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Objective@#To investigate whether endogenous nociceptin/orphanin FQ (N/OFQ) can inhibit arrhythmia and expression of β1-adrenergic receptor (β1-AR) on the surface of myocardial cell membrane in acute myocardial ischemia rats by Raf kinase inhibitory protein (RKIP).@*Methods@#① Experiment one: according to random number table method, 30 adult male Sprague-Dawley (SD) rats with only 6 weeks of age were divided into Sham group (open the chest but do not ligate the coronary artery), myocardial ischemia model group (coronary ligation of left anterior descending branch), and endogenous N/OFQ antagonists UFP-101 pretreatment group (UFP-101 group, preoperative 10 minutes after tail vein injection of 1 mL/kg UFP-101), with 10 rats in each group. Arrhythmia was recorded within 15 minutes after operation. The expression of phosphorylated RKIP (p-RKIP) was detected by Western Blot. ② Experiment two: according to the random number table method, 30 4-week-old male SD rats were divided into UFP-101 control group, RKIP over expression group and RKIP antagonism group, with 10 rats in each group. The UFP-101 control group was intraperiton eally injected with corn oil every day, while the other two groups were injected with up adjuster of RKIP (Didymin). The rats in the three groups were all ligated after 4 weeks of feeding, and UFP-101 was injected through the tail vein 10 minutes before the operation. The RKIP antagonist group received intraperitoneal injection of the RKIP-specific antagonist locostatin 2 hours before surgery. Arrhythmia results were recorded within 15 minutes after operation. Western Blot was used to detect the expression of p-RKIP in myocardial tissue and expression of β1-AR on the surface of myocardial cell membrane 15 minutes after surgery.@*Results@#①Experiment one: compared with Sham group, ventricular ectopic beat (VEB), ventricular tachycardia (VT) and ventricular fibrillation (VF) increased significantly in the model group and UFP-101 group, and arrhythmia score increased significantly. In addition, compared with the Sham group, p-RKIP expression was increased in the model group and decreased in the UFP-101 group. Compared with the model group, preconditioning with UFP-101 significantly reduced the occurrence of arrhythmia [arrhythmia score: 1.5 (0.3, 5.0) vs. 4.0 (2.0, 5.0), P < 0.05], and the expression of p-RKIP in myocardial tissue significantly decreased (p-RKIP/total RKIP: 0.20±0.11 vs. 0.43±0.11, P < 0.05). This indicated that antagonistic N/OFQ could reduce the phosphorylation of RKIP and the occurrence of arrhythmia. ② Experiment two: compared with the UFP-101 control group, overexpression of RKIP significantly increased the occurrence of arrhythmia events, and the expression of β1-AR on the surface of the myocardial cell membrane significantly increased. And antagonism RKIP overexpression could make the occurrence of arrhythmia eased [arrhythmia score: 3.0 (2.0, 3.0) vs. 4.0 (2.0, 5.0), P < 0.05], and significantly reduce the expression of myocardial cell membrane surface β1-AR (β1-AR/Na+-K+-ATPase: 0.88±0.09 vs. 1.02±0.08, P < 0.05), while there was no significant difference in total RKIP expression (total RKIP/GAPDH: 5.40±0.21 vs. 5.36±0.19, P > 0.05). This indicated that endogenous N/OFQ affected the expression of plasma β1-AR on the surface of myocardial cell membrane and ischemic arrhythmia in rats through RKIP.@*Conclusion@#Endogenous N/OFQ can affect the expression of plasma β1-AR on the membrane surface of ischemic myocardium and arrhythmia in rats via increased expression of RKIP phosphorylation.
