Yamanaka K, Muramatsu I, Kigoshi S
Pharmacol Biochem Behav. 1987 Feb;26(2):259-63. doi: 10.1016/0091-3057(87)90115-8.
Alpha 2 and beta adrenoceptors, and muscarinic cholinoceptors in 2 brain regions (cerebral cortex and hippocampus) were measured in rats which received either tap water or nicotine added to the drinking water (5-8 mg/kg/day) for 4 weeks, and immobilization stress (daily 2 hr) for the last 5 days. The repeated stress induced a reduction in the maximum number of binding sites (Bmax) for (3H)dihydroalprenolol (DHA) in the cerebral cortex of rats with tap water, without affecting (3H)clonidine binding. Nicotine-treatment also caused a decrease in the Bmax of cortical (3H)DHA binding comparable to the case of stress, and increased the (3H)clonidine binding. However, the combination of nicotine- and stress-treatments failed to induce further no changes in the 2 radioligands binding. The binding of (3H)quinuclidinyl benzilate in the cerebral cortex and of the 3 radioligands in the hippocampus was unaltered by nicotine- and/or stress-treatments. These results indicate that long-term administration of nicotine induces down-regulation of cortical beta adrenoceptors and seemingly attenuates the receptor alteration by repeated stress.
在接受自来水或添加到饮用水中的尼古丁（5 - 8毫克/千克/天）4周，并在最后5天接受固定应激（每天2小时）的大鼠中，测量了2个脑区（大脑皮层和海马体）中的α2和β肾上腺素能受体以及毒蕈碱胆碱能受体。反复应激导致饮用自来水的大鼠大脑皮层中（3H）二氢烯丙洛尔（DHA）结合位点的最大数量（Bmax）减少，而不影响（3H）可乐定结合。尼古丁处理也导致皮层（3H）DHA结合的Bmax降低，与应激情况相当，并增加了（3H）可乐定结合。然而，尼古丁和应激处理的组合未能在这两种放射性配体结合上诱导进一步的变化。大脑皮层中（3H）奎宁环基苯甲酸酯的结合以及海马体中3种放射性配体的结合不受尼古丁和/或应激处理的影响。这些结果表明，长期给予尼古丁会导致皮层β肾上腺素能受体下调，并且似乎减弱了反复应激引起的受体改变。
