α7烟碱型乙酰胆碱受体（nAChR）主要分布于中枢神经系统（CNS），包括大脑的海马、纹状体和皮质。 α7 nAChR具有高Ca2+通透性，可快速激活和脱敏，与阿尔茨海默病（AD）、癫痫、精神分裂症、肺癌、帕金森病（PD）、炎症等疾病密切相关。来自海洋锥螺毒液的 α-芋螺毒素通常是短的、富含二硫键的神经肽，以 nAChR 为靶点，可以区分各种亚型，为 nAChR 的功能研究提供重要的药理学工具。 [Q1G, ΔR14]LvlB 是一种大鼠 α7 nAChRs 选择性拮抗剂，由 α-芋螺毒素 LvlB 修饰而成。在本研究中，我们利用N-羟基琥珀酰亚胺（NHS）活化处理后的三种荧光素：6-TAMRA-SE、Cy3 NHS和BODIPY-FL NHS，在弱光下标记[Q1G，ΔR14]LvIB的N端碱性条件下，获得三种荧光类似物：LvIB-R、LvIB-C和LvIB-B。 [Q1G，ΔR14]LvIB荧光类似物的效力在非洲爪蟾卵母细胞中表达的大鼠α7 nAChR上进行评估。使用两电极电压钳（TEVC），LvIB-R、LvIB-C和LvIB-B的半最大抑制浓度（IC50）值分别为643.3 nM、298.0 nM和186.9 nM。脑脊液稳定性分析显示，孵育12 h后，3种荧光类似物的保留率分别为52.2%、22.1%和0%。应用[Q1G, ΔR14]LvlB荧光类似物探讨α7 nAChRs在大鼠脑组织海马和纹状体中的分布，发现Cy3和BODIPY FL标记的[Q1G, ΔR14]LvlB表现出比6更好的成像特性-塔玛拉-。还发现α7 nAChR广泛分布于大脑皮层和小脑小叶。考虑到效力、成像和稳定性，[Q1G, ΔR14]LvlB -BODIPY FL 是研究 α7 nAChR 的组织分布和功能的理想药理学工具。我们的研究结果不仅为芋螺毒素作为视觉药理学探针的开发提供了基础，而且还证明了α7 nAChRs在大鼠大脑中的分布。

α7 nicotinic acetylcholine receptors (nAChRs) are mainly distributed in the central nervous system (CNS), including the hippocampus, striatum, and cortex of the brain. The α7 nAChR has high Ca2+ permeability and can be quickly activated and desensitized, and is closely related to Alzheimer's disease (AD), epilepsy, schizophrenia, lung cancer, Parkinson's disease (PD), inflammation, and other diseases. α-conotoxins from marine cone snail venom are typically short, disulfide-rich neuropeptides targeting nAChRs and can distinguish various subtypes, providing vital pharmacological tools for the functional research of nAChRs. [Q1G, ΔR14]LvΙB is a rat α7 nAChRs selective antagonist, modified from α-conotoxin LvΙB. In this study, we utilized three types of fluorescein after N-Hydroxy succinimide (NHS) activation treatment: 6-TAMRA-SE, Cy3 NHS, and BODIPY-FL NHS, labeling the N-Terminal of [Q1G, ΔR14]LvΙB under weak alkaline conditions, obtaining three fluorescent analogs: LvIB-R, LvIB-C, and LvIB-B, respectively. The potency of [Q1G, ΔR14]LvΙB fluorescent analogs was evaluated at rat α7 nAChRs expressed in Xenopus laevis oocytes. Using a two-electrode voltage clamp (TEVC), the half-maximal inhibitory concentration (IC50) values of LvIB-R, LvIB-C, and LvIB-B were 643.3 nM, 298.0 nM, and 186.9 nM, respectively. The stability of cerebrospinal fluid analysis showed that after incubation for 12 h, the retention rates of the three fluorescent analogs were 52.2%, 22.1%, and 0%, respectively. [Q1G, ΔR14]LvΙB fluorescent analogs were applied to explore the distribution of α7 nAChRs in the hippocampus and striatum of rat brain tissue and it was found that Cy3- and BODIPY FL-labeled [Q1G, ΔR14]LvΙB exhibited better imaging characteristics than 6-TAMARA-. It was also found that α7 nAChRs are widely distributed in the cerebral cortex and cerebellar lobules. Taking into account potency, imaging, and stability, [Q1G, ΔR14]LvΙB -BODIPY FL is an ideal pharmacological tool to investigate the tissue distribution and function of α7 nAChRs. Our findings not only provide a foundation for the development of conotoxins as visual pharmacological probes, but also demonstrate the distribution of α7 nAChRs in the rat brain.