Todtenkopf M S, Stellar J R
Department of Psychology, Northeastern University, Boston, Massachusetts 02115, USA.
Synapse. 2000 Dec 1;38(3):261-70. doi: 10.1002/1098-2396(20001201)38:3<261::AID-SYN5>3.0.CO;2-E.
To explore the effects of behavioral sensitization on the anatomy of the nucleus accumbens shell, we employed a typical cocaine dosing paradigm and assessed tyrosine hydroxylase immunoreactive varicosities in five different areas of the shell, as well as the core of the nucleus accumbens. Rats were given bidaily injections of either saline (1 ml/kg i.p.) or cocaine (15 mg/kg i.p.) for 5 consecutive days, and sacrificed either 2 or 14 days from the last injection. Sections of the nucleus accumbens were processed for tyrosine hydroxylase immunoreactivity and the number of immunoreactive varicosities in contact with neuronal cell bodies was quantified in each of the subregions of the shell, as well as the core of the nucleus accumbens. Compared to saline controls, the cocaine-treated animals showed a significant augmentation in tyrosine hydroxylase immunoreactivity in two of the five subregions after 2 days of withdrawal in the shell, but not in the core. No differences were found in any region tested after 14 days of withdrawal. These data are the first to suggest that increases in nucleus accumbens presynaptic tyrosine hydroxylase may play a role in the development of behavioral sensitization, but not in the long-term expression of this phenomenon.
为了探究行为敏化对伏隔核壳部解剖结构的影响，我们采用了一种典型的可卡因给药模式，并评估了伏隔核壳部五个不同区域以及伏隔核核心中酪氨酸羟化酶免疫反应性曲张体。大鼠连续5天每天接受两次注射，分别注射生理盐水（1毫升/千克腹腔注射）或可卡因（15毫克/千克腹腔注射），并在最后一次注射后的2天或14天处死。对伏隔核切片进行酪氨酸羟化酶免疫反应性处理，并对壳部各亚区域以及伏隔核核心中与神经元细胞体接触的免疫反应性曲张体数量进行量化。与生理盐水对照组相比，可卡因处理的动物在撤药2天后，壳部五个亚区域中的两个区域酪氨酸羟化酶免疫反应性显著增强，但伏隔核核心未出现这种情况。撤药14天后，在任何测试区域均未发现差异。这些数据首次表明，伏隔核突触前酪氨酸羟化酶的增加可能在行为敏化的发展中起作用，但在该现象的长期表达中不起作用。
