N，N'-二环己基碳二亚胺对电鳐突触体中新合成的和预先形成的乙酰胆碱的区室化及释放的影响

Effect of N,N'-dicyclohexylcarbodiimide on compartmentation and release of newly synthesized and preformed acetylcholine in Torpedo synaptosomes.

作者信息

Dolezal V, Sbia M, Diebler M F, Varoqui H, Morel N

机构信息

Department of Neurochemistry, Institute of Physiology, Czech Academy of Sciences, Prague.

出版信息

J Neurochem. 1993 Oct;61(4):1454-60. doi: 10.1111/j.1471-4159.1993.tb13640.x.

DOI:10.1111/j.1471-4159.1993.tb13640.x

Abstract

Using isolated cholinergic synaptosomes prepared from Torpedo electric organ, we studied the effects of N,N'-dicyclohexylcarbodiimide (DCCD) on acetylcholine (ACh) synthesis, compartmentation, and release after stimulation. Whereas ACh synthesis was unchanged, ACh compartmentation inside synaptosomes was affected by the presence of DCCD. In resting conditions, the uptake into the synaptic vesicle pool of newly synthesized ACh (i.e., [14C]ACh synthesized in the presence of the drug) was progressively and markedly inhibited as the duration of DCCD preincubation was increased, whereas compartmentation of endogenous ACh was unchanged in the presence of DCCD. After stimulation, the release of endogenous ACh from DCCD-treated synaptosomes was similar to that of control, in contrast to the release of [14C]ACh, which was markedly inhibited. This inhibition was observed whatever the conditions of stimulation used (gramicidin D, calcium ionophore A23187, or KCl depolarization). The study of the compartmentation of [14C]ACh during stimulation revealed a transfer of highly labeled ACh from the free to the bound ACh compartment in the presence of DCCD, suggesting the existence of several ACh subcompartments within the free and bound ACh pools. The present results are discussed in comparison with the previously reported effects of vesamicol (AH5183) on ACh compartmentation and release.

摘要

我们使用从电鳐电器官制备的分离胆碱能突触体，研究了N,N'-二环己基碳二亚胺（DCCD）对刺激后乙酰胆碱（ACh）合成、区室化及释放的影响。虽然ACh合成未发生变化，但DCCD的存在影响了突触体内ACh的区室化。在静息状态下，随着DCCD预温育时间的延长，新合成的ACh（即在药物存在下合成的[14C]ACh）进入突触小泡池的摄取逐渐且显著受到抑制，而内源性ACh的区室化在DCCD存在时未发生变化。刺激后，DCCD处理的突触体中内源性ACh的释放与对照相似，这与[14C]ACh的释放形成对比，[14C]ACh的释放受到显著抑制。无论使用何种刺激条件（短杆菌肽D、钙离子载体A23187或氯化钾去极化）均观察到这种抑制作用。对刺激过程中[14C]ACh区室化的研究表明，在DCCD存在下，高标记的ACh从游离ACh区室转移至结合ACh区室，提示在游离和结合ACh池中存在多个ACh亚区室。本文结果与先前报道的vesamicol（AH5183）对ACh区室化和释放的影响进行了比较讨论。