Identification functional characterization of brainstem cannabinoid CB2 receptors.
Identification functional characterization of brainstem cannabinoid CB2 receptors.
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CB 2受体在中枢神经系统（CNS）神经元中的存在和功能一直存在争议.本文报道了CB 2受体mRNA在脑干神经元上的表达及其蛋白定位.脑干中的这些功能性CB 2受体被CB 2受体激动剂2-花生四烯酸甘油和内源性大麻素水平升高激活，内源性大麻素也作用于CB 1受体。CB 2受体代表内源性大麻素的另一个作用部位，它开启了在局部脑区使用增强的内源性大麻素水平进行非精神治疗干预的可能性。观察他人的动作会激活猴子的腹侧前运动皮质，其中编码动作意义，而不是对象身份。在一项功能性磁共振成像（fMRI）研究中，我们调查了其他猴子的额叶区域是否会对其他人的行为做出反应。观察一只手抓住物体激活四个额叶区域：喙F5和区域45 B，45 A和46。观察一个人抓住一个物体也激活了尾F5，这表明不同程度的动作抽象的F5。观察形状激活区45，但不是前运动F5。在区域45中的对象和动作信息的会聚对于动作的完全理解可能是重要的。理解他人的行为是一种基本的社交能力。现在有广泛的共识，运动系统的激活是这种能力的必要条件。一个单纯的视觉表示，没有运动系统的参与，提供了一个代理人的运动的可见方面的说明，但没有给出理解动作语义，即，行动是关于什么的，它的目标是什么，以及它与其他行动的关系（1，2）。然而，在不知道作用于其上的对象的身份的情况下，动作信息不足以提供对所观察到的动作的充分理解。只有当关于对象身份的信息被添加到关于动作的语义信息中时，才能完全理解其他个体的动作。猴子腹侧运动前皮层（F5区）的一组神经元的功能特性证明了运动系统参与动作理解。这些B反映了神经元在
The presence and function of CB 2 receptors in central nervous system (CNS) neurons are controversial. We report the expression of CB 2 receptor messenger RNA and protein localization on brainstem neurons. These functional CB 2 receptors in the brainstem were activated by a CB 2 receptor agonist, 2-arachidonoylglycerol, and by elevated endogenous levels of endocannabinoids, which also act at CB 1 receptors. CB 2 receptors represent an alternative site of action of endocannabinoids that opens the possibility of nonpsychotropic therapeutic interventions using enhanced endocannabinoid levels in localized brain areas. Observation of actions performed by others activates monkey ventral premotor cortex, where action meaning, but not object identity, is coded. In a functional MRI (fMRI) study, we investigated whether other monkey frontal areas respond to actions performed by others. Observation of a hand grasping objects activated four frontal areas: rostral F5 and areas 45B, 45A, and 46. Observation of an individual grasping an object also activated caudal F5, which indicates different degrees of action abstraction in F5. Observation of shapes activated area 45, but not premotor F5. Convergence of object and action information in area 45 may be important for full comprehension of actions. Understanding actions performed by others is a fundamental social ability. There is now wide consensus that the activation of the motor system is a necessary requisite for this ability. A mere visual representation, without involvement of the motor system, provides a descrip-tion of the visible aspects of the movements of the agent, but does not give information critical for understanding action semantics, i.e., what the action is about, what its goal is, and how it is related to other actions ( 1 , 2 ). Action information, however, without knowledge about the identity of the object acted upon, is not sufficient to provide a full understanding of the observed action. Only when information about the object identity is added to the se-mantic information about the action can the actions of other individuals be completely understood ( 3 ). The functional properties of a set of neurons in monkey ventral premotor cortex (area F5) evidence for the involvement of the motor system in action understanding. These B mirror [ neurons both when the when the