Histamine H1- and H2-receptor-mediated gastric microcirculatory effects in the aetiology of stress ulceration in the rat stomach

Summary Stress produced severe mucosal ulcers, increased mucosal microcirculation and lowered mast cell counts in the glandular wall of rat stomachs. Mepyramine i.m. or metiamide i.p. effectively prevented both ulceration and microcirculatory changes but not stress-reduced mast cell counts.Acknowledgment. The authors thank Dr W.A.M. Duncan (Smith, Kline and French Labs Ltd, England) for the generous gift of metiamide.     

Different effects of the H2-antagonists on gastric emptying in the rat

Summary H₂-receptor antagonists, in doses capable of inhibiting gastric secretion, did not generally affect gastric emptying. Exceptions were burimamide, which delayed the emptying rate, and ranitidine, which accelerated it. At higher doses burimamide, metiamide cimetidine and oxmetidine delayed gastric emptying, but ranitidine accelerated it to a greater extent. Tiotidine remained ineffective. These data suggest that changes in emptying rate are independent of the H₂-receptor blockade.This work was supported by a grant from the C.N.R., Rome.     

Different effects of the H2-antagonists on gastric emptying in the rat

H2-receptor antagonists, in doses capable of inhibiting gastric secretion, did not generally affect gastric emptying. Exceptions were burimamide, which delayed the emptying rate, and ranitidine, which accelerated it. At higher doses burimamide, metiamide cimetidine and oxmetidine delayed gastric emptying, but ranitidine accelerated it to a greater extent. Tiotidine remained ineffective. These data suggest that changes in emptying rate are independent of the H2-receptor blockade.     

Histamine release and mast cell degranulation induced by 2-4 dinitrophenol in rat tissues

Resumen El 2–4-dinitrofenol es capaz de producir degranulación rápida aunque parcial de mastocitos y liberación de histamina de los tejidos de la rata in vitro. Estos efectos solamente pueden ser demostrados en tejidos mantenidos a baja temperatura antes del tratamiento; son inhibidos por glucosa. La estimulación del consumo de oxígeno no parece ser la causa de los efectos del dinitrofenol.     

A comparative study of the gastric ulcerogenic effects of stress and reserpine in rats with decreased stomach wall mast cell populations

Summary Stress-induced gastric glandular ulcers in rats appeared less severe than those evoked by reserpine, although glandular mucosal mast cell counts were equally decreased. Prior depletion of the glandular mucosal mast cell population confirmed the hypothesis that an additional mechanism contributes to reserpine ulceration.     

Synapses in the rat stomach and small intestine

Riassunto Nel plesso mienterico dello stomaco e dell'intestino tenue di ratto si osservano tipiche giunzioni sinaptiche sia axo-somatiche sia axo-dendritiche. Il numero di contatti sinaptici per unità di superficie di sezione o per cellula nervosa è piÚ di sei volte maggiore nello stomaco che nell'intestino tenue.     

Histamine stimulation of gastric pepsin and hydrochloric acid in patients of vitiligo

Zusammenfassung Die stündliche Pepsinsekretion bei dreissig Vitiligo-kranken und 15 gesunden Personen wurde nach Histaminstimulation gemessen. Bei den Vitiligo-Kranken wurden zwei Drittel der normalen Pepsinsekretion beobachtet.

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Thanks are due to Mr.R. K. Soraut for his valuable assistance in this work.     

Histamine as an extremely potent releaser of vasopressin in the rat

Summary Intraperitoneal and intraventricular injection of histamine induces a very fast and high elevation of vasopressin in rat plasma as determined by radioimmunoassay. The effects are dose and time related. The intraventricular injection is more effective with regard to time and dose than the intraperitoneal injection.     

Effects of aluminium hydroxide on restraint-induced and restraint delay-induced gastric ulceration in rats

Summary Rats given aluminium hydroxide after cold-restraint stress but before the post-stress delay period, ulcerated significantly less severely and less frequently than rats given the drug before cold-restraint stress or those given water at either time period. Both aluminium hydroxide treated groups exhibited less ulceration than non-drug groups. These data suggest profound parasympathetic and hence, gastric acid, involvement in restraint delay-induced ulceration in rats.     

