Hepatic modulation of insulin-induced gastric acid secretion and EMG activity in rats

1980 ◽  
Vol 238 (5) ◽  
pp. R346-R352 ◽  
Author(s):  
J. Granneman ◽  
M. I. Friedman
Keyword(s):  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Acid Output ◽  
Emg Activity ◽  
Glucose Levels ◽  
Hepatic Portal Vein ◽  
Inhibited Acid ◽  
Hepatic Portal ◽  
The Brain

Intravenous infusions of fructose, a hexose that does not cross the blood-brain barrier, suppressed insulin-induced gastric acid secretion and electromyographic (EMG) activity despite continuing hypoglycemia. Hepatic portal vein infusions of 0.15 M fructose inhibited acid output while the same concentration delivered via the jugular vein did not, suggesting a hepatic site of action of the hexose. Only infusions of fructose that began before onset of the insulin-induced gastric responses were effective, whereas glucose infusions, which elevated plasma glucose levels, readily reversed ongoing gastric activity. The suppressive effects of fructose on gastric activity were prevented by prior section of the hepatic branch of the vagus nerve. In contrast, hepatic vagotomy did not prevent suppression of gastric responses by infusions of glucose, a hexose utilized by both brain and liver. These results suggest that receptors in the brain may initiate and terminate insulin-induced gastric acid secretion and motor activity, whereas sensors in the liver may inhibit these responses.

Effect of luminal somatostatin on pentagastrin-stimulated gastric acid secretion in the rat

1983 ◽  
Vol 245 (2) ◽  
pp. G297-G300
Author(s):  
R. Morz ◽  
J. Prager-Petz ◽  
H. Pointner
Keyword(s):  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Intravenous Injection ◽  
Acid Output ◽  
Significant Inhibition ◽  
Rat Stomach ◽  
Luminal Perfusion ◽  
Inhibited Acid ◽  
Peak Acid Output

The perfused rat stomach was used to investigate the effect of intragastrically administered somatostatin (S-14) on basal and pentagastrin-stimulated gastric acid secretion. Intravenous injection of pentagastrin (10 micrograms/kg body wt) induced a peak acid output (PAO) of 6.3 +/- 0.45 mu eq H+. With luminal perfusion of the stomach by S-14 (100 micrograms X kg-1 X min-1), no significant inhibition of gastric acid secretion was observed (PAO: 5.9 +/- 0.6 mu eq H+). The same dose of S-14 administered intravenously significantly inhibited acid secretion (PAO: 1.7 +/- 0.4 mu eq H+) as did intravenous injection of neutralized S-14-containing gastric perfusate obtained by perfusion from a different rat stomach (PAO: 1.9 +/- 0.5 mu eq H+). Intravenous injection of a saline gastric perfusate containing no S-14 did not alter gastric acid secretion (PAO: 6.3 +/- 0.7 mu eq H+). It is concluded that S-14 does inhibit gastric acid secretion when administered systemically but not by intraluminal application.

Inhibition of acid secretion by electrical acupuncture is mediated via beta-endorphin and somatostatin

1996 ◽  
Vol 271 (3) ◽  
pp. G524-G530 ◽  
Author(s):  
H. O. Jin ◽  
L. Zhou ◽  
K. Y. Lee ◽  
T. M. Chang ◽  
W. Y. Chey
Keyword(s):  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Acid Output ◽  
Sham Acupuncture ◽  
Electrical Pulse ◽  
Intragastric Administration ◽  
Sham Feeding ◽  
Beta Endorphin ◽  
Inhibited Acid

