1,721,569 research outputs found
Renin-angiotensin system unresponsiveness in pheochromocytoma
No full textRenin-angiotensin system unresponsiveness in phaeochromocytoma.
Coruzzi P, Musiari L, Biggi A, Mossini GL, Novarini A.
SourceInstitute of Semeiotica Medica, University of Parma, Italy.
Abstract
Water immersion to the neck is able to provoke a profound suppression of the renin-angiotensin system in several clinical conditions associated with hyper-reninaemia. Both hyper-reninaemia and secondary aldosteronism have sometimes been described in phaeochromocytoma. We report on two patients, with surgically proven phaeochromocytoma, in whom water immersion, performed before surgery, failed to induce any significant change in plasma renin activity
Renin aldosterone system suppression during water immersion in renovascular hypertension
No full textRenin-aldosterone system suppression during water immersion in renovascular hypertension.
Coruzzi P, Biggi A, Musiari L, Ravanetti C, Novarini A.
Abstract
We studied renin-aldosterone system behaviour in five renovascular hypertensive patients during central hypervolaemia by water immersion to the neck. Water immersion significantly suppressed the high peripheral renin levels of the patients despite an autonomic renin secretion from the stenotic kidney, a significant reduction of mean blood pressure and an increase in distal tubule sodium concentration. The effect of immersion on plasma aldosterone appeared to be primarily mediated via suppression of plasma renin activity (PRA). Our data suggest that: (a) the renin secretion is mainly modulated by cardiopulmonary receptors activity; (b) the neurogenic reflex control of plasma renin activity is very effective in renovascular hypertension
Low-pressure receptor activity and exaggerated natriuresis in essential hypertension
No full textLow-pressure receptor activity and exaggerated natriuresis in essential hypertension.
Coruzzi P, Novarini A, Biggi A, Lazzeroni E, Musiari L, Ravanetti C, Tagliavini S, Borghetti A.
Abstract
Urinary sodium excretion, central hemodynamics, and mean arterial pressure (MAP) were studied in 7 normal subjects and 19 hypertensive patients during both central hypervolemia by water immersion to the neck (NI) and extracellular volume expansion by i.v. saline infusion. During 2-hour NI, 12 out of the 19 hypertensives exhibited a significant fall in MAP (p less than 0.001). Exaggerated natriuresis did not occur in these patients (ns). In the remaining 7 hypertensive patients in whom, during NI, MAP was unchanged, exaggerated natriuresis was found (p less than 0.001). During saline infusion, MAP was either unchanged or increased and exaggerated natriuresis was found in all hypertensive patients (p less than 0.001) previously submitted to NI. Our findings suggest that a high MAP is a major determinant of exaggerated natriuresis in arterial hypertension
Dopamine blockade and natriuresis during water immersion in normal man
No full textDopamine blockade and natriuresis during water immersion in normal man.
Coruzzi P, Biggi A, Musiari L, Ravanetti C, Vescovi PP, Novarini A.
Abstract
Natriuresis was studied during water immersion in eight normal subjects either in the absence or in the presence of dopamine blockade by domperidone. Creatinine clearance showed no significant changes; urine flow remained significantly above control values during water immersion, implying persistent suppression of antidiuretic hormone. The marked natriuresis seen during water immersion alone was significantly blunted (P less than 0.05) but not abolished during water immersion plus domperidone. Suppression of the renin-aldosterone system by water immersion alone was not significantly different from that obtained during water immersion plus dopamine blockade. On the contrary, plasma prolactin levels, previously suppressed during water immersion alone, were significantly stimulated during water immersion plus domperidone, thus indirectly suggesting a role of dopamine in mediating the blunted natriuresis seen during water immersion
Circulating opioid peptides during water immersion in normal man
No full textCirculating opioid peptides during water immersion in normal man.
Coruzzi P, Ravanetti C, Musiari L, Biggi A, Vescovi PP, Novarini A.
SourceIstituto di Semeiotica Medica, University of Parma, Italy.
Abstract
1. This study was designed to evaluate variations in plasma beta-endorphin, methionine-enkephalin, adrenocorticotropic hormone and serum prolactin in healthy volunteers during head-out water immersion. 2. Water immersion induced an increase in methionine-enkephalin plasma levels, which was associated with a significant fall in mean arterial pressure and heart rate. 3. Conversely, a suppression of plasma beta-endorphin, adrenocorticotropic hormone and serum prolactin was detected during water immersion. 4. We suggest that a dopaminergic inhibitory control mechanism may be involved in regulating circulating levels of beta-endorphin, adrenocorticotropic hormone and prolactin in normal subjects undergoing extracellular fluid volume expansion produced by water immersion
Pertinenze tra gli obiettivi professionali ed i bisogni della salute nell'educazione e formazione medica
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