Gerrits P O, Veening J G, Blomsma S A, Mouton L J
Department of Anatomy and Embryology, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands.
Horm Behav. 2008 Feb;53(2):329-41. doi: 10.1016/j.yhbeh.2007.10.011. Epub 2007 Nov 12.
Receptive female hamsters display very rigid lordotic postures. Estradiol facilitates this behavior via activation of estrogen receptors. In the hamster brainstem estrogen receptor-alpha-immunoreactive neurons (ER-alpha-IR) are present in various brainstem regions including nucleus retroambiguus (NRA) in the caudal ventrolateral medulla (CVLM) and nucleus of the solitary tract. ER-alpha-IR neurons in the CVLM project to the thoracic and upper lumbar cord. However, A1 neurons in this region do not project to the spinal cord, in contrast to overlapping C1 neurons. The question now arises: are ER-alpha-IR cells in the CVLM part of the A1/C1 group, or do they belong to the NRA or do they compose a separate cluster. A study in ovariectomized female hamsters using a combination of double immunostaining and retrograde tracing techniques and measurement of soma diameters was carried out. The results showed that A1/C1 neurons in the CVLM are almost never ER-alpha-positive; neurons inside or bordering the NRA can be divided in two different types: large multipolar and small; the large NRA-neurons, projecting caudally, are neither tyrosine hydroxylase- (TH) nor ER-alpha-IR; the small neurons, bordering the NRA and projecting caudally, are ER-alpha-IR but not TH-IR. From the available evidence and the present findings it can be concluded that the group of small ER-alpha-IR neurons in the CVLM has to be considered as a distinct entity, probably involved in the autonomic physiological changes concurring with successive phases of the estrous cycle. Because the location is closely related to the NRA itself the nucleus is called nucleus para-retroambiguus, abbreviated (NPRA).
处于接受状态的雌性仓鼠会表现出非常僵硬的脊柱前凸姿势。雌二醇通过激活雌激素受体来促进这种行为。在仓鼠脑干中，雌激素受体α免疫反应性神经元（ER-α-IR）存在于各个脑干区域，包括尾侧腹外侧延髓（CVLM）中的疑后核（NRA）和孤束核。CVLM中的ER-α-IR神经元投射到胸段和腰段上段脊髓。然而，与重叠的C1神经元不同，该区域的A1神经元不投射到脊髓。现在问题来了：CVLM中的ER-α-IR细胞是A1/C1组的一部分，还是属于NRA，或者它们构成一个单独的集群。利用双重免疫染色、逆行追踪技术和体细胞直径测量相结合的方法，对卵巢切除的雌性仓鼠进行了一项研究。结果表明，CVLM中的A1/C1神经元几乎从不呈ER-α阳性；NRA内部或边界的神经元可分为两种不同类型：大型多极神经元和小型神经元；向尾侧投射的大型NRA神经元既不是酪氨酸羟化酶（TH）免疫反应性的，也不是ER-α-IR的；与NRA相邻并向尾侧投射的小型神经元是ER-α-IR的，但不是TH-IR的。根据现有证据和目前的研究结果可以得出结论，CVLM中一组小型ER-α-IR神经元必须被视为一个独特的实体，可能参与了与发情周期连续阶段同时发生的自主生理变化。由于其位置与NRA本身密切相关，该核被称为疑旁核，缩写为（NPRA）。
