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Prukop T, Wernick S, Boussicault L, Ewers D, Jäger K, Adam J, Winter L, Quintes S, Linhoff L, Barrantes-Freer A, Bartl M, Czesnik D, Zschüntzsch J, Schmidt J, Primas G, Laffaire J, Rinaudo P, Brureau A, Nabirotchkin S, Schwab MH, Nave KA, Hajj R, Cohen D, Sereda MW. Synergistic PXT3003 therapy uncouples neuromuscular function from dysmyelination in male Charcot-Marie-Tooth disease type 1A (CMT1A) rats. J Neurosci Res 2020; 98:1933-1952. [PMID: 32588471 DOI: 10.1002/jnr.24679] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 05/13/2020] [Accepted: 05/31/2020] [Indexed: 12/11/2022]
Abstract
Charcot-Marie-Tooth disease 1 A (CMT1A) is caused by an intrachromosomal duplication of the gene encoding for PMP22 leading to peripheral nerve dysmyelination, axonal loss, and progressive muscle weakness. No therapy is available. PXT3003 is a low-dose combination of baclofen, naltrexone, and sorbitol which has been shown to improve disease symptoms in Pmp22 transgenic rats, a bona fide model of CMT1A disease. However, the superiority of PXT3003 over its single components or dual combinations have not been tested. Here, we show that in a dorsal root ganglion (DRG) co-culture system derived from transgenic rats, PXT3003 induced myelination when compared to its single and dual components. Applying a clinically relevant ("translational") study design in adult male CMT1A rats for 3 months, PXT3003, but not its dual components, resulted in improved performance in behavioral motor and sensory endpoints when compared to placebo. Unexpectedly, we observed only a marginally increased number of myelinated axons in nerves from PXT3003-treated CMT1A rats. However, in electrophysiology, motor latencies correlated with increased grip strength indicating a possible effect of PXT3003 on neuromuscular junctions (NMJs) and muscle fiber pathology. Indeed, PXT3003-treated CMT1A rats displayed an increased perimeter of individual NMJs and a larger number of functional NMJs. Moreover, muscles of PXT3003 CMT1A rats displayed less neurogenic atrophy and a shift toward fast contracting muscle fibers. We suggest that ameliorated motor function in PXT3003-treated CMT1A rats result from restored NMJ function and muscle innervation, independent from myelination.
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Affiliation(s)
- Thomas Prukop
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Institute of Clinical Pharmacology, University Medical Center Göttingen, Göttingen, Germany
| | - Stephanie Wernick
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany
| | | | - David Ewers
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany
| | - Karoline Jäger
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Julia Adam
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Lorenz Winter
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Susanne Quintes
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany
| | - Lisa Linhoff
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany
| | | | - Michael Bartl
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany
| | - Dirk Czesnik
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany
| | - Jana Zschüntzsch
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Jens Schmidt
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | | | | | | | | | | | - Markus H Schwab
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | | | | | - Michael W Sereda
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany
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Kairupan TS, Cheng KC, Asakawa A, Amitani H, Yagi T, Ataka K, Rokot NT, Kapantow NH, Kato I, Inui A. Rubiscolin-6 activates opioid receptors to enhance glucose uptake in skeletal muscle. J Food Drug Anal 2019; 27:266-274. [PMID: 30648580 PMCID: PMC9298623 DOI: 10.1016/j.jfda.2018.06.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 06/25/2018] [Indexed: 12/21/2022] Open
Abstract
Rubiscolin-6 is an opioid peptide derived from plant ribulose bisphosphate carboxylase/oxygenase (Rubisco). It has been demonstrated that opioid receptors could control glucose homeostasis in skeletal muscle independent of insulin action. Therefore, Rubiscolin-6 may be involved in the control of glucose metabolism. In the present study, we investigated the effect of rubiscolin-6 on glucose uptake in skeletal muscle. Rubiscolin-6-induced glucose uptake was measured using the fluorescent indicator 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxyglucose (2-NBDG) in L6 and C2C12 cell lines. The protein expressions of glucose transporter 4 (GLUT4) and AMP-activated protein kinase (AMPK) in L6 cells were observed by Western blotting. The in vivo effects of rubiscolin-6 were characterized in streptozotocin (STZ)-induced diabetic rats. Rubiscolin-6 induced a concentration-dependent increase in glucose uptake levels. The increase of phospho-AMPK (pAMPK) and GLUT4 expressions were also observed in L6 and C2C12 cells. Effects of rubiscolin-6 were blocked by opioid receptor antagonists and/or associated signals inhibitors. Moreover, Rubiscolin-6 produced a dose-dependent reduction of blood glucose and increased GLUT4 expression in STZ-induced diabetic rats. In conclusion, rubiscolin-6 increases glucose uptake, potentially via an activation of AMPK to enhance GLUT4 translocation after binding to opioid receptors in skeletal muscle.
