Sandkühler J, Herdegen T
II. Physiologisches Institut, Universität Heidelberg, Germany.
J Comp Neurol. 1995 Jul 10;357(4):546-53. doi: 10.1002/cne.903570406.
This study provides a map of those neurons in the midbrain periaqueductal gray which are activated by chemical stimulation within different subdivisions of the periaqueductal gray. In pentobarbital anesthetized rats, the expression of the c-FOS protein was detected by immunocytochemistry and was used as a marker of neuronal activity. Microinjections of the gamma-aminobutyric acid (GABAA) receptor antagonist bicuculline (200 pmol in 50 nl) were used to increase selectively the firing rate of neurons originating from the injection site. The pattern of c-FOS immunoreactivity was highly specific for different injection sites. Dorsal injections were characterized by an extensive distribution of c-FOS immunoreactivity along the entire rostrocaudal extent of the periaqueductal gray, while ventral injections produced a much more restricted labeling. Following injection into the dorsal subdivision of the rostral periaqueductal gray, c-FOS immunoreactivity was present bilaterally in the dorsal and dorsolateral subdivisions of the rostral periaqueductal gray and was found in all subdivisions of the caudal periaqueductal gray. Dorsolateral injections at the level of the oculomotor nuclei produced strictly ipsilateral labeling in the dorsal and dorsolateral periaqueductal gray at the level of injection and throughout the ipsilateral half of the periaqueductal gray at more caudal levels. Stimulation in the ventrolateral periaqueductal gray induced FOS in the ventrolateral periaqueductal gray and the adjoining reticular formation. At rostral levels c-FOS immunoreactivity was also seen in the lateral periaqueductal gray but was absent caudal to the injection site. The identified patterns of activity in the periaqueductal gray provide a new basis for the interpretation of the diverse functional consequences of stimulation at periaqueductal gray sites.
本研究绘制了中脑导水管周围灰质中那些被导水管周围灰质不同亚区的化学刺激激活的神经元图谱。在戊巴比妥麻醉的大鼠中，通过免疫细胞化学检测c-FOS蛋白的表达，并将其用作神经元活动的标志物。微量注射γ-氨基丁酸（GABAA）受体拮抗剂荷包牡丹碱（50 nl中含200 pmol）用于选择性提高源自注射部位的神经元的放电率。c-FOS免疫反应性模式对不同注射部位具有高度特异性。背侧注射的特征是c-FOS免疫反应性沿导水管周围灰质的整个前后范围广泛分布，而腹侧注射产生的标记则更为局限。向 Rostral导水管周围灰质的背侧亚区注射后，c-FOS免疫反应性双侧出现在 Rostral导水管周围灰质的背侧和背外侧亚区，并在尾侧导水管周围灰质的所有亚区中发现。在动眼神经核水平进行背外侧注射，在注射水平的背侧和背外侧导水管周围灰质以及更尾侧水平的同侧导水管周围灰质的同侧半部产生严格的同侧标记。在腹外侧导水管周围灰质的刺激在腹外侧导水管周围灰质和相邻的网状结构中诱导FOS。在 Rostral水平，在外侧导水管周围灰质中也可见c-FOS免疫反应性，但在注射部位尾侧则不存在。导水管周围灰质中确定的活动模式为解释导水管周围灰质部位刺激的各种功能后果提供了新的基础。
