Influence of 5‐HT1A agonist administration associated with E2 replacement on neuroendocrine in ovariectomized rats (707.11)

Abstract

We intend to examine the effect of repeated use of an agonist of 5‐HT1A receptor in sodium appetitive response in ovariectomized (OVX) rats and investigate the effect of estrogen therapy. Female Wistar rats (n=6‐14) were ovariectomized and formed groups as follow: OVX and OVX + E2 (estradiol cypionate, 80µg/Kg, SC, 14 days) separated in groups of 8‐OH‐DPAT (5‐HT1A receptor agonist, 250µg/Kg, IP, 7 days) or vehicle (0.9% NaCl) in baseline and sodium depletion (furosemide 20mg/kg, SC) protocols. The animals were submitted to following analyses: (i) plasma Na+ (ii) radioimmunoassay to measure oxytocin (OT), vasopressin (AVP), angiotensin II (ANG II) plasma levels. The E2 increased Na+ (P<0.01) plasma levels in OVX‐E2‐8‐OH‐DPAT compared to the OVX‐E2‐OH‐DPAT group in sodium depletion condition. Plasma OT increased (P<0.001) in OVX‐E2‐8‐OH‐DPAT group compared to OVX‐E2 group in baseline condition. OT plasma levels also significantly increased in OVX‐E2 group compared to OVX rats (P<0.01). AVP plasma concentration increased in OVX‐E2‐DPAT group in relation to OVX‐E2 (P<0.001) group following volume depletion. Plasma concentration of ANG II decreased in OVX group compared to OVX‐E2 (P<0.01) group in basal condition. Plasma concentration of ANG II decreased in OVX group compared to OVX‐E2 (P<0.01) group in basal condition. Thus, these results suggest that repeated administration of 5‐HT1A agonist associated with E2 replacement differentially trigger mechanisms for neuroendocrine in electrolyte homeostasis.Grant Funding Source: FAPERJ, CNPq and CAPES