Christ G J, Pieper J A, Blizard D A, Dunlap C E
Department of Physiology and Pharmacology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, NC 27103.
Life Sci. 1988;43(22):1773-84. doi: 10.1016/0024-3205(88)90276-7.
The effects of beta-adrenoceptor blockade on left ventricular beta-receptor characteristics were evaluated in the Maudsley Reactive (MR/Har) and Non-Reactive (MNRA/Har) rat strains. After propranolol infusion for one week administered by subcutaneously implanted osmotic minipumps, differences in beta-adrenoceptor-agonist interactions between strains were assessed by comparison of isoproterenol competition for [125I]iodocyanopindolol (ICYP) binding sites in crude left ventricular homogenate preparations from both strains. Propranolol exposure had no significant effect on the binding parameters investigated (Bmax, Kd, % receptors in high affinity state, IC50). In contrast to previous observations in naive animals, these experiments revealed no strain differences in the sham-implanted Maudsleys in any of the left ventricular beta-adrenoceptor parameters investigated. We hypothesize that the surgical procedures and/or presence of the plastic inserts acted as stressors in the Maudsley strains and thus altered beta-adrenoceptor function. This hypothesis is supported by the observation that exposure to another stress (footshock) also eliminated strain differences in ventricular beta-receptor binding variables.
在莫兹利反应型（MR/Har）和非反应型（MNRA/Har）大鼠品系中评估了β-肾上腺素能受体阻断对左心室β受体特征的影响。通过皮下植入渗透微型泵给予普萘洛尔一周后，通过比较两种品系的粗制左心室匀浆制剂中异丙肾上腺素对[125I]碘氰吲哚洛尔（ICYP）结合位点的竞争，评估了品系间β-肾上腺素能受体激动剂相互作用的差异。普萘洛尔暴露对所研究的结合参数（Bmax、Kd、高亲和力状态下的受体百分比、IC50）没有显著影响。与之前在未处理动物中的观察结果相反，这些实验表明，在任何所研究的左心室β-肾上腺素能受体参数方面，假手术植入的莫兹利大鼠品系之间没有差异。我们推测，手术操作和/或塑料植入物的存在对莫兹利大鼠品系起到了应激源的作用，从而改变了β-肾上腺素能受体功能。这一推测得到了以下观察结果的支持：暴露于另一种应激（电击）也消除了心室β受体结合变量中的品系差异。
