Sex differences in body fluid homeostasis: Sex chromosome complement influences on bradycardic baroreflex response and sodium depletion induced neural activity

VIVAS, L.; DADAM, F.; CAEIRO, XE

PHYSIOLOGY AND BEHAVIOR

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2015 vol. 152 p. 416 - 421

0031-9384

Clinical and basic findings indicate that angiotensin II (ANG II) differentially modulates hydroelectrolyte and cardiovascularresponses in male and female. But are only the activational and organizational hormonal effects toblame for such differences?Males and females not only differ in their sex (males are bornwith testes and femaleswith ovaries) but also carry different sex chromosome complements and are thus influenced throughout life bydifferent genomes. In this review, we discuss our recent studies in order to evaluate whether sex chromosomecomplement is in part responsible for gender differences previously observed in ANG II bradycardic-baroreflexresponse and sodium depletion-induced sodium appetite and neural activity. To test the hypothesis that XX orXY contributes to the dimorphic ANG II bradycardic-baroreflex response, we used the four core genotypemouse model, in which the effects of gonadal sex (testes or ovaries) and sex chromosome complement (XX orXY) are dissociated. The results indicate that ANG II bradycardic-baroreflex sexual dimorphic response may beascribed to differences in sex chromosomes, indicating an XX-sex chromosome complement facilitatorybradycardic-baroreflex control of heart rate. Furthermore, we evaluated whether genetic differences withinthe sex chromosome complement may differentially modulate the known sexually dimorphic sodium appetiteas well as basal or induced brain activity due to physiological stimulation of the renin?angiotensin systemby furosemideand low-sodiumtreatment. Our studies demonstrate an organizational hormonal effect on sexually dimorphicinduced sodium intake in mice, while at the brain level (subfornical organ and area postrema) weshowed a sex chromosome complement effect in sodium-depletedmice, suggesting a sex chromosomegene participationin the modulation of neural pathways underlying regulatory response to renin?angiotensinstimulation