钠离子对α_1肾上腺素能受体结合抑制配基能力的影响

Effect of Sodium Ion on Binding Blocker of α_1-adrenoceptor in Myocardium and Kidney of Rats

大鼠心、肾α１肾上腺素能受体与呱唑嗪结合能力在不同浓度的Ｎａ＋中，呈现不同的反应。肾脏的α１受体在低浓度Ｎａ＋时（１３０ｍｍｏｌ／Ｌ），其Ｂｍａｘ和Ｋｄ均明显升高（Ｐ＜０．０５）；心肌无明显变化。在高浓度Ｎａ＋时（１５０ｍｍｏｌ／Ｌ），心肌的α１受体结合容量明显下降（Ｐ＜０．０１）。提示：Ｎａ＋对具α１受体以结合抑制配基的能力可能有直接调节作用；心肌和肾脏α１受体以不同的亚型为主，对Ｎａ＋应答存在差异。

The Bmax and Kd changes of myocardial α1-adrenoceptor differed from that of kidney in rat when α1-adrenoceptor bound prazosin at low- or high-sodium ion concentration. At low-sodium (130mmol/L),the density and Kd of renal α1-adrenoceptor were increased (P<0.05),and the myocardial α1-adrenoceptor distinct changed;At high-sodium,(150mmol/L),the myocardial α1-adrenoceptor was decreased.The result suggests that regulation of α1-adrenoceptor stimulation may be regulated to changes of sedium. Myocardial and renal α1-adrenoceptor may have two subtypes (α1a,α1b), which may differ in responding to sodium.