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Biomedical subjects

E Rubio

Publications and source records attributed to E Rubio.

At least 91 records · Page 5Linked to original sources
PubMed1988

Effect of domperidone on the contractility of isolated guinea-pig atria.

This study was undertaken to investigate whether or not dopamine receptors are responsible for the cardiac action of domperidone and to gain a better understanding of the mechanism of the cardiac effects of this compound. In isolated electrically driven guinea-pig atria, domperidone (0.1-30 microM) produced a negative inotropic effect (-56.7 +/- 4.9% at 30 microM) and at a concentration of 0.1 microM significantly decreased the positive inotropic response to histamine (0.5-271 microM). In spontaneously beating guinea-pig atria, domperidone failed to modify the chronotropic responses elicited by dopamine and noradrenaline. In the isolated guinea-pig ileum, domperidone alone did not produce any effect, but produced a right-ward displacement of the contractile dose-response curve to histamine. At concentrations of 0.01, 0.1 and 1 microM, domperidone also depressed the maximum response to histamine. The results obtained suggest that the negative inotropic effect of domperidone is not due to dopamine or adrenergic receptor antagonism. This cardiac effect of domperidone can be partially explained by its influence on the effects of histamine acting on H1-receptors, although other mechanisms may be involved.

Animals↗
PubMed1987

The lack of the effect of DA-1 and DA-2 dopamine agonists on the isolated guinea-pig atria.

1 The effects of dopamine and both DA-1 and DA-2 dopamine receptor agonists have been studied on the contractile force of electrically driven guinea-pig left atria and frequency of spontaneously beating right atria. 2 Pretreatment of animals with reserpine caused a parallel rightward shift of the concentration-response curve to dopamine of either preparation. 3 Propranolol, but not domperidone, shifted to the right the dose-response curve for the positive inotropic and chronotropic effects of dopamine. 4 Neither apomorphine, fenoldopam, bromocriptine nor piribedil had effects on the frequency and contractile force of the isolated guinea-pig atria. 5 These results suggest that DA-1 and DA-2 dopamine receptors are neither directly nor indirectly (prejunctional effect) involved in the inotropic and chronotropic effects of dopamine in isolated guinea-pig atria.

Animals↗
PubMed1986

Chronic alcoholism. Frequently overlooked cause of osteoporosis in men.

A radiographic survey was made of 96 fully ambulatory male patients who were admitted to a rehabilitation center for patients with chronic alcoholism in an attempt to estimate the incidence of skeletal demineralization in these patients. The age of the patients ranged from 24 to 62 years. Forty-five of the 96 male patients, or 47 percent of this group, showed radiographic evidence of extensive bone loss. Fourteen or 31 percent of these 45 patients with bone loss were relatively young (age 31 to 45 years), and half of this group of 14 patients were less than 40 years old. The majority of the 45 patients with radiographic evidence of osteoporosis, namely, 31 patients or 69 percent, were older and ranged in age from 46 to 62 years. One third of the patients in this group were less than 50 years old. The radiographic survey of the 96 patients indicates the high incidence of extensive bone loss, most likely osteoporosis, in relatively young and middle-aged ambulatory men with chronic alcoholism. In 12 additional patients with chronic alcoholism who were observed in the Metabolic Research Ward, and who were not part of this survey, bone biopsy specimens confirmed the radiographic diagnosis of osteoporosis.

Adult↗
PubMed1986

Pharmacological investigation into the effects of histamine and histamine analogues on guinea-pig and rat colon in vitro.

The effects of histamine and specific histamine agonists has been examined on isolated longitudinal colon strips of guinea-pig and rat. Histamine and 2-pyridyl-ethylamine but not 4 methylhistamine produced a concentration-related contractile response in the guinea-pig colon. The H1-antagonist clemizole antagonized competitively the effect of histamine but the H2-antagonist ranitidine did not modify the dose-response curve to histamine in the guinea-pig colon. Atropine, hexamethonium, prazosin and propranolol failed to modify the contractile response to histamine. Tone induced with KCl in guinea-pig isolated colon was not modified by histamine agonists even in tissues pretreated with clemizole or ranitidine. Histamine and histamine analogues were without effect on the isolated longitudinal strip of the rat colon. It is concluded that histamine produced dose-dependent contractions of the guinea-pig colon due to direct activation of H1-histamine receptors. There is no evidence in favour of the existence of H2-histamine receptors in this preparation. The lack of effect of histamine agonists in rat colon strip argues against the existence of histamine receptors in this preparation.

