Wagner C K, Sisk C L, Clemens L G
Department of Zoology, Michigan State University, East Lansing 48824, USA.
J Neuroendocrinol. 1993 Oct;5(5):545-51. doi: 10.1111/j.1365-2826.1993.tb00520.x.
The location and distribution of estradiol-concentrating neurons in the hypothalamus afferent to segments of lumbar spinal cord that contain the sexually dimorphic spinal nucleus of the bulbocavernosus (SNB) were determined by combining retrograde fluorescent tract tracing with steroid hormone autoradiography. Injections of Fluorogold were made into segments of L5-L6 of the spinal cord of adult male rats and 12 days later animals were castrated. One week following castration, males received injections of [3H]estradiol and were perfused. Their brains were then processed for steroid hormone autoradiography. Following exposure times of 11 to 12 months, autoradiograms were developed and the hypothalamus was analyzed for neurons that concentrate estradiol and project to the spinal cord. Numerous neurons in the hypothalamus projected to the spinal cord, specifically neurons in the paraventricular nucleus (PVN), the lateral hypothalamus and the dorsal area of the hypothalamus. Although many subnuclei of PVN, as well as lateral hypothalamus, contained Fluorogold labelled neurons and estradiol concentrating neurons, the majority of double labeled cells were found in the lateral parvocellular (LP) subnucleus of PVN. Approximately 30% of the neurons in the lp subnucleus that projected to spinal cord also concentrated estradiol. Up to one half of the estradiol-concentrating neurons in lp sent axons to the lower lumbar spinal cord. These results suggest that some of the effects of gonadal steroid hormones on SNB development, plasticity and function may in fact, be indirect, via steroid-sensitive afferents.
通过将逆行荧光束追踪与类固醇激素放射自显影相结合，确定了下丘脑内与包含球海绵体肌性二态性脊髓核（SNB）的腰段脊髓节段传入相关的雌二醇浓缩神经元的位置和分布。将荧光金注射到成年雄性大鼠脊髓的L5-L6节段，12天后对动物进行去势。去势一周后，雄性大鼠接受[3H]雌二醇注射并进行灌注。然后对它们的大脑进行类固醇激素放射自显影处理。在曝光11至12个月后，显影放射自显影片，并分析下丘脑内浓缩雌二醇并投射到脊髓的神经元。下丘脑内有许多神经元投射到脊髓，特别是室旁核（PVN）、下丘脑外侧和下丘脑背侧区域的神经元。尽管PVN的许多亚核以及下丘脑外侧都含有荧光金标记的神经元和雌二醇浓缩神经元，但大多数双标记细胞位于PVN的外侧小细胞（LP）亚核中。投射到脊髓的LP亚核中约30%的神经元也浓缩雌二醇。LP中多达一半的雌二醇浓缩神经元将轴突发送到腰段脊髓下部。这些结果表明，性腺类固醇激素对SNB发育、可塑性和功能的一些影响实际上可能是通过类固醇敏感的传入神经间接产生的。
