Estimating extracellular concentrations of dopamine and 3,4-dihydroxyphenylacetic acid in nucleus accumbens and striatum using microdialysis: relationships between in vitro and in vivo recoveries.
Estimating extracellular concentrations of dopamine and 3,4-dihydroxyphenylacetic acid in nucleus accumbens and striatum using microdialysis: relationships between in vitro and in vivo recoveries.
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使用微透析估计伏核和纹状体中多巴胺和 3,4-二羟基苯乙酸的细胞外浓度：体外和体内回收率之间的关系。
DOI：
10.1046/j.1471-4159.1994.62052017.x
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发表时间：
1994
影响因子：
4.7
通讯作者：
Carlson,JN
中科院分区：
文献类型：
--
作者：
Glick,SD;Dong,N;KellerJr,RW;Carlson,JN
在微透析研究中，通常的做法是在人工CSF中对探针进行“校准”，并确定所有待测物质的体外回收率。然后，对这些物质的透析液浓度进行体外回收“校正”，以提供细胞外浓度的“估计值”。至少对于多巴胺，体外和体内回收率是显著不同的，因此，基于体外回收率校正的细胞外多巴胺的估计可能是错误的。然而，一般来说，动物之间的这种估计的相对关系是感兴趣的，而不是“真正的”细胞外值。这种关系在估计值与真实值相关或预测真实值的程度上是有效的。使用“无净流量”程序，本研究试图确定多巴胺及其代谢产物3，4-二羟基-苯乙酸（DOPAC）的体外和体内回收率是否相互关联，以及这些物质的各自估计值和真实值（无净流量）是否相互关联。探头（3 mm; BAS/CMed MF-5393），在开始样品采集前一天，将其放入自由活动大鼠的丘脑核和纹状体中。在体外和体内回收率没有显着相关性（r= 0.1-0.3），无论是多巴胺或DOPAC。然而，对于多巴胺和DOPAC，估计值和真实值之间存在显著相关性（r= 0.7-0.8）。令人惊讶的是，当使用这些商业探头时，两种物质的绝对透析液水平与真实值的相关性甚至更好（r = 0.9-0.95）。这表明，使用这些探针，当不实际进行净通量研究时，可以使用透析液浓度的直接比较来确定多巴胺和DOPAC的基础细胞外水平的相对变化（例如，因为表征药物作用所需的时间）。使用体外校准可将值调整为更接近真实值，但也会给每个值增加噪声，因此应避免使用。
It is common practice in microdialysis studies for probes to be “calibrated” in artificial CSF and in vitro recoveries determined for all substances to be measured in vivo. Dialysate concentrations of such substances are then “corrected” for in vitro recoveries to provide “estimates” of extracellular concentrations. At least for dopamine, in vitro and in vivo recoveries are significantly different and, therefore, an estimate of extracellular dopamine based on correction for in vitro recovery is likely to be erroneous. Generally, however, the relative relationships of such estimates among animals are of interest rather than the “true” extracellular values. Such relationships would be valid to the extent that estimated values are correlated with or predictive of true values. Using the “no net flux” procedure, the present study sought to determine, for both dopamine and its metabolite 3,4‐dihydroxy‐phenylacetic acid (DOPAC), whether in vitro and in vivo recoveries would correlate with each other as well as whether respective estimated and true (no net flux) values of these substances would correlate with each other. Probes (3 mm; BAS/CMed MF‐5393), previously calibrated, were lowered into both the nucleus accumbens and striatum of freely moving rats the day before sample collection was begun. In vitro and in vivo recoveries were not significantly correlated (r= 0.1–0.3), for either dopamine or DOPAC. For both dopamine and DOPAC, however, there were significant correlations (r= 0.7–0.8) between estimated and true values. Surprisingly, when using these commercial probes, absolute dialysate levels for both substances were even better correlated (r = 0.9–0.95) with true values. This suggests that, with these probes, a direct comparison of dialysate concentrations can be used to determine relative changes in basal extracellular levels of dopamine and DOPAC when it is not practical to do no net flux studies (e.g., because of the time required to characterize a drug effect). The use of in vitro calibrations adjusts the values closer to the true values but also adds noise to each value and therefore should be avoided.