“Fluid and cardiovascular regulation: perinatal influences and gender differences responses”.

VIVAS L

Simposio; III INF Summer School in Neuroendocrinology.; 2011

Fluid and cardiovascular regulation: perinatal influences and gender differences responses. Laura Vivas, Ana Fabiola Macchione and Ximena Caeiro. Instituto de Investigación Médica M. y M. Ferrreyra. INIMEC-CONICET, Córdoba, Argentina.     Changes in body water/sodium balance are tightly controlled by the central nervous system (CNS) to avoid an abnormal cardiovascular function and develop of pathological states. This process of sensory integration takes place in different nuclei, with diverse phenotype and at different levels of the CNS and is modulated by different factors such as perinatal history programming or gonadal steroids among them. We will discuss our recent evidence showing how the availability of a rich sodium source during perinatal period modifies the pattern of restoration of fluid balance in the offspring, affecting their drinking behaviour and the neural activity of specific brain neuronal groups. We will also analyze our results supporting the hypothesis that sex chromosomal complement (SCC) is responsible for gender differences in Ang II-bradycardic baroreflex response. To this end, we used the four core genotype mouse model in which gonadal sex is separated from the SCC enabling comparisons among XX and XY females and XX and XY males. This mouse model incorporates a spontaneous mutation of the Sry gene on the Y sex chromosome (referred to as Y−) and a Sry transgene that randomly inserts on an autosome, thus, testes determination is disassociated from SCC. As a result, all individuals possessing the Sry transgene develop testes, regardless of their SCC, while individuals lacking the transgene have ovaries. The resulting genotypes are XX and XY− females (ovary-bearing) along with XXSry and XY−Sry males (testes-bearing). Our evidence demonstrated that baroreflex regulation of heart rate is under the control of XY sex chromosome complement regardless of the gonadal status of the animals.