季淑梅, 薛建梅, 王川, 苏素文, 何瑞荣
燕山大学生物医学工程系. 河北, 秦皇岛 066004；河北医科大学, 药理室, 生理室. 河北, 石家庄 050017
经荧光探针Fluo 3-AM标记细胞内游离钙后,用激光共聚焦显微镜检测肾上腺髓质素(adrenomedullin,ADM)对原代培养大鼠海马神经元内游离钙浓度([Ca~(2+)]_(i))的影响.实验结果如下:ADM(0.01～1.0μmol/L)浓度依赖性地降低细胞内钙浓度。降钙素基因相关肽受体阻断剂(calcitonin gene-related peptide,CGRP_(8-37))预处理可部分抑制ADM的效应。ADM可显著抑制高钾引起的[Ca~(2+)]_(i)增加。ADM可显著抑制三磷酸肌醇(inositol 1,4,5-trisphosphate,IP_(3))引起的内钙释放,而对兰尼定(ryanodine)引起的内钙释放无显著影响.以上结果提示,ADM降低培养海马神经元内游离钙浓度,此作用与其抑制IP_(3)引起的内钙释放有关,ADM对静息状态下的Ca~(2+)内流无影响,但可显著抑制高钾引起的Ca~(2+)内流,CGRP受体介导了ADM的上述效应。
Adrenomedullin reduces intracellular calcium concentration in cultured hippocampal neurons
Ji Shumei, Xue Jianmei, Wang Chuan, Su Suwen, He Ruirong
Department of Biomedical Engineering, Yanshan University. Qinhuangdao 066004, Hebei, China；Departments of Pharmacology and Physiology, Hebei Medical University. Shijiazhuang 050017, Hebei, China
The effects of adrenomedullin (ADM) on intracellular calcium concentration ([Ca~(2+)]_(i)) were investigated in cultured hippocampal neurons. Changes in [Ca~(2+)]_(i) were detected by laser scanning confocal microscopy using Fluo 3-AM as the calcium fluorescent probe. [Ca~(2+)]_(i) was represented by relative fluorescent intensity. The results showed that: ADM (0.01～1.0 #mu#mol/L) decreased the resting [Ca~(2+)]_(i) in a concentration-dependent manner. Calcitonin gene-related peptide receptor antagonist CGRP_(8-37) significantly inhibited the effects of ADM. ADM significantly reduced the increase in [Ca~(2+)]_(i) induced by high K~(+). ADM markedly inhibited the inositol 1,4,5-trisphosphate (IP_(3))-induced increase in [Ca~(2+)]_(i), while did not influence ryanodine-evoked increase in [Ca~(2+)]_(i). These results suggest that ADM reduces [Ca~(2+)]_(i) in cultured hippocampal neurons through suppressing Ca~(2+) release from IP3-sensitive stores. Although ADM does not alter resting Ca~(2+) influx, it significantly suppresses Ca~(2+) influx activated by high K~(+). These effects may be partly mediated by CGRP receptors. ADM in the CNS may act as a cytoprotective factor in ischemic/hypoxic conditions.
Key words: Adrenomedullin;Hippocampal neurons;Intracellular calcium;Calcitonin gene-related peptide receptor antagonist (CGRP_(8-37));Inositol 1,4,5-trisphosphate;Ryanodine;Laser scanning confocal microscopy
季淑梅, 薛建梅, 王川, 苏素文, 何瑞荣. 肾上腺髓质素降低培养海马神经元胞内游离钙离子浓度[J]. 生理学报 2005; 57 (3): .
Ji Shumei, Xue Jianmei, Wang Chuan, Su Suwen, He Ruirong. Adrenomedullin reduces intracellular calcium concentration in cultured hippocampal neurons. Acta Physiol Sin 2005; 57 (3): (in Chinese with English abstract).