Cat Stomach Research Articles

Acute gastritis in cats. Effect of water lavage and local hypothermia on gastric blood flow.

In the present investigation gastric blood flow was determined in cat stomachs with acute inflammation during continuous local irrigation with ice water (4 degrees C) or water at body temperature (37 degrees C). Acute gastritis was induced by a 10% acetic acid solution and gastric mucosal and muscularis blood flow were measured by means of gamma-labelled microspheres. The mucosa and muscularis blood flow remained essentially unchanged during irrigation either with ice water or warm water during the observation time of 2 h. The difference in gastric blood flow between the ice-water and warm-water-irrigated groups was not significant.

Evidence of the dual innervation of the cat stomach by the vagal dorsal motor and medial solitary nuclei as demonstrated by the horseradish peroxidase method

Evidence of the dual innervation of the cat stomach by the vagal dorsal motor and medial solitary nuclei as demonstrated by the horseradish peroxidase method

Effect of Pentagastrin on Blood Flow Distribution in the Stomach of Cats with Gastric Ulcer

Ulcer was induced in the anterior wall of the antrum by injection of acetic acid solution. Carbonized microspheres 15 +/- 5 mj in diameter and labelled with 85Sr and 141Ce were used to measure blood flow in different regions and layers of the stomach. The radioactivity of the blood and tissue samples was determined, and the blood flow was calculated for each tissue sample. Three groups of anaesthetized animals were used: 1) animals, with normal stomachs, 2) animals with normal stomachs given pentagastrin, 3)animals with a one-week ulcer given pentagastrin. In animals with normal stomachs given pentagastrin during 20 minutes, the mucosal blood flow increased in all areas of the stomach apart from the antrum. In animals with a gastric ulcer pentagastrin was not found to influence the mucosal blood flow significantly. Pentagastrin was not found to change the muscularis flow in animals with normal stomachs, or in animals with a gastric ulcer.

Effect of partial devascularization on the blood flow distribution in the cat stomach.

Partial devascularization of the stomach was performed in cats anesthetized with pentobarbital. Gastric blood flow distribution and cardiac output were determined by means of the microsphere distribution technique. Blood flow was determined before and 30 min after the partial devascularization. Devascularization of the lesser curvature caused a significant decrease in the mucosal and muscularis blood flow at the lesser curvature. After devascularization of the greater curvature, localized reduction in mucosal and muscularis blood flow occurred at the greater curvature. In the sham-operated animals the muscularis blood flow was significantly higher than in the nonoperated animals.

Effects of gastrointestinal hormones on the electrical and mechanical activity of the cat stomach.

Effects of gastrointestinal hormones on electrical and mechanical activity of smooth muscle of cat stomach were studied. Spontaneous electrical activity of the antrum preparation consisted of slow waves with superimposed spike-like potentials. Phasic contractions occurred synchronously with the electrical activity. Pentagastrin, tetragastrin, pancreozymin and secretin increased frequency of slow wave component and amplitude of phasic contraction. Atropine and tetrodotoxin did not block the spike-like potential and slow wave component. Noradrenaline and verapamil blocked the phasic contraction. The excitatory effects of these gastrointestinal hormones were observed in the presence of atropine, tetrodotoxin and dibenamine, but not in verapamil. When the mechanical activity of the antral strips was depressed by caffeine or theophylline, the excitatory effects of gastrointestinal hormones were also suppressed. The excitatory effects produced by these hormones were potentiated by imidazole. These results suggest that gastrointestinal hormones have a direct excitatory action on the longitudinal smooth muscle of the antrum region and that the excitatory action is associated with phosphodiesterase activity and intracellular cyclic AMP content.

