基底外侧杏仁核—外侧下丘脑通路对类鸦片诱导的脂肪摄入的作用

Effect of basolateral amygdale-lateral hypothalamic pathway upon opioid-induced fat intake

研究了大鼠脑横核(Acb)内注入μ-类鸦片受体激活剂DAMGO诱导的脂肪摄入增加与基底外侧杏仁核(BLA)—外侧下丘脑(LH)通路激活的关系。通过立体定位技术将微型不锈钢套管植入大鼠脑的Acb、BLA和LH,通过注射GABA_A受体激活剂muscimol的方法暂时失活试验脑区的神经元活性,然后观察失活一侧BLA或对侧LH以及同时失活上述两区对于Acb内注入DAMGO诱导的脂肪摄入增加的影响。单纯Acb内注入DAMGO的大鼠(2组)较生理盐水对照组大鼠(1组)2h脂肪摄入量显著增加[(19.10±1.07)g vs.(8.12±0.80) g,F=1080.74,p<0.001],而失活一侧BLA(3组)、失活对侧LH(4组)、同时失活一侧BLA与对侧LH的大鼠(5组)其2h脂肪摄入量分别为(18.24±1.04)g、(18.50±0.96)g和(7.59±0.71)g,均分别与2组大鼠进行比较,结果显示只有5组和2组大鼠间的差异有统计学意义(F=1281.07,p<0.001)。失活大鼠脑一侧BLA或对侧LH对于Acb内注入DAMGO诱导的脂肪摄入增加无影响,但同时失活上述两区则完全阻断这种摄入增加,提示Acb内注入DAMGO所诱导的脂肪摄入增加依赖于BLA-LH通路内复杂、严格的交互作用。

The objective of this experiment was to study the relation between the increasing of intra-accumbens μ-opioid-agonist （DAMGO） -induced fat intake with the activation ofa basolateral amygdale-lateral hypothalamic pathway. Bilateral guide stainless steel cannulae were stereotaxically implanted into the nucleus accumbens （Acb）, basolateral amygdale （BLA） and lateral hypothalamus （LH）. Administration of GABAA agonist （muscimol） was used as a method to induce temporary neural inactivation. The impact of unilateral inactivation of either the BLA or the LH in the opposite hemispheres on the intra-accumbens DAMGO-induced fat intake was observed, and so was the impact of simultaneous bilateral inactivation of both the BLA and the LH in the opposite hemispheres. Compared with that of the salt control group （group 1）, the fat intake in 2 h of group2 induced by intra-accumbens DAMGO increased significantly [（19.10±1.07） g vs. （8.12±0.80） g, F=1080.74, p〈0.001]. The fat intake in 2 h was （18.24±1.04） g, （18.50±0.96） g and （7.59±0.71） g after unilateral inactivation of the BLA （group3）, unilateral inactivation of the LH in the opposite hemispheres （group4）, and bilateral inactivation of both the BLA and the LH in the opposite hemispheres （group5）, each of which was compared with that of group2, and a significant difference only existed between group 5 and group2 （F=1281.07, p〈0.001）. Unilateral inactivation of either the BLA or the LH in the opposite hemispheres had no effect on the intra-accumbens DAMGO-induced fat intake, while simultaneous bilateral inactivation of both the BLA and the LH in the opposite hemispheres completely blocked the effect, which suggested that intra-accumbens opioid-induced fat intake depended on a critical interaction within a basolateral amygdale-lateral hypothalamic pathway.