Beitz A J
Department of Veterinary Biology, University of Minnesota, St. Paul 55108.
Brain Res Bull. 1989 Jul-Aug;23(1-2):25-35. doi: 10.1016/0361-9230(89)90159-7.
The possible origin of glutamatergic input to the rodent periaqueductal gray (PAG) was analyzed utilizing a combined retrograde transport-immunocytochemical technique. Injections of wheat germ agglutinin-horseradish peroxidase were made into the PAG of 12 adult rats and into the deep layer of the superior colliculus in 2 rats. The brain tissue was first reacted histochemically to demonstrate the retrograde tracer and subsequently processed with immunohistochemical techniques using a recently developed monoclonal glutamate antibody. Following PAG injections, several brain areas were found to contain double-labeled neurons. The greatest number of double-labeled glutamate-like immunoreactive neurons were observed in the zona incerta, spinal trigeminal nucleus, cuneiform nucleus, cingulate cortex, cerebellar interpositus nucleus, deep mesencephalic nucleus and the PAG itself. Double-labeled neurons were also observed in several other nuclei including the pretectal nuclei, the frontal and occipital cortex, several reticular nuclei, the dorsomedial hypothalamic nucleus, and the substantia nigra. Many of the same nuclei contained double-labeled neurons following collicular injections, but in addition, double-stained cells were found in the primary visual cortex, lateral dorsal and lateral posterior thalamic nuclei, nucleus of the posterior commissure, ventral lateral geniculate nucleus, dorsal column nuclei and several additional pretectal nuclei. The results of this double-labeling study raise the possibility that these nuclei may provide glutamatergic inputs to the midbrain PAG and/or superior colliculus. These putative glutamatergic afferent projections may ultimately influence the PAG's role in several important functions including antinociception, defensive mechanisms or vocalization and may also play a role in the superior collicular involvement in defensive mechanisms, in visuo-motor integration in the orienting reflex and in facilitating shifts in gaze.
利用逆行转运-免疫细胞化学联合技术分析了啮齿动物中脑导水管周围灰质（PAG）谷氨酸能输入的可能来源。将小麦胚凝集素-辣根过氧化物酶注入12只成年大鼠的PAG和2只大鼠的上丘深层。脑组织首先进行组织化学反应以显示逆行示踪剂，随后使用最近开发的单克隆谷氨酸抗体通过免疫组织化学技术进行处理。在PAG注射后，发现几个脑区含有双标记神经元。在未定带、三叉神经脊束核、楔形核、扣带回皮质、小脑间位核、中脑深核和PAG本身中观察到最多数量的双标记谷氨酸样免疫反应性神经元。在其他几个核中也观察到双标记神经元，包括顶盖前核、额叶和枕叶皮质、几个网状核、下丘脑背内侧核和黑质。在丘注射后，许多相同的核含有双标记神经元，但此外，在初级视觉皮质、丘脑背外侧和后外侧核、后连合核、外侧膝状体腹侧核、薄束核和几个额外的顶盖前核中发现了双染细胞。这项双标记研究的结果提出了这些核可能为中脑PAG和/或上丘提供谷氨酸能输入的可能性。这些假定的谷氨酸能传入投射可能最终影响PAG在包括抗伤害感受、防御机制或发声在内的几种重要功能中的作用，也可能在上丘参与防御机制、定向反射中的视觉运动整合以及促进注视转移中发挥作用。
