Moreno-López B, Estrada C, Escudero M
Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, 28029 Madrid, Spain.
J Neurosci. 1998 Dec 15;18(24):10672-9. doi: 10.1523/JNEUROSCI.18-24-10672.1998.
Nitric oxide (NO) production by neurons in the prepositus hypoglossi (PH) nucleus is necessary for the normal performance of eye movements in alert animals. In this study, the mechanism(s) of action of NO in the oculomotor system has been investigated. Spontaneous and vestibularly induced eye movements were recorded in alert cats before and after microinjections in the PH nucleus of drugs affecting the NO-cGMP pathway. The cellular sources and targets of NO were also studied by immunohistochemical detection of neuronal NO synthase (NOS) and NO-sensitive guanylyl cyclase, respectively. Injections of NOS inhibitors produced alterations of eye velocity, but not of eye position, for both spontaneous and vestibularly induced eye movements, suggesting that NO produced by PH neurons is involved in the processing of velocity signals but not in the eye position generation. The effect of neuronal NO is probably exerted on a rich cGMP-producing neuropil dorsal to the nitrergic somas in the PH nucleus. On the other hand, local injections of NO donors or 8-Br-cGMP produced alterations of eye velocity during both spontaneous eye movements and vestibulo-ocular reflex (VOR), as well as changes in eye position generation exclusively during spontaneous eye movements. The target of this additional effect of exogenous NO is probably a well defined group of NO-sensitive cGMP-producing neurons located between the PH and the medial vestibular nuclei. These cells could be involved in the generation of eye position signals during spontaneous eye movements but not during the VOR.
舌下前置核（PH）神经元产生的一氧化氮（NO）对于警觉动物眼球运动的正常执行是必需的。在本研究中，已对NO在动眼系统中的作用机制进行了研究。在向PH核微量注射影响NO - cGMP途径的药物之前和之后，记录了警觉猫的自发和前庭诱发的眼球运动。还分别通过免疫组织化学检测神经元型一氧化氮合酶（NOS）和NO敏感的鸟苷酸环化酶，研究了NO的细胞来源和靶点。注射NOS抑制剂会使自发和前庭诱发的眼球运动的眼速度发生改变，但眼位置不变，这表明PH神经元产生的NO参与速度信号的处理，但不参与眼位置的产生。神经元型NO的作用可能施加于PH核中含氮能胞体背侧富含产生cGMP的神经毡上。另一方面，局部注射NO供体或8 - Br - cGMP会使自发眼球运动和前庭眼反射（VOR）期间的眼速度发生改变，以及仅在自发眼球运动期间使眼位置产生发生变化。外源性NO这种额外作用的靶点可能是位于PH和内侧前庭核之间一组明确的对NO敏感的产生cGMP的神经元。这些细胞可能参与自发眼球运动期间眼位置信号的产生，但不参与VOR期间眼位置信号的产生。
