AIM:To observe the effects of cholecystokinin octapeptide (CCK-8) and its receptor antagonists on cAMP response element binding protein ( CREB) and phosphorylated CREB ( pCREB) expression in frontal cortex and hippocampus of morphine withdrawal rats , which aim to explore the post-receptor mechanism through which CCK-8 regu-lates morphine withdrawal .METHODS: After the morphine dependence and naloxone-precipitated withdrawal animal models were established, the effects of CCK-8, L-364718 (CCK1 receptor antagonist) and LY-288513 (CCK2 receptor an-tagonist) pretreatment on CREB and pCREB expression in frontal cortex and hippocampus were observed by Western blot -ting and immunohistochemistry .RESULTS:In rat frontal cortex neuron , CREB was expressed in both cytoplasm and nu-cleus, but pCREB was only highly expressed in the nucleus .In the pyramidal cell layer of hippocampal CA 1 region, CREB showed high expression in the cytoplasm and low expression in the nucleus , while pCREB was only expressed in the nu-cleus.No obvious change of CREB was observed after either chronic morphine treatment or naloxone withdrawal .The pCREB expression was increased after chronic morphine treatment and further increased after naloxone withdrawal .Com-pared with the withdrawal group , chronic pretreatment with CCK-8, L-364718 and LY-288513 had no effect on CREB expression in the frontal cortex , but obviously decreased the pCREB expression .In the hippocampus , pretreatment with L-364718 and LY-288513 decreased CREB and pCREB expression , but only the pCREB expression was decreased after CCK-8 treatment.CONCLUSION:CCK-8 and CCK receptor antagonists may alleviate morphine withdrawal symptoms by regulating CREB , with specificity in different brain regions .

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous syestem (CNS) triggered by an autoimmune mechanism, which is the main cause of neurological disability in young people. In MS, a variety of glial cells participate in the pathogenesis and development of the disease, and oligodendrocytes (OL) and myelin cytes are destroyed by autoimmune mediated inflammation. Impaired OL production of oligodendrocyte progenitor cells (OPC) leads to persistent demyelination, myelin fragment accumulation and axonal injury, with clinical manifestation of CNS disability. Microglia (MG), which is involved in the inflammatory response and removal of myelin debris, plays a pivotal role in OPC differentiation and OL maturation, thereby directly or indirectly influencing the process of myelin regeneration. An interactive mechanism exists between these 2 components. The comprehension of the interrelationship between the 2 factors can provide enhanced insights into the pathogenesis of MS and facilitate the development of novel therapeutic strategies, thereby addressing pivotal scientific challenges encountered in clinical management of MS. Therefore, this review summarizes the dynamic changes of microglia in MS and its classic animal models, explores the internal relationship between MG and OL in this process, and focuses on the beneficial effects of targeted regulation of microglia, thereby promoting OPC differentiation and myelin regeneration, in order to provide a new research direction for MS treatment.