Finkelstein Y, Sternfeld M, Yegana Y, Ben-Menahem N, Flechter S, Hod I
Department of Neurology, Rambam Medical Center, Haifa, Israel.
Exp Neurol. 1987 Oct;98(1):130-6. doi: 10.1016/0014-4886(87)90078-1.
In vivo studies have shown that high blood concentrations of pituitary-adrenocortical hormones can activate the hippocampal cholinergic terminals. Incubation of hippocampal synaptosomal preparations with methylprednisolone, or with ACTH at concentrations comparable to stress-induced high concentrations in plasma, did not have any significant effects on the cholinergic parameters measured under unactivated conditions. In the presence of either high K+ or of ACh, choline uptake was decreased. This decrease was not affected by methylprednisolone. However, methylprednisolone did enhance ACh release both after a previous increase (induced by K+) or a decrease (induced by ACh) of ACh release. In contrast, ACTH had no direct effects on either unactivated or K+-stimulated synaptosomes. Thus, a differential effect was exerted by methylprednisolone on the two presynaptic regulatory mechanisms: choline uptake (no change) and ACh release (increase). We suggest that the activation, observed in vivo, resulted mainly from indirect action of the hormones on the hippocampal cholinergic terminals, in view of the fact that the direct effect in vitro was partial.
体内研究表明，垂体 - 肾上腺皮质激素的高血浓度可激活海马胆碱能终末。用甲泼尼龙或与血浆中应激诱导的高浓度相当的促肾上腺皮质激素（ACTH）孵育海马突触体标本，对在未激活条件下测量的胆碱能参数没有任何显著影响。在高钾或乙酰胆碱（ACh）存在的情况下，胆碱摄取减少。这种减少不受甲泼尼龙的影响。然而，甲泼尼龙确实在先前ACh释放增加（由钾诱导）或减少（由ACh诱导）后增强了ACh释放。相比之下，ACTH对未激活或钾刺激的突触体没有直接影响。因此，甲泼尼龙对两种突触前调节机制产生了不同的作用：胆碱摄取（无变化）和ACh释放（增加）。鉴于体外直接作用是部分的，我们认为在体内观察到的激活主要是由于激素对海马胆碱能终末的间接作用。
