Girdler S S, Hinderliter A L, Light K C
Department of Psychology, University of North Carolina, Chapel Hill 27599.
J Psychosom Res. 1993;37(2):177-93. doi: 10.1016/0022-3999(93)90085-t.
Ten White males, ten Black males, ten White females, and seven Black females (aged 22-48 yr) were exposed to a competitive reaction time task (enhancing beta-receptor activity), the forehead cold pressor (enhancing alpha-receptor activity), and a speech task on four separate occasions: twice under a saline placebo condition, once under a beta-blockade condition using i.v. propranolol, and once under a combined beta- and alpha-blockade condition using both i.v. propranolol and i.v. phentolamine. Order of placebo session and blockade session was counterbalanced across each race/gender group. Beta-blockade abolished the greater heart rate, cardiac index, and stroke volume index responses, and the lesser vascular tone seen under placebo in White vs. Black males. No differences between White and Black women were seen with or without beta-blockade. Gender differences in beta-receptor contribution to stress responses were restricted to the White subjects. Beta-blockade abolished the greater stroke volume index responses and less vascular tone observed in White males vs. White females. Although alpha-receptor blockade significantly decreased vascular resistance in each race/gender group, it did not differentially affect any of the subgroups. These data suggest that race and gender differences in cardiovascular stress responses of normotensive individuals are at least partly a function of differential beta-receptor activity/sensitivity. No clear support for differences in alpha-receptor activity/sensitivity was obtained.
十名白人男性、十名黑人男性、十名白人女性和七名黑人女性（年龄在22至48岁之间）在四个不同场合接受了竞争性反应时任务（增强β受体活性）、前额冷加压试验（增强α受体活性）和言语任务：两次在生理盐水安慰剂条件下，一次在静脉注射普萘洛尔的β受体阻滞剂条件下，一次在同时静脉注射普萘洛尔和酚妥拉明的联合β和α受体阻滞剂条件下。安慰剂组和阻滞剂组的顺序在每个种族/性别组中进行了平衡。β受体阻滞剂消除了白人男性与黑人男性在安慰剂条件下出现的更大的心率、心脏指数和每搏量指数反应以及较小的血管张力。无论有无β受体阻滞剂，白人女性和黑人女性之间均未观察到差异。β受体对应激反应的贡献中的性别差异仅限于白人受试者。β受体阻滞剂消除了白人男性与白人女性相比更大的每搏量指数反应和更低的血管张力。尽管α受体阻滞剂显著降低了每个种族/性别组的血管阻力，但并未对任何亚组产生差异影响。这些数据表明，血压正常个体心血管应激反应中的种族和性别差异至少部分是β受体活性/敏感性差异的函数。未获得α受体活性/敏感性存在差异的明确证据。