Electroacupuncture (EAP) was shown to inhibit basal gastric acid secretion in dogs and sham feeding-stimulated acid secretion in humans. However, its effect on a meal-stimulated acid secretion in dogs and the mechanisms involved remain unclear. In five dogs prepared with gastric cannulas, gastric acid secretion was determined by a dye-dilution technique for 60 min after intragastric administration of 200 ml of 4% mixed amino acid meal in six different experiments: study 1, no acupuncture; study 2, sham acupuncture (SAP); study 3, EAP; study 4, EAP plus naloxone; study 5, naloxone alone; and study 6, intravenous infusion of somatostatin (SS) and vasoactive intestinal peptide (VIP) at doses of 0.5 and 1.0 micrograms.kg-1.h-1, respectively. EAP was performed on three different points including Pishu, ZusanLi, and Neiguan. Biphasic electrical pulse (25-100 Hz, 12-16 mA) was applied continuously via needles for 75 min starting 15 min before meal. SAP on nonacupoints in hind- and forelegs was performed with the same electrical pulse. Plasma SS, VIP, beta-endorphin, and gastrin were determined by specific radioimmunoassays. EAP significantly inhibited acid secretion (75%; P < 0.01), which coincided with significant increases in plasma SS, VIP, and beta-endorphin and a significant decrease in plasma gastrin. Naloxone completely reversed EAP-induced inhibition of acid secretion and changes in plasma concentration of peptides. SAP also significantly suppressed acid output (30%; P < 0.05), with a modest but significant increase in plasma beta-endorphin. However, the inhibition by EAP on the acid output was significantly greater than that by SAP (P < 0.01). Furthermore, exogenous SS (0.5 microgram.kg-1.h-1) significantly inhibited acid output (78%), whereas VIP failed to inhibit gastric acid secretion. We conclude that, in dogs, EAP significantly inhibits meal-stimulated acid secretion. This acid inhibition is mediated by the release of beta-endorphin and somatostatin, and an endogenous opiate or opiates appear to play an important role in the release of SS, VIP, and beta-endorphin.

Inhibition of ovine gastric acid secretion by intraduodenal long-chain fatty acids

1982 ◽  
Vol 243 (2) ◽  
pp. G127-G133
Author(s):  
L. M. McLeay ◽  
J. M. Fitzgerald
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Unsaturated Fatty Acids ◽  
Acid Output ◽  
Saturated Fatty Acids ◽  
Fatty Acid Content ◽  
Conscious Sheep

Effects on ovine gastric function of procedures that increase intestinal unsaturated fatty acid content are unknown, and the present aim was to compare the effects of duodenal unsaturated and saturated fatty acids on gastric secretion in conscious sheep. During the maximal gastric secretory response to a meal, 10 ml gallbladder bile alone or with myristic, palmitic, and stearic acids and oleic, linoleic, and linolenic acids were infused into the duodenum at a rate of 5 g fatty acid . h-1 for 1 h. Compared with control 154 mM NaCl (100%), acid output was reduced to 4-7% of control with infusion of oleic, linoleic, and linolenic acids and myristic acids plus bile. Reductions in acid secretion persisted for up to 5 h from the end of infusion. In contrast, the infusion of palmitic and stearic acids with bile caused mean maximal reductions in acid output, respectively, to only 64 and 55% of control, and levels returned to control within 1 h of the end of infusion. Bile infusion alone caused no reduction in acid secretion. Under the conditions used, C18 unsaturated fatty acids and myristic acid were potent inhibitors of ovine gastric acid secretion. The lesser effects of palmitic and stearic acids were probably related to their reduced solubility and absorption.

Inhibitory effects of beta-adrenergic agonists on gastric acid secretion in dogs

1986 ◽  
Vol 251 (4) ◽  
pp. G453-G459
Author(s):  
M. H. Stevens ◽  
R. C. Thirlby ◽  
C. T. Richardson ◽  
M. A. Fredrickson ◽  
R. H. Unger ◽  
...  
Keyword(s):  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Intravenous Infusion ◽  
Acid Output ◽  
Gastric Fistula ◽  
Adrenergic Agonists ◽  
Inhibitory Effects ◽  
Beta Adrenergic ◽  
Beta Adrenergic Agonists

