FIRING PATTERNS OF MIDBRAIN DOPAMINE NEURONS - DIFFERENCES BETWEEN A9-CELLS AND A10-CELLS
FIRING PATTERNS OF MIDBRAIN DOPAMINE NEURONS - DIFFERENCES BETWEEN A9-CELLS AND A10-CELLS
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DOI：
10.1111/j.1748-1716.1988.tb08468.x
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发表时间：
1988-09-01
期刊：
影响因子：
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通讯作者：
SVENSSON, TH
中科院分区：
文献类型：
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作者：
GRENHOFF, J;UGEDO, L;SVENSSON, TH
黑质（A9）和腹侧被盖区（a10）的多巴胺神经元分别产生黑质纹状体和中边缘多巴胺通路，通常认为它们表现出类似的电生理活动。然而，在某些情况下，这两个系统的调制方式是不同的。为了评估A9和A10神经元活性可能的生理差异，在水合氯醛麻醉的雄性大鼠中随机取样单细胞进行细胞外记录。除射速外，还定量分析了爆轰程度和射轰规律。我们的研究结果表明，尽管A9和A10在放电速率上没有差异，但从峰间时间间隔直方图的分析可以判断，A10神经元的活动明显不那么规律，并且表现出更高程度的突发放电。A9神经元的平均放电值为3%，A10神经元的平均放电值为23%。规律由峰间时间间隔直方图的变异系数描述。A9组和A10组的平均变异系数分别为38.4%和63.8%，即AIO神经元放电的规律性较差。规律性的差异部分地（但不是完全）取决于爆发射击的差异。先前的生化和生理学研究强烈支持中脑多巴胺细胞放电模式的调节变化的功能意义。由于中脑多巴胺细胞的放电模式似乎是由突触输入控制的，我们的研究结果表明，对阿罗神经元的张力调节作用高于对A9神经元的张力调节作用。因此，目前的结果暗示了优先影响AIO和A9多巴胺细胞功能的药理学可能性。
Dopamine neurons of the substantia nigra (A9) and the ventral tegmental area (A 10), giving rise to the nigrostriatal and mesolimbic dopamine pathways, respectively, are commonly supposed to show similar electrophysiological activity. There are, however, instances where the two systems are differently modulated. To assess possible physiological differences in the neuronal activity of A9 and A10 neurons, randomly sampled single cells were extracellularly recorded in the chloral hydrate‐anaesthetized male rat. In addition to firing rate, the degree of burst firing and the regularity of firing were quantitatively analysed. Our results show that although A9 and A10 do not differ in firing rates, A10 neuronal activity is markedly less regular and shows a higher degree of burst firing, as judged from analysis of inter‐spike time interval histograms. Mean burst firing values were 3% for the A9, and 23% for the A10 neurons. Regularity was described by variation coefficients of inter‐spike time interval histograms. The mean variation coefficient was 38.4% in the A9 group and 63.8% in the A10 group, i. e. the AIO neuronal firing was less regular. The difference in regularity is partly, but not fully, dependent on the difference in burst firing. Previous biochemical and physiological studies strongly support the functional significance of modulatory changes in midbrain dopamine‐cell firing patterns. Since the firing pattern of midbrain dopamine cells seems to be controlled by synaptic inputs, our results indicate a higher tonic modulatory influence on the Aro than on the A9 neurons. Thus the present results imply the pharmacological possibility of preferentially affecting AIO versus A9 dopamine cell function.