Altered vascular reactivity of rats with adrenal-regeneration hypertension

Résumé La forme d'hypertension qui accompagne la régénération de la glande surrénale énucléée à été étudiée chez les rats. Au cours de l'évolution de l'hypertension, la réaction vasculaire à la noradrénaline, l'adrénaline, la vasopressine et l'ocitocine est modifiée de manière qualitative, mais les effets vasculaires de l'hypertensine et de l'acétylcholine restent inchangés. Ces modifications diffèrent selon la phase de développement de l'hypertension. Hormis la vasopressine, les agents hypertenseurs ne sont pas plus actifs. Ces changements reflètent en toute probabilité le déséquilibre hormonal lié à ce type d'hypertension.

---

---

Supported by a grant from the National Institutes of Health, Washington.     

Vascular reactivity in chronic Goldblatt two kidney-one clip hypertensive rats

Summary We studied the possible contribution of increased vascular reactivity in the chronic phase of Goldblatt two kidney-one clip hypertension. Vascular reactivity was evaluated in aortic strips from hypertensive rats (16 weeks after inducing hypertension) and age-matched control rats. The findings were: a) increased sensitivity to vasopressin in the aortic tissue of hypertensive rats, b) a similar response to angiotensin II, noradrenaline and KCl in hypertensive and control rats, and c) reduced maximal response to angiotensin II compared with other vasoconstrictors in both groups of rats. These results suggest a possible role for vasopressin in the chronic phase of this model of hypertension.The authors thank Ms Karen Shashok for revising the English style.     

Vascular reactivity in chronic Goldblatt two kidney-one clip hypertensive rats

We studied the possible contribution of increased vascular reactivity in the chronic phase of Goldblatt two kidney-one clip hypertension. Vascular reactivity was evaluated in aortic strips from hypertensive rats (16 weeks after inducing hypertension) and age-matched control rats. The findings were: a) increased sensitivity to vasopressin in the aortic tissue of hypertensive rats, b) a similar response to angiotensin II, noradrenaline and KCl in hypertensive and control rats, and c) reduced maximal response to angiotensin II compared with other vasoconstrictors in both groups of rats. These results suggest a possible role for vasopressin in the chronic phase of this model of hypertension.     

The effect of ouabain on water consumption in the rat

Résumé L'ouabain diminue la consommation d'eau, stimulée par l'injection d'une solution sallée hypertonique, chez les rats normaux ou néphrectomisés.     

Altered wound healing in X-irradiated rats: The effect of bone marrow shielding

Zusammenfassung Weibliche, 10–12 Wochen alte Ratten erhielten eine einmalige Ganzkörperbestrahlung (250 kV_Sch; 800 R freie Luft); bei einem Teil der Tiere waren das Becken und die Hinterbeine durch Bleizylinder abgeschirmt. Vier Tage später wurde der Hälfte der Tiere eine Wunde beigebracht. Sowohl bei den verwundeten wie nichtverwundeten Tieren führte Abschirmung des Knochenmarks zu starker Sterblichkeitsminderung. Die fast normale Schliessungsgeschwindigkeit der Wunde scheint vom intakten Knochenmark abhängig.     

Lymphocyte reactivity in Imuran-treated guinea-pigs and in vitro effect of colchicine

Summary Imuran treatment significantly diminished macrophage migration inhibition in immunized guinea-pigs and the percentage of E-rosette forming cells in all treated animals. 10^–6 M colchicine in vitro significantly increased the percentage of E-rosette forming cells in Imuran-treated animals. The results suggest possible alteration of the lymphocyte receptors after treatment with Imuran.This work was supported by the grants of the Republic Research Fund of Serbia.     

Inhibitory effect of taurine on decrease in the inotropic action of ouabain at high concentrations in isolated atria

Summary In vitro, taurine was shown to inhibit the decrease in the inotropic effect of ouabain at large doses in the normal and also low K⁺ medium in which this decrease in the inotropism of ouabain was facilitated. This inhibitory effect of taurine was, at least in part, due to the inhibition of the efflux of intracellular K⁺ in the isolated heart.     

Inhibitory effect of ouabain on in vitro and in vivo gastric acid secretion in the frog and the rat

The in vitro and in vivo effects of ouabain on gastric acid secretion in the frog and the rat, the 2 species known to have different sensitivity to ouabain, were studied. It was found that ouabain was a potent inhibitor of histamine-stimulated acid secretion in the isolated frog gastric mucosa. Ouabain administered i.v. at dose levels far below the lethal range also produced a marked and significant reduction of histamine-stimulated gastric acid secretion in the anesthetized frogs and rats. It is considered that the inhibitory effect of ouabain on acid secretion could be partly related to its specific antagonizing action on the Na+ -K+ -ATPase in the gastric mucosa.     

Inhibitory effect of ouabain on in vitro and in vivo gastric acid secretion in the frog and the rat

Summary The in vitro and in vivo effects of ouabain on gastric acid secretion in the frog and the rat, the 2 species known to have different sensitivity to ouabain, were studied. It was found that ouabain was a potent inhibitor of histamine-stimulated acid secretion in the isolated frog gastric mucosa. Ouabain administered i.v. at dose levels far below the lethal range also produced a marked and significant reduction of histamine-stimulated gastric acid secretion in the anesthetized frogs and rats. It is considered that the inhibitory effect of ouabain on acid secretion could be partly related to ist specific antagonizing action on the Na⁺-K⁺-ATPase in the gastric mucosa.     

Toxicity of ouabain on Drosophila melanogaster

Summary Ouabain, also called g-strophantin, is an inhibitor of the Na⁺/K⁺-activated plasma membrane ATPase. Treatment of Drosophila melanogaster with 3–6 mM of this substance leads to a markedly reduced survival of the flies.     

The action of ouabain in promoting the release of catecholamines

Summary It is suggested that ouabain promotes catecholamine release by causing a rise in intracellular Na⁺ which, in turn, causes an elevated steady-state level of intracellular Ca²⁺. It is suggested that the Na⁺–K⁺-ATPase is not directly involved in exocytosis at either adrenergic or cholinergic synapses.     

Potentiation by taurine of the inotropic effect of ouabain and the content of intracellular Ca++ and taurine in the heart

Summary Under certain conditions, taurine (3.0 mM) potentiated cardiac contractile response to ouabain in the normal medium. The potentiation by taurine was also observed in the low K⁺ medium, in which the positive inotropic effect of ouabain increased. The potentiation as seen in both media was, at least in part, due to the increase by taurine of Ca⁺⁺ content in the heart. Taurine in the heart was not directly related to this potentiation.     

Potentiation by taurine of the inotropic effect of ouabain and the content of intracellular Ca++ and taurine in the heart.

Under certain conditions, taurine (3.0mM) potentiated cardiac contractile response to ouabain in the normal medium. The potentiation by taurine was also observed in the low K+ medium, in which the positive inotropic effect of ouabain increased. The potentiation as seen in both media was, at least in part, due to the increase by taurine of Ca++ content in the heart. Taurine in the heart was not directly related to this potentiation.