Effect of hemilabyrinthectomy on monoamine metabolism in the medial vestibular nucleus, locus coeruleus, and other brainstem nuclei of albino and pigmented rats.
Effect of hemilabyrinthectomy on monoamine metabolism in the medial vestibular nucleus, locus coeruleus, and other brainstem nuclei of albino and pigmented rats.
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DOI：
10.3233/ves-1996-6403
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
H. Cransac;L. Peyrin;F. Farhat;J. Cottet-Emard;J. Pequignot;A. Reber
中科院分区：
文献类型：
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作者：
H. Cransac;L. Peyrin;F. Farhat;J. Cottet-Emard;J. Pequignot;A. Reber
我们比较了白化大鼠和色素沉着大鼠单侧迷路切除术（UL）对前庭内侧核（MVN）、蓝斑、背中音和耳蜗核中单胺（去甲肾上腺素、多巴胺、血清素）及其相应代谢物（3-甲氧基、4-羟基苯基乙二醇（MHPG）、3,4-二羟基苯基乙酸（DOPAC）和5-羟基吲哚乙酸（5HIAA））浓度的早期影响。研究在两种菌株的UL后6小时进行，其中央前庭神经元的功能光动力学反应和前庭代偿的时间过程不同。结果表明，两大品系的单胺能变化不同。在白化大鼠的MVN中，双侧MHPG增加，同侧多巴胺增加，提示去甲肾上腺素的合成和代谢被激活，而在色素大鼠的MVN中没有观察到这种变化。另一方面，白化大鼠对侧蓝斑中去甲肾上腺素和DOPAC同时升高提示去甲肾上腺素合成增强，而色化大鼠同侧蓝斑中去甲肾上腺素含量降低可能反映了NE释放较早的强烈刺激。这些生化结果证实了蓝斑去肾上腺素能神经支配在前庭代偿中的相关作用，并指出了前庭代偿过程的早期阶段MVN的去甲肾上腺素的参与。在第6小时观察到的不同品系相关的去甲肾上腺素能反应表明，中枢去甲肾上腺素的参与，特别是来自蓝斑神经的参与，可能在白化大鼠中比在色素大鼠中更重要和更持久。白化大鼠脑干核内血清素和5HIAA均未见改变。相比之下，色素大鼠背中叶、同侧蓝斑和双侧MVN中5HIAA/5HT比值的增加表明，UL诱导了该品系5HT利用的扩大和增强。
We compared in albino and pigmented rats the early effect of unilateral labyrinthectomy (UL) on the concentrations of monoamines (norepinephrine, dopamine, serotonin) and their respective metabolites--3-methoxy,4-hydroxyphenylglycol (MHPG), 3,4-dihydroxy-phenylacetic acid (DOPAC), and 5-hydroxyindoleacetic acid (5HIAA)--in medial vestibular nuclei (MVN), locus coeruleus, raphe dorsalis, and cochlear nuclei. The study was conducted 6 hours after UL in both strains, differing by the functional optokinetic responses of their central vestibular neurons and the time-course of their vestibular compensation. The results show that the monoaminergic changes are different in the two rat strains. In the MVN of albino rats, there was a bilateral increase of MHPG and an ipsilateral increase of dopamine suggesting activation of norepinephrine synthesis and metabolism, whereas no such changes were observed in the MVN of pigmented rats. On the other hand, the simultaneous increase of norepinephrine and DOPAC observed in the contralateral locus coeruleus of albino rats suggested enhanced norepinephrine synthesis, whereas in pigmented rats the decreased norepinephrine content found in the ipsilateral locus coeruleus might reflect an earlier strong stimulation of NE release. These biochemical results confirm the relevant role of locus coeruleus noradrenergic innervation in vestibular compensation and also point out the involvement of norepinephrine of the MVN in the early stages of this process. The different strain-related noradrenergic responses observed on the 6th hour suggest that the involvement of central norepinephrine, particularly from locus coeruleus innervation, may be more crucial and more sustained in the albino than in pigmented rats. No serotonin and 5HIAA changes were found in either brainstem nuclei of albino rats. In contrast, the increase of the ratio 5HIAA/5HT observed in raphe dorsalis, in ipsilateral locus coeruleus, and in both sides of MVN of pigmented rats suggested that UL induced an extended and enhanced utilization of 5HT in this strain.