在大鼠Vogel饮水冲突模型上盐酸纳曲酮的致焦虑作用

Anxiogenic effect of naltrexone in Vogel’s conflict procedure in rats

用Ｖｏｇｅｌ饮水冲突模型发现，盐酸纳曲酮（ＮＴＸ）０．１－１０ｍｇ·ｋｇ￣（－１）剂量依赖性地降低大鼠在冲突期的反应数，以给药后１５－４５ｍｍ作用明显，６０ｍｍ后作用减弱。预先外周给予吗啡可拮抗ＮＴＸ的这种作用，而５—羟色胺对此无效。在非冲突期，上述剂量的ＮＴＸ也可减少大鼠的舔水次数，该效应能被吗啡或５—羟色胺所拮抗。在大鼠甩尾实验，ＮＴＸ对大鼠痛阈无明显影响。在转杆实验中，上述剂量的ＮＴＸ也不改变大鼠的运动功能．结果提示，在Ｖｏｇｅｌ’ｓ冲突实验中，ＮＴＸ具有致焦虑作用；中枢内阿片系统参与焦虑情绪的调控。

The effect of naltrexone (NTX),avery potent antagonist of opioid receptor,on conflictstate of rats was investigated in modified Vogel’s con-flict procedure.NTX(0.1-10 mg·kg-1)dose- andtime-dependentlv decreased the number of licks by46%-65 % during the period of shock-punished(P<0.01),which was antagonized by morphine(5mg.kg-1,sc), but not by 5-HT(2mg· kg-1 ,ip).During the period ofunpunished,NTX(0.1-10 mg·kg-1)also reduced the number of licks significantly,thoughonly by 18%-21%。 Such an effect of NTX was antago-nized either by morphine or 5-HT. In the tail flick test,the above doses of NTX did not affect the tail flicklatency in rats except at the dose 1 0 mg·kg-1,whichincreased the tail flick latency unexpectedly(P<0.01).Although the central α2 agonist xylazine increased thenumber of falls significantly in the rotarod test,NTXhad no effect on it.These results suggetsed that NTXhad anxiogenic effect in Vogel’s conflict procedure andthat central endogenous opioid system might be in-volved in the modulation of anxiety state.