Cerebral Activity during the Anesthesia-Like State Induced by Mesopontine Microinjection of Pentobarbital
Cerebral Activity during the Anesthesia-Like State Induced by Mesopontine Microinjection of Pentobarbital
复制标题
DOI：
10.1523/jneurosci.1357-08.2009
复制
发表时间：
2009-05-27
影响因子：
5.3
通讯作者：
Devor, Marshall
中科院分区：
文献类型：
--
作者：
Abulafia, Ruth;Zalkind, Vladimir;Devor, Marshall
将戊巴比妥显微注射到大鼠脑干的受限区域，即中脑桥被盖麻醉区（MPTA），可诱导可逆的麻醉样状态，其特征是翻正反射丧失，神经张力下降，抗痛觉和意识丧失，脑电图同步评估。我们用FOS表达作为标记来检测这种状态下的大脑活动。用戊巴比妥连续脑内微量注射或全身戊巴比妥和脑内微量注射载药麻醉动物50分钟。与清醒动物微注射载药后FOS的表达进行比较。无论是全身麻醉还是MPTA麻醉，整个皮层的神经活动都受到抑制。皮层下的变化不太一致。在麻中带和中缝苍白核中，表达在全身麻醉时被强烈抑制，而在mpta诱导麻醉时仅轻度抑制。分离见于结节乳头核，仅在全身麻醉时抑制发生，在外侧缰核，活动在全身麻醉时明显增加，但在脑内显微注射后没有。先前与大脑觉醒相关的几个皮质下核没有受到影响。全身麻醉时MPTA本身的FOS表达被抑制。两种麻醉模式下脑活动模式的差异与麻醉终点可能通过其他机制实现的可能性是一致的：全身麻醉的直接药物作用或mpta诱导的麻醉的上升通路。然而，也有可能全身给药的药物诱导麻醉，至少部分是通过MPTA的主要作用，其次发生皮质抑制。
Microinjection of pentobarbital into a restricted region of rat brainstem, the mesopontine tegmental anesthesia area (MPTA), induces a reversible anesthesia-like state characterized by loss of the righting reflex, atonia, antinociception, and loss of consciousness as assessed by electroencephalogram synchronization. We examined cerebral activity during this state using FOS expression as a marker. Animals were anesthetized for 50 min with a series of intracerebral microinjections of pentobarbital or with systemic pentobarbital and intracerebral microinjections of vehicle. FOS expression was compared with that in awake animals microinjected with vehicle. Neural activity was suppressed throughout the cortex whether anesthesia was induced by systemic or MPTA routes. Changes were less consistent subcortically. In the zona incerta and the nucleus raphe pallidus, expression was strongly suppressed during systemic anesthesia, but only mildly during MPTA-induced anesthesia. Dissociation was seen in the tuberomammillary nucleus where suppression occurred during systemic-induced anesthesia only, and in the lateral habenular nucleus where activity was markedly increased during systemic-induced anesthesia but not following intracerebral microinjection. Several subcortical nuclei previously associated with cerebral arousal were not affected. In the MPTA itself FOS expression was suppressed during systemic anesthesia. Differences in the pattern of brain activity in the two modes of anesthesia are consistent with the possibility that anesthetic endpoints might be achieved by alternative mechanisms: direct drug action for systemic anesthesia or via ascending pathways for MPTA-induced anesthesia. However, it is also possible that systemically administered agents induce anesthesia, at least in part, by a primary action in the MPTA with cortical inhibition occurring secondarily.