Koliatsos V E, Price D L, Clatterbuck R E
Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2196.
J Comp Neurol. 1994 Jul 22;345(4):510-27. doi: 10.1002/cne.903450404.
The present study establishes that populations of neurons in the lumbosacral cord, which innervate pelvic striated muscles, express p75NGFR throughout their life spans. These neuronal groups comprise the Onuf's nucleus in humans and its principal rat homologues, dorsolateral (DL) and dorsomedial (DM) nuclei, as well as the cremasteric (CRE) nucleus. The p75NGFR in these neurons is localized in the rough endoplasmic reticulum, Golgi complex, and lysosomes. Almost all neurons that project to striated perineal muscles in the male rat express p75NGFR; very low levels of p75NGFR are detected in neurons that innervate perineal sphincters of the female. In the female rat, p75NGFR expression is masculinized with perinatal androgen treatment. In addition, the expression of p75NGFR in DM and DL neurons in the adult is up-regulated by injury (i.e., pudendal axotomy) but is not influenced by gonadectomy. The results of this study establish that neurons of Onuf's nucleus and its rat homologues differ from general somatic motor neurons in that they express p75NGFR from early postnatal life (i.e., when all motor neurons express p75NGFR) into the adult (when the former, but not the latter, express the receptor). In view of growing evidence for the role of neurotrophins in the physiology of motor neurons, the above differentiating feature between general somatic and sexually dimorphic motor neurons suggests that p75NGFR may be involved in motor neuron plasticity and may participate in mechanisms by which neurons can protect themselves from degenerative insults.
本研究证实，支配盆腔横纹肌的腰骶脊髓神经元群体在其整个生命周期中均表达p75神经营养因子受体（p75NGFR）。这些神经元群包括人类的奥努夫核及其在大鼠中的主要同源物，即背外侧（DL）核和背内侧（DM）核，以及提睾肌（CRE）核。这些神经元中的p75NGFR定位于粗面内质网、高尔基体和溶酶体中。雄性大鼠中几乎所有投射到会阴横纹肌的神经元都表达p75NGFR；而支配雌性会阴括约肌的神经元中检测到的p75NGFR水平非常低。在雌性大鼠中，围产期雄激素治疗可使p75NGFR表达男性化。此外，成年大鼠DM和DL神经元中p75NGFR的表达受损伤（即阴部神经切断术）上调，但不受性腺切除术影响。本研究结果表明，奥努夫核及其大鼠同源物的神经元与一般躯体运动神经元不同，因为它们从出生后早期（即所有运动神经元都表达p75NGFR时）到成年期（此时前者而非后者表达该受体）都表达p75NGFR。鉴于越来越多的证据表明神经营养因子在运动神经元生理学中的作用，一般躯体运动神经元和性二态性运动神经元之间的上述差异特征表明，p75NGFR可能参与运动神经元可塑性，并可能参与神经元保护自身免受退行性损伤的机制。
