Muscimol diffusion after intracerebral microinjections: A reevaluation based on electrophysiological and autoradiographic quantifications
Muscimol diffusion after intracerebral microinjections: A reevaluation based on electrophysiological and autoradiographic quantifications
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DOI：
10.1006/nlme.2001.4035
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发表时间：
2002-07-01
影响因子：
2.7
通讯作者：
Cotillon, N
中科院分区：
文献类型：
--
作者：
Edeline, JM;Hars, B;Cotillon, N
脑内肌醇注射被广泛用于在行为任务中使离散的脑结构失活。然而，很少有人努力量化muscimol扩散的程度。作者报告了在大细胞基底核（0.1-0.4 μ l）或丘脑网状核（0.05-0.1 μ l）注射肌药后获得的电生理和放射自显影结果。在52只大鼠中，在注射muscimol后的2小时内，在RE或听觉丘脑中收集了多单元记录。在距注射部位3mm处观察到神经元活性下降；它们发生的时间是注射点和记录点之间距离的函数。因为这些减少不能用生理效应来解释，它们可能反映了到记录部位的muscimol扩散。25只大鼠在不同的实验条件下进行放射自显影研究。光密度（OD）测量表明，在存活15分钟后，0.05 μ l的注射在注射部位产生了5.25 mm(2)的标记区域和1.7 mm的背侧标记。将存活时间增加到60分钟，或将注射体积增加到0.1 ml，会导致注射部位的标记区域（8-12 mm(2)）和更大的背侧扩散（2.0-2.5 mm）。通过高分辨率放射成像仪对放射性的直接量化验证了OD测量，甚至表明更大的muscimol扩散（高达3.25 mm）。因此，这些数据表明，脑内显微注射后的muscimol扩散比通常认为的要大。讨论了这些结果与行为研究结果之间的关系。(C) 2002 Elsevier Science （USA）。
Intracerebral muscimol injection is widely used to inactivate discrete brain structures during behavioral tasks. However, little effort has been made to quantify the extent of muscimol diffusion. The authors report here electrophysiological and autoradiographic results obtained after muscimol injection either into the nucleus basalis magnocellularis (0.1-0.4 mul) or into the thalamic reticular nucleus (RE, 0.05-0.1 mul). In 52 rats, multiunit recordings were collected either in the RE or in the auditory thalamus during the 2 It following muscimol injection. Decreases in neuronal activity were observed up to 3 mm from the injection site; their time of occurrence was a function of the distance between the injection and recording site,. Because these decreases cannot be explained by physiological effects, they likely reflected muscimol diffusion up to the recording sites. Autoradiographic studies involved 25 rats and different experimental conditions. Optical density (OD) measures indicated that after a survival time of 15 min, a 0.05-mul injection produced a labeled area of 5.25 mm(2) at the injection site and a rostrocaudal labeling of 1.7 mm. Increasing the survival time to 60 min, or increasing the injected volume to 0.1 mul, systematically led to a larger labeled area at the injection site (8-12 mm(2)) and to a larger rostrocaudal diffusion (2.0-2.5 mm). Direct quantifications of radioactivity by a high-resolution radioimager validated the OD measures and even indicated a larger muscimol diffusion (up to 3.25 mm). Thus, these data point out that muscimol diffusion after intracerebral microinjection is larger than usually supposed. The relationships between these results and those obtained in behavioral studies are discussed. (C) 2002 Elsevier Science (USA).