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Affiliation(s)
- Timothy Sean Kairupan
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan; Faculty of Medicine, Sam Ratulangi University, Manado, Indonesia
| | - Kai-Chun Cheng
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Akihiro Asakawa
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Haruka Amitani
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Takakazu Yagi
- Department of Orthodontics and Dentofacial Orthopedics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Koji Ataka
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Natasya Trivena Rokot
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | | | - Ikuo Kato
- Department of Medical Biochemistry, Kobe Pharmaceutical University, Kobe, Japan
| | - Akio Inui
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.
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Yadlapalli JSK, Dogra N, Walbaum AW, Prather PL, Crooks PA, Dobretsov M. Preclinical assessment of utility of M6S for multimodal acute and chronic pain treatment in diabetic neuropathy. Life Sci 2018; 192:151-159. [DOI: 10.1016/j.lfs.2017.11.042] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 11/17/2017] [Accepted: 11/26/2017] [Indexed: 12/31/2022]
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Niu CS, Chen LJ, Niu HS. Antihyperglycemic action of rhodiola-aqeous extract in type1-like diabetic rats. Altern Ther Health Med 2014; 14:20. [PMID: 24417880 PMCID: PMC3897963 DOI: 10.1186/1472-6882-14-20] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Accepted: 01/09/2014] [Indexed: 12/21/2022]
Abstract
Background Rhodiola rosea (Rhodiola) is a plant in the Crassulaceae family that grows in cold regions of the world. It is mainly used in clinics as an adaptogen. Recently, it has been mentioned that Rhodiola increases plasma β-endorphin to lower blood pressure. Thus, the present study aims to investigate the antidiabetic action of Rhodiola in relation to opioids in streptozotocin-induced diabetic rats (STZ-diabetic rats). Methods In the present study, the plasma glucose was analyzed with glucose oxidase method, and the determination of plasma β-endorphin was carried out using a commercially available enzyme-linked immunosorbent assay. The adrenalectomy of STZ-diabetic rats was used to evaluate the role of β-endorphin. In addition, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blotting analysis were performed to investigate mRNA and protein expressions. Results Rhodiola-water extract dose-dependently lowered the plasma glucose in STZ-diabetic rats and this action was reversed by blockade of opioid μ-receptors using cyprodime. An increase of plasma β-endorphin by rhodiola-water extract was also observed in same manner. The plasma glucose lowering action of rhodiola-water extract was attenuated in bilateral adrenalectomized rats. In addition, continuous administration of rhodiola-water extract for 3 days in STZ-diabetic rats resulted in an increased expression of glucose transporter subtype 4 (GLUT 4) in skeletal muscle and a marked reduction of phosphoenolpyruvate carboxykinase (PEPCK) expression in liver. These effects were also reversed by blockade of opioid μ-receptors. Conclusions Taken together, rhodiola-water extract improves hyperglycemia via an increase of β-endorphin secretion from adrenal gland to activate opioid μ-receptors in STZ-diabetic rats.
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Pharmacological traits of delta opioid receptors: pitfalls or opportunities? Psychopharmacology (Berl) 2013; 228:1-18. [PMID: 23649885 PMCID: PMC3679311 DOI: 10.1007/s00213-013-3129-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 04/15/2013] [Indexed: 12/11/2022]
Abstract
RATIONALE Delta opioid receptors (DORs) have been considered as a potential target to relieve pain as well as treat depression and anxiety disorders and are known to modulate other physiological responses, including ethanol and food consumption. A small number of DOR-selective drugs are in clinical trials, but no DOR-selective drugs have been approved by the Federal Drug Administration and some candidates have failed in phase II clinical trials, highlighting current difficulties producing effective delta opioid-based therapies. Recent studies have provided new insights into the pharmacology of the DOR, which is often complex and at times paradoxical. OBJECTIVE This review will discuss the existing literature focusing on four aspects: (1) Two DOR subtypes have been postulated based on differences in pharmacological effects of existing DOR-selective ligands. (2) DORs are expressed ubiquitously throughout the body and central nervous system and are, thus, positioned to play a role in a multitude of diseases. (3) DOR expression is often dynamic, with many reports of increased expression during exposure to chronic stimuli, such as stress, inflammation, neuropathy, morphine, or changes in endogenous opioid tone. (4) A large structural variety in DOR ligands implies potential different mechanisms of activating the receptor. CONCLUSION The reviewed features of DOR pharmacology illustrate the potential benefit of designing tailored or biased DOR ligands.
