973b).…”

Section: Abomnal Cannulationmentioning

confidence: 99%

A radiological study of gastric (abomasal) emptying in calves before and after vagotomy.

Bell¹,

Holbrooke²,

Titchen³

1977

SUMMARY1. Gastric emptying has been studied in the conscious, standing calf by lateral radiography and fluoroscopy of radiopaque meals instilled into the abomasum before and after vagotomy.2. Bilateral cervical vagotomy proved to be the only certain way of achieving total vagal transaction. By instillation of milk into the abomasum through a cannula calves were maintained in normal, healthy condition for up to 36 days after vagotomy.3. Motility of the antrum was not impaired by vagotomy so that some movement of gastric chyme to the duodenum occurred within minutes of instillation into the abomasum. Complete transference of the test meal was, however, delayed after vagotomy.4. The greatest effect of vagotomy appeared to be on the abomasal body so that inadequate amounts of chyme were transferred to the antrum for pumping to the duodenum.5. Delay in passage of contrast material through the intestine was related to delay in gastric emptying although vagotomy may have affected the intestine directly.6. Following vagotomy the abomasum showed a resumption of normal motility and emptying after 7-29 days. This effect of vagotomy is similar to that seen in the simple stomach and is probably due to the establishment of intrinsic gastric control.