Ricardo P. Garay

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1. At high internal K concentrations the efflux of Na from red cells increases with internal Na concentration following an S-shaped curve. As internal K is reduced the S-shaped region and the value of internal Na for which the Na efflux is half-maximal are both shifted progressively towards zero.2. The effects of internal Na on the shape of the Na efflux(More)
A screening of several families of compounds on NEM-stimulated K+ efflux in human red cells allowed us to select a [(dihydroindenyl)oxy] alkanoic acid (DIOA) as the first potent inhibitor of this K+ flux (IC50 of 10(-5) M) without side effects on the bumetanide-sensitive [Na+,K+,Cl-]-cotransport system. Incubation of human red cells in hypotonic media (179(More)
5-HT(2A) receptor antagonism seems to explain the low incidence of extrapyramidal side effects with atypical neuroleptics. Whether the neuroleptic cyamemazine, which at low doses is also devoid of extrapyramidal side effects, possesses 5-HT(2A) receptor antagonist properties is unknown. Cyamemazine was tested for its ability to antagonize 5-HT(2A)-mediated(More)
Iminodibenzyl-, iminostilbene-, dibenzocycloheptadiene-, dibenzooxepine- and dibenzothiepine-derivatives of tricyclic antidepressant drugs were able to inhibit Na+-stimulated Mg2+ efflux in human erythrocytes at concentrations of 10−5−10−3 mol/l. Tricyclic antidepressant drugs belonging to other chemical groups, non-tricyclic antidepressant drugs and(More)
Animal studies indicate that the anxiolytic properties of the antipsychotic agent cyamemazine may result from blockade of serotonin 5-HT(2C) receptors and to a lesser extent from blockade of serotonin 5-HT(3) receptors. Here, we used human recombinant receptors to determine the relative affinity of cyamemazine for serotonin and dopamine receptor subtypes.(More)
In 50 normotensive controls, the increase in erythrocyte Na+ concentration up to 12.4 +/- 2.0 mmol/l cells (mean +/- SD) ensures half-maximal stimulation of outward Na+,K+ cotransport fluxes. Forty-six out of sixty-five patients with essential hypertension required more than 16 mmol/l cells of internal Na+ concentration to obtain a similar effect, strongly(More)
Net fluxes of sodium and potassium ions were determined in sodium-loaded, potassium-depleted erythrocytes from 370 white subjects, 194 of whom had essential hypertension or had been born to parents with essential hypertension. Findings were compared with those in 86 controls who were normotensive and did not have a family history of hypertension. Compared(More)
This paper reports some kinetic properties of Na−K cotransport in human red cells. All fluxes were measured in the presence of 10−4 M ouabain. We measured Na and K efflux from cells loaded by the PCMBS method to contain different concentrations of these ions into a medium that contained neither Na nor K (MgCl2-sucrose substitution) in the absence and(More)
An abnormally low sodium-potassium net flux ratio in erythrocytes was recently described in human essential hypertension. We have confirmed this finding in 65 patients with essential hypertension who were compared with 33 normotensive controls born of normotensive parents. In 23 other subjects with documented secondary hypertension and normotensive parents,(More)