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目的探讨杏仁中央核内的μ-阿片受体对大鼠摄食和摄水的影响,并评估杏仁中央核内的谷氨酸信号系统在阿片肽介导的摄食行为过程中的作用。方法将不锈钢套管植入成年雄性SD大鼠一侧的杏仁中央核内,向饱食或脱水后大鼠杏仁中央核内注射不同剂量的μ-阿片受体选择性激动剂[D-Ala2,N-Me-Phe4,Gly5-ol]-脑啡肽(DAMGO)。注射后60、120和240 min时测量大鼠的摄食量和摄水量。向饱食后大鼠杏仁中央核内联合注射阿片受体非选择性拮抗剂纳曲酮(naloxone,NTX)和DAMGO,或联合注射N-甲基-D-天冬氨酸(NMDA)型谷氨酸受体选择性拮抗剂D-AP-5和DAMGO,注射后60、120和240 min时测量大鼠的摄食量。结果杏仁中央核内注射DAMGO(1~4 nmol)后,饱食大鼠的摄食量明显增加,而脱水大鼠的摄水量变化不大。NTX(26.5 nmol)可拮抗DAMGO诱导的摄食效应,D-AP-5(6.3~25.4 nmol)则对DAMGO诱导的摄食效应没有影响。结论杏仁中央核μ-阿片受体参与对大鼠摄食而不是摄水的调节,这种促食欲作用不依赖于杏仁中央核内的NMDA受体的激活。
Objective To investigate the effects of μ-opioid receptors in central almonds on food intake and water intake in rats and to evaluate the role of glutamate signaling system in opiate peptide-mediated ingestion behavior. Methods The stainless steel cannula was implanted into the central almond of adult male SD rats. After the rats were fed or dehydrated, different doses of μ-opioid receptor selective agonist [D-Ala2, N-Me-Phe4, Gly5-ol] -enkephalin (DAMGO). The rats’ food intake and water intake were measured at 60, 120 and 240 min after injection. After nourishing the rats with almond central nucleus, naloxone (NTX) and DAMGO (non-selective antagonist of opioid receptor) The selective receptor antagonists of D-AP-5 and DAMGO were measured at 60, 120 and 240 min after injection. Results After injections of DAMGO (1-4 nmol) into the central nucleus of almonds, the food intake of rats increased significantly, while the water intake of dehydrated rats did not change much. NTX (26.5 nmol) antagonized DAMGO-induced feeding effect, and D-AP-5 (6.3 ~ 25.4 nmol) had no effect on DAMGO-induced feeding effect. Conclusion Almond core μ-opioid receptors are involved in the regulation of food intake rather than water intake in rats. This pro-appetitive effect does not depend on the activation of NMDA receptors in the central nucleus of almonds.