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Biomedical subjects

T Vitali

Publications and source records attributed to T Vitali.

At least 37 records · Page 2Linked to original sources
PubMed1979

Action of histamine receptor agonists and antagonists on the rat uterus.

1 Histamine and a series of compounds acting selectively on H1- and H2-receptors were tested on the isolated oestrous uterus of the rat. 2 Histamine had a dose-dependent inhibitory effect on the contractions elicited by acetylcholine. This action was unaffected by H1-blockers but was competitively inhibited by H2-blockers. The H1-selective agonist, 2-(2-aminoethyl)thiazole was ineffective at doses 100 times greater than those of histamine. Conversely, all the H2-agonists showed activity in the order of potency: N'-methylhistamine greater than histamine greater than N'-N'-dimethylhistamine greater than 5-methylhistamine greater than 5-methyl-N'-methylhistamine. Among the non-imidazole compounds, dimaprit had an activity identical to that of histamine, but all the dimaprit-like compounds showed negligible activity. 3 The data obtained suggest that in the rat uterus, (a) the activation of H2-receptors is responsible for the inhibitory effect of histamine and its analogues; (b) the integrity of the histamine molecule seems to be less crucial than that of the dimaprit molecule for the maintenance of the H2-activity, since changes in its structure modify but do not abolish the biological activity as they do in the case of dimaprit; (c) the order of activity of the various H2-receptor agonists is different from that observed in other tissues.

Animals↗
PubMed1979

Antagonistic properties of N-methyl-N'-[2-(5-ethyl-4-imidazolyl-methylthio)ethyl]thiourea.

In the present paper the Authors describe the synthesis and the biological effects of N-methyl-N'-[2-(5-ethyl-4-imidazolylmethylthio)ethyl]thiourea (etiamide). This compound appeared to inhibit, to a certain extent, the effect of histamine on H2-receptors. This inhibition, however, was less pronounced than that elicited by metiamide and in some of the preparations examined appeared to be of the non-competitive type.

Animals↗
PubMed1979

[N-Alkyl-2-(5-methyl-4-imidazolyl)ethylamines. Synthesis and effect on gastric secretion].

Synthesis of some 5-methylhistamines alkylated on the amino group (form. I) together with a new method (C) of obtaining them via 5-methylhistaminol, are described. Both the agonistic and antagonistic pharmacological activities of these methylhistamines were studied in vivo on gastric secretion of different animal species (conscious dogs and cats and anaesthetized rats). The potency of the compounds, as far as the H2-receptor stimulant effect is concerned, was very remarkable in the first members of the series and decreased by increasing the degree of substitution. Independently from their "potency" some members of the series showed an "efficacy" which was actually greater than that of histamine. All the compounds tested were completely devoid of any antagonistic activity against gastric hypersecretion induced by histamine.

Animals↗
PubMed1978

[Biological activity of 1,2-benzylisothiazoles. Relationship between the structure and the auxinlike activity of the 1,2-benzylisothiazol-3-ylacetic acid class].

The LFER model was used to study quantitatively the interrelations between chemical structure and auxinic activity of some methyl esters of 1,2-benzisothiazol-3-ylacetic acids, using as biological response the cell enlargement induced in etiolated stems of Pisum sativum, var. Alaska. Having demonstrated that activity, expressed as log 1/C, is correlated, by Eq. 8, with factionary charge (-- Qs) calculated for the sulfur atom and with the logarithm of retention time (log t), determined by reverse phase HPLC, the AA. deal with the influences of the latter parameters on the effect registered.

Fabaceae↗
PubMed1978

[Effect of 2-(5-methyl-4-imidazolyl)-1-methylethylamine on histamine receptors].

Compound 2-(5-methyl-4-imidazolyl)-1-methylethylamine was tested on different preparations for its histamine-like activity. It was found to markedly affect H2 receptors and at the same time to be practically devoid of any activity on H1 receptors. This high selectivity of action indicates that this compound may represent a useful tool for characterizing the distribution of H2 and H1 receptor sites.

Airway Resistance↗
PubMed1976

Biological activities of a new specific stimulant of histamine H2 receptors.

Compound N-methyl-2-(5-methyl-4-imidazolyl)ethylamine (5-methyl-N-methylhistamine) was submitted to a thorough pharmacological examination and was found to be a potent stimulant of H2 receptors, devoid of any appreciable effect on H1 receptors. Because of its high degree of specificity it therefore seems to represent an interesting drug to be used in clinical gastric secretory tests and an useful tool for the study of histamine H2 receptors.

Animals↗
PubMed1976

[High pressure liquid-liquid chromatography: correlation between retention times and biological activity of 1,3,5-triazine derivatives].

An investigation has been made of the possibility of using the retention times t obtained by reversed phase high pressure liquid-liquid chromatography in the study of quantitative structure-activity relatiionships. Taking as an example a group of herbicides which inhibit the Hill reaction, it was found that log t is additive and can be used as the hydrophobic parameter in regression analyses. The characteristics, advantages and possible developments of the method are discussed and the analytical interest is highlighted.

Chromatography, High Pressure Liquid↗