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Objective To investigate whether endogenous nociceptin/orphanin FQ (N/OFQ) can inhibit arrhythmia and expression of β1-adrenergic receptor (β1-AR) on the surface of myocardial cell membrane in acute myocardial ischemia rats by Raf kinase inhibitory protein (RKIP). Methods ① Experiment one: according to random number table method, 30 adult male Sprague-Dawley (SD) rats with only 6 weeks of age were divided into Sham group (open the chest but do not ligate the coronary artery), myocardial ischemia model group (coronary ligation of left anterior descending branch), and endogenous N/OFQ antagonists UFP-101 pretreatment group (UFP-101 group, preoperative 10 minutes after tail vein injection of 1 mL/kg UFP-101), with 10 rats in each group. Arrhythmia was recorded within 15 minutes after operation. The expression of phosphorylated RKIP (p-RKIP) was detected by Western Blot. ② Experiment two: according to the random number table method, 304-week-old male SD rats were divided into UFP-101 control group, RKIP over expression group and RKIP antagonism group, with 10 rats in each group. The UFP-101 control group was intraperiton eally injected with corn oil every day, while the other two groups were injected with up adjuster of RKIP (Didymin). The rats in the three groups were all ligated after 4 weeks of feeding, and UFP-101 was injected through the tail vein 10 minutes before the operation. The RKIP antagonist group received intraperitoneal injection of the RKIP-specific antagonist locostatin 2 hours before surgery. Arrhythmia results were recorded within 15 minutes after operation. Western Blot was used to detect the expression of p-RKIP in myocardial tissue and expression of β1-AR on the surface of myocardial cell membrane 15 minutes after surgery. Results ①Experiment one: compared with Sham group, ventricular ectopic beat (VEB), ventricular tachycardia (VT) and ventricular fibrillation (VF) increased significantly in the model group and UFP-101 group, and arrhythmia score increased significantly. In addition, compared with the Sham group, p-RKIP expression was increased in the model group and decreased in the UFP-101 group. Compared with the model group, preconditioning with UFP-101 significantly reduced the occurrence of arrhythmia [arrhythmia score: 1.5 (0.3, 5.0) vs. 4.0 (2.0, 5.0), P < 0.05], and the expression of p-RKIP in myocardial tissue significantly decreased (p-RKIP/total RKIP: 0.20±0.11 vs. 0.43±0.11, P < 0.05). This indicated that antagonistic N/OFQ could reduce the phosphorylation of RKIP and the occurrence of arrhythmia. ② Experiment two:compared with the UFP-101 control group, overexpression of RKIP significantly increased the occurrence of arrhythmia events, and the expression of β1-AR on the surface of the myocardial cell membrane significantly increased. And antagonism RKIP overexpression could make the occurrence of arrhythmia eased [arrhythmia score: 3.0 (2.0, 3.0) vs. 4.0 (2.0, 5.0), P < 0.05], and significantly reduce the expression of myocardial cell membrane surface β1-AR (β1-AR/Na+-K+-ATPase: 0.88±0.09 vs. 1.02±0.08, P < 0.05), while there was no significant difference in total RKIP expression (total RKIP/GAPDH: 5.40±0.21 vs. 5.36±0.19, P > 0.05). This indicated that endogenous N/OFQ affected the expression of plasma β1-AR on the surface of myocardial cell membrane and ischemic arrhythmia in rats through RKIP. Conclusion Endogenous N/OFQ can affect the expression of plasma β1-AR on the membrane surface of ischemic myocardium and arrhythmia in rats via increased expression of RKIP phosphorylation.
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Pain is not only a common syndrome in clinic, but also a disease harming people’s health and quality of life. Discovery of potent and low-or non-addictive analgesic agent is a great challenge and our expectation. Nociceptin/orphanin FQ opioid peptide (NOP)receptor, the fourth member of the opioid receptor family, was discovered in 1994. Growing evidence has revealed that NOP receptor plays an important role in pain transduction and modulation and becomes a potential target for novel analgesics development. This review focuses on the progresses in exploring the biological characteristics of NOP receptor and its complex role in pain modulation, as well as the discovery of novel analgesic agents targeting NOP receptor, which provides reference for understanding the mechanisms of pain and analgesia and finding ideal analgesics.
