Evaluation of radiolabeled acetylcholine synthesis and release in rat striatum
Evaluation of radiolabeled acetylcholine synthesis and release in rat striatum
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DOI：
10.1111/jnc.15556
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发表时间：
2021-12-17
影响因子：
4.7
通讯作者：
Masuoka, Takayoshi
中科院分区：
文献类型：
--
作者：
Muramatsu, Ikunobu;Uwada, Junsuke;Masuoka, Takayoshi
胆碱能传递是认知和运动等高级大脑功能的基础。为了阐明中枢神经系统中乙酰胆碱 (ACh) 释放维持和调节的过程，在大鼠纹状体节段中研究了 [H-3] 胆碱的摄取以及随后的 [H-3]ACh 的合成和释放。与 [H-3] 胆碱一起孵育可通过高亲和力胆碱转运蛋白 1 诱导有效摄取，从而导致 [H-3] 胆碱和 [H-3]ACh 的积累。然而，抑制乙酰胆碱酯酶 (AChE) 后，与 [H-3] 胆碱一起孵育主要导致 [H-3]ACh 的积累。电刺激和 KCl 去极化选择性释放 [H-3]ACh，但不释放 [H-3]胆碱。 [H-3]ACh 释放在重复刺激下逐渐下降，而在 AChE 抑制下释放可重复。用维沙考（一种囊泡乙酰胆碱转运蛋白抑制剂）治疗后，[H-3]乙酰胆碱释放被消除。这些结果表明，可释放的乙酰胆碱不断从细胞质补充到可释放的胆碱能囊泡池中，以维持胆碱能传递。电刺激引起的[H-3]ACh释放被河鲀毒素消除，但KCl引起的释放很大程度上具有抵抗性。 ACh 释放是 Ca2+ 依赖性的，并且在两种刺激之间对 N 型和 P 型 Ca2+ 通道毒素（分别为 omega-芋螺毒素 GVIA 和 omega-agatoxin IVA）表现出略有不同的敏感性。 [H-3]ACh 释放受到 M2 毒蕈碱受体和 D2 多巴胺能受体的负调节。目前的结果表明，抑制胆碱能神经元内的AChE和突触前ACh释放的负调节有助于胆碱能传递的维持和促进，除了抑制突触间隙AChE之外，还为胆碱能功能障碍相关疾病的治疗开发提供了潜在有用的线索。
Cholinergic transmission underlies higher brain functions such as cognition and movement. To elucidate the process whereby acetylcholine (ACh) release is maintained and regulated in the central nervous system, uptake of [H-3]choline and subsequent synthesis and release of [H-3]ACh were investigated in rat striatal segments. Incubation with [H-3]choline elicited efficient uptake via high-affinity choline transporter-1, resulting in accumulation of [H-3]choline and [H-3]ACh. However, following inhibition of ACh esterase (AChE), incubation with [H-3]choline led predominantly to the accumulation of [H-3]ACh. Electrical stimulation and KCl depolarization selectively released [H-3]ACh but not [H-3]choline. [H-3]ACh release gradually declined upon repetitive stimulation, whereas the release was reproducible under inhibition of AChE. [H-3]ACh release was abolished after treatment with vesamicol, an inhibitor of vesicular ACh transporter. These results suggest that releasable ACh is continually replenished from the cytosol to releasable pools of cholinergic vesicles to maintain cholinergic transmission. [H-3]ACh release evoked by electrical stimulation was abolished by tetrodotoxin, but that induced by KCl was largely resistant. ACh release was Ca2+ dependent and exhibited slightly different sensitivities to N- and P-type Ca2+ channel toxins (omega-conotoxin GVIA and omega-agatoxin IVA, respectively) between both stimuli. [H-3]ACh release was negatively regulated by M2 muscarinic and D2 dopaminergic receptors. The present results suggest that inhibition of AChE within cholinergic neurons and of presynaptic negative regulation of ACh release contributes to maintenance and facilitation of cholinergic transmission, providing a potentially useful clue for the development of therapies for cholinergic dysfunction-associated disorders, in addition to inhibition of synaptic cleft AChE.