Han W, Zhang S, Han D, Jiang S, Yang W
Department of Otolaryngology, Head and Neck Surgery, General Hospital of PLA, Beijing 100853, China.
Chin Med J (Engl). 2001 Jul;114(7):714-7.
To better understand the cholinergic receptors in vestibular hair cells (VHC) and their subtypes, and to investigate the effects of cholinergic agonists on intracellular calcium concentration ([Ca2+]i) in guinea pig VHCs.
VHCs were isolated from guinea pig crista ampullaris by enzymatic and mechanical methods. The effect of cholinergic agonists on [Ca2+]i was examined using laser scanning confocal microscopy and the Ca2+ sensitive dye Fluo-3.
The results showed that the addition of acetylcholine (ACh) and carbachol (CCh), muscamic and nicotinic agonists, induced [Ca2+]i increases in all the VHCs, whereas acetylcholine bromide (ACh-Br), a nicotinic agonist, induced the [Ca2+]i increase in only a small percentage of VHCs. The ACh or CCh-induced Ca2+ response could be partially suppressed by atropine. In the presence of 0.1 mmol/L atropine, the amplitudes of ACh or CCh-induced [Ca2+]i responses became significantly smaller than those in atropine free medium (P < 0.01).
The results suggest the existence of cholinergic receptors in guinea pig VHCs. It is the muscamic agonists rather than nicontic receptors that dominate [Ca2+]i variation. Atropine can suppress muscamic agonist-induced Ca2+ responses.
更好地了解前庭毛细胞（VHC）中的胆碱能受体及其亚型，并研究胆碱能激动剂对豚鼠VHCs细胞内钙浓度（[Ca2+]i）的影响。
采用酶解法和机械法从豚鼠壶腹嵴分离VHCs。使用激光扫描共聚焦显微镜和Ca2+敏感染料Fluo-3检测胆碱能激动剂对[Ca2+]i的影响。
结果显示，添加乙酰胆碱（ACh）、卡巴胆碱（CCh）、毒蕈碱和烟碱激动剂可使所有VHCs中的[Ca2+]i升高，而烟碱激动剂溴化乙酰胆碱（ACh-Br）仅使一小部分VHCs中的[Ca2+]i升高。阿托品可部分抑制ACh或CCh诱导的Ca2+反应。在0.1 mmol/L阿托品存在的情况下，ACh或CCh诱导的[Ca2+]i反应幅度明显小于无阿托品培养基中的反应幅度（P < 0.01）。
结果表明豚鼠VHCs中存在胆碱能受体。主导[Ca2+]i变化的是毒蕈碱激动剂而非烟碱受体。阿托品可抑制毒蕈碱激动剂诱导的Ca2+反应。