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Pain is not only a common syndrome in clinic,but also a disease harming people′s health and quality of life. Dis?covery of potent and low-or non-addictive analgesic agent is a great challenge and our expectation. Nociceptin/orphanin FQ opioid pep?tide (NOP)receptor,the fourth member of the opioid receptor family,was discovered in 1994. Growing evidence has revealed that NOP receptor plays an important role in pain transduction and modulation and becomes a potential target for novel analgesics develop?ment. This review focuses on the progresses in exploring the biological characteristics of NOP receptor and its complex role in pain modulation,as well as the discovery of novel analgesic agents targeting NOP receptor,which provides reference for understanding the mechanisms of pain and analgesia and finding ideal analgesics.
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PURPOSE: Nociceptin/orphanin FQ (N/OFQ) as an endogeneous hexadecapeptide is known to exert antinociceptive effects spinally. The aims of this study were to demonstrate the antinociceptive effects of i.t. N/OFQ and to investigate the possible interaction between N/OFQ and endogenous opioid systems using selective opioid receptor antagonists in rat formalin tests. MATERIALS AND METHODS: I.t. N/OFQ was injected in different doses (1-10 nmol) via a lumbar catheter prior to a 50 microL injection of 5% formalin into the right hindpaw of rats. Flinching responses were measured from 0-10 min (phase I, an initial acute state) and 11-60 min (phase II, a prolonged tonic state). To observe which opioid receptors are involved in the anti-nociceptive effect of i.t. N/OFQ in the rat-formalin tests, naltrindole (5-20 nmol), beta-funaltrexamine (1-10 nmol), and norbinaltorphimine (10 nmol), selective delta-, micro- and kappa-opioid receptor antagonists, respectively, were administered intrathecally 5 min after i.t. N/OFQ. RESULTS: I.t. N/OFQ attenuated the formalin-induced flinching responses in a dose-dependent manner in both phases I and II. I.t. administration of naltrindole and beta-funaltrexamine dose-dependently reversed the N/OFQ-induced attenuation of flinching responses in both phases; however, norbinaltorphimine did not. CONCLUSION: I.t. N/OFQ exerted an antinociceptive effect in both phases of the rat-formalin test through the nociceptin opioid peptide receptor. In addition, the results suggested that delta- and micro-opioid receptors, but not kappa-opioid receptors, are involved in the antinociceptive effects of N/OFQ in the spinal cord of rats.
Subject(s)
Animals , Male , Rats , Analgesics/administration & dosage , Formaldehyde/toxicity , Injections, Spinal , Naltrexone/administration & dosage , Narcotic Antagonists/administration & dosage , Opioid Peptides/administration & dosage , Pain Measurement , Rats, Sprague-Dawley , Receptors, Opioid/agonistsABSTRACT
BACKGROUND: Nociceptin/orphanin FQ (N/OFQ) is an endogenous opioid heptadecapeptide. Preclinically, the pharmacologic action of N/OFQ has been characterized for the treatment of pain in non-human primates. Clinically, the pharmacologic action of N/OFQ is unclear, and concentrations have only been measured under certain clinical conditions. The aims of this study were to measure the plasma concentrations of N/OFQ in different postoperative pain states and to identify the potential relationship between postoperative pain states and N/OFQ plasma concentrations. METHODS: Two groups of 14 patients scheduled for knee arthroscopy were included in this study. Postoperative pain in the first group (IV group) was controlled by intravenous patient-controlled analgesia (IV-PCA). Postoperative pain in the second group (ES group) was controlled by epidural patient-controlled analgesia (E-PCA) or the remnant analgesic effects of spinal anesthesia. Plasma concentrations of N/OFQ were measured by enzyme-linked immunosorbent assay. Numerical rating scale (NRS) scores were recorded for all patients. Differences between the two groups with regards to plasma concentrations of N/OFQ and NRS scores were evaluated by the Mann-Whitney U-test. RESULTS: Plasma concentrations of N/OFQ (mean +/- SD) were 70.4 +/- 128.0 pg/ml in the IV group and 19.2 +/- 43.4 pg/ml in the ES group. NRS scores (mean +/- SD) were 3.1 +/- 1.9 in the IV group and 0.5 +/- 1.1 in the ES group. The differences in plasma N/OFQ concentrations between groups were not significant (P = 0.06). NRS scores were significantly lower in the ES group as compared with the IV group (P = 0.0019). CONCLUSIONS: Plasma concentrations of N/OFQ increase in acute postoperative pain states, but are not correlated with the level of postoperative pain.
