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Objective To evaluate the expression of ? opioid receptor of the knee joint synovium tissue in patients with chronic inflammation. Methods The patients were divided into inflammatory group and control group(n=25 for both). Those who were allocated to the inflammatory group were diagnosed as osteoarthritis by arthroscopy, and in the control group, the patients were having dislocation of patella and took internal fixation with arthroscopy. The synovium tissues were harvested from suprapateller bursa, articulation vestibule, intercondylar fossa and articulation metacele. The synovium were taken to measure ? opioid receptor by immunohistochemistry and RT-PCR in both groups. Results Immunohistochemical and RT-PCR results revealed that the expression of mRNA and the optical density (OD) of immunoreaction of ?-opioid receptor in the knee synovium tissue in the chronic inflammation group were significantly higher than those in the control group (P0.05). Conclusion The expression of ? opioid receptor of the knee joint synovium tissue in chronic inflammation was significantly up-regulated. It may play a partial role in the peripheral mechanism of morphine.
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Aim To examine the effect of ? opioid receptor agonist U50488H on the levels of interleukin-6(IL-6) and interleukin-8(IL-8) from angiotensinⅡ(AngⅡ) stimulated endothelial cells.Methods In the in vivo study,the modulation of U50488H(1.5 mg?kg~-1) intravenously on the level of AngⅡ was evaluated.In the in vitro study,endothelial cells from human umbilical vein(HUVEC) were cultured and divided into four groups:Control group,AngⅡ group,and AngⅡ plus U50488H and/or nor-BNI(a selective ? opioid receptor antagonist) group.These groups were treated respectively with phosphate buffered solution(PBS),AngⅡ(10~-9~10~-5 mol?L~-1),and AngⅡ in the presence of U50488H and/or nor-BNI for 0~24 hours.Culture supernatant and endothelial cells were collected at 0,3,6,12 and 24 h.IL-6 and IL8 levels in culture supernatant were measured by enzyme linked immunosorbent assay(ELISA).Results The level of AngⅡ in the blood was significantly decreased following U50488H intravenously,which was blocked by nor-BNI administration(2 mg?kg~-1).AngⅡ stimulated the productions of IL-6 and IL-8 from HUVEC in the dose-dependent and time-dependent manners.U50488H at 10~-5 mol?L~-1 significantly inhibited this process,and the inhibitory effect of U50488H was blocked by nor-BNI,which itself had no effect.Conclusion ? opioid receptor may play a role in the process of anti-inflammation via down regulation of AngⅡ level and inhibition of the AngⅡ-stimulated IL-6 and IL-8 productions from endothelium cells.
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Objective:To observe the development of tolerance and dependence to endomorphin 1(EM 1) and its regulation on ? opioid receptor(MOR) in rat brain,providing references for the mechanism of the EM 1 dependence. Methods: Totally 60 SD rats were randomly divided into saline, acute EM 1 treatment and chronic EM 1 treatment groups. For acute EM 1 treatment, rats were injected intracerebroventricularly with 10 ?g/kg EM 1 30 min prior to sacrifice. The chronic group were treated with EM 1 daily administration at 8:00 and 15:00 starting with 10 ?g/kg on day 1 to 50 ?g/kg on day 9. After chronic EM 1 treatment on day 1, 3, 6 and 9, the antinociceptive AD 50 or catatonic ED 50 values were determined by modified Dixon's method. The B max and K d values of 3H DAMGO saturation binding to MOR were measured by Scatchard analysis. The gene expression of MOR was appraised by RT PCR. Results:(1) EM 1 chronic treatment produced a high degree of tolerance to the antinociceptic and catatonic effects on the 3rd day (3.1 fold and 1.9 fold) and the 9th day (28.4 fold and 8.5 fold). The jumping times, weight lost and withdrawal score of rats were significantly higher than that of the control group after 9 d chronic EM 1 treatment. (2) After 9 d of administration with EM 1, the specific binding capacity and mRNA expression of MOR in rat cortex, midbrain and striatum were all decreased compared with those of the control and acute treatment groups, but the K d values were not significantly altered. Conclusion:Endomorphin 1 has the tolerant and dependent potent. For long term chronic treatment, Endomorphin 1 induces downregulation of the binding capacity and mRNA of MOR, which may be related to the dependence development.
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As for the ? opioid receptor, there are some disputes about the domains involved in the selective recognition of ligands, the relative spatial orientation of the amino acids within the TM affect the affinities of selective ligands. Regulation of opioid receptor activities does not appear to involve in their ability to promote the association of GTP onto the G proteins and the subsequent dissociation of heterotrimers. It is not very clear if phosphorylation correlates with agonist induced receptor desensitization. The celluar processing of ? opioid receptors requires the formation of multiple protein complexes, it is clear that interactions of ubiquitous transcriptional factors determine gene transcription.
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Objective To investigate the synaptic connections between endomorphin-immunoreactive(ir) terminals and ? opioid receptor-ir neurons in the superficial layers(laminae Ⅰ and Ⅱ) of the rat spinal dorsal horn. Methods The double-labeling immunohistochemical electron microscopic technique,i.e.pre-embedding immunohistochemical detection of endomorphin combin with pre-embedding immuno-gold particles labeling technique to identify ? opioid receptor-immunoreactivity,was used in the present study. Results ? opioid receptor-ir neuronal cell bodies,fibers as well as axon terminals were observed in laminae Ⅰ and Ⅱ of the spinal dorsal horn,meanwhile dense endomorphin-ir axon terminals were located mainly within the same region.Under electron microscope,the synaptic connections formed by endomorphin-ir axon terminals labeled with diaminobenzidine(DAB) reaction products and ? opioid receptor-ir neuronal cell bodies and dendritic profiles labeled with immuno-gold particles were observed.The principle synaptic type was asymmetric synapse.There were more axon-dendritic synapses than axon-somatic ones as encountered in the present study.Conclusion The distribution patterns of endomorphin-ir and ? opioid receptor-ir structures match with each other in the superficial laminae of the spinal dorsal horn,that provides morphological base for the antinociceptive effects of endomorphin and ? opioid receptor in the processing of nociceptive information transmission.