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目的：通过观察胆碱能受体激动剂对离体前庭毛细胞内钙离子浓度的影响，探讨前庭毛细胞膜所存在的胆碱能受体及其分型、受体的脱敏现象。方法：用胶原酶消化后机械分离法，分离豚鼠壶腹嵴前庭毛细胞（VHC)， 钙敏荧光探针 Fluo-3 荧光染色，用激光扫描共聚焦显微镜记录VHC细胞内游离钙离子浓度（[Ca2+]i）的动态变化。结果：①胆碱能M和N型受体激动剂乙酰胆碱(ACh)、氨甲酰胆碱(CCh)均可引起离体VHC内[Ca2+]i的升高；N型受体激动剂溴化乙酰胆碱(Ach-Br)仅在高浓度（10 mmol/L）时引起部分（4/5）离体VHC内[Ca2+]i升高，在低浓度(1mmol/L)时影响不明显；②ACh、CCh 引起 VHC内[Ca2+]i升高在同一细胞不能重复出现，存在脱敏现象；而不同类型的受体激动剂先后作用时无脱敏现象；③阿托品对ACh、CCh引起的VHC内[Ca2+]i的升高有抑制作用；加入 0.1 mmol/L 阿托品可使 1 mmol/L ACh 或 CCh 引起的 VHC 内[Ca2+]i升高的峰值明显减小(t检验均有极显著差异，P<0.01)。结论：豚鼠前庭毛细胞膜上存在 M 型和 N 型两种受体，M 型受体激动剂引起 VHC 内[Ca2+]i的升高较 N 型明显。阿托品对 M 型受体激动剂引起的[Ca2+]i 升高有抑制作用；前庭毛细胞膜上的胆碱能受体对同一类型的激动剂有脱敏现象，而不同类型的激动剂
OBJECTIVE: To investigate the effect of cholinergic receptor agonist on the intracellular calcium concentration in isolated vestibular hair cells and to explore the desensitization of cholinergic receptors, their subtypes and receptors in the vestibular hair cell membrane. Methods: The isolated vestibular hair cells (VHC) and Fluo-3 of calcium-sensitive fluorescent probe were isolated by mechanical separation after collagenase digestion, and the intracellular free calcium concentration in VHC cells was recorded by laser scanning confocal microscopy ([ Ca2 +] i) dynamic changes. Results: (1) Cholinergic M and N receptor agonists, acetylcholine (ACh) and carbachol (CCh), all induced the increase of [Ca2 +] i in isolated VHC; Acetylcholine (Ach-Br) caused an increase of [Ca2 +] i in some (4/5) ex vivo VHC only at high concentration (10 mmol / L) CCh induced [Ca2 +] i increase in VHC can not be repeated in the same cell, there desensitization phenomenon, and different types of receptor agonists have no desensitization effect; ③ atropine on ACh, CCh-induced [Ca2 + ] i increased inhibition; Addition of 0.1 mmol / L atropine can make 1 mmol / L ACh or CCh-induced peak VHC [Ca2] i increased significantly decreased (t test were significantly different, P < 0.01). CONCLUSION: There are M and N receptors on the membrane of vestibular hair cells in guinea pigs. M-type receptor agonists cause the increase of [Ca2 +] i in VHC compared with N type. Atropine inhibits the increase of [Ca2 +] i induced by M-type receptor agonists; the cholinergic receptors on membrane of vestibular hair cell membrane desensitize to the same type of agonist, and different types of agonists