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.     

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     

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.     

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.     

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

Summary 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.The authors are grateful to Dr V. Srinivasan, Director, Sarabhai Research Centre, Baroda, India, for donating the animals required for carrying out this work.     

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.     

Role of calcium in the histamine release induced by D-galactosamine from rat mast cells

Rat peritoneal mast cells were isolated and purified by differential centrifugation in Ficoll. Cells pooled from three to four rats were suspended at approximately 10(6) cells/ml in a buffered salt solution and incubated for 1 h at 37 degrees C in 300 microliter volumes in the absence or presence (9 X 10(-4) M) of calcium chloride. Addition of D-galactosamine hydrochloride (DGM; 2.8 X 10(-4)M) caused (in addition to basal release) a mean +/- SEM percent histamine release of 15.7 +/- 5.2 in the presence of Ca++ and 19 +/- 4.9 in the absence of Ca++ (p greater than 0.05). It is suggested that D-galactosamine does not require extracellular Ca++ for the release of histamine from the rat mast cell.     

Role of calcium in the histamine release induced by D-galactosamine from rat mast cells

Summary Rat peritoneal mast cells were isolated and purified by differential centrifugation in Ficoll. Cells pooled from three to four rats were suspended at approximately 10⁶ cells/ml in a buffered salt solution and incubated for 1 h at 37°C in 300 l volumes in the absence or presence (9×10^–4 M) of calcium chloride. Addition of D-galactosamine hydrochloride (DGM; 2.8×10^–4 M) caused (in addition to basal release) a mean ±SEM percent histamine release of 15.7±5.2 in the presence of Ca⁺⁺ and 19±4.9 in the absence of Ca⁺⁺ (p>0.05). It is suggested that D-galactosamine does not require extracellular Ca⁺⁺ for the release of histamine from the rat mast cell.A preliminary analysis of these results was presented at the International Symposium on calcium entry blockers and tissue protection, Rome, 15–16 March 1984.     

Evidence for a cholinergic mechanism inducing histamine increase in the rat brain in vivo

Résumé Pendant l'excitation du système nerveux central chez le rat, un mécanisme cholinergique augmente l'histamine cérébrale.     

Adaptation of the guinea-pig to histamine. sensitivity of the guinea-pig's ileum to histamine and acetylcholine

Résumé L'adaptation des cobayes à l'histamine par voie intrapéritonéale diminue la sensibilité de leur jéjunum isolé à l'histamine. En même temps le jéjunum isolé de cobayes adaptés réagit à l'acétylcholine sans changer remarquablement de susceptibilité. L'activité de l'histaminase dans le jéjunum adapté ne démontre pas la différence en relation avec celle du jéjunum non adapté.

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The study was supported by the Polish Academy of Sciences.