Thomas D N, Holman R B
Reckitt and Colman Psychopharmacology Unit, School of Medical Sciences, Bristol, Avon, England.
J Neurochem. 1991 May;56(5):1741-6. doi: 10.1111/j.1471-4159.1991.tb02075.x.
In vivo microdialysis was used to investigate the regulation of noradrenaline release in rat hippocampus. Idazoxan, an alpha 2-adrenoreceptor antagonist (1-10 mg/kg), increased noradrenaline release in a dose-dependent manner. Inhibition of noradrenaline uptake by desipramine (0.05-20 microM; via the probe) also increased the extracellular content of the transmitter. In the presence of this increased noradrenaline content (desipramine via the probe), the effect of a low dose of idazoxan (1 mg/kg) was potentiated. Local perfusion of idazoxan (1-500 microM) in the hippocampus also increased noradrenaline release but not to the same extent as following systemic administration. In the presence of desipramine, unlike the systemic injection of idazoxan, local perfusion did not potentiate noradrenaline release. The data are consistent with the regulation of extracellular noradrenaline content in the hippocampus by neuronal uptake and to a lesser extent by presynaptic autoreceptors.
采用体内微透析技术研究大鼠海马中去甲肾上腺素释放的调节机制。咪唑克生，一种α2-肾上腺素能受体拮抗剂（1-10毫克/千克），以剂量依赖的方式增加去甲肾上腺素的释放。地昔帕明（0.05-20微摩尔；通过探针）抑制去甲肾上腺素摄取也增加了递质的细胞外含量。在这种去甲肾上腺素含量增加的情况下（通过探针给予地昔帕明），低剂量咪唑克生（1毫克/千克）的作用得到增强。在海马中局部灌注咪唑克生（1-500微摩尔）也增加去甲肾上腺素释放，但程度不如全身给药后。在存在地昔帕明的情况下，与全身注射咪唑克生不同，局部灌注并未增强去甲肾上腺素释放。这些数据与神经元摄取以及较小程度上的突触前自身受体对海马中细胞外去甲肾上腺素含量的调节一致。
