de Villiers Sabina H L, Lindblom Nina, Kalayanov Genadiy, Gordon Sandra, Johansson Anette M, Svensson Torgny H
Department of Physiology and Pharmacology, Section of Neuropsychopharmacology, Karolinska Institutet, Nanna Svartz väg 2, 17177 Stockholm, Sweden.
Naunyn Schmiedebergs Arch Pharmacol. 2004 Oct;370(4):299-304. doi: 10.1007/s00210-004-0960-3. Epub 2004 Sep 16.
We have previously shown that active immunization with the nicotine immunoconjugate IP18-KLH attenuates the reinforcing effects of nicotine, i.e., suppresses the nicotine-induced brain dopamine release and prevents reinstatement of the nicotine-seeking behavior in rats. These effects are thought to be due to an alteration of the kinetics of nicotine distribution by the antibodies, resulting in an attenuated nicotine distribution to the brain. In this study, the distribution of nicotine administered at doses corresponding to those used in our previous studies, was investigated in immunized rats and controls. Male Wistar rats received two immunizations with IP18-KLH in Freund's incomplete adjuvant, 21 days apart, and experiments were performed 7-11 days post-immunization under chloral hydrate anesthesia. Blood samples were collected to determine antibody titer and nicotine selectivity using enzyme-linked immunosorbent assay (ELISA) techniques. The animals received an intravenous nicotine dose and were sacrificed either 3 min or 60 min after nicotine administration. Trunk blood was collected and the brains were removed for analysis of nicotine content. The results showed that immunization against nicotine increases the nicotine concentration in blood and significantly decreases the amount of nicotine that reaches the brain. The present findings thus demonstrate an altered distribution of nicotine after immunization with IP18-KLH. Despite the sustained nicotine binding by the antibodies, the active immunization did not alter the metabolism of nicotine to cotinine, the major nicotine metabolite. In conclusion, the attenuation of the reinforcing effect of nicotine after immunization with IP18-KLH, shown previously, is indeed associated with an altered distribution of nicotine.
我们之前已经表明，用尼古丁免疫偶联物IP18-KLH进行主动免疫可减弱尼古丁的强化作用，即抑制尼古丁诱导的脑多巴胺释放，并防止大鼠恢复觅尼古丁行为。这些作用被认为是由于抗体改变了尼古丁分布的动力学，导致进入脑内的尼古丁分布减少。在本研究中，我们在免疫大鼠和对照大鼠中研究了以与我们之前研究中使用的剂量相当的剂量给予尼古丁后的分布情况。雄性Wistar大鼠在弗氏不完全佐剂中接受两次IP18-KLH免疫，间隔21天，并在免疫后7 - 11天在水合氯醛麻醉下进行实验。采集血样，使用酶联免疫吸附测定（ELISA）技术测定抗体滴度和尼古丁选择性。给动物静脉注射尼古丁剂量，并在注射尼古丁后3分钟或60分钟处死。采集躯干血并取出大脑用于分析尼古丁含量。结果表明，针对尼古丁的免疫可增加血液中的尼古丁浓度，并显著减少进入脑内的尼古丁量。因此，本研究结果证明了用IP18-KLH免疫后尼古丁分布发生了改变。尽管抗体持续结合尼古丁，但主动免疫并未改变尼古丁向主要尼古丁代谢产物可替宁的代谢。总之，之前显示的用IP18-KLH免疫后尼古丁强化作用的减弱确实与尼古丁分布的改变有关。
