Roles of spinal N-methyl-D-aspartic acid receptor-extracellular signal-regulated protein kinase 5 signaling pathway in naloxone-induced withdrawal response in morphine-dependent rats / 中华行为医学与脑科学杂志

ABSTRACT

Objective To investigate the roles of spinal N-methyl-D-aspartic acid receptor-extracellular signal-regulated protein kinases 5 signaling pathway in naloxone-induced withdrawal response in morphine-dependent rats.Methods Ninety-six adult male SD rats weighting 230-250 g were randomly divided into 4 groupscontrol group,withdrawal group,DMSO group and MK801 group.Rats were subcutaneously injected with morphine.On day 6,rats were injected with naloxone (intraperitoneal) to precipitate morphine withdrawal syndromes.To identify the function of NMDAR-ERK5 signaling pathway in morphine withdrawal,morphine withdrawal-like behavior test and western blot technique were used in this research.The scores of morphine withdrawal symptom,morphine withdrawal-induced allodynia and the activation of ERK5 in spinal cord were observed after intrathecal injection of MK801.Results There was no withdrawal symptoms and withdrawal-induced allodynia in group A after intraperitoneal injection of naloxone.Compared with group A,withdrawal score (45.2±7.3),score of withdrawal-induced allodynia (14.4±3.7) of group B,withdrawal score (44.7±6.2),score of withdrawal-induced allodynia (13.2±2.7) of group C and withdrawal score (28.3±1.6),score of withdrawal-induced allodynia (5.9± 1.1) of group D were significantly increased (P＜ 0.05).Compared with group C,the total withdrawal score (28.3 ± 1.6),score of withdrawal-induced allodynia (5.9± 1.1) of group D were significantly decreased (P＜0.05).Compared with group A,the expression of spinal p-ERK5 of group B (12848±621) and group C (12579±396) were significantly increased (P＜0.05).Compared with group C,the expression of spinal p-ERK5 of group D (5 123±546) was significantly decreased (P＜0.05).Condusion The signaling pathway of spinal N-methyl-D-aspartic acid receptor-extracellular signal-regulated protein kinases 5 contributes to naloxone-induced withdrawal response in morphine-dependent rats.