电损毁伏核核部或壳部对大鼠吗啡奖赏效应及其性功能的影响

EFFECTS OF ELECTROLYTIC LESIONS OF THE NAC CORE OR SHELL ON MORPHINE INDUCED REWARD AND SEXUAL ABILITY IN RATS

目的:研究直流电损毁伏核(nucleus accumbens NAc)核部及壳部对大鼠吗啡奖赏效应及其性功能的影响。方法:建成♂大鼠吗啡条件性位置偏爱(5mg.kg-1,ip)后,用直流电损毁或假损毁其NAc核部或壳部。损毁术后7d及10d时再次测试大鼠位置偏爱的表达。12d时给予大鼠小剂量吗啡(2.5mg.kg-1,ip)后,再次进行测试。之后,让大鼠进行一轮交配,记录性功能相关指标。结果:假损毁组大鼠在各时间点测试时,均可稳定表达已形成的吗啡条件性位置偏爱,而核部及壳部损毁组大鼠在术后7d及10d测试时未表达对吗啡伴药侧的偏爱,但12d给予小剂量吗啡后,壳部损毁组动物再次表达出对伴药侧的偏爱,而核部损毁组则仍未表达任何偏爱;各组大鼠的性功能未受影响。结论:NAc核部损毁能抑制大鼠吗啡CPP的重建,而壳部损毁则不能,且该损毁手术对大鼠的性功能无影响。

Objective ： To investigate the effects of electrolytic lesions of the NAc core or shell on morphine induced conditioned place preference （CPP） and sexual ability in rats. Methods： After acquiring stable morphine induced CPP （5 mg·kg^-1, ip） , rats were given electrolytic （ or sham） lesions of either the NAc core or shell. On the 7th and 10th day after lesions, the rats were given a test to assess CPP,and on the 12th day, they were tested again with an injection of a small amount of morphine（2. 5 mg·kg^- 1, ip）. After above - mentioned experiments, animals were given a chance to mate, and the indices relating to sexual ability were recorded. Results：The sham lesion group showed preference for morphine paired site at all tests after surgery. The rats with lesions of the NAc core or shell did not show any preference at the first two tests after surgery. However, when injected with a small amount of morphine, rats with lesions of the NAc shell, but not core, showed preference to morphine paired site again. And the sexual ability of the three groups was not affected. Conclusion ： Lesions of the NAc core, but not shell can prohibit the reinstatement of morphine induced CPP in rats, while leaving their sexual ability unaffected.