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目的：观察长期给予盐酸多巴胺对大鼠肾皮质多巴胺受体亚型所介导的腺苷酸环化酶活性的影响．方法：用放免分析法测定ｃＡＭＰ含量，作为反映多巴胺受体功能的指标．结果：长期给予盐酸多巴胺可显著减少肾皮质由非诺多泮引起的ｃＡＭＰ增加的量和在Ｓｃｈ２３３９０存在下由ＰＢＤＡ引起的ｃＡＭＰ降低的量，但其变量百分比则与对照组无显著差异．Ｓｃｈ２３３９０可阻断由非诺多泮和ＰＢＤＡ引起的ｃＡＭＰ的增加，而多潘立酮可阻断在Ｓｃｈ２３３９０存在下由ＰＢＤＡ引起的ｃＡＭＰ的降低．结论：长期应用多巴胺可使大鼠肾皮质的ＤＡ１和ＤＡ２受体均发生明显的“下调”，但余留受体的反应性不变．
OBJECTIVE: To observe the effect of long-term administration of dopamine hydrochloride on adenylate cyclase activity mediated by dopamine receptor subtype in rat renal cortex. Methods: Radioimmunoassay was used to determine cAMP content as an indicator of dopamine receptor function. Long-term administration of dopamine hydrochloride significantly reduced the amount of cAMP increased in the renal cortex caused by fenoldopam and the amount of cAMP decreased by PBDA in the presence of Sch-23390, but the percentage of variation was not significantly different from that of the control group. Sch23390 blocked the increase in cAMP caused by fenoldopam and PBDA, whereas domperidone blocked the decrease in cAMP induced by PBDA in the presence of Sch23390. CONCLUSION: Chronic administration of dopamine markedly “down-regulates” both DA1 and DA2 receptors in the rat renal cortex, but the remaining receptor remains unchanged.