摘要
用激光扫描共聚焦显微镜研究了一般公认的耳蜗传出神经递质乙酰胆碱（ＡＣｈ）和三磷酸腺苷（ＡＴＰ）对豚鼠耳蜗外毛细胞（ＯＨＣｓ）胞内游离Ｃａ２＋浓度（［Ｃａ２＋］ｉ）的作用，ＯＨＣｓ用Ｃａ２＋敏感荧光染料Ｆｌｕｏ－３着色，胞内Ｃａ２＋的分布以细胞底部稍强。ＡＣｈ在ＯＨＣ底部引起［Ｃａ２＋］ｉ的缓慢上升并维持在一个较高水平。ＡＴＰ在整个ＯＨＣ引起一个急剧的［Ｃａ２＋］ｉ升高，升高的幅度在ＯＨＣ顶部最大。随着ＡＴＰ的持续作用，［Ｃａ２＋］ｉ缓慢下降，呈耗竭趋势，但此时用ＡＣｈ刺激仍能引起［Ｃａ２＋］ｉ的升高，这提示ＡＣｈ引起的［Ｃａ２＋］ｉ升高有胞外Ｃａ２＋流入的成分，ＡＴＰ引起的［Ｃａ２＋］ｉ；升高可能主要为胞内Ｃａ２＋库的释放，但也不排除通过ＡＴＰ门控的阳离子通道的直接进入。
Effects of acetylcholine (ACh) and ATP as the candidates of efferent neurotransmitter on intracellular Ca2+ concentrations ([Ca2+]i) of the isolated outer hair cells (OHCs) from guinea pig cochlea were studied with laser scanning confocal microscope. The OHCs were loaded with Ca2+ sensitive dye Fluo-3, whose fluorescent intensity was strongest at the hasal end in resting OHC. The presence of ACh gradually increased [Ca2+]i to a higher level at the hasal end of OHCs. Continuous application of ATP caused a rapid [Ca2+]i increase followed by a gradual exhaustion throughout the whole OHC. Magnitude of the increase at the apex was greater than that at the base. In OHCs whose calcium had been exhausted by ATP, ACh induced a temporary increase in [Ca2+]i. It seems likely that the ACh-induced [Ca2+]i rise is partly due to an influx of extracellular Ca2+. The bursting nature of ATP-induced [Ca2+]i rise may be a conse quence of Ca2+ influx through the ATP-gated canon channels and of the mobilization of intracellular store mediated by ATP.
出处
《生理学报》
CAS
CSCD
北大核心
1995年第2期105-110,共6页
Acta Physiologica Sinica
关键词
钙
外毛细胞
乙酰胆碱
腺苷三磷酸
耳蜗
豚鼠
calcium
outer hair cell
acetylcholine
ATP
con focal microscopy
