Gastrin: Obligatory intermediate in the postprandial mobilization of gastric histamine in the rat

Summary In unoperated fasted rats, feeding raised the serum gastrin concentration, reduced the gastric mucosal histamine content and activated the gastric histidine decarboxylase. The reduction of gastric histamine and activation of histidine decarboxylase was induced also by the injection of pentagastrin. In antrectomized rats, feeding failed to produce these effects. Injection of pentagastrin, however, still lowered gastric histamine and activated gastric histidine decarboxylase. Thus, antral gastrin seems to be an obligatory mediator of the postprandial activation of histidine decarboxylase and mobilization of histamine.Acknowledgments. Grant support from the Swedish and Danish Medical Research Councils (14P-4822, 04X-1007, 17X-4144 and 512-2540).     

Gastrin stimulated H+ secretion in amphibian gastric mucosa: Effect of tetrodotoxin

Summary The role of neural mechanisms in gastrin stimulated H⁺ secretion was studied using amphibian gastric fundic mucosa. Spontaneously secreting mucosae were converted to resting state (zero H⁺ secretory rate) using Burimamide. Following removal of burimamide, 3×10^–6 M tetrodotoxin did not block gastrin stimulation of H⁺ secretion indicating that neural mechanisms are not required.This work was supported by U.S. Public Health Service NIH Grant AM17315 and by the Medical Research Service of the Veterans Administration.     

Dopamine synthesis in rat striatum: mobilization of tyrosine from non-dopaminergic cells

Unilateral nigrostriatal lesions in rats that almost totally depleted striatal dopamine had no effect on striatal levels of dopamine's precursor, tyrosine, nor on those of leucine. Since prolonged electrical stimulation of the slices markedly depletes them of tyrosine (1,2) we conclude that tyrosine can be mobilized from non-dopaminergic striatal cells to augment dopamine release.     

Effect of stimulation of vagus nerves on gastric tissue histamine concentration in albino rats.

2 different time schedules were applied in order to stimulate vagus nerves around the oesophagus at the region of the cardio-oesophageal junction. The result shows a significant reduction in gastric tissue histamine concentration following vagal stimulation, the reduction being more when the duration of stimulation was longer.     

Colchicine inhibits stimulated release of gastric histamine but not activation of histidine decarboxylase.

In the rat, gastric mucosal histamine is mobilized and histidine decarboxylase activated by treatment with insulin or pentagastrin. Colchicine pretreatment prevented the histamine release without preventing the enzyme activation. The results suggest a) that histamine release and histidine decarboxylase activation are independent events, and b) that microtubules are involved in the release of histamine.     

The effects of histamine dihydrochloride on blastocyst implantation in the laboratory rat

Summary This investigation studied the effects of intrauterine injections of histamine dihydrochloride on blastocyst implantation in the laboratory rat. Results of this study lend support to the idea that histamine is the initiator of implantation through the induction of decidualization in this species.     

Urinary excretion of 5-hydroxyindoleacetic acid and histamine in the pregnant rat

Zusammenfassung Bei schwangeren Ratten wurde die urinäre Ausscheidung von 5-Hydroxyindolessigsäure im Gegensatz zu der von Histamin nicht erhöht. Das deutet darauf hin, dass die Bildung von 5-Hydroxytryptamin nicht wie diejenige von Histamin vermehrt wird.     

Formation of histamine in transplants from a rat mammary carcinoma

Zusammenfassung Tumorgewebe von Ratten mit subcutan transplantiertem Walker-Milchdrüsencarcinom 256 produzierte¹⁴C-Histamin mit beträchtlicher Geschwindigkeit bei Inkubation des Krebsgewebes mit¹⁴C-Histidin. Zusatz von Pyridoxal-5-phosphat aktivierte die Histidindecarboxylase des Krebsgewebes. In normalem Milchdrüsengewebe lag die Histaminbildung ausserhalb des Messbereichs. Der Histamingehalt des Krebsgewebes war sehr niedrig und Mastzellen wurden keine gefunden. Der Histaminmetabolismus des Carcinoms 256 ist demjenigen im Rattenembryo und im Granulationsgewebe heilender Hautwunden ähnlich.     

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     

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.     

Retardation of protein synthesis in rat tumours on inhibiting histamine formation

Zusammenfassung Untersuchung der Proteinsynthese bei Virustumoren. Anhand der Inkorporierungsgeschwindigkeit von¹⁴C-Leucin wurde festgestellt, dass die Hemmung der Proteinsynthese im Rous-Sarkom höher ist als im Walker-Karzinom.     

Temperature changes following microinjection of histamine into the thermoregulatory centers of the rat

Résumé Par administration intracérébrale (hypothalamus rostral), l'histamine engendre de l'hypothermie chez le rat. L'administration d'une antihistamine, 1 h avant l'injection de l'histamine empêche cet abaissement de température. On discute la question de savoir si l'histamine peut être ou non un neurotransmetteur dans les centres thermorégulateurs.