恒河猴中脑导水管周围灰质中雌激素受体α免疫反应性神经元向延髓外侧的投射。

Projections from estrogen receptor-alpha immunoreactive neurons in the periaqueductal gray to the lateral medulla oblongata in the rhesus monkey.

作者信息

VanderHorst V G J M, Terasawa E, Ralston H J

机构信息

Department of Anatomy, University of California at San Francisco, San Francisco, CA 94143, USA.

出版信息

Neuroscience. 2004;125(1):243-53. doi: 10.1016/j.neuroscience.2003.12.044.

DOI:10.1016/j.neuroscience.2003.12.044

PMID:15051163

Abstract

The periaqueductal gray (PAG) contains numerous estrogen receptor-alpha immunoreactive (ER-alpha IR) neurons that are distributed in a species-specific way. These neurons might modulate different types of behavior that are mediated by the PAG such as active and passive coping responses, analgesia, and reproductive behavior. In primates, it is not known whether ER-alpha IR PAG neurons represent local interneurons and/or neurons that project to brainstem areas that control these behaviors. In this double labeling study, we asked whether ER-alpha IR neurons in the PAG of the rhesus monkey project to the nucleus retroambiguus (NRA), an area in the ventrolateral caudal medulla oblongata that is involved in expiration, vocalization, and reproductive behavior. Tracer was injected into the caudal lateral medulla oblongata to retrogradely label PAG neurons, and ER-alpha was visualized immunohistochemically. Although ER-alpha IR neurons and NRA-projection neurons were present at similar levels of the PAG, their distributions hardly overlapped. ER-alpha IR PAG neurons that project to the lateral caudal medulla represented less than 2% of ER-alpha IR PAG neurons. These double-labeled neurons were mainly located in the ipsilateral caudal PAG. The cluster of neurons in the medial part of the lateral PAG that projects specifically to the NRA-region did not contain double-labeled cells. The results indicate that only a few ER-alpha IR PAG neurons project to the NRA-region. This might be related to the modest effects of estrogen on mating-related behavior in primates compared most other mammalian species. Remaining ER-alpha IR PAG neurons might act locally on other PAG neurons, or they might represent neurons that project to other areas. Furthermore, the finding that the distributions of ER-alpha IR neurons and neurons that project to premotor neurons in the NRA-region scarcely overlap illustrates that the PAG in primates is very highly organized into anatomically distinct regions compared with other species.

摘要

导水管周围灰质（PAG）含有大量以物种特异性方式分布的雌激素受体α免疫反应性（ER-α IR）神经元。这些神经元可能调节由PAG介导的不同类型行为，如主动和被动应对反应、镇痛和生殖行为。在灵长类动物中，尚不清楚ER-α IR PAG神经元是代表局部中间神经元和/或投射到控制这些行为的脑干区域的神经元。在这项双重标记研究中，我们探究了恒河猴PAG中的ER-α IR神经元是否投射到疑核后核（NRA），NRA是延髓尾侧腹外侧的一个区域，参与呼气、发声和生殖行为。将示踪剂注入延髓尾侧外侧以逆行标记PAG神经元，并通过免疫组织化学方法观察ER-α。尽管ER-α IR神经元和NRA投射神经元在PAG的相似水平存在，但它们的分布几乎不重叠。投射到延髓尾侧外侧的ER-α IR PAG神经元占ER-α IR PAG神经元的比例不到2%。这些双重标记的神经元主要位于同侧尾侧PAG。外侧PAG内侧部分专门投射到NRA区域的神经元簇中不包含双重标记的细胞。结果表明，只有少数ER-α IR PAG神经元投射到NRA区域。这可能与雌激素对灵长类动物交配相关行为的影响相对大多数其他哺乳动物物种较小有关。其余的ER-α IR PAG神经元可能在局部作用于其他PAG神经元，或者它们可能代表投射到其他区域的神经元。此外，ER-α IR神经元和投射到NRA区域前运动神经元的神经元分布几乎不重叠这一发现表明，与其他物种相比，灵长类动物的PAG在解剖学上高度组织成不同的区域。