Meyer J M, Weyhenmeyer J A
Am J Physiol. 1986 Jul;251(1 Pt 1):C17-22. doi: 10.1152/ajpcell.1986.251.1.C17.
Recent evidence has demonstrated that dissociated fetal rat brain cells in culture synthesize an angiotensin II (ANG II)-like peptide that shares common properties with authentic ANG II, suggesting that brain has a complete renin angiotensin system that is independent of peripheral substrates. Although ANG II has been postulated to function as a neurotransmitter/neuromodulator, the release of ANG II from presynaptic nerve terminals has not been established. To investigate the mechanism of ANG II release, brain cells from 20-day gestational age Sprague-Dawley rats were dissociated by mild trypsinization and grown in culture. The cells were maintained in serum-free medium for 5 days prior to experimental analysis. Cultured brain cells were challenged with 59 mM KCl in the presence or absence of 5 mM CaCl2, and the incubation medium was measured for the release of ANG II by radioimmunoassay and high-performance liquid chromatography. The data demonstrate that K+ stimulation results in a rapid and time-dependent release of ANG II-like peptide that is Ca2+ dependent. We have concluded that these findings are consistent with those for other neurotransmitter/neurohormone systems and therefore provide further support for the role of ANG II as a chemical transmitter in the brain.
最近的证据表明，培养的离体胎鼠脑细胞能合成一种血管紧张素II（ANG II）样肽，它与天然ANG II具有共同特性，这表明大脑拥有一个独立于外周底物的完整肾素血管紧张素系统。尽管已推测ANG II可作为神经递质/神经调节剂发挥作用，但尚未证实其从突触前神经末梢释放。为研究ANG II的释放机制，通过轻度胰蛋白酶消化法分离20日龄斯普拉格-道利大鼠的脑细胞并进行培养。在实验分析前，将细胞置于无血清培养基中培养5天。在有或无5 mM氯化钙存在的情况下，用59 mM氯化钾刺激培养的脑细胞，并用放射免疫测定法和高效液相色谱法测定孵育培养基中ANG II的释放量。数据表明，钾离子刺激导致ANG II样肽快速且呈时间依赖性释放，且这种释放依赖于钙离子。我们得出结论，这些发现与其他神经递质/神经激素系统的发现一致，因此进一步支持了ANG II作为大脑中化学递质的作用。
