Gordon J H, Nance D M, Wallis C J, Gorski R A
Brain Res Bull. 1979 Jan-Feb;4(1):85-9. doi: 10.1016/0361-9230(79)90062-5.
Septal lesions (SL) in female rats result in an increased sensitivity to the behavioral effects of acute estradiol benzoate (ACUTE-EB; 2 microgram/day X 3) treatment as measured by the lordosis quotient (LQ: number of lordotic responses X 100/number of mounts). Male rats, intact or castrated, do not show this enhanced behavioral response to ACUTE-EB unless they are treated with EB (2 microgram/day) for 2--4 weeks immediately following the production of SL. The present study was undertaken to examine possible neurochemical alterations which could account for the enhanced behavioral sensitivity to ACUTE-EB seen in the SL male rat treated chronically with EB during the postlesion period (SL-EB). Three groups, normal males, SL-EB and SL males chronically treated with oil (SL-oil), were subdivided and treated with ACUTE-EB or oil and decapitated. The brains were removed, frozen and stored at -50 degrees C prior to dissection and assay. Tyrosine hydroxylase (TH) activity was assayed in the dopamine (DA) rich areas of the forebrain (striatum, STR, nucleus accumbens septi, ACB; and olfactory tubercle). The TH activity was significantly suppressed in both the STR and ACB of the SL-EB males treated with ACUTE-EB. The glutamic acid decarboxylase (GAD) activity in both the substantia nigra and ventral tegmentum was significantly increased in the SL-EB males given ACUTE-EB relative to that of all other groups. In summary, SL-EB males given ACUTE-EB show (1) an enhanced LQ, (2) decreased TH activity in the region of DA terminals, and (3) increased GAD activity in the region of DA cell bodies. The increase in GAD activity is suggested to be a result of an altered neuronal feedback because of plastic changes that occur during chronic EB treatment following production of SL. This probable increase in inhibitory tone in the region of the DA cell bodies may explain the observation that the SL-EB male exhibits decreased DA turnover following ACUTE-EB treatment. Moreover, since DA may be inhibitory to the display of lordosis behavior, the SL-EB males may show an enhanced LQ, at least partially, because of this reduction in DA activity.
雌性大鼠的中隔损伤（SL）会导致对急性苯甲酸雌二醇（ACUTE-EB；2微克/天×3）治疗行为效应的敏感性增加，这通过脊柱前凸商数（LQ：脊柱前凸反应次数×100/爬跨次数）来衡量。完整或阉割的雄性大鼠，除非在产生SL后立即用EB（2微克/天）治疗2至4周，否则不会表现出对ACUTE-EB这种增强的行为反应。本研究旨在检查可能的神经化学改变，这些改变可以解释在损伤后用EB长期治疗的SL雄性大鼠（SL-EB）中观察到的对ACUTE-EB增强的行为敏感性。将三组，正常雄性、SL-EB和用橄榄油长期治疗的SL雄性（SL-油）进行细分，并用ACUTE-EB或橄榄油处理后断头。取出大脑，冷冻并在-50℃下储存，然后进行解剖和检测。在前脑富含多巴胺（DA）的区域（纹状体、STR、伏隔核、ACB；和嗅结节）检测酪氨酸羟化酶（TH）活性。在用ACUTE-EB处理的SL-EB雄性大鼠的STR和ACB中，TH活性均显著受到抑制。相对于所有其他组，给予ACUTE-EB的SL-EB雄性大鼠黑质和腹侧被盖区的谷氨酸脱羧酶（GAD）活性均显著增加。总之，给予ACUTE-EB的SL-EB雄性大鼠表现出（1）增强的LQ，（2）DA终末区域TH活性降低，以及（3）DA细胞体区域GAD活性增加。GAD活性的增加被认为是由于SL产生后慢性EB治疗期间发生的可塑性变化导致神经元反馈改变的结果。DA细胞体区域这种可能的抑制性张力增加可以解释在ACUTE-EB治疗后SL-EB雄性大鼠表现出DA周转减少的现象。此外，由于DA可能对脊柱前凸行为的表现具有抑制作用，SL-EB雄性大鼠可能至少部分地由于DA活性的降低而表现出增强的LQ。
