Ikeda K, Saito Y, Nishiyama A, Takasaka T
Department of Otolaryngology, Tohoku University School of Medicine, Sendai, Japan.
ORL J Otorhinolaryngol Relat Spec. 1991;53(2):78-81. doi: 10.1159/000276192.
The cytosolic calcium concentration [( Ca2+]i) of the isolated outer hair cell of the guinea pig was measured using fluorescence imaging microscopy and the effects of efferent neuroregulators such as acetylcholine, ATP, GABA, substance P, enkephalin, calcitonin gene-related peptide, serotonin, dopamine, norepinephrine, and glutamate were investigated. Among the drugs tested only ATP induced an elevation of the [Ca2+]i of the outer hair cell. In the resting condition, [Ca2+]i averaged 104.5 +/- 31.1 nM (n = 27), while 100 microM ATP significantly increased [Ca2+]i to 146.3 +/- 43.5 nM (n = 19). Superfusion with Ca2(+)-free solution (pCa = 7.5) abolished the increase in [Ca2+]i induced by ATP, suggesting that ATP causes an entry of external Ca2+. The relevance of [Ca2+]i to the inhibitory actions of efferent neuroregulators is discussed.
利用荧光成像显微镜测量豚鼠分离出的外毛细胞的胞质钙浓度[（Ca2+]i），并研究了乙酰胆碱、ATP、GABA、P物质、脑啡肽、降钙素基因相关肽、5-羟色胺、多巴胺、去甲肾上腺素和谷氨酸等传出神经调节剂的作用。在所测试的药物中，只有ATP能引起外毛细胞[Ca2+]i升高。在静息状态下，[Ca2+]i平均为104.5±31.1 nM（n = 27），而100μM ATP可使[Ca2+]i显著升高至146.3±43.5 nM（n = 19）。用无Ca2+溶液（pCa = 7.5）灌流可消除ATP诱导的[Ca2+]i升高，表明ATP导致细胞外Ca2+内流。本文讨论了[Ca2+]i与传出神经调节剂抑制作用的相关性。
