Hoffmann I S, Cubeddu L X
J Neurochem. 1982 Aug;39(2):585-8. doi: 10.1111/j.1471-4159.1982.tb03987.x.
Superfused rabbit neostriatal slices prelabeled with [3H]dopamine ([3H]DA) were polarized with electrical pulses (12 V, 1 ms). Although transmitter release showed a proportional increase with a greater number of pulses (30-360 pulses), flat frequency-release curves were obtained. Haloperidol (0.03-0.3 micro M) enhanced 3H overflow without affecting its metabolism or time course, and antagonized apomorphine-induced inhibition of transmitter release. Maximal enhancement of release by haloperidol was obtained with 30-60 pulses delivered at a rate of 3 Hz, whereas much less facilitation of release was seen at 0.3 and 1 Hz (30-90 pulses) or with 360 pulses at either of the three frequencies. Therefore, the slope of the frequency-release curve was markedly increased by haloperidol. These results indicate that activation of presynaptic DA receptors, and thus facilitation of release by haloperidol was highly dependent on the rate and duration of stimulation of striatal dopaminergic terminals. In these neurons the feedback loop seems to act physiologically to depress the slope of the frequency-release curve.
预先用[3H]多巴胺（[3H]DA）标记的兔新纹状体切片在电脉冲（12V，1ms）作用下发生极化。尽管递质释放随脉冲数量增加（30 - 360个脉冲）呈比例增加，但得到的是平缓的频率 - 释放曲线。氟哌啶醇（0.03 - 0.3微摩尔）增强了3H溢出，而不影响其代谢或时间进程，并拮抗阿扑吗啡诱导的递质释放抑制。氟哌啶醇在以3Hz频率施加30 - 60个脉冲时能最大程度增强释放，而在0.3Hz和1Hz（30 - 90个脉冲）时或在三个频率中的任何一个频率施加360个脉冲时，释放促进作用要小得多。因此，氟哌啶醇显著增加了频率 - 释放曲线的斜率。这些结果表明，突触前DA受体的激活以及因此氟哌啶醇对释放的促进高度依赖于纹状体多巴胺能终末的刺激速率和持续时间。在这些神经元中，反馈回路似乎在生理上起到降低频率 - 释放曲线斜率的作用。