Histamine as an extremely potent releaser of vasopressin in the rat.

Intraperitoneal and intraventricualr injection of histamine induces a very fast and high elevation of vasopressin in rat plasma as determined by radioimmunoassay. The effects are dose and time related. The intraventricular injection is more effective with regard to time and dose than the intraperitoneal injection.     

VIP and histamine H2 receptor activity in human fetal gastric glands

Summary Vasoactive intestinal peptide (VIP, EC₅₀=6.4×10^–10 M) and histamine (EC₅₀=3×10^–6 M) activated the cyclic AMP generating system in gastric glands isolated from two human fetuses at 23 weeks gestation. Histamine antagonism by the H₂ receptor blockers cimetidine (Ki=0.35×10^–6 M) and ranitidine (ki=0.51×10^–7 M) clearly characterized the histaminic activation as being of the H₂ type. It is suggested that these two vasoactive hormones may operate as neurocrine/paracrine regulators of the differentiation and/or function of the human gastric mucosa in utero.     

VIP and histamine H2 receptor activity in human fetal gastric glands

Vasoactive intestinal peptide (VIP, EC50 = 6.4 X 10(-10)M) and histamine (EC50 = 3 X 10(-6)M) activated the cyclic AMP generating system in gastric glands isolated from two human fetuses at 23 weeks gestation. Histamine antagonism by the H2 receptor blockers cimetidine (Ki = 0.35 X 10(-6)M) and ranitidine (ki = 0.51 X 10(-7)M) clearly characterized the histaminic activation as being of the H2 type. It is suggested that these two vasoactive hormones may operate as neurocrine/paracrine regulators of the differentiation and/or function of the human gastric mucosa in utero.     

Histidine decarboxylase and DOPA decarboxylase in the stomach of the developing rat

Zusammenfassung Im Magen der fötalen Ratte erreicht die Dopadecarboxylase-Aktivität 19 Tage nach der Paarung Werte, die den Aktivitätswerten des erwachsenen Tieres entsprechen. Die Aktivität bleibt auch während der weiteren Entwicklung hoch. Die Histidindecarboxylase des fötalen Rattenmagens ist während der embryonalen Entwicklung hoch, aber die Aktivitätswerte fallen bei der Geburt zu nicht messbaren Werten ab. Ungefähr 8 Tage post partum steigt die Histidindecarboxylase des Magens wieder an und erreicht einen Monat nach der Geburt Werte, die den Aktivitätswerten des erwachsenen Tieres entsprechen. In der jungen Ratte wird die Magenhistidindecarboxylase weder durch Gastrininjektion noch durch Hungern beeinträchtigt. Vom 18. Tag nach der Geburt an kann die Enzymaktivität durch Hungern verringert und durch Gastrin wieder erhöht werden.     

Activation of rat stomach histidine decarboxylase after inhibition of acid secretion with 2-Phenyl-2-(2-Pyridyl)-Thioacetamide (SC-15396)

Zusammenfassung 2-Phenyl-2(2-Pyridyl)-Thioacetamide (SC-15396) ist ein kräftiger Inhibitor von sowohl basaler als auch stimulierter gastrischer Säuresekretion und aktiviert die Histidindecarboxylase in der Magenschleimhaut. Die enzymaktivierende Wirkung von SC-15396 wird durch Resektion des Antrums verhindert. Daraus kann geschlossen werden, dass die durch SC-15396 hervorgerufene Enzymaktivierung eine Folge von erhöhter Freisetzung von antralem Gastrin ist.     

Running activity and gastric ulcers in the rat

Zusammenfassung Nachweis von Magenulzerationen und Magenerosionen bei Albinoratten nach bestimmter Fütterung und nachherigem Laufkäfig-Aufenthalt. Problem der Stressulzeration und die Rolle der Diät werden erörtert.

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The authors appreciate the excellent technical assistance of Messrs.J. Krebs andJ. Tomlinson