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目的：研究Ｋ＋去极化对大鼠纹状体突触体酪氨酸３单加氧酶（ＴＭ）激活的机制及ＳＰＤ对此激活的影响．方法：应用ＨＰＬＣＥＣＤ法测定ＤＯＰＡ为ＴＭ的活性，并应用同位素法测定ＰＫⅡ和ＰＫＣ的活性．结果：ＳＰＤ１，１０和１００μｍｏｌ·Ｌ－１增强Ｋ＋去极化对突触体ＴＭ的活性，ＰＫＣ抑制剂ＰＭＢ１０μｍｏｌ·Ｌ－１能完全逆转Ｋ＋去极化的激活效应，而选择性Ｄ２受体激动剂ＱＰ，ＣａＭ拮抗剂Ｗ７和去除反应液中的Ｃａ２＋均不影响Ｋ＋去极化对ＴＭ的激活．Ｋ＋去极化使突触体ＰＫＣ的活性增加５３％，而对ＰＫⅡ的活性无影响．ＳＰＤ和ＱＰ均不影响Ｋ＋去极化对ＰＫＣ的激活．结论：Ｋ＋去极化对突触体ＴＭ的激活作用是由ＰＫＣ介导的，不受突触前ＤＡ自身受体的调控，但被ＳＰＤ增强．
OBJECTIVE: To investigate the mechanism of K + depolarization on the activation of tyrosine 3monooxygenase (TM) in synaptosomes of striatum and the effect of SPD on this activation. Methods: The activity of DOPA was determined by HPLC-ECD method and the activity of PKⅡ and PKC was measured by isotope method. Results: SPD at 1, 10 and 100 μmol·L-1 enhanced the activity of K + depolarization on synaptosome TM. PKC inhibitor PMB 10 μmol·L-1 completely reversed the activation effect of K + depolarization, while selective D2 receptor activation Neither agent QP, CaM antagonist W7 nor Ca2 + in the reaction solution affected the activation of TM by K + depolarization. K + depolarization increased PKC activity by 53%, but had no effect on PKII activity. Neither SPD nor QP affected K + depolarization activation of PKC. CONCLUSION: Activation of synaptosome TM by K + depolarization is mediated by PKC and is not regulated by presynaptic DA autoreceptors but enhanced by SPD.