Barbe P, Senard J M, Estan L, Berlan M, Tran M A, Louvet J P, Montastruc J L
Service d'endocrinologie-diabétologie, hôpital Purpan, Toulouse, France.
Arch Mal Coeur Vaiss. 1990 Jul;83(8):1245-8.
Plasma catecholamine levels, total platelet alpha 2-adrenoceptor number and affinity state (using [3H]-yohimbine binding) have been investigated in insulin-dependent diabetic patients with (n = 12) or without (n = 10) orthostatic hypotension as well as in normal control subjects (n = 6). Mean resting basal catecholamine values were similar in the three groups. One min standing elicited an increase in norepinephrine plasma level (but not in epinephrine plasma levels) in control group but not in diabetic patients (with or without orthostatic hypotension). The maximal number of platelet alpha 2-adrenoceptors (and Kd) calculated by [3H]-yohimbine saturation experiments was similar in the three groups. The percentage of platelet alpha 2-adrenoceptors in high affinity state determined by inhibition experiments of [3H]-yohimbine binding by UK14,304 (a specific alpha 2-adrenergic full agonist) was significantly lower in diabetic patients with orthostatic hypotension (29.2 +/- 5.3%) than in the other two groups. No significant difference was found between the control group (60.0 +/- 2.0%) and diabetic patients without orthostatic hypotension (64.3 +/- 3.1%). These results indicate that orthostatic hypotension in insulin-dependent diabetic patients is marked by a lack of noradrenaline increase in standing position and by a decrease in platelet alpha 2-adrenoceptors in high affinity state. Thus we suggest that orthostatic hypotension of diabetes mellitus is the result of sympathetic nerves injuries and of abnormalities in alpha 2-adrenoceptors coupling.
我们对12例患有体位性低血压和10例未患体位性低血压的胰岛素依赖型糖尿病患者以及6名正常对照者的血浆儿茶酚胺水平、血小板α2 -肾上腺素能受体总数及亲和状态（采用[3H] -育亨宾结合法）进行了研究。三组的平均静息基础儿茶酚胺值相似。对照组站立1分钟后去甲肾上腺素血浆水平升高（肾上腺素血浆水平未升高），但糖尿病患者（无论有无体位性低血压）则不然。通过[3H] -育亨宾饱和实验计算得出的三组血小板α2 -肾上腺素能受体的最大数量（及解离常数）相似。用UK14,304（一种特异性α2 -肾上腺素能完全激动剂）抑制[3H] -育亨宾结合实验所测定的处于高亲和状态的血小板α2 -肾上腺素能受体百分比，在患有体位性低血压的糖尿病患者中（29.2±5.3%）显著低于其他两组。对照组（60.0±2.0%）与未患体位性低血压的糖尿病患者（64.3±3.1%）之间未发现显著差异。这些结果表明，胰岛素依赖型糖尿病患者的体位性低血压表现为站立时去甲肾上腺素升高不足以及高亲和状态的血小板α2 -肾上腺素能受体减少。因此，我们认为糖尿病体位性低血压是交感神经损伤及α2 -肾上腺素能受体偶联异常的结果。
