MOTONEURON MORPHOLOGY IN THE DORSOLATERAL NUCLEUS OF THE RAT SPINAL-CORD - NORMAL DEVELOPMENT AND ANDROGENIC REGULATION
MOTONEURON MORPHOLOGY IN THE DORSOLATERAL NUCLEUS OF THE RAT SPINAL-CORD - NORMAL DEVELOPMENT AND ANDROGENIC REGULATION
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DOI：
10.1002/cne.903380408
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发表时间：
1993-12-22
影响因子：
2.5
通讯作者：
SENGELAUB, DR
中科院分区：
文献类型：
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作者：
GOLDSTEIN, LA;SENGELAUB, DR
大鼠腰椎脊髓包含两个性别二型运动核，球海绵体脊髓核（SNB）和背外侧核（DLN）。这些运动核支配着解剖学上不同的会阴肌，这些会阴肌参与了功能上不同的交配反射。SNB和DLN中的运动神经元具有不同的树突形态。在中间位置的SNB中，运动神经元的树突呈径向重叠排列，而在外侧位置的DLN中，运动神经元的树突具有双极和严格的单侧组织。在发育过程中，SNB运动神经元树突生长旺盛，然后缩回到成熟长度。在本实验中，我们确定成体SNB和DLN运动神经元形态的差异是否反映在正常发育过程中树突生长的不同模式上。此外，这两个细胞核的发育都受到雄激素的控制。在缺乏雄激素的情况下，SNB树突不能生长；睾酮替代支持正常的树突生长。因此，我们还研究了DLN树突的发育，以寻找雄激素调节的类似证据。通过使用霍乱毒素-辣根过氧化物酶（BHRP）逆行标记运动神经元，我们测量了正常雄性和在出生后(P) 7、P28、P49和P70时使用睾酮或油/空白植入物处理的阉割动物DLN运动神经元的形态。结果表明，与SNB中枝晶的双相生长模式相反，DLN中的枝晶生长是单调的；运动神经元的树突长度在P7和P70之间增加了500%以上。然而，与SNB一样，DLN运动神经元形态的发育依赖于雄激素。与正常或睾酮处理的雄性阉割鼠相比，油/空白植入物处理的阉割鼠DLN染色体和树突生长大大减弱。因此，虽然雄激素对于SNB和DLN中运动神经元的生长显然是必需的，但它们不同的发育模式表明，必须有其他因素参与调节这种生长。(C) 1993 Wiley-Liss, Inc。
The rat lumbar spinal cord contains two sexually dimorphic motor nuclei, the spinal nucleus of the bulbocavernosus (SNB), and the dorsolateral nucleus (DLN). These motor nuclei innervate anatomically distinct perineal muscles that are involved in functionally distinct copulatory reflexes. The motoneurons in the SNB and DLN have different dendritic morphologies. The dendrites of motoneurons in the medially positioned SNB have a radial, overlapping arrangement, whereas the dendrites of the laterally positioned DLN have a bipolar and strictly unilateral organization. During development, SNB motoneuron dendrites grow exuberantly and then retract to their mature lengths. In this experiment we determined whether the adult difference in SNB and DLN motoneuron morphology was reflected in different patterns of dendritic growth during normal development. Furthermore, the development of both these nuclei is under androgenic control. In the absence of androgens, SNB dendrites fail to grow; testosterone replacement supports normal dendritic growth. Thus, we also examined the development of DLN dendrites for similar evidence of androgenic regulation.By using cholera toxin-horseradish peroxidase (BHRP) to label motoneurons retrogradely, we measured the morphology of DLN motoneurons in normal males, and in castrates treated with testosterone or oil/blank implants at postnatal day (P) 7, P28, P49, and P70. Our results demonstrate that in contrast to the biphasic pattern of dendritic development in the SNB, dendritic growth in the DLN was monotonic; the dendritic length of motoneurons increased more than 500% between P7 and P70. However, as in the SNB, development of DLN motoneuron morphology is androgen-dependent. In castrates treated with oil/blank implants, DLN somal and dendritic growth were greatly attenuated compared to those of normal or testosterone-treated males. Thus, while androgens are clearly necessary for the growth of motoneurons in both the SNB and DLN, their different developmental patterns suggest that other factors must be involved in regulating this growth. (C) 1993 Wiley-Liss, Inc.