Subject(s)
Humans , Analgesia, Patient-Controlled , Anesthesia , Anesthesia, Spinal , Arthroscopy , Enzyme-Linked Immunosorbent Assay , Knee , Opioid Peptides , Pain, PostoperativeABSTRACT
Oyecave:To observe the influence of nociceptin/orphanin FQ(N/OFO)on cerebral infarction volume and somatosellsOry evoked potential(SEP)in focal cerebral ischemia in rats.Methods:Forty one SD rats were randomly alloomed into middle artery occlusion(MCAO)sham-operation(n=5),isehemic(n=8),N/OFQ 10μg(n=7),N/OFQ 1 μg(n=7),N/OFQ0.1 μg(n=7),and artificiai cerebrospinal fluid(ACSF)(n=7)groups.A model of middle cerebral artery occlusion(MCAO)in rats was induced using intraluminal suture method.Reperfusion was performed 2 hours after MCAO.One hour after MCAO,N/OFQ 10 μg,N/OFQ 1 μg,N/OFQ O. 1 μg,and the same volume of ACSF were injected intraventricularly in the N/OFQ 10 μg,N/OFQ 1 μg,N/OFQ 0. 1 μg,and ACSF groups,respectively. The cerebral infarction volurne was detected 24 hours after reperfusion,and SEP was recorded. Results:1he amplitude of SEP P1 decreased in the sham-operation group. There was no significant change in P1 peak latencies.There were no significant differences hetween the N/OFQ 0. 1 μg group and the ACSF group in SEP amplitudes,P1 peak lantecies and cerebral infarction volume. As compared with the ACSF group,the SEP amplitudes were further decreased in the N/OFQ 1 μg and N/OFQ 10 μg groups,but there were no significant change in P1 peak lantecies. One hour after reperfusion,the SEP amplitude in the ACSF group almost returned to the level of preischemia,the recovery slowed down in the N/OFQ 1 μg group,and it still did not recovered 3 hours after reperfusion in the N/OFQ 10 μg group. The dose of N/OFQ and SEP response showed dose-effect relationship,The higher the dose,the deeper the SEP depression and the slower the recovery. At 24 hours after reperfusion,the cerebral infarction vlumes in the shamoperation,ACSF,N/OFQ 0. 1 μg,N/OFQ 1 μg,and N/OFQ 10 μg groups were 0 mm3,24.180 ±4.088 mm3,23.090±4.523 mm3,35.304 ± 6. 824 mm3,and 40. 806±6. 716 mm3,respectively. There was no significant difference between N/OFQ 0. 1 and ACSF groups. There were significant differences between N/OFQ 1 μg and 10 μg groups and ACSF group (all P ＜ 0.01 ). Conclusions:Intracerebroventricular injection of N/OFQ in the early stage of cerebral ischemia decreases the SEP amplitude,prolongs the time of recovery,and increases cerebral infarction volume,which shoves that it may aggravate cerebral ischemic injury.