Blood Flow Distribution in the Stomach of Cats with Gastric Ulcer

Ulcer was induced in the anterior wall of the antrum by a subserous injection of 0.3 ml of a 20% acetic acid solution. Carbonized microspheres 15 plus or minus 5 mu in diameter and labelled with 169Yb were used to measure blood flow in different regions and layers of the stomach. Approximately 2-3 million microspheres were injected into the left ventricle of the heart. Simultaneously a blood sample was drawn from the distal aorta at a flow of 1 ml/min. Standardized tissue samples were punched from the lesser curvature and the anterior and posterior walls of the antrum, corpus, and fundus. In each sample the mucosa was separated from the muscularis. The radioactivity of the blood and tissue samples was determined, and the blood flow was calculated for each tissue sample. Three groups of animals were examined: 1) anaesthetized control animals, 2) animals laparotomized one week before examination, 3) animals with a one-week ulcer. In the control animals the blood flow was found to be the same in corresponding regions of the anterior and posterior walls of the stomach. The flow was slightly lower in the antrum than the fundus. The flow was similar in the different regions of the muscularis. The muscularis flow was markedly lower than the mucosa flow. In the laparotomized animals the blood flow was found to be increased in the muscularis of the corpus. In the ulcer animals the mucosa flow was increased in the anterior wall of the antrum, and the muscularis flow was increased in the antrum and the anterior wall of the corpus.

Measurement of Immunoreactive Gastrin in Gastric Mucosa

A method for measurement of gastrin in gastric mucosa has been developed, and distribution of gastrin in the stomach of pig, dog, cat, rabbit, and man was examined. Measurable amounts of gastrin were found in corpus of all species, but the content in the antrum was considerably higher. The highest concentration of gastrin was seen in man. The borderline between corpus and antrum was abrupt, and in both parts of the stomach gastrin was evenly distributed. In 44 patients with duodenal ulcer the antral gastrin concentration was 21.3 mug eqv. per g mucosa, in 15 patients with prepyloric ulcer 23.0, in 10 patients with gastric ulcer 5.9, and in 16 patients with gastric carcinoma 7.9. The control group consisted of 10 healthy volunteers and 12 patients with minor abdominal complaints. Mean antral gastrin concentrations were 28.1 and 20.7 respectively. No significant relationship was observed between PAO and gastrin content of antral mucosa in any group.

Distribution and properties of glucagon immunoreactivity in the digestive tract of various mammals: an immunohistochemical and immunochemical study.

Numerous epithelial cells in the oxyntic gland area of the stomach of cat and dog appear to store pancreatic-type glucagon, as evidenced by immunohistochemistry and--in the case of the dog--also by radioimmunoanalysis. No glucagon immunoreactive cells are found in the antropyloric mucosa. Disseminated cells in the intestinal mucosa store gut-type glucagon. In all species studied, these cells predominate in ileum and colon.

Microcirculation of the cat stomach.

Radioactive microspheres 15 mum in diameter were injected into the left ventricle of the heart of cats. Simultaneously a blood sample was drawn from the aorta. Standardized samples of the stomach wall were separated into mucosa and muscularis samples. For each sample the blood flow was calculated in terms of ml/minute/100 g tissue weight. The distribution of microspheres to different layers of the samples was determined microscopically. In the mucosa samples the majority of spheres were found in the propria and glandular layer, only a few persent in the submucosa. In the mscularis samples most of the microspheres were present in the muscle tissue, only 1--9% in the submucosa fraction. The present method is considered to give a good expression of the capillary blood flow in the glandular layer of the mucosa and the muscularis.

On the possible role of bradykinin in functional hyperemia of cat's stomach.

AbstractFasth, S. and J. Martinson. On the possible role of bradykinin in functional hyperemia of cat's stomach. Acta physiol. scand. 1973. 89. 334–341.The reactions of the consecutive vascular sections of the stomach were studied with a plethysmography technique at “rest”, during graded and maximal vasodilatation induced by isoprenaline and during infusion of bradykinin, supposed to be involved in functional hyperemia evoked by vagal nerve stimulation. It is shown that the stomach has a great capacity to maintain a rather constant area for filtration even during large variations in peripheral resistance. Bradykinin evoked an atropine resistant vasodilatation. This is similar to the effect of vagal stimulation. In contrast bradykinin did not increase capillary permeability which is one effect recognized for vagal stimulation. It is concluded that this plasmakinin may not play a role of mediator of functional hyperemia in the stomach since the whole pattern of vascular effects known for vagal stimulation is not reproduced.

