Klooster J, Vrensen G F
The Netherlands Ophthalmic Research Institute, Department of Morphology, Amsterdam.
Anat Embryol (Berl). 1998 Aug;198(2):123-32. doi: 10.1007/s004290050170.
The pupillary light reflex (PLR) is under the control of retinal ganglion cells projecting to the olivary pretectal nucleus (OPN). The OPN has a major projection to the Edinger-Westphal (EW) nucleus, which exerts its parasympathetic action on the iris musculature via the ciliary ganglion. The accessory oculomotor nuclei (AON) and the periaqueductal gray (PAG) receive input from the OPN and influence the PLR. The present study in rats aimed to elucidate the possible projections from the AON and PAG to the EW nucleus. The anterograde tracer Phaseolus vulgaris leucoagglutinin (PHA-L) was iontophoretically injected into the interstitial nucleus of Cajal (INC), the nucleus of the posterior commissure (NPC), the nucleus of Darkschewitsch (ND) and the rostral part of the PAG. The projections were studied at the light and electron microscopic level. The INC, NPC and ND have small projections to the EW nucleus, whereas the rostral part of the PAG densely projects to the EW nucleus. Without exception INC, NPC, ND and PAG varicosities are presynaptic to dendritic profiles in the EW nucleus and contain electron dense mitochondria, round vesicles and make asymmetric synaptic contacts. In addition the ND and PAG project to the thoracic level of the spinal cord. The fibres are presynaptic to dendritic profiles and contain electron dense mitochondria, round vesicles and make asymmetric synaptic contacts. The present observations allow the conclusion that the parasympathetic preganglionic neurons in the EW nucleus are not only controlled by the OPN-EW pathway but also by indirect pathways running via the AON and PAG. Moreover light-sensitive information is also transferred via an OPN-PAG-spinal cord pathway to the sympathetic superior cervical ganglion (SCG) that innervates the iris, suggesting that the PAG may have an integrative function in the sympathetic and parasympathetic control of the PLR.
瞳孔对光反射（PLR）受投射至橄榄前顶盖核（OPN）的视网膜神经节细胞控制。OPN主要投射至动眼神经副核（EW），该核通过睫状神经节对虹膜肌肉组织发挥副交感神经作用。动眼神经副核（AON）和导水管周围灰质（PAG）接受来自OPN的输入并影响PLR。本项对大鼠的研究旨在阐明AON和PAG至EW核的可能投射。将顺行示踪剂菜豆白细胞凝集素（PHA-L）通过离子电渗法注入 Cajal间质核（INC）、后连合核（NPC）、Darkschewitsch核（ND）和PAG的头端部分。在光镜和电镜水平研究投射情况。INC、NPC和ND对EW核有少量投射，而PAG的头端部分密集投射至EW核。无一例外，INC、NPC、ND和PAG的膨体在EW核内位于树突轮廓的突触前，含有电子致密的线粒体、圆形囊泡并形成不对称突触联系。此外，ND和PAG投射至脊髓胸段水平。这些纤维在树突轮廓的突触前，含有电子致密的线粒体、圆形囊泡并形成不对称突触联系。目前的观察结果可以得出结论，EW核内的副交感神经节前神经元不仅受OPN-EW通路控制，还受经由AON和PAG的间接通路控制。此外，光敏感信息也通过OPN-PAG-脊髓通路传递至支配虹膜的交感神经颈上神经节（SCG），这表明PAG可能在PLR的交感和副交感神经控制中具有整合功能。
