权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Analysis of the store-dependent Ca entry mechanisms in adrenal chromaffin cells

肾上腺嗜铬细胞中储存依赖性 Ca 进入机制的分析

基本信息

批准号：
11660290
负责人：
OHTA Toshio
金额：
$ 2.3万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

In this project, I analyzed membrane currents, intracellular Ca concentration ([Ca2+]i) and catecholamine (CA) secretion from isolated adrenal chromaffin cells to identify the functional roles of internal Ca stores and the store-dependent Ca entry mechanisms. A simultaneous on-line system for measurement of CA and ATP was made using culture cells. 1) In voltage-clamped chromaffin cells, Ca released from internal stores produced a transient [Ca2+]i increase concomitant with a transient outward K current. 2) In Ca-free conditions, [Ca2+]i increases derived from internal stores were abolished by inhibitors of Ca-ATPase and the elevation of [Ca2+]i was occurred after the re-application of external Ca. 3) CA secretion was elicited by Ca released from internal stores in single voltage-clamped cells. 4) The molar ratio of CA to ATP was constant regardless of secretagogues used. 5) Tyrosine kinase inhibitors suppressed the store-dependent Ca entry in smooth muscle cells. 6) Non-selective cation channel blockers and La inhibited Ca entry but in a different manner each other. It was revealed that internal Ca stores play functional roles in many cellular responses, including the regulation of ionic channels, change in [Ca2+]i and exocytosis. Store-dependent Ca entry may be partly mediated by tyrosine kinases. Further research is needed to identify the functional molecules such as trp-gene products, responsible for the store-dependent Ca entry mechanisms.

在这个项目中，我分析了分离的肾上腺染色质细胞的膜电流、细胞内钙浓度（[Ca2+] I）和儿茶酚胺（Ca）分泌，以确定内部钙储存的功能作用和钙储存依赖的钙进入机制。利用培养细胞，建立了CA和ATP在线同步测量系统。1)在电压箝制的染色质细胞中，钙从内部储存中释放出来，产生瞬态[Ca2+]i增加，同时产生瞬态向外K电流。2)在无Ca条件下，Ca- atpase抑制剂消除了由内源性钙离子引起的[Ca2+]i升高，而在外源性钙离子再次应用后，[Ca2+]i升高。3)单个电压箝位细胞中由内源性钙离子释放的Ca引起Ca分泌。4)无论使用何种促分泌剂，CA与ATP的摩尔比都是恒定的。5)酪氨酸激酶抑制剂抑制平滑肌细胞储存依赖性钙的进入。6)非选择性阳离子通道阻滞剂和La抑制Ca进入，但方式不同。研究发现，钙离子在细胞内的储存在许多细胞反应中起着重要的作用，包括离子通道的调节、[Ca2+]i的变化和胞吐作用。储存依赖性钙的进入可能部分由酪氨酸激酶介导。需要进一步的研究来确定功能分子，如色氨酸基因产物，负责储存依赖的钙进入机制。