引用

怀孕的特点是血容量增加和基本交感神经活动增加，以及深刻的心血管适应。松弛素(RLX)是一种卵巢激素，在怀孕期间升高，激活与控制血容量和交感神经活动相关的下形器官(SFO)和下丘脑区域。本实验对RLX激活的下丘脑室旁核(PVN)和视上核(SON)细胞进行了表型分析。在怀孕(P)和未怀孕(NP)的雌性大鼠脊髓中外侧柱预先微量注射逆行运输的荧光示踪剂(90nl)来标记PVN中的脊髓突出细胞。5天后，将人rlx2 (1 μg/hr)或生理盐水(SAL, 1 ml/hr)注入清醒大鼠前脑循环(颈动脉内)(1.5 hr)。RLX显著提高NP大鼠的心率(+50±5)和短暂性提高平均动脉压(+13±1 mmHg)，而SAL没有影响(+0.5±2 mmHg)。RLX或SAL对P大鼠的血流动力学无明显影响。大鼠被安乐死，大脑切片，并评估Fos-(神经元激活指数)，抗利压素(AVP-)和脊髓投射神经元。NP大鼠RLX后，SFO侧缘细胞表达Fos-IR，与pvn投射神经元的激活一致。颈动脉内RLX激活了NP大鼠21±5%的AVP-IR细胞和19±2%的脊髓投射细胞(Fos-IR)。 Fos-IR was not significantly increased in SAL treated rats, or in pregnant rats after either treatment. These data provide an anatomical substrate for a role of RLX in adaptations in regulation of blood volume (activation of AVP cells) and sympathetic nerve activity (activation of spinally projecting cells). In P rats, lack of response to exogenous RLX, might be due to pre-existing maximum activation by elevated endogenous levels of RLX.