Sliwowska Joanna H, Billings Heather J, Goodman Robert L, Coolen Lique M, Lehman Michael N
Department of Cell Biology, Neurobiology, and Anatomy, University of Cincinnati, College of Medicine, Cincinnati, Ohio 45267, USA.
Biol Reprod. 2004 Jun;70(6):1768-75. doi: 10.1095/biolreprod.103.024182. Epub 2004 Feb 18.
Recent evidence suggests that the ovine premammillary hypothalamic area (PMH) is an important target for the pineal hormone, melatonin, and its role in seasonal reproduction. In rodents, the PMH is a complex region consisting of several cell groups with differing neurochemical content and anatomical connections. Therefore, to obtain a better understanding of the potential neural targets for melatonin in this area of the sheep brain, we have undertaken a detailed anatomical characterization of the PMH, including its nuclear divisions and the location of neuropeptide/neurotransmitter cells within them. By combining immunocytochemistry for NeuN, a neuronal marker, with Nissl staining in anestrous, ovariectomized, estradiol-treated ewes, we identified three nuclei within the PMH: a caudal continuation of the hypothalamic arcuate nucleus (cARC), the ventral division of the premammillary nucleus (PMv), and the ventral tuberomammillary nucleus (TMv). The cARC contained neurons that were immunoreactive for tyrosine hydroxylase, dynorphin, estrogen receptor alpha, cocaine- and amphetamine-regulated transcript peptide (CART), and nitric oxide synthase (NOS). The PMv was also characterized by the presence of cells that contained NOS and CART, although the size of these cells was larger than that of their corresponding phenotype in the cARC. By contrast, in the TMv, of the markers examined in the present study, only fibers immunoreactive for orexin were seen. Thus, the ovine PMH is a heterogeneous region comprised of three subdivisions, each with distinct morphological and neurochemical characteristics. This anatomical map of the PMH provides a basis for future studies to determine the functional contribution of each component to the influence of melatonin on seasonal reproduction.
最近的证据表明，绵羊乳头前下丘脑区域（PMH）是松果体激素褪黑素及其在季节性繁殖中作用的重要靶点。在啮齿动物中，PMH是一个复杂的区域，由几个具有不同神经化学含量和解剖连接的细胞群组成。因此，为了更好地了解绵羊脑这一区域中褪黑素的潜在神经靶点，我们对PMH进行了详细的解剖学特征分析，包括其核分区以及其中神经肽/神经递质细胞的位置。通过在处于乏情期、卵巢切除且经雌二醇处理的母羊中，将神经元标记物NeuN的免疫细胞化学与尼氏染色相结合，我们在PMH中识别出三个核：下丘脑弓状核的尾侧延续部分（cARC）、乳头前核的腹侧部（PMv）和腹侧结节乳头核（TMv）。cARC包含对酪氨酸羟化酶、强啡肽、雌激素受体α、可卡因和苯丙胺调节转录肽（CART）以及一氧化氮合酶（NOS）具有免疫反应性的神经元。PMv的特征还在于存在含有NOS和CART的细胞，尽管这些细胞的大小比cARC中相应表型的细胞大。相比之下，在TMv中，在本研究中检测的标记物中，仅观察到对食欲素具有免疫反应性的纤维。因此，绵羊PMH是一个由三个亚区组成的异质性区域，每个亚区都具有独特的形态和神经化学特征。PMH的这一解剖图谱为未来研究确定每个组分对褪黑素对季节性繁殖影响的功能贡献提供了基础。
