INIMEC - CONICET   05467
INSTITUTO DE INVESTIGACION MEDICA MERCEDES Y MARTIN FERREYRA
Unidad Ejecutora - UE
artículos
Título:
Serotonergic mechanisms of the lateral parabrachial nucleus in renal and hormonal responses to isotonic blood volume expansion.
Autor/es:
MARGATHO OLIVEIRA, L.; GIUSTI-PAIVA, A.; MENANI, J.V.; KAGOHARA ELIAS K., L.K.; VIVAS, L.; ANTUNES-RODRIGUES.
Revista:
AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY, INTEGRATIVE AND COMPARATIVE PHYSIOLOGY
Referencias:
Año: 2007 vol. 292 p. 1190 - 1197
ISSN:
0363-6119
Resumen:
This study investigated the involvement of serotonergic mechanisms of the lateral parabrachial
nucleus (LPBN) in the control of sodium (Na+) excretion, potassium
(K+) excretion, and urinary volume in unanesthetized rats subjected
to acute isotonic blood volume expansion (0.15 M NaCl, 2 ml/100 g
of body wt over 1 min) or control rats. Plasma oxytocin (OT),
vasopressin (VP), and atrial natriuretic peptide (ANP) levels were also
determined in the same protocol. Male Wistar rats with stainless steel
cannulas implanted bilaterally into the LPBN were used. In rats
treated with vehicle in the LPBN, blood volume expansion increased
urinary volume, Na+ and K+ excretion, and also plasma ANP and
OT. Bilateral injections of serotonergic receptor antagonist methysergide
(1 or 4 ug/200 nl) into the LPBN reduced the effects of blood
volume expansion on increased Na+ and K+ excretion and urinary
volume, while LPBN injections of serotonergic 5-HT2a/HT2c receptor
agonist, 2.5-dimetoxi-4-iodoamphetamine hydrobromide (DOI; 1 or 5
ug/200 nl) enhanced the effects of blood volume expansion on Na+
and K+ excretion and urinary volume. Methysergide (4 ug) into the
LPBN decreased the effects of blood volume expansion on plasma
ANP and OT, while DOI (5 ug) increased them. The present results
suggest the involvement of LPBN serotonergic mechanisms in the
regulation of urinary sodium, potassium and water excretion, and
hormonal responses to acute isotonic blood volume expansion.