Animals↗
PubMed1985

Effect of verapamil and diltiazem on isolated gastro-oesophageal sphincter of the rat.

The effect of verapamil and diltiazem on the contraction induced by agonists on the rat lower oesophageal sphincter in-vitro has been studied. Both calcium entry blockers inhibited the contractile response to acetylcholine, carbachol and KCl. The potency of the inhibitory action was diltiazem greater than verapamil. The results give substance to the use of calcium entry blockers in the treatment of oesophageal spasm.

Animals↗
PubMed1985

Effect of methoxamine on spontaneous motility of the isolated rat uterus.

In the present study the effect of methoxamine and its modification by several adrenergic antagonists is described in the isolated oestrogenized rat uterus. Methoxamine produced a dose-related increase in uterine activity, prazosin produced a rightward displacement of the dose-response curve of methoxamine reaching the same maximal effect. Yohimbine abolished the contractile response to methoxamine. propranolol or reserpine failed to modify the effect of methoxamine. Pretreatment with reserpine abolished the inhibitory effect of yohimbine. These results suggest the presence of excitatory alpha-adrenoceptors in the rat uterus.

Adrenergic alpha-Agonists↗
PubMed1984

The inhibitory effect of histamine on the motility of rat uterus in vivo.

The experiments concerned the effects of histamine and its analogs 4-methylhistamine and 2-pyridyl-ethylamine on the spontaneous activity of the estrogenized rat uterus in vivo. These agonists given intravenously inhibited uterine activity. Histamine and 4-methylhistamine, but not 2-pyridyl ethylamine, produced this effect in a dose-dependent manner. The ability of histamine to reduce uterine activity was lowered by pretreatment with reserpine, adrenalectomy or 6-hydroxydopamine. The effect of 4-methylhistamine also was reduced by reserpine or adrenalectomy. The inhibitory effect of 2-(2-pyridyl) ethylamine was completely abolished by reserpine or adrenalectomy. Cimetidine attenuated the residual inhibitory effect of histamine in reserpinized rats. These results suggest that the uterine inhibitory action of histamine and 4-methylhistamine is mediated through catecholamine release and direct stimulation of the H2-receptors. The effect of 2-(2-pyridyl) ethylamine is only mediated by release catecholamine.

Adrenalectomy↗
PubMed1984

Hypotensive action and alpha-adrenolytic properties of a new dopaminergic agonist, CU 32-085, in the rat.

The effect of an 8-alpha-amino-ergoline-derivative, CU 32-085, recently characterized as a dopamine agonist, was studied on blood pressure and heart rate in normotensive anesthetized rats. The effects of CU 32-085 and bromocriptine on dose-response curves to sympathomimetic agents (adrenaline, noradrenaline, methoxamine and clonidine), intravenously administered, were also studied. CU 32-085 slowed heart rate and lowered blood pressure. The hypotensive effect was antagonized by pretreatment with sulpiride. CU 32-085 and bromocriptine reduced the pressor effect of adrenaline, noradrenaline and methoxamine and the hypotensive action of clonidine. These results suggest that the hypotensive action of CU 32-085, like bromocriptine, is mainly due to an action on dopaminergic receptors. In addition, the data obtained with sympathomimetic agents suggest that CU 32-085 is a compound with mixed alpha 1 and alpha 2 antagonist properties, similar to bromocriptine.

Adrenergic alpha-Antagonists↗
PubMed1983

Giant calcified aneurysm on the posterior cerebral artery in a nine-year-old child.

We report the case of a 9-year-old child in whom, after a plain x-ray examination of the skull was performed for a suppurating otitis in the left ear, a calcified lesion was discovered in the left temporal region. Angiographic study showed it to be an aneurysm of the left posterior cerebral artery. The rarity of these lesions is discussed, as well as the successful surgical treatment in this case.

Calcinosis↗