Condé G L, Herbison A E, Fernandez-Galaz C, Bicknell R J
Laboratory of Neuroendocrinology, Babraham Institute, Cambridge, UK.
Brain Res. 1996 Oct 7;735(2):197-207. doi: 10.1016/0006-8993(96)00611-7.
The preoptic area of the rat brain is a site at which gonadal steroids act to regulate sexual behaviour and gonadotrophin secretion. The expression of the immediate-early gene product, Fos, in the preoptic area was investigated in conscious ovariectomised, vehicle and estrogen-treated animals which had received an intracerebroventricular (i.c.v.) infusion of noradrenaline, and also in anaesthetised proestrous and ovariectomised rats following electrical stimulation of the brainstem A1 or A2 noradrenergic cell groups. In ovariectomised oil-treated rats, a third ventricular infusion of noradrenaline (45 micrograms) resulted in a significant (P < 0.05) increase in the numbers of Fos-immunoreactive cell nuclei throughout the preoptic area, compared to vehicle controls. In contrast, Fos expression in animals which had received estrogen replacement showed no change in response to i.c.v. noradrenaline compared with saline-treated controls. In anaesthetised, ovariectomised animals electrical stimulation of the A1 cell group resulted in a significant increase (P < 0.05) in Fos-like immunoreactivity compared with sham controls, specifically within the ventral preoptic area whilst stimulation of the A2 cell group had no significant effect. In anaesthetised, proestrous rats receiving electrical stimulation no significant changes in Fos-like immunoreactivity were detected within the preoptic area after either A1 or A2 stimulation compared with paired controls. These results show that noradrenaline-induced Fos expression in the preoptic area is dependent on estrogen status and suggest that the estrogenic regulation of reproductive functions may thus involve altered responses to noradrenaline in sub-populations of preoptic neurones.
大鼠脑的视前区是性腺类固醇作用于调节性行为和促性腺激素分泌的部位。在清醒的去卵巢、接受载体处理和雌激素处理的动物中，研究了视前区即刻早期基因产物Fos的表达，这些动物接受了脑室内（i.c.v.）注入去甲肾上腺素，同时也研究了在麻醉的动情前期和去卵巢大鼠中，电刺激脑干A1或A2去甲肾上腺素能细胞群后的情况。在去卵巢并用油处理的大鼠中，与载体对照组相比，向第三脑室注入45微克去甲肾上腺素导致整个视前区Fos免疫反应性细胞核数量显著增加（P<0.05）。相反，与盐水处理的对照组相比，接受雌激素替代的动物中Fos表达对i.c.v.去甲肾上腺素无反应变化。在麻醉的去卵巢动物中，与假手术对照组相比，电刺激A1细胞群导致Fos样免疫反应性显著增加（P<0.05），特别是在腹侧视前区内，而刺激A2细胞群则无显著影响。在麻醉的动情前期大鼠中，与配对对照组相比，在A1或A2刺激后，视前区内未检测到Fos样免疫反应性的显著变化。这些结果表明，去甲肾上腺素诱导的视前区Fos表达取决于雌激素状态，并提示生殖功能的雌激素调节可能因此涉及视前神经元亚群对去甲肾上腺素反应的改变。
