Granata A R, Kitai S T
Department of Anatomy and Neurobiology, College of Medicine, University of Tennessee, Memphis 38163.
Exp Brain Res. 1991;86(3):459-66. doi: 10.1007/BF00230520.
Responses of 43 pedunculopontine area (PPN area) neurons to electrical stimulation of the substantia nigra (SN) were studied in anesthetized rats. An intracellular recording technique was used to demonstrate that SN stimulation evoked hyperpolarizing potentials, which were identified by intracellular injections as inhibitory postsynaptic potentials (IPSPs). These IPSPs were often followed by a rebound depolarization that originates several spike potentials. These IPSPs were characterized as monosynaptic, with latencies varying from 1.0 to 8.5 ms. Similar results were observed in some animals with chronic unilateral coronal lesion just rostral to subthalamic nucleus (STH), which severed the rostral afferents. PPN are neurons were also antidromically activated by SN stimulation. Two PPN area projection neurons were clearly identified. Mean latency of one group was 0.71 ms; mean latency of the second group was 5.16 ms. The morphological analysis of a neuron inhibited by SN stimulation and labeled with horseradish peroxidase (HRP) demonstrated that the soma was fusiform in shape, with the axon originating in the soma and collaterals and a large dendritic field extending in the ventrodorsalis direction. The results indicate that the PPN area is reciprocally connected with the SN, which elicits an inhibitory effect on PPN area neurons.
在麻醉大鼠中研究了43个脚桥核区域（PPN区域）神经元对黑质（SN）电刺激的反应。采用细胞内记录技术证明，SN刺激诱发超极化电位，经细胞内注射鉴定为抑制性突触后电位（IPSP）。这些IPSP之后常跟随一个反弹去极化，该去极化产生几个动作电位。这些IPSP的特征为单突触，潜伏期为1.0至8.5毫秒。在一些患有慢性单侧冠状病变（病变位于丘脑底核（STH）前方，切断了其前方传入纤维）的动物中也观察到了类似结果。SN刺激也能逆向激活PPN区域神经元。明确鉴定出两个PPN区域投射神经元。一组的平均潜伏期为0.71毫秒；第二组的平均潜伏期为5.16毫秒。对一个受SN刺激抑制并用辣根过氧化物酶（HRP）标记的神经元进行形态学分析表明，其胞体呈梭形，轴突起源于胞体，有侧支，大的树突野沿腹背方向延伸。结果表明，PPN区域与SN相互连接，SN对PPN区域神经元产生抑制作用。