Gastric absorption of L(+) and D(-) lactic acid and their effects on the transmucosal ion transport in innervated, non-secreting cat stomachs.

AbstractOn instillation of 170 mM lactic acid (L or D) into unstimulated whole stomach pouches in cats the hydrogen ion concentration decreased more slowly than on instillation of 170 mM hydrochloric acid. When 700 mM lactic acid (L or D) was instilled the reverse was found. On instillation of 170 mM HCI subsequent to an instillation of 170 mM lactic acid (L or D) the changes in concentration of eleotrolytes as well as the net fluxes of electrolytes were of the same order of magnitude as during a preceding control instillation of HCI. On instillation of 170 mM HCI subsequent to an instillation of 700 mM lactic acid (L or D) the decrease in hydrogen ion concentration and the increase in sodium ion concentration were significantly larger than in the control instillation of HCI. The net influx of sodium ions was significantly increased but not the net efflux of hydrogen ions. After exposure of the gastric mucosa to 700 mM lactic acid (L or D) it produced a mucoid fluid that contained mainly sodium and chloride ions. This explained the results obtained when HCl was instilled subsequent to an instillation of 700 mM lactic acid. No morphological changes were found on examination in the scanning electron microscope of gastric mucosae exposed to 6 ml of 700 mM L lactic acid.

Propagation and electrical entrainment of intestinal slow waves.

Gastric and intestinal slow waves were electrically entrained in longitudinally oriented strips of muscle removed from the stomach and small intestine of cats. The maximal driven frequency approached twice the intrinsic frequency recorded from stomach, duodenum, jejunum and distal ileum. Slow waves propagated at velocities which varied inversely with the driven frequency. It is concluded that gastrointestinal slow waves are electrically excitable, they may exhibit properties of relaxation oscillators such as threshold and refractoriness, and they propagate by means of local circuit currents. As a corollary, these experiments support the concept that longitudinal intestinal muscle behaves electrically as an interconnected cable.

The disappearance of acetylsalicylic acid (ASA) in aqueous solution from the cat stomach and its influence on the transmucosal ion transport in the innervated non-secreting stomach.

AbstractDuring instillation of aqueous solutions of acetylsalicylic acid (ASA) into innervated, non‐secreting whole stomach pouches in the cat, parallel decreases in the salicylate and hydrogen ion concentrations took place. There was a decrease in volume by an average of 20–25%. Secretion did not affect the absorption of ASA. To study the effect of ASA in aqueous solution on the ionic permeability of the gastric mucosa, HC1 was instilled before and repeatedly after an instillation of ASA. The gastric mucosal permeability for ions was increased after an instillation of ASA. A study of the changes in electrolyte concentration in the instilled HC1 solutions showed that a significant effect on the decreases in hydrogen and chloride ion concentration persisted 90 and 60 min respectively after an ASA instillation. The net effluxes of hydrogen and chloride ions and the net influx of sodium ions were, however, significantly increased only during 30 min. After an instillation of ASA a 2‐fold increase in the pepsin output was obtained during instillations of HC1. In no case was hemorrhage observed during instillation of ASA, and only in 1 expt. during the immediately following instillation of HC1. In all but 1 expts. hemorrhages occurred during the subsequent HC1 instillations. It is suggested that the permeability‐increasing effect of ASA is due to loosening of the mucosa with a consequent increase of the extracellular space.

Methyl histamines and gastric secretion.

