Churchill P C, Rossi N F, Churchill M C
Am J Physiol. 1987 May;252(5 Pt 2):F872-6. doi: 10.1152/ajprenal.1987.252.5.F872.
Previous observations by others have shown that Na deprivation augments and Na loading attenuates the inhibitory effect of exogenous adenosine on renin secretion in vivo. The purpose of the present experiments was to test the hypothesis that Na deprivation and Na loading alter the sensitivity of the adenosine receptors (A1 subclass) that mediate the inhibitory effect. The rat renal cortical slice preparation was used. Na loading decreased and Na deprivation increased tissue renin content and the basal renin secretory rate; these two variables were directly related (r = 0.84, P less than 0.00005). N6-cyclohexyladenosine (CHA), an adenosine analogue that selectively activates the A1 subclass of adenosine receptors in the nanomolar to micromolar concentration range inhibited renin secretion over the same range of concentrations (nM-microM) and to approximately the same maximal extent (to 50% of the mean basal secretory rate) in cortical slices taken from Na-loaded, control, and Na-deprived rats. These results demonstrate that changes in the intrinsic sensitivity of adenosine receptors do not explain dietary Na-induced changes in the in vivo renin secretory response to exogenous adenosine.
其他人之前的观察结果表明，缺钠会增强而钠负荷会减弱外源性腺苷对体内肾素分泌的抑制作用。本实验的目的是检验以下假设：缺钠和钠负荷会改变介导这种抑制作用的腺苷受体（A1亚类）的敏感性。使用了大鼠肾皮质切片制备物。钠负荷降低而缺钠增加了组织肾素含量和基础肾素分泌率；这两个变量呈直接相关（r = 0.84，P小于0.00005）。N6-环己基腺苷（CHA）是一种腺苷类似物，在纳摩尔至微摩尔浓度范围内选择性激活腺苷受体的A1亚类，在来自钠负荷、对照和缺钠大鼠的皮质切片中，在相同浓度范围（纳摩尔-微摩尔）内抑制肾素分泌，且最大抑制程度大致相同（至平均基础分泌率的50%）。这些结果表明，腺苷受体内在敏感性的变化并不能解释饮食中钠诱导的体内肾素对外源性腺苷分泌反应的变化。