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BACKGROUND: This study was examined whether or not the orphanin FQ (OFQ)-stimulated [35S]GTPgammaS activity interact with DAMGO in the whole brain of mice. METHODS: ICR mice (male, n = 20, 20-25 g) were euthanized for the membrane preparations. In the agonist-stimulated [35S]GTPgammaS binding dose-response curves by OFQ, Ro-64-6198 and DAMGO, the EC50 (effective concentration 50, nM) and maximum stimulation (% over basal) were determined in the presence or absence of J-113397 (10 nM), a NOP (nociceptin-opioid peptide) receptor antagonist. OFQ (1micrometer), Ro-64-6198 (10micrometer), DAMGO (10micrometer) and their combination cocktail were used to determine the interaction between the NOP and MOP (micron-opioid peptide) receptor. RESULTS: The values of EC50 and maximum stimulation of [35S]GTPgammaS binding were as follows: OFQ (9.2 +/- 0.2 nM/17.9 +/- 0.1%), Ro-64-6198 (143.5 +/- 0.5 nM/18.1 +/- 0.4%), and DAMGO (680.6 +/- 0.7 nM/18.1 +/- 0.5%). J-113397 produced a 8.7 and 7.1 fold rightward shifting in the OFQ and Ro-64-6198-stimulated [35S]GTPgammaS binding dose-response curve respectively, but not in the DAMGO. OFQ combined with DAMGO-stimulated [35S]GTPgammaS binding had an additive effect, but not in the OFQ combined with Ro-64-6198. CONCLUSIONS: OFQ, Ro-64-6198 and DAMGO-stimulated [35S]GTPgammaS binding in the brain of mice has receptor selectivity. The [35S]GTPgammaS stimulation of OFQ and DAMGO had an additive effect rather than an anti-opioid effect on the level of intracellular signal transduction through agonist-stimulated [35S]GTPgammaS bindings.
Subject(s)
Animals , Mice , Brain , Enkephalin, Ala(2)-MePhe(4)-Gly(5)- , Guanosine 5'-O-(3-Thiotriphosphate) , Membranes , Mice, Inbred ICR , Signal TransductionABSTRACT
Objective To investigate the effect of intracerebroventricular injection of morphine and orphanin FQ (OFQ) on somatosensory evoked potential (SEP) and Na+-K+ATPase activity in cerebral cortex of rat. MethodsTo study the SEP with the BL-420 biological signal collecting system. The cerebral cortex tissues were extracted, homogenized and centrifuged. Na+-K+ATPase activity was measured with ATPase analytical kit. Results After intracerebroventricular injection with OFQ 0.9 ?g, the amplitude of P1-N1 and N1-P2 increased significantly(P
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BACKGROUND: The aim of this in vitro study was to investigate [35S]GTP gamma S binding stimulated activation by orphanin FQ in monkey cerebral, thalamic, and spinal membranes. METHODS: A rhesus monkey (Macaca mulatta, female, n = 1) was euthanized to obtain cerebral, thalamic, and spinal cord membrane preparations. In the orphanin FQ-stimulated [35S]GTP gamma S binding dose-response curve, EC50 (effective concentration 50, nanomolar) and maximum stimulation (% over basal) were determined in the absence or presence of each opioid receptor antagonist, namely, naloxone (20 nM), nor-BNI (3 nM), naltrindole (3 nM), or J-113397 (10 nM) antagonists of the micron-, kappa-, delta-, and nociceptin- opioid receptors respectively. RESULTS: The values of EC50 and maximum stimulation of [35S]GTP gamma S binding were as follows: cortex (5.1 +/- 1.4 nM / 55.6 +/- 8.2%), thalamus (8.5 +/- 1.3 nM / 27.8 +/- 4.9%), and spinal cord (11.3 +/- 0.2 nM / 15.2 +/- 4.5%). Maximum stimulation for these three membranes were significantly different (P < 0.05). J-113397 produced a 11.8 fold rightward shift in the OFQ-stimulated [35S]GTP gamma S binding dos0e-response curve, but the other opioid receptor antagonists had no effect. CONCLUSIONS: Maximum stimulation of [35S]GTP gamma S binding by OFQ in each membrane showed significantly different profiles, suggesting different pharmacologic efficacies by region. The OFQ-stimulated [35S]GTP gamma S bindings in this study were mediated via nociceptin-opioid peptide receptor stimulation.
