Gender differences of gene expression profiles in brain cardiovascular centers of WKY rats [nucleus of solitarii tract]

Arterial pressure (AP) is lower in pre-menopausal women than in men of similar age. Pre-menopausal women exhibit a lower sympathetic outflow and a greater baroreceptor reflex, however molecular mechanisms for the gender differences of AP regulation are still not well understood. Since the nucleus tractus solitarius (NTS), a pivotal region of the medulla oblongata for regulating the set-point of AP is strongly associated with the AP level, we hypothesized that a different neuronal functions at the level of the NTS between men and women could contribute to the gender difference in cardiovascular homeostasis. Females Spontaneous Hypertensive Rats (SHRs) clearly exhibit lower AP levels than their male counterparts at similar age and their NTS is characterized by a specific gene expression profile. This gender dependence of AP level is less marked in the normotensive strain, Wistar Kyoto rats (WKY). In this study, we investigated the gender-dependent gene expression profile of the NTS of WKY by using microarray technique. 2 groups of adult WKY rats (9 weeks old) were formed : males (n=5) and females(n=5). NTS was dissected and total RNAs were extracted from each rat. For each group, 100ng of total RNAs from each rats were pooled together before being processed in the microarray experiment.