[The renin-angiotensin system and the sympathetic nervous system in essential hypertension].

In 112 patients with essential hypertension (HTA), free of any therapeutic and receiving the standard ward, a significant inverse relationship was found between age and plasma renin activity (PRA) and plasma aldosterone (PA), measured in the supine and upright position. Urinary epinephrine and norepinephrine were not related with age. When dividing the patients in 4 different age groups, it appeared that those younger than 30 years exhibited a significantly higher PRA and PA values and a higher frequency of borderline hypertension (45 p.

[Relation between dopamine and serotonin motor effects on isolated rat duodenum. Possible participation of an excitatory dopaminergic receptor].

The experimental facts presented here allow us to establish a relationship between DA motor effects on isolated rat duodenum, studied in a previous work, (excito-motor between 10(-9) M and 10(-5) M and inhibitor beyond 10(-5) M) and the functional aptitude of this duodenum to answer to 5-HT : 5-HT excito-motor effects are amplified by DA at concentrations less than or equal to 2.6 X 10(-6) M and on the contrary antagonized by DA at concentrations above 5 X 10(-6) M. On the other hand, DA excito-motor effects do not appear on 5-HT-desensitized duodenums.

Plasma renin activity, aldosterone and dopamine beta-hydroxylase activity as a function of age in normal children.

In 149 children between 6 days and 15 years of age, plasma renin activity (PRA) and aldosterone (PA) were measured by radioimmunoassay and plasma dopamine beta hydroxylase activity (DBH) by the method of Nagatsu. PRA and PA decreased with age from 496 +/- 119 ng/1/min for PRA and 643 +/- 158 pg/ml for PA in 6 to 30 day-old newborns to 37.8 +/- 4.

[Effects of precursors and metabolites of catecholamines on motricity of isolated rat duodenum. Particular reference to dopamine].

Studying the effects, on the isolated rat duodenum motricity, of ten compounds precursors or metabolites of catecholamines, the following results were obtained: The direct metabolites of epinephrine and norepinephrine (metanephrine, normetanephrine), are either ineffective at concentrations below 5 X 10(-6) M, or weakly inhibitory at higher concentrations. Such inhibitory effects are prevented by alpha- and beta-blockers. 3-methoxy, 4-hydroxyphenylglycol and vanylmandelic acid have no significant effect.

The pattern of urinary catecholamines and their metabolites in Duchenne myopathy, in relation to disease evolution.

In this report we have tried to determine whether or not catecholamines are involved in the progressive muscular dystrophy. Catecholamines and their metabolites were studied in urines of children with Duchenne disease or other forms of myopathy (limb-girdle and facio-scapulo humeral myopathies). Catecholamine deaminated metabolites were normal in either form of myopathy; in contrast, Duchenne patients, contrarily to other children, eliminated excessive amounts of most amines (catecholamines and methoxylated amines) in relation to age and degree of disease evolution.

[Role of duodenal serotonin in the pharmacological effects of DOPA and dopamine in the isolated rat duodenum].

We have studied the responsibility of tissue serotonin reserves in the excito-motor effects induced by DOPA and dopamine on the isolated rat duodenum in vitro in certain experimental conditions. Two groups of experiments have been performed: first the determination of serotonin endogenous stores after administration of repeated high doses of DOPA and dopamine in the organ bath, secondly the evaluation of motor effects of DOPA and dopamine on rat duodenums experimentally depleted of their endogenous serotonin stores. Serotonin levels were lowered after DOPA and the excito-motor effect of this compound was suppressed in serotonin-depleted duodenums.

[Cultured cell isolates of the smooth muscle layer from the rat duodenum].

A culture obtained from rat duodenal smooth muscle layer is described. The cells were isolated by trypsinization (0.2%), and the medium used for culture was either MEM with glutamine and non-essential AA or RPMI, both containing 10% foetal calf serum.

[Research on the mechanism of the motor action of dopamine on in vitro isolated rat duodenum].

The study of the direct action of dopamine on the rat duodenum serotoninergic receptors and the parallelism of the results obtained with the motricity curves of this organ in vitro allows us to conclude that dopamine recognizes serotoninergic receptors : the excito- motor effect observed with certain dopamine concentrations on the isolated rat duodenum may be attributed to this action of dopamine on serotoninergic receptors. These results seem in agreement with the observations of other authors.

[Effect of DOPA and dopamine on the motility of isolated rat duodenum in vitro].

The motor effects of DOPA and Dopamine on the isolated rat duodenum in vitro have been studied by establishing successive dose- response curves. These effects are either excitatory or inhibitory according to the concentrations used. In every case they are of small amplitude.

[Culture of cells isolated from the smooth muscle of the rat duodenum].

A culture obtained from rat duodenal smooth muscle layer is described. The cells are isolated by trypsinization (0.2 %) and the medium used for culture is either MEM with glutamine and non essentiel AA, or RPMI, both containing 10 % foetal calf serum.

Plasma renin activity in normal subjects from infancy to puberty.

Immunoassayable Plasma renin activity (PRA) was measured in normal subjects aged from 15 days to 15 years. A very progressive decrease of PRA with age could be demonstrated. Practical conditions for the study of PRA were defined.