The mu opioid receptor (MOR) has been regarded as the main site of interaction with analgesics in major clinical use, particularly morphine. The repressor element-1 silencing transcription factor (REST) functions as a transcriptional repressor of neuronal genes in non-neuronal cells. However, it is expressed in certain mature neurons, suggesting that it may have complex and novel roles. In addition, the interactions between MOR and REST and their functions remain unclear. In this study, we examined the effects of morphine on the expression of REST mRNA and protein in human neuroblastoma NMB cells to investigate the roles of REST induced by MOR activation in neuronal cells. To determine the effects of morphine on REST expression, we performed RT-PCR, real-time quantitative RT-PCR, western blot analysis and radioligand binding assays in NMB cells. By RTPCR and real-time quantitative RT-PCR, the expression of REST was found to be unchanged by either the MOR agonist morphine or the MOR specific antagonist CTOP. By western blot, morphine was shown to significantly inhibit the expression of REST, but this suppression was completely blocked by treatment with CTOP. In the radioligand binding assay, the overexpression of REST led to an increased opioid ligand binding activity of endogenous MOR in the NMB cells. These results together suggest that morphine inhibits the expression of REST in human neuroblastoma cells through a post-transcriptional regulatory mechanism mediated through MOR.

The purpose 01' pl'esent study was to examine the molecular events in apoptosis by CoCl2, mimicking hypoxic cond ition and recovering effects by LED ir l'adiation on Human SH-SY5Y neuroblastoma cells The SOUl'ce 0 1' light for ir l'adiation was a continuous-wave LED emitting at a wavelenl양h of 590 nm, and manufactured that ene rgy density was 5 mW!cm2 on sample surface, After ir l'adiation, cell viabi lity was measured with BrdU , cell morphol ogy was examined with Diff- Quik staining, cell signaling was monitored with various apoptosis-related molecules using RNase Pl'otection Assay(RPA) , W11en treated with CoC12, apoptotic induction was found in the SH-SY5Y cells in a concentration-dependent and time-dependent manner , Diff-Quik s taining was revealed that DNA fragmentation re presented apoptosis was examined in CoC12-tl'eated group, Moreover, RPA assay of SH-SY5Y cclls lIs ing val'iolls apoptosis-related molecllles showed that the apoptotic cell population was mcreased J-loweve. there was sorne signifïcant change in LED irradiatied cells aftel' treatement of CoC12 The main mechanism for Lhese a poptosis appearecl to be mito c hondriεt - m ecliated pathway, such as cytochrome- c‘ caspase-9, caspase-3, pro-apototic protein ßax, anti-apototic protein Bcl-2, and death receptor• mediated pathway, such as Fas, cas pase- 8, a ncl TNFRl These results demonstrate that CoCI2 induce apoptosis in SH-SY5Y via different dual apop tosis pathway through death receptor pathway as well as mitochondria- dependent pathway and LED irradiation can recl llces the CoCl2-induced apoptosis by blocking their internal signaling pathway