PubMed Health⌕ Search

Biomedical subjects

A Cariani

Publications and source records attributed to A Cariani.

41 records · Page 3Linked to original sources
PubMedDate not supplied

[Dopamine, catecholamine receptors, and neurohumoral regulation of renal function].

Were studied in healthy human subjects under conditions of hydro-saline retention the intrarenal mechanism underlying the hydronatriuretic effect of Dopamine (DA) and the changes in DA renal effects induced by Sulpiride (S). DA was infused i.v. in a subpressor dose (0,1 microgram/kg . min) during induced hypotonic polyuria. In each experiment four clearance periods of 15 min were performed; DA was administered during the second and third clearance periods. The glomerular filtration rate and renal effective plasma flow were estimated as endogenous creatinine and PAH clearances, respectively. Tubular sodium and potassium reabsorptions were also determined. 1) In the state of hydro-saline retention, renal arteriolar (mainly preglomerular) vasodilation was produced by DA. Moreover, both sodium isosmotic reabsorption as a percentage of sodium filtered load and sodium anisosmotic reabsorption as a percentage of sodium distal load were inhibited. These tubular inhibitions were found to be correlated with the haemodynamic effects of DA. 2) Sulpiride treatment (4,4 mg/kg . day given orally for two days prior to the experiment and 100 mg i.m. 40 min before DA infusion) caused (a) an increase in the hydro-natriuretic response to hydration during control clearance and (b) a decrease in DA haemodynamic effects. An interpretation is proposed accounting for these DA effects as well as for dependence of DA renal effects on the extracellular fluid volume.

Adult↗
PubMedDate not supplied

[Dopamine as a regulator of natriuresis. Experimental bases and their implications].

Renal effects of dopamine (DA) infused i.v. in a subpressor dose (0.1 microgram. kg.-1 min-1) were investigated in healthy human subjects during steady hypotonic polyuria. In each experiment four clearance (cl.) periods of 15 min were performed; DA was administered during the second and the third cl. periods. The glomerular filtration rate and renal effective plasma flow were estimated as endogenous creatinine and PAH clearances. Moreover the following variables were evaluated: a) sodium total and sodium isosmotic reabsorption as a % of sodium filtered load (s.f.l.); b) sodium anisosmotic reabsorption as a % of sodium distal load (s.d.l.); c) total renal vascular resistance (RT), arteriolar afferent (RA) and efferent (RE) resistances. Three groups of experiments were performed: A) in hydro-saline retention by DOCA pretreatment (24 subjects); B) in hydro-saline depletion by natriuretic pretreatment (20 subjects); C) in hydro-saline depletion and beta-adrenergic blockade induced by natriuretic and propranolol pretreatments (9 subjects). In A experimental condition DA significantly increased renal plasma flow, glomerular filtration rate, urinary flow, urine sodium concentration and osmolarity; on the contrary DA significantly decreased RT, RA, sodium total and isosmotic reabsorption, % of s.f.l., and sodium anisosmotic reabsorption, % of s.d.l. In B condition no significant changes were observed during DA infusion in either haemodynamic parameters or urinary flow; on the other hand DA significantly blunted urinary osmolarity, urinary sodium concentration and sodium excretion rate suggesting an increased sodium anisosmotic reabsorption (% of s.d.l.). In C condition the vasodilating and hydrosaluretic effects of DA were restored. Our results suggest that DA activates, besides "dopaminic" vascular receptors, the presynaptic facilitory beta-adrenergic receptors in renal adrenergic pathways. Thus the renal action of DA depends on renal adrenergic activity.

Adult↗