α_(1D)-肾上腺素受体的稳定表达及其Ca^(2+)调控

Stable expression and Ca^(2+) regulation of human α_(1D)-adrenergic receptor subtype

目的探讨人α_(1D)-肾上腺素受体（α_(1D)-adrcnerslcreceptor，α_(1D)-AR）触发细胞的Ca(2+)释放和Ca(2+)内流机制。方法：将编码人α_(1D)-ARcDNA转染到缺乏α1－AR的中国仓鼠卵巢（CHO）细胞，建立稳定表达纯一α_(1D)-AR的细胞系。采用Fura－2技术观察细胞胞浆Ca(2+)浓度变化。结果：肾上腺素激活α_(1D)-AR后既触发了CHO细胞的Ca(2+)释放又引起细胞外Ca(2+)内流。磷脂酶C（phospholipaseC，PLC）抑制剂U－73122抑制α_(1D)-AR激发Ca(2+)释放的同时也抑制了Ca(2+)内流。结论：人α_(1D)-AR与PLC激活途径相耦联释放细胞内储存Ca(2+)并通过“充电式Ca(2+)内流”机制触发细胞外Ca(2+)内流。

To investigate the mecha-nisms underlying the intracellular Ca2+ releaseand extracellular Ca2+ entry triggered by humanα1D- adrenergic receptor (a1D- AR ). METHODS:The cDNA encoding human a1D AR was transfected into Chinese hamster ovary (CHO) cellsto establish a cell line which stably expressedthis receptor. [Ca2+], transient was determinedthrough using Fura-2 technique. RESULTS: a1DAR, stimulated with epinephrine, triggeredboth the Ca2+ release and Ca2+ influx of the a1D-AR-expressing CHO cells. U-73122, an inhibitor of phospholipase C (PLC ), could almostcompletely abolish not only Ca2- release but alsoCa2+ Influx mediated by olD AR. CONCLUSION: Human aiD- AR, coupled to the pathwayof PLC activation. can release CaZ- from intracellular Ca2- store and evoke Ca2~ influx via 'capacitative Ca2+ entry' pathway.