EXPRESSION OF NEUROTROPHIC FACTORS RELATED TO PLASTICITY OF MOTONEURONS

雄性大鼠球海绵体脊束核的运动神经元支配附着于阴茎的会阴横纹肌、球海绵体肌和提肛肌。它们在交配行为中起着重要作用，而交配行为对循环中雄激素水平的变化很敏感。会阴运动神经元被认为是由肌源性神经营养因子调节的。为了阐明肌源性神经营养因子的调控机制，我们用免疫组织化学和原位杂交的方法检测了神经营养因子脑源性神经营养因子(BDNF)、神经营养因子-3(NT-3)、睫状神经营养因子(CNTF)和胰岛素样生长因子-1(LGF-1)的表达。用抗BDNF、-NT-3、-CNTF和-IGF-1进行免疫组织化学染色，用BGNF、NT-3、CNTF和IGF-1进行原位杂交。在球颈静脉肌中未检测到CNTF和NT-3免疫反应。部分脑源性神经营养因子和胰岛素样生长因子-1免疫反应阳性。NT-3mRNA在球海绵体肌内膜的肌细胞和成纤维细胞中表达。而CNTF、IGF-1和BDNF的mRNAs在两者中均不表达。这些结果似乎表明，虽然免疫组织化学检测不到NT-3在球海绵体肌中的表达，但NT-3mRNA在球海绵体肌中表达。

Motoneurons of the spinal nucleus of the bulbocavernosus of male rats innervate the perineal striated muscles bulbocavernosus and levator ani that attach to penis. They have an important role in copulatory behavior, which is sensitive to alterations in circulating levels of androgen. The perineal motoneurons are thought to be regulated by muscle-derived neurotrophic factors. To clarify regulatory mechanisms of muscle-derived neurotrophic factors, we examined expression of neurotrophic factors such as brain-derived neurotrophic factor (BDNF), neurotropnin-3 (NT-3), ciliary neurotrophic factor (CNTF) and insulin-like growth factor-1 (LGF-1) by immunohistochemistry and in situ hybridization. For immunohistochemistry, anti-BDNF,-NT-3,-CNTF and -IGF-1 were used, and for in situ hybridization, cDNAs for BGNF, NT-3,CNTF and IGF-1 were used. CNTF and NT-3 immunoreactivity was not detected in the bulbocarvenosus muscles. BDNF and IGF-1 immunoreactivtiy was partially detected in them. mRNA of NT-3 expressed in the muscle cells and fibroblasts of endomysium of the bulbocavernosus muscles. However, mRNAs of CNTF, IGF-1 and BDNF were not expressed in both of them. These results seem to indicate that mRNA of NT-3 expresses in the bulbocavernosus muscles although NT-3 is not detected in them by immunohistochemistry.