Yamanaka K, Oshita M, Muramatsu I
Brain Res. 1985 Dec 2;348(2):241-8. doi: 10.1016/0006-8993(85)90442-1.
Adrenergic and muscarinic binding sites in 4 brain regions (cerebral cortex, corpus striatum, hypothalamus/thalamus and brainstem) and in heart ventricles were measured in rats chronically treated with nicotine added to the drinking water in doses ranging from 6 to 8 mg/kg/day, for 4 weeks. Control rats received only tap water. The nicotine treatment led to increases in the specific binding of both [3H]prazosin and [3H]clonidine in the cerebral cortex. An increase in [3H]prazosin binding was also observed in the hypothalamus/thalamus of nicotine-treated rats. These changes were all due to an increase of about 23% in Bmax. In the brainstem and heart left ventricle, respectively, an increase and a decrease in the affinity of [3H]quinuclidinyl benzilate binding were observed. There were no changes of the binding parameters for the 3 radioligands in other regions tested, and no alteration of [3H]dihydroalprenolol binding was detected in any region examined. These results indicate that chronic administration of nicotine causes an increase in the density of alpha 1- and alpha 2-binding sites in some brain regions and reciprocal changes of the affinity of muscarinic binding sites in the brain and in the heart.
对长期饮用添加尼古丁（剂量为6至8毫克/千克/天）的水达4周的大鼠，测定其4个脑区（大脑皮层、纹状体、下丘脑/丘脑和脑干）以及心室中的肾上腺素能和毒蕈碱结合位点。对照大鼠仅饮用自来水。尼古丁处理导致大脑皮层中[3H]哌唑嗪和[3H]可乐定的特异性结合增加。在尼古丁处理大鼠的下丘脑/丘脑中也观察到[3H]哌唑嗪结合增加。这些变化均归因于最大结合容量（Bmax）增加约23%。在脑干和心脏左心室中，分别观察到[3H]喹核醇基苯甲酸酯结合亲和力的增加和降低。在所测试的其他区域中，3种放射性配体的结合参数没有变化，并且在任何检查区域均未检测到[3H]二氢普萘洛尔结合的改变。这些结果表明，长期给予尼古丁会导致某些脑区中α1和α2结合位点密度增加，以及大脑和心脏中毒蕈碱结合位点亲和力的相反变化。
