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采用放射配体结合方法观察外源性氧自由基对大鼠心肌α_１肾上腺素受体（α_１受体）及其亚型α_（１Ａ）与α_（１Ｂ）的影响和对β肾上腺素受体（β受体）的影响。发现：（１）·ＯＨ，使α_１受体与~（１２５）ＩＢＥ２２５４最大结合量（Ｂ_（ｍａｘ））分别下降５５％与３６％。（２）·ＯＨ可使α_１受体与~（１２５）ＩＢＥ２２５４结合的Ｋ_ｄ值增高１７１％，而对Ｋ_ｄ值无影响。（３）·ＯＨ，均使α_１受体亚型α_（１Ａ）与α_（１Ｂ）之间的比例增加。（４）·ＯＨ，对β受体与~（１２５）ＩＰＩＮ最大结合量Ｂ_（ｍａｘ）和Ｋ_ｄ值均无影响。（５）氧自由基清除剂甘露醇或超氧化物歧化酶均可对抗氧自由基引起α_１受体及其亚型的改变。上述结果提示，氧自由基可直接作用于心肌膜，引起α_１受体数量和亲和性下降，α_１受体亚型α_（１Ａ）与α_（１Ｂ）之间的比例改变。
Radioligand binding assay was used to observe the effects of exogenous oxygen free radicals on α 1 adrenoceptor (α 1 receptor) and its subtypes α 1 (1A) and α 1 (1B) in rat myocardium and the effects of adrenergic receptor beta receptors). The results showed that: (1) · OH, the maximum binding capacity of α_1 receptor to 125EBE2254 decreased by 55% and 36% respectively. (2) · OH increased the K_d value of α_1 receptor binding to 125EBE2254 by 171%, but had no effect on K_d. (3) · OH, both increased the ratio of α_1 receptor subtype α 1A and α 1B. (4) · OH, had no effect on the maximum binding amount of β-adrenoceptor with ~ (125) IPIN B_ (max) and K_d. (5) Oxygen free radical scavengers mannitol or superoxide dismutase against oxygen free radicals caused by α_1 receptor and its subtypes. These results suggest that oxygen free radicals can act directly on the myocardial membrane, causing a decline in the number and affinity of α 1 receptors, α 1 receptor subtypes α 1A and α 1B ratio changes.