1. The previous findings that N-methylhistamine and N-dimethylhistamine are more potent stimulators of gastric secretion than histamine have been confirmed in dogs with Heidenhain pouches or gastric fistulas.2. In cats with gastric fistulas, doses of N-methylhistamine of 0.25 or 0.5 mumole/hr produced 1.4-1.6 times as much HCl as equimolar doses of histamine.3. The maximal HCl outputs of dogs with Heidenhain pouches to histamine, N-methylhistamine, and N-dimethylhistamine were not significantly different, though lesser doses of the N-methyl derivatives were required to produce the maxima. At the one-half maximal level, N-dimethylhistamine showed a twofold greater potency than histamine.4. When given slowly or quickly via arteries supplying blood to the stomach of dogs or cats with gastric fistulas or via the artery to a Heidenhain pouch in a dog, 0.1-1.0 mumole N-methylhistamine or N-dimethylhistamine produced 4.1-13.9 times as much HCl as equimolar doses of histamine.5. Injection of histamine or N-methylhistamine via the portal vein in two dogs with gastric pouches stimulated less secretion of HCl than injection of the same doses via a systemic vein.6. The results allow the conclusion that N-methylhistamine and N-dimethylhistamine are more potent stimulators of acid gastric secretion than histamine in dogs and cats, particularly when delivered directly via the arterial route to the gastric mucosa, and support the prospect that N-methylhistamine or N-dimethylhistamine or both are natural chemostimulators of the parietal cells.

Reactions of blood vessels of the cat's stomach to exposure of the hind limbs to wet and cold

Reactions of blood vessels of the cat's stomach to exposure of the hind limbs to wet and cold

Effect of reflexes of somatic afferents on the adrenergic outflow to the stomach in the cat.

AbstractThe adrenergic activity to the stomach in cats anesthetized with chloralose was modified by electric stimulation of somatic afferent nerves. Electric stimulation of “somatic pressor” afferents promptly elicited inhibitory responses of stomach contractions which contractions were, in turn, dependent on cholinergic nervous activity. However, in the absence of such cholinergic activity, corresponding somatic afferent stimulation had only an insignificant effect on the stomach, despite a considerable myogenic activity, suggesting that the inhibitory adrenergic nervous mechanism preferentially operated by interfering with the cholinergic nervous activity.—Activation of “somatic depressor” afferents, on the other hand, suppressed the prevailing supply, if any, of adrenergic nervous activity to the stomach, which could result in augmentation of vagally induced gastric motor responses. Similar effects were obtained also after spinal cord transection indicating that the “somatic depressor” afferents made propriospinal reflex connections with the sympathetic outflow to the stomach.

Electric slow waves in circular muscle of cat colon.

Electric slow waves in circular muscle of cat colon.

Patterns of canine gastric electrical activity.

Patterns of canine gastric electrical activity.

Two-component slow waves in smooth muscle of cat stomach.

Two-component slow waves in smooth muscle of cat stomach.

THE TRANSMUCOSAL MIGRATION OF WATER AND HYDROGEN IONS IN THE STOMACH.

AbstractA preparation, consisting of an isolated flap of the ventral wall of a cat's stomach with an intact blood supply, was mounted between two perspex chambers. The transmucosal potential was measured. The mucosa was electrically shortcircuited and the current registrered. A mixture of HCl and Na2SO4 was instilled in the mucosal chamber and the disappearance rates for the hydrogen and sulphate ions were determined. The quotient between these two, Qm, was calculated. No stimulation to secretion of HCl was given, but a complete secretory rest could not be garanteed. A slight secretory activity tended to give too low values of Qm. The highest values of Qm coincided with a similar quotient for a cellophane membrane, Qc, which was considered to indicate that hydrogen ions disappeared through the gastric mucosa in the same way as did the sulphate ions, which were thought to migrate by way of an intercellular diffusion. The results were thought to support the diffusion hypothesis of Teorell. Similar experiments with tritiated water suggested that 75 per cent of the water migration is transcellular.