de Castilhos Juliana, Forti Claudia D, Achaval Matilde, Rasia-Filho Alberto A
Department of Morphological Sciences, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Brain Res. 2008 Nov 13;1240:73-81. doi: 10.1016/j.brainres.2008.09.002. Epub 2008 Sep 12.
The posterodorsal medial amygdala (MePD) is a sex steroid-responsive area in the rat brain. The dendritic spine density of Golgi-impregnated MePD neurons were studied in: (1) adult gonadectomized (GDX) males after a short or a longer postcastration period (8 and 90 days, respectively), compared to age-matched sham operated and to intact controls; (2) adult GDX females, which received oil, estradiol benzoate (EB) alone or EB and progesterone as substitutive therapy; and, (3) EB-treated GDX females that concomitantly received saline or LY235959, a competitive antagonist of NMDA receptors, to test a possible glutamatergic mediation on the estrogen-mediated increase in spine density in this brain area. Intact males showed a higher spine density than males studied 8 days after sham operation or those in both short- and long-term GDX groups (p<0.02), but not when compared to males at 90 days after sham operation (p=0.12). In females, dendritic spine density increased following EB injections when compared to the oil group (p=0.05), with an effect that was potentiated by progesterone (p<0.01). LY235959 was not able to block the stimulating effect of EB on dendritic spines of GDX females (p>0.2). These data provide novel evidence that MePD dendritic spines are affected by sex steroid manipulations in adult rats, GDX males had a specific spine density decrease after a long postcastration period, and estrogen (apparently independently of a NMDA receptor interaction) and progesterone have stimulatory effects on the number of dendritic spines in GDX females.
杏仁核后内侧背侧区（MePD）是大鼠脑中一个对性类固醇有反应的区域。我们研究了高尔基染色的MePD神经元的树突棘密度，研究对象包括：（1）成年去势雄性大鼠，在短时间（8天）或长时间（90天）去势后，与年龄匹配的假手术组和完整对照组进行比较；（2）成年去势雌性大鼠，分别接受油剂、单独的苯甲酸雌二醇（EB）或EB与孕酮作为替代疗法；以及（3）接受EB治疗的去势雌性大鼠，同时给予生理盐水或LY235959（一种NMDA受体竞争性拮抗剂），以测试谷氨酸能在该脑区雌激素介导的树突棘密度增加中可能的介导作用。完整雄性大鼠的树突棘密度高于假手术8天后研究的雄性大鼠或短期和长期去势组的雄性大鼠（p<0.02），但与假手术90天后的雄性大鼠相比则无差异（p=0.12）。在雌性大鼠中，与油剂组相比，注射EB后树突棘密度增加（p=0.05），孕酮可增强这种作用（p<0.01）。LY235959不能阻断EB对去势雌性大鼠树突棘的刺激作用（p>0.2）。这些数据提供了新的证据，表明成年大鼠中MePD的树突棘受性类固醇操纵的影响，去势雄性大鼠在长时间去势后树突棘密度有特定降低，雌激素（显然独立于NMDA受体相互作用）和孕酮对去势雌性大鼠的树突棘数量有刺激作用。