Subject(s)
Female , Humans , Cerebrum , GTP-Binding Proteins , Guanosine 5'-O-(3-Thiotriphosphate) , Haplorhini , Macaca mulatta , Membranes , Naloxone , Receptors, Opioid , Receptors, Peptide , Spinal Cord , ThalamusABSTRACT
Objective: To observe the effects of OFQ on endomorphin-1 in pain modulation. Methods: OFQ and endomorphin-1 were microinjected intracerebroventricularly or intrathecally in rats. The pain thresholds were measured by tail-flick test and acetic-acid induced twitching test, and the changes of antinociceptive effects induced by endomorphin-1 were observed. Results: OFQ antagonizing endomorphin-1 antinociception at the supraspinal level, while enhancing at the spinal level were observed. Conclusion: OFQ has functional effects on endomorphin-1 in pain modulation,both in the brain and the spinal cord. The mechanisms of its effect may be different.
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Subject(s)
Animals , Child , Humans , Rats , Brain Stem , Capsaicin , Child, Orphaned , Nerve Fibers, Unmyelinated , Neurons , Perfusion , Receptors, AMPA , Receptors, N-Methyl-D-Aspartate , Receptors, Opioid , Sensitivity and Specificity , Synaptic TransmissionABSTRACT
Objective:To assess whether intrathecal orphanin FQ can develop the antinociceptive effect tolerance,and whether there is a cross tolerance between the antinociceptive effect of intrathecal orphanin FQ and the ? opioid receptor agonist morphine.Methods: Tail flick test was used to observe the change of antinociceptive effect after orphanin FQ/morphine intrathecal microinjection into the rats tolerant to acute or chronic morphine/orphanin FQ.Results:Like morphine,large dosage of continuous intrathecal orphanin FQ microinjection produced tolerance to the antinociceptive effect,but there was no apparent cross tolerance between the orphanin FQ and morphine; Hyperalgesic response was found in morphine tolerant rats,but not in orphanin FQ tolerant rats.Conclusion:Lack of cross tolerance between the antinociceptive effect of intrathecal orphanin FQ and morphine indicates that the mechanism of tolerance to orphanin FQ may differ from that to morphine; The antinociceptive effect of intrathecal orphanin FQ may be largely related with its specific receptor in the spinal cord.
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AIM:To evaluate the effect of Huazhuo Jiedu Huoxue Recipe(Herba Agastaches,Herba Eupatorii,Rhizoma Pinelliae,Pericarpium Citri reticulatae,Poria,etc.) on plasma orphanin FQ(OFQ) and prostaglandins in the patients of endometriosis(EM) with pain.METHODS:The concentrations of plasma OFQ and prostaglandins were measured by radioimmunoassay before and after the treatment on the patients of EM with pain.29 patients of EM with severe pain(severe group),31 patients with slight pain(slight group) and 25 patients without pain(control group) were studied.RESULTS:The levels of OFQ、 PGF_(2a)、 PGE_2、 6-keto-PGF_(1a) and TXB_2 in plasma were significantly higher in patients of EM with pain than that of patients without pain(P
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Objective\ To investigate the cardiovascular distribution of orphanin FQ (OFQ) and OFQ precursor mRNA in spontaneously hypertensive rat(SHR) and rabbit. Methods\ Reverse transcription polymerase chain reacrtion(RT PCR), and immunohistochemical method were used. Results\ The expression of OFQ precursor mRNA was detected from aorta, pulmonary artery, renal artery and vein of rat at a high level comparable with the amounts of brain, and a weak expression signal could also be observed in the atrium. The positive immunoreactive OFQ was detected in the tissues of aorta, atrium and renal of rabbit, as well as in smooth cells, endothelium and glomerulus. Conclusion\ These observations suggest that orphanin FQ might play a role in regulating the function of cardiovascular system and kidney, but the exact underlying mechanism needs further studying.