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Dietary zinc deficiency in rats causes increased osmotic fragility of their erythrocytes. In this study, the influence of supplementary antioxidants (vitamin C, vitamin E or beta-carotene) on osmotic fragility, oxidative damage and components of the primary defense system of erythrocytes of zinc-deficient rats was investigated. Indicators of hemolysis in(More)
1. In anesthetized cats, posterior and anterior hypothalamic areas were superfused with CSF through double-walled cannulae. The release of endogenous catecholamines (dopamine, noradrenaline and adrenaline) was determined in the superfusate by a radioenzymatic assay. 2. Transection of the brain caudal to the hypothalamus almost abolished the release of(More)
In anaesthetized rabbits guide cannulae were stereotaxically inserted into the anterior hypothalamic area and into the posterior hypothalamic nucleus. Additionally, catheters were inserted into the carotid artery and the jugular vein. Some days after the operation push-pull cannulae were inserted through the guide cannulae into the hypothalamic regions of(More)
The posterior hypothalamus of anaesthetized cats was superfused through a push-pull cannula with histamine agonists and antagonists and the release of endogenous catecholamines was determined in the superfusate. Hypothalamic superfusion with histamine, 2-methylhistamine (H1-agonist), dimaprit (H2-agonist) or metiamide (H2-antagonist) enhanced the release of(More)
Previous studies revealed pharmacological differences between human and guinea pig histamine H(2) receptors (H(2)Rs) with respect to the interaction with guanidine-type agonists. Because H(2)R species variants are structurally very similar, comparative studies are suited to relate different properties of H(2)R species isoforms to few molecular determinants.(More)
N1-Aryl(heteroaryl)alkyl-N2-[3-(1H-imidazol-4-yl)propyl]guanidines are potent histamine H2-receptor (H2R) agonists, but their applicability is compromised by the lack of oral bioavailability and CNS penetration. To improve pharmacokinetics, we introduced carbonyl instead of methylene adjacent to the guanidine moiety, decreasing the basicity of the novel H2R(More)
Both the histamine H1-receptor (H1R) and H2-receptor (H2R) exhibit pronounced species selectivity in their pharmacological properties; i.e., bulky agonists possess higher potencies and efficacies at guinea pig (gp) than at the corresponding human (h) receptor isoforms. In this study, we examined the effects of N-acylated imidazolylpropylguanidines(More)
Residues in the second extracellular loop (e2) play a role in ligand binding in certain aminergic G protein coupled receptors (GPCRs). N-[3-(1H-Imidazol-4-yl)propyl)]guanidines and N G-acylated derivatives are more efficacious and potent agonists at fusion proteins of the guinea pig histamine H2 receptor and the short splice variant of Gsα, GsαS(More)
The present study was designed to investigate the effect of antioxidant supplementation on the in vitro osmotic fragility of erythrocytes from zinc-deficient rats. Rats were fed either a zinc-adequate diet, zinc-deficient diet or a zinc-deficient diet enriched either with vitamin C or vitamin E or beta-carotene. Components of the primary antioxidant system(More)
In a steady-state GTPase activity assay, N-[3-(1H-imidazol-4-yl)propyl)]guanidines and N(G)-acylated derivatives are more potent and efficacious at fusion proteins of guinea pig (gpH(2)R-G(salphaS)) than human (hH(2)R-G(salphaS)) histamine H(2) receptor, coupled to the short splice variant of G(salpha), G(salphaS). Whereas Ala-271 (hH(2)R) and Asp-271(More)