微量透析法－－活體生物內藥物分析之新取樣技術   全文下載

In Vivo Microdialysis: A Novel Sampling Technique for Drug Analysis in Live Subjects

本實驗採用微量透析技術（microdialysis）配合高效液相層析儀，偵測在靜脈投予不同劑量的古柯鹼（1.5 mg／kg, 3.0 mg／kg）之後，大白鼠內前額皮質區（mPFC）中古柯鹼及多巴胺的濃度變化情形。其結果發現：在靜脈投予古柯鹼前透析液中多巴胺濃度為0.39 ± 0.06 nM；在投予古柯鹼之後不論高劑量組或低劑量處，二組的透析液中古柯鹼及多巴胺濃度均在二十分鐘內上升至最高，然後兩者相對應迅速下降，約一百分鐘後恢復到正常值。多巴胺上升最高百分比分別為劑量組的118.7 ± 15.0%及高劑量組的214.1 ± 20.3%；古柯鹼最高濃度則分別為0.20 ± 0.08 μM及0.60 ± 0.08 μM。由於古柯鹼的體內回收率為33 + 5%，因此可以推算出實驗動物mPFC處實際古柯鹼最高濃度分別為1.84 ± 0.61及4.00 ± 0.94 μM。總括而言，靜脈投予古柯鹼可引起mPFC多巴胺濃度上升，並呈劑量相關性，且mPFC處古柯鹼濃度與多巴胺濃度上升百分比成一次方線性關，其相關係數為0.976。從此一應用實例中，我們知道微量透析技術不僅可以偵測活體動物內特定區域中的藥物濃度，並可以同時獲得內生性物質的變化情形，是值得推廣之藥物分析技術。"

By using an in vivo microdialysis technique, extracellular dopamine (DA) and cocaine concentration in the medial prefrontal cortex (mPFC) after intravenous cocaine injection (1.5 mg/kg in group A and 3.0 mg/kg in group B) were evaluated in adult male Sprague-Dawley rate anesthetized with chloral hydrate (400 mg/ kg, i.p., with 80 mg/kg/h supplements). Dialysate samples were collected at 20-min intervals for a 100-min period and were analyzed for DA content by an HPLC/electrochemical detector, and for cocaine content by an HPLC /ultraviolet ' . detector. After intravenous (i.v.) cocaine injection, both DA and cocaine concentrations is the dialysate reached maximum within 20 minutes, correlated nicely, and then rapidly declined. The maximal DA increase was 214.0±20.3% for the high dose group and 118.7±5.0%, for the low dose group. The DA baseline concentration in dialysate was 0.390±0.058nM. The maximal cocaine concentration was 0.20±0.08µM, and 0.6±0.08µM respectively. By using an in vivo calibration method for microdidalysis, the in vivo reccovery of cocaine in the mPFC was obtained as 33±5%. The actual extracellular cocaine concentration was therefore calculated to be 1.84±0.64µM in group A dnd 4.00±0.94µgM in group B. Form the results, extracellular cocaine concentraion was found to be higly correlated with a DA percentile increase over the 100 min period of time. After first-order linear regression, the correlation coefficient was 0.976. In summary, in vivo microdialysis is not only a sampling technique for determining the drug concentration at a specific area in live subjects, but is also useful simultaneously to observe the changes of endogenous compound. Therefore, microdialysis technique is a popluar research tool with great potential in the immediate future and is a valuable new state of the art to be introduced into our research society.