We evaluated the effect of two beta-adrenergic agonists, isoproterenol (nonselective agonist) and terbutaline (selective beta 2-agonist), on gastric acid secretion stimulated by intravenous pentagastrin, bethanechol, or histamine in dogs with gastric fistulas. Intravenous infusion of isoproterenol or terbutaline inhibited pentagastrin-stimulated acid secretion to a significantly greater extent than they inhibited bethanechol- or histamine-stimulated acid secretion. For example, isoproterenol (12 micrograms X kg-1 X h-1) reduced mean pentagastrin-, bethanechol-, and histamine-stimulated acid output by 86, 63, and 14%, respectively. Percent inhibition of acid secretion with terbutaline (30 micrograms X kg-1 X h-1) averaged 60, 17, and 24% for pentagastrin, bethanechol, and histamine, respectively. Terbutaline also inhibited pentagastrin-stimulated acid secretion from vagally denervated fundic pouches in a dose-related manner. Plasma somatostatin-like immunoreactivity was significantly higher during infusion of terbutaline plus pentagastrin than during infusion of pentagastrin alone. However, an intravenous infusion of 0.3 microgram X kg-1 X h-1 somatostatin-14 had no effect on pentagastrin-stimulated acid secretion from the gastric fistula, even though this infusion increased plasma somatostatin-like immunoreactivity to the same extent as terbutaline plus pentagastrin infusion. Thus the amount of somatostatin released during terbutaline infusion was not sufficient to explain the inhibition of pentagastrin-stimulated acid secretion observed.

Gastric effects of TRH analogue and bicuculline injected into dorsal motor vagal nucleus in cats

1990 ◽  
Vol 259 (2) ◽  
pp. G321-G326 ◽  
Author(s):  
H. S. Feng ◽  
R. B. Lynn ◽  
J. Han ◽  
F. P. Brooks
Keyword(s):  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Acid Output ◽  
Motor Nucleus ◽  
Inhibitory Influence ◽  
Gastric Acid Output ◽  
Minimal Effective Dose ◽  
Gabaa Receptor Antagonist ◽  
Dose Dependent

We investigated the gastric acid secretory and motility responses to microinjection into the dorsal motor nucleus of the vagus (DMV) of RX 77368, a stable thyrotropin-releasing hormone (TRH) analogue, and bicuculline, a gamma-aminobutyric acid (GABAA) receptor antagonist in ketamine-chloralose-anesthetized cats. Gastric acid output was collected every 15 min through a gastric cannula after saline flush and titrated to pH 7.0. Antral contractions were continuously recorded by an extraluminal strain gauge force transducer. The chemicals were dissolved in saline and unilaterally microinjected in volumes of 200 nl. RX 77368 or bicuculline microinjected into the DMV induced significant dose-dependent (50-500 ng) increases in gastric acid secretion and significant dose-dependent (50-200 ng) increases in the force of antral contractions. In response to both chemicals the gastric acid output increased in the first 15 min and peaked in the second and third collections. RX 77368 (500 ng) had a second greater peak 90 min after microinjection. The motility responses were rapid in onset and lasted 60 min for RX 77368 and 30 min for bicuculline. The minimal effective dose for eliciting increased motility was consistently lower than inducing acid secretion. Electrical stimulation of the DMV with 100 microA, 50-Hz, and 0.2-ms pulse duration increased the force of antral contractions but had no effect on gastric acid secretion. Our results demonstrate that the DMV exerts important control over both gastric acid secretion and motility in cats. TRH exerts a stimulatory influence, while GABAA receptors mediate an inhibitory influence on this vagal control.

scholarly journals Helicobacter pylori infection potentiates the inhibition of gastric acid secretion by omeprazole

Gut ◽  
1999 ◽  
Vol 44 (4) ◽  
pp. 468-475 ◽  
Author(s):  
D Gillen ◽  
A A Wirz ◽  
W D Neithercut ◽  
J E S Ardill ◽  
K E L McColl
Keyword(s):  
Helicobacter Pylori ◽  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Acid Output ◽  
Intragastric Ph ◽  
Ammonia Production ◽  
Intragastric Acid ◽  
H Pylori

