Turchan J, Lasoń W, Budziszewska B, Przewłocka B
Department of Molecular Neuropharmacology, Institute of Pharmacology, Kraków, Poland.
Neuropeptides. 1997 Feb;31(1):24-8. doi: 10.1016/s0143-4179(97)90015-9.
Effects of single (20 mg/kg i.p.) and repeated morphine administration (increasing doses: from 10 to 50 mg/kg i.p. twice daily for 7 days) on the proenkephalin (PENK), prodynorphin (PDYN) and dopamine D2 receptor (D2) mRNA levels in the nucleus accumbens and striatum of the mouse were investigated. As shown by an in situ hybridization, a single dose of morphine had no significant effect on the PDYN, PENK and D2 mRNA levels in the nucleus accumbens and striatum. Repeated treatment with morphine increased the PDYN mRNA level in both those structures after 2 and 72 h. In contrast to PDYN, the PENK mRNA level was reduced in the nucleus accumbens and remained unchanged in the striatum following repeated morphine administration. Repeated morphine had no effect on the D2 mRNA level in the nucleus accumbens and striatum after 2 h, and decreased it in the nucleus accumbens after 72 h only. The above results indicate that repeated morphine leads to long-lasting upregulation of the PDYN gene expression in the mouse nucleus accumbens and striatum; on the other hand, the PENK and D2 mRNA gene expressions are either inhibited or remain unchanged, significant changes being observed in the nucleus accumbens only.
研究了单次注射吗啡（腹腔注射20 mg/kg）和重复注射吗啡（剂量递增：从10至50 mg/kg，每天腹腔注射两次，共7天）对小鼠伏隔核和纹状体中前脑啡肽原（PENK）、强啡肽原（PDYN）和多巴胺D2受体（D2）mRNA水平的影响。原位杂交结果显示，单次剂量的吗啡对伏隔核和纹状体中的PDYN、PENK和D2 mRNA水平无显著影响。重复注射吗啡后，在2小时和72小时时，这两个结构中的PDYN mRNA水平均升高。与PDYN相反，重复注射吗啡后，伏隔核中的PENK mRNA水平降低，而纹状体中的PENK mRNA水平保持不变。重复注射吗啡在2小时时对伏隔核和纹状体中的D2 mRNA水平无影响，仅在72小时时使伏隔核中的D2 mRNA水平降低。上述结果表明，重复注射吗啡可导致小鼠伏隔核和纹状体中PDYN基因表达的长期上调；另一方面，PENK和D2 mRNA基因表达要么受到抑制，要么保持不变，仅在伏隔核中观察到显著变化。
