THE ONSET OF SODIUM APPETITE: ROLE OF OXITOCINERGIC AND SEROTONERGIC CENTRAL SYSTEMS

C. PORCARI; MECAWI A; REIS L; ANTUNES-RODRIGUES J; CAEIRO XE; L VIVAS; ANDREA GODINO

Workshop; ?The neurohumoral control of body fluid and cardiovascular homeostasis in males and females - vive la difference!?; 2019

A temporal dissociation exists between sodium depletion(SD) and the appearance of sodium appetite(SA), and an inhibitory modulation can be postulated. Previous studies demonstrated the inhibitory participation of serotonergic(5-HT) and oxytocinergic(OT) neurons on SA induced by SD. Our aim was to evaluate during the delay of SA appearance after SD, gene expression changes of different components of central OT and 5HT systems. Wistar rats were SD using furosemide combined with low sodium diet, and then at 2h or 24h later the animals were decapitated. Specific brain areas: dorsal raphe nucleus(DRN), subfornical organ(SFO), lateral parabrachial(LPBN) and anteroventral area of third ventricule plus supraoptic nucleus(AV3V+SON), were submitted to RT-PCR of oxytocin receptor(OTR), serotonin 2A receptor(5HT2A), tryptophan hydroxylase 2(TPH2) and serotonin transporter (SERT). OTR mRNA expression significantly increases(p=0.045) early at 2 hs after SD along AV3V+SON in comparison to control and 24 h SD groups. Also, the OTR mRNA expression along the DRN, decreasing 24 h after SD in relation to control and 2h SD groups, but this differences did not reach significant levels(p=0.06). Non-significant changes in the SERT and TPH2 mRNA expression were find along the DRN or the 5HT2A mRNA expression in the LPBN and SFO. In sum, our results suggest that OT circuit acting thought its receptors along nuclei previously involved in the regulation of sodium appetite may modulate SA appearance.