BACKGROUNDOmeprazole has a greater intragastric pH elevating effect in Helicobacter pylori positive than negative subjects. Ammonia production byH pylori has been suggested as a probable mechanism.AIMSTo assess the effect ofH pylori status on gastric acid secretion during omeprazole treatment, and to examine the possible role of ammonia neutralisation of intragastric acid in increased omeprazole efficacy in infected subjects.METHODSTwentyH pylori positive and 12H pylori negative healthy volunteers were examined before and six to eight weeks after commencing omeprazole 40 mg/day. On both occasions plasma gastrin and acid output were measured basally and in response to increasing doses of gastrin 17 (G-17). Gastric juice ammonium concentrations were also measured.RESULTSPrior to omeprazole, measurements were similar in the H pyloripositive and negative subjects. During omeprazole, median basal intragastric pH was higher in the H pyloripositive (7.95) versus negative (3.75) subjects (p<0.002). During omeprazole basal, submaximal (180 pmol/kg/h G-17), and maximal acid outputs (800 pmol/kg/h G-17) were lower in H pylori positive subjects (0.0, 3.6, 6.0 mmol/h respectively) versus negative subjects (0.3, 14.2, 18.6 mmol/h) (p<0.03 for each). This effect was not explained by neutralisation by ammonia.CONCLUSIONThe presence ofH pylori infection leads to a more profound suppression of acid secretion during omeprazole treatment. The effect cannot be explained by neutralisation of intragastric acid by bacterial ammonia production and its precise mechanism has to be explained.

Ventromedial hypothalamic lesions elevate basal and cephalic phase gastric acid output

1980 ◽  
Vol 239 (3) ◽  
pp. G221-G229 ◽  
Author(s):  
H. P. Weingarten ◽  
T. L. Powley
Keyword(s):  
Weight Gain ◽  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Acid Output ◽  
Gastric Acid Output ◽  
Full Development ◽  
Cephalic Phase ◽  
A New Technique ◽  
Induced Changes

With the use of a new technique for the measurement of gastric acid output in the rat, this study identifies ventromedial hypothalamic (VMH) lesion-induced changes in gastric acid secretion. Basal and cephalic phase gastric acid secretion were monitored in VMH- and sham-lesioned control rats on days 1, 5, 9, 13, and 17 postlesion as well as after the full development of obesity. VMH lesions resulted in increases of both phases of secretion. The magnitude of hypersecretion in lesioned rats developed with time and was fully developed by day 9 postlesion. The hypersecretion did not require a hyperphagia or weight gain, but its degree correlated with subsequent weight gain. These data, in conjunction with a review of VMH lesion effects on insulin secretion, suggest a widespread effect of VMH lesions on visceral secretory responses. The relevance of these data to the etiology of the VMH syndrome is discussed.

Relationship between maternal milk PGE2 and gastric acid secretion in newborn rats

1990 ◽  
Vol 259 (5) ◽  
pp. G702-G708
Author(s):  
A. Wirbel ◽  
R. Ducroc ◽  
B. Garzon ◽  
C. Merlet-Benichou ◽  
J. P. Geloso
Keyword(s):  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Acid Output ◽  
Sesame Oil ◽  
Newborn Rats ◽  
Maternal Milk ◽  
Infant Rats

We previously demonstrated that in rats gastric acid secretion declines after birth and drops steeply on day 12 of life. In the present study, we investigated the part played in this decline by prostaglandin E2 (PGE2) from maternal milk. PGE2 content was first measured in the milk of untreated dams 0, 1, 5, 10, 12, 15, and 18 days after parturition. PGE2 levels were high during the first 5 days (123.5-200.5 pg/ml), declined significantly between days 10 and 15 (56.6-85.4 pg/ml; P less than 0.05), and dropped to 18.4 pg/ml on day 18. We also found that depleting milk of PGE2 prevented drop of acid secretion in 12-day-old suckling rats. Injecting lactating dams with indomethacin significantly reduced milk PGE2 content by 65% vs. milk of untreated dams. Surprisingly, administration of sesame oil, the indomethacin vehicle to the dams, increased milk PGE2 content by 182%. In the pups of the indomethacin-treated dams, acid secretion did not drop. On the contrary, in vivo basal and histamine-induced acid output rose markedly by 40 and 50%, respectively, and in vitro the net movements of 36Cl and 22Na measured in the isolated stomach indicated that active Cl- secretion had resumed. Mucosal PGE2 did not appear to be significantly involved in early development of acid secretion because administration of indomethacin to pups from untreated dams did not significantly modify the secretion measured on day 12. Data indicate that maternal milk depletion of PGE2 prevents the drop of gastric acid secretion previously observed in 12-day-old pups and suggest that in infant rats maternal PGE2 plays a physiological part in regulating acid secretion.

