心脏β_1肾上腺素受体对钙通道调节及其在心肌重塑中作用

Effects of cardiac β_1-adrenergic receptor on myocardial remodeling and modulating calcium channel

目的 探讨 β1肾上腺素受体对心肌钙通道的调节及其在心肌重塑中的作用。方法 建立Wistar大鼠心肌梗死后心肌重塑模型 ,用免疫组化法观测心肌I型、III型胶原和纤维连接蛋白 (FN)表达的变化 ;RT -PCR和原位杂交方法检测Ica -T通道、Ica -L通道、β1受体mRNA表达的变化 ,原子吸收光谱法测定心肌总Ca2 +浓度。结果 倍他乐克组心肌Ⅰ型、Ⅲ型胶原及纤维连接蛋白的表达均比梗死组显著减少 (P <0 0 5或P <0 0 1) ,胚胎型Ica -L通道mRNA表达被抑制 ,Ica -T通道mRNA表达无明显改变 ,β1受体mRNA的表达比梗死组减少 4 1 18% ,心肌总Ca2 +浓度比梗死组显著降低 (P <0 0 5 )。结论 心肌梗死后胚胎型Ica -T通道和Ica -L通道的mRNA表达增强可能在于增加Ca2 +内流 ,触发心肌重塑 ;β1受体可能是通过胚胎型Ica

Objective To inquire into the effects of cardiac β 1 -adrenergic receptor on myocardial remodeling and modulating calcium channel. Methods The models of myocardial remodeling after myocardial infarction in Wistar rats were used to study the expression changes of cardiac collagen subtype Ⅰ,Ⅲ,fibronectin (FN) with immunohistochemistry,and changes of T-type calcium channel,L-type calcium channel and β 1 -adrenergic receptor mRNA expressions by reverse transcription and polymerase chain reaction(RT-PCR) and in situ hybridization. Cardiac total Ca 2+ was tested by atomic absorption/flame emission spectrophotometer. Results Cardiac collagenⅠ,collagen Ⅲ,FN protein expressions in betaloc group were remarkably decreased (P<0 05 or P<0 01) compaed with that in infarcted group;The fetal pattern of L-type calcium channel gene expression was inhibited,but T-type calcium channel gene expression was not significantly affected ; Expression of β 1-adrenergic receptor mRNA was reduced by 41 18% in betaloc group ; Cardiac Ca 2+ were significantly decreased(P<0 05) in betaloc group. Conclusions Ca 2+ influxion via the calcium channel triggers myocardial remodeling.β 1 -adrenergic receptor may affeet myocardial remodeling through the fetal pattern of L-type calcium channel.