TRPV1 osmosensitive channel involvement in the control of sodium appetite

GODINO A; PORCARI C; DEBARBA LK; CAEIRO X; REIS. L; MECAWI, A; ANTUNES-RODRIGUES J.; VIVAS L.

Acapulco

Simposio; 22nd International Symposium on Regulatory Peptides.; 2019

International Symposium on Regulatory Peptides.

There is a temporal dissociation between sodium depletion (SD) and theappearance of sodium appetite (SA) behavior. After an acute SD, the natremiadecreases immediately however SA takes at least 16 h to appear. Our recentresults demonstrated in Wistar rats that the transient receptor potential vanilloidtype 1 (TRPV1) channel, required for normal osmoregulation, is involved in SAcontrol. The TRPV1 mRNA expression was increased in the kidney andpreviously involved brain nuclei, during the delay of SA (2 h after SD) andsignificantly decreased during the appearance of SA (24 h after SD), possiblyallowing the hypertonic sodium consumption. The aim of the present work wasto evaluate in TRPV1 knockout mice (KO), sodium intake and the urinarypattern of renal excretion at different times after SD. In particular, we analyzedthe sodium and water intake and the renal response at 2 h and 24 h after SDinduced by furosemide (50mg/kg) in combination with low sodium diet in wildtype (WT) and KO mice.After SD, the KO animals showed an increase in the sodium preference(F=8.49; p=0.006) and consumed a higher hypertonic cocktail (F=8.49;p=0.0059) in relation to WT animals, independent of the time after SD. Thesedata suggest that KO animals, when stimulated to drink water and sodium,make a hypertonic cocktail instead of the isotonic one usually made by thecontrol animals. The urinary volume (F=5.45; p=0.0003) and sodium excretion(F=3.99; p=0.028) induced by Furosemide at 30 minutes were both reduced inKO animals in comparison to WT. There was no change in plasma osmolalitybetween the groups 2 h and 24 h after SD.In sum, these data suggest that the TRPV1 channels are involved in theosmoregulatory behavioral and renal responses after acute body SD.