scholarly journals Acute Effect of Gamma Irradiation on Gastric Acid Secretion and Gastric Mucosal Integrity in the Rat

2005 ◽  
Vol 5 ◽  
pp. 195-204
Author(s):  
Omar M. E. Abdel Salam ◽  
Ihsan Hadajat ◽  
Ayman Ragab Bayomy ◽  
Siham El-Shinawy ◽  
Mahmoud S. Arbid
Keyword(s):  
Acid Secretion ◽  
Gamma Irradiation ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Acid Output ◽  
Whole Body ◽  
Mucosal Barrier ◽  
Dependent Manner ◽  
Gastric Acid Output ◽  
Direct Stimulation

The effect of 3- or 6-Gray (Gy) whole-body gamma irradiation on basal and stimulated gastric acid secretion was studied in pylorus-ligated rats. Different groups of rats were irradiated with a single 3- or 6-Gy fraction and examined 7 days after irradiation. Exposure to 3-Gy fraction led to marked increase in basal (nonstimulated) gastric acid output in the 4-h pylorus-ligated rat (47.5% compared with unirradiated controls). After exposure to 6 Gy, only 18.2% increase in gastric acid output was noted compared with unirradiated controls. Under pentagastrin or histamine stimulation, gastric acid secretion in those irradiated with 3- or 6-Gy fraction was markedly reduced compared to that of unirradiated controls. Exposure to 3- or 6-Gy gamma irradiation intensified the degree of gastric mucosal injury evoked by indomethacin or 50% ethanol in a dose-dependent manner. It is concluded that in the pylorus-ligated rat model, lower doses of gamma irradiation increase basal gastric acid secretion and impair the gastric mucosal barrier with marked increase in its permeability to H+following stimulation of acid secretion or exposure to barrier breakers. Exposure to irradiation is likely to result in failure of the parietal cell to respond to direct stimulation with histamine or pentagastrin.

Pancreatic polypeptide stimulates gastric acid secretion through a vagal mechanism in rats

1995 ◽  
Vol 269 (5) ◽  
pp. R983-R987 ◽  
Author(s):  
D. M. McTigue ◽  
R. C. Rogers
Keyword(s):  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Pancreatic Polypeptide ◽  
Acid Output ◽  
Arterial Infusion ◽  
Efferent Limb ◽  
Cervical Vagotomy ◽  
The Central Nervous System ◽  
Gastric Circulation

The present study examined the effect of pancreatic polypeptide (PP) on gastric acid secretion. A 45-min infusion of PP was delivered into the jugular vein of urethan-anesthetized rats. Rat PP (100 pmol) significantly increased acid secretion over baseline; bilateral cervical vagotomy or peripheral atropine both eliminated this acid response. Neither intraperitoneal infusion nor close intra-arterial infusion of 100 pmol PP into the gastric circulation altered acid secretion. These results suggest that although PP requires intact vagal reflexes to stimulate acid output, it does not act on afferent or presynaptic efferent terminals of the vagus or directly within the stomach. Given that vagal reflexes consist of an afferent limb, an efferent limb, and a central relay, it may be that the target of circulating PP lies within the central nervous system. Indeed, previous studies from our laboratory have shown that microinjection of PP into the dorsal vagal complex results in long-lasting vagal-dependent elevation of gastric acid secretion.

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