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Biomedical subjects

A Villar

Publications and source records attributed to A Villar.

At least 127 records · Page 7Linked to original sources
PubMed1986

Relaxant effects of sulfonylureas on induced contractions of rat uterine smooth muscle: role of intracellular calcium.

We have investigated the action of tolbutamide and glibenclamide in a Ca-dependent process: the contractile activity of smooth muscle (uterus). The results obtained show that sulfonylureas are capable of relaxing contractions of rat uterus induced by various agents: oxytocin, acetylcholine and KCl in a medium with Ca2+. The capacity of sulfonylureas to also relax oxytocin-induced Ca-free contraction indicates the possibility that the action of these drugs could be due, above all, to a decrease in the intracellular free calcium level. Since maintained contraction induced by oxytocin in a Ca-free solution could be repeated after making a relaxation dose-response curve to sulfonylurea, the most likely mechanism of sulfonylurea-induced uterine relaxation is not an increase in the efflux of Ca but an increase in the Ca-uptake by intracellular organelles.

Acetylcholine↗
PubMed1985

Calcium requirement of uterine contraction induced by PGE1: importance of intracellular calcium stores.

The contraction of the rat uterus in response to PGE1 in high K+ medium and in Ca-free solution which contained EDTA has been investigated in order to examine whether excitation-contraction coupling involves the release of Ca from an intracellular store. In uterus maximally contracted by K+, cumulative concentrations of PGE1 (1.25 - 20 ng/ml) caused maintained concentration-dependent contraction. PGE1 induced sustained contraction of rat uterus in Ca-free medium after incubation with 3mM EDTA for 50 min. In these conditions the involvement of extracellular Ca is highly unlikely. The PGE1-induced contraction could be repeated without exposure to external Ca ions and with only slight reduction in magnitude. The PGE1 concentrations required to elicit uterine contraction in Ca-free solution were about 1000 times higher than the effective doses in KCl-depolarized uterus. In conclusion, the present investigation shows that Ca influx is not essential for PGE1-induced contraction of rat uterus, although extracellular Ca enhances it presumably by increasing the free Ca levels in the cytosol.

Alprostadil↗
PubMed1985

[Action of radiation on the lung. Classic concepts and current interpretations].

The effects of irradiation on the pulmonary system are analyzed according to the classical radiobiological theories and the new ones. Special emphasis is put on the lineal-quadratic model which predicts the possibility of a greater tumor control without increasing the damage to the normal lung tissue, based on the differences between the survival curves for acute and late effects of irradiation. The clinical applications of the new radiobiological concepts can be carried out in the treatment of lung cancer and other neoplasms, especially those using total body irradiation.

Humans↗
PubMed1985

Effects of chlorpromazine and the antidepressant drugs amitriptyline, clomipramine and mianserin on the Ca-depleted rat uterus.

We have investigated the effect of three antidepressants and one phenothiazine on the EDTA-treated rat uterus. It was found that these drugs induce a sustained contraction of tissue in a Ca-free medium (called Ca-free contraction) at concentrations between 5 X 10(-5) and 1 X 10(-4) M. These responses allowed the construction of dose-response curves. However, higher concentrations caused a relaxation of strips contracted by lower doses previously applied. Oxytocin 1 X 10(-2) IU/ml accelerates the appearance of this relaxation. The antidepressants and chlorpromazine at high doses inhibit the oxytocin-induced Ca-free contraction. The drugs-induced Ca-free contraction could be repeated in the same preparation with only a slight reduction in magnitude.

Amitriptyline↗
PubMed1985

[Inhibitory effect of PGE1 on the liberation of insulin induced by glibenclamide].

Glycemia and insulinemia in rat blood samples have been determined at different times before and after administration of glibenclamide, PGE1, glibenclamide and PGE1, glibenclamide and glucose, PGE1 and glucose, and glibenclamide, PGE1 and glucose. PGE1 led to a partial inhibition of glibenclamide induced insulin release, with and without glucose administration, but a total inhibition did not occur. The inhibitory action of PGE1 on insulin secretion was also reflected on the glycemia curves. Defects in insulin release in diabetes could be due in part to an excessive production of PGs, that involve a failure in the beta-cells to respond to glucose signals. The present paper shows that glibenclamide secretory action was not cancelled out by PGE1. These results could explain the availability of glibenclamide in the treatment of diabetes mellitus.

Alprostadil↗
PubMed1984

Anti-inflammatory and anti-ulcer properties of hypolaetin-8-glucoside, a novel plant flavonoid.

The anti-inflammatory, analgesic and anti-ulcer activities of a novel flavonoid, hypolaetin-8-glucoside, obtained from Sideritis mugronensis, have been tested in the rat. The flavonoid was more potent than phenylbutazone in suppressing the acute phase of adjuvant-carrageenan-induced inflammation, but had less effect in the prolonged inflammatory phase. However, unlike phenylbutazone, it did not cause gastric erosions. Both compounds were equiactive in inhibiting the development of carrageenan-induced abscesses, whereas phenylbutazone had greater analgesic activity in tests on pressure pain threshold. The flavonoid and cimetidine both prevented the formation of cold-restraint induced gastric lesions, but cimetidine was more potent. These results show that hypolaetin-8-glucoside combines both anti-inflammatory and anti-ulcer properties and suggest that it may offer useful alternatives to anti-inflammatory drugs of the aspirin type.

Abscess↗