吗啡依赖大鼠脑内催产素和精氨酸升压素含量的变化

Changes in oxytocin and arginine vasopressin contents in brain of morphine dependent rats 1

应用核团微穿刺取样和放射免疫测定技术，观察了在吗啡依赖和戒断期间大鼠中枢催产素（ＯＴ）和精氨酸升压素（ＡＶＰ）含量的变化．结果表明，慢性吗啡处理（剂量由５，１０，１５，２０，３０，４０，５０ｍｇ·ｋｇ－１逐日递增，同一剂量ｉｐ每日３次）大鼠的视上核和伏隔核ＯＴ含量显著降低；蓝斑ＯＴ含量显著增加．纳洛酮（１０ｍｇ·ｋｇ－１，ｉｐ）可使正常大鼠视上核，腹侧被盖区，隔区和伏隔核的ＯＴ含量明显降低，而在吗啡依赖大鼠使视上核内ＯＴ含量增加，同时室旁核的ＯＴ含量也明显增加，而蓝斑的ＯＴ含量则明显降低．吗啡，纳洛酮及吗啡加纳洛酮处理均不明显影响各核团内ＡＶＰ的含量．以上结果表明：慢性吗啡处理可抑制大鼠视上核细胞合成ＯＴ，中枢其他部位ＯＴ的减少可能与视上核ＯＴ合成减少有关；纳洛酮可以部分拮抗吗啡对ＯＴ神经元的抑制作用．

Changes in oxytocin(OT) and arginine vasopressin (AVP) contents in some nuclei were investigated in morphine dependent rats. Rats were given ip morphine with increasing doses daily (5, 10, 15, 20, 30, 40 and 50 mg·kg 1 ) for 7 d, 3 times a day. Chronic administration of morphine reduced the OT content in supraoptic nucleus(SON) and nucleus accumbens septi(NAc), and increased it in locus ceruleus(LC), but did not influence the OT content in ventral tegment area(VTA), paraventricular nucleus(PVN) and other nuclei including septum, raphe magnus nucleus(NRM) and periaquaductal gray matter (PAG), with which was associated closely morphine dependence; AVP content had no alteration in any nuclei observed. In morphine naive rats, naloxone(10 mg·kg 1 ip) reduced the OT content in SON, VTA, LS and NAc. In morphine dependen rats, naloxone increased the OT content in SON to the level of morphine naive rats, also elevated it in PVN, but declined it in LC. There were no obvious alteration in AVP content in different treatment groups. The results suggest that chronic morphine treatment inhibit the OT synthesis but not AVP in SON, the decrease in OT content in other nuclei be due to the inhibition of OT synthesis in OT neurons in SON, and naloxone relieve the restrain of OT neurons caused by morphine.