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Czyzyk TA, Romero-Picó A, Pintar J, McKinzie JH, Tschöp MH, Statnick MA, Nogueiras R. Mice lacking δ-opioid receptors resist the development of diet-induced obesity. FASEB J 2012; 26:3483-92. [PMID: 22593549 DOI: 10.1096/fj.12-208041] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Pharmacological manipulation of opioid receptors alters feeding behavior. However, the individual contributions of each opioid receptor subtype on energy balance remain largely unknown. Herein, we investigated whether genetic disruption of the δ-opioid receptor (DOR) also controls energy homeostasis. Mice lacking DOR and wild-type mice were fed with standard diet and high-energy diet (HED). Mice were analyzed in vivo with the indirect calorimetry system, and tissues were analyzed by real-time PCR and Western blot analysis. DOR-knockout (KO) mice gained less weight (P<0.01) and had lower fat mass (P<0.01) when compared to WT mice fed an HED. Although DOR-KO mice were hyperphagic, they showed higher energy expenditure (P<0.05), which was the result of an increased activation of the thermogenic program in brown adipose tissue. The increased nonshivering thermogenesis involved the stimulation of uncoupling protein 1 (UCP1; P<0.01), peroxisome proliferator-activated receptor γ coactivator (PGC1α; P<0.05), and fibroblast growth factor 21 (FGF21; P<0.01). DOR deficiency also led to an attenuation of triglyceride content in the liver (P<0.05) in response to an HED. These findings reveal a novel role of DOR in the control of thermogenic markers and energy expenditure, and they provide a potential new therapeutic approach for the treatment of obesity.
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Affiliation(s)
- Traci A Czyzyk
- Obesity Research, Lilly Research Laboratories, Indianapolis, Indiana, USA
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Olianas MC, Dedoni S, Onali P. δ-Opioid receptors stimulate GLUT1-mediated glucose uptake through Src- and IGF-1 receptor-dependent activation of PI3-kinase signalling in CHO cells. Br J Pharmacol 2011; 163:624-37. [PMID: 21250979 DOI: 10.1111/j.1476-5381.2011.01234.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND AND PURPOSE Although opioids have been reported to affect glucose homeostasis, relatively little is known on the role of δ-opioid receptors. We have investigated the regulation of glucose transport by human δ-opioid receptors expressed in Chinese hamster ovary cells. EXPERIMENTAL APPROACH The uptake of [(3)H]-2-deoxy-D-glucose and 3-O-[methyl-[(3)H]]-D-glucose in response to δ-opioid receptor ligands and the expression of GLUT1, GLUT3 and GLUT4 glucose transporters were examined. Moreover, the effects of intracellular signal transduction inhibitors on δ-opioid receptor-regulated [(3)H]-2-deoxy-D-glucose uptake and protein phosphorylation were investigated. KEY RESULTS Activation of δ-opioid receptors rapidly stimulated [(3)H]-2-deoxy-D-glucose and 3-O-[methyl-[(3)H]]-D-glucose uptakes, which were blocked by the GLUT inhibitors cytochalasin B and phloretin. The stimulation of [(3)H]-2-deoxy-D-glucose uptake that occurred without a change in plasma membrane GLUT1 - required the coupling to G(i) /G(o) proteins - was independent of cAMP and extracellular signal-regulated protein kinases, and was suppressed by blockade of Src and insulin-like growth factor-1 receptor (IGF-1R) tyrosine kinases. Inhibition of phosphatidylinositol 3-kinase (PI3K) by wortmannin or LY294002 and by PI3Kα, but not γ, isoform-selective inhibitors greatly reduced the δ-opioid receptor stimulation of glucose uptake. Moreover, the response was attenuated by overexpressing a dominant-negative kinase-deficient Akt form and by chemical inhibition of Akt. Stimulation of δ-opioid receptors increased protein kinase Cζ/λ (PKCζ/λ) phosphorylation and a selective PKCζ/λ inhibitor slightly reduced opioid stimulation of glucose uptake. CONCLUSIONS AND IMPLICATIONS δ-Opioid receptors stimulated glucose transport probably by enhancing GLUT1 intrinsic activity through a signalling cascade involving G(i)/G(o), Src, IGF-1R, PI3Kα, Akt and, to a minor extent, PKCζ/λ. This effect may contribute to the opioid regulation of glucose homeostasis in physio-pathological conditions.
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Affiliation(s)
- Maria C Olianas
- Section of Biochemical Pharmacology, Department of Neuroscience, University of Cagliari, Monserrato, Italy
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Olianas MC, Dedoni S, Olianas A, Onali P. δ-Opioid Receptors Stimulate the Metabolic Sensor AMP-Activated Protein Kinase through Coincident Signaling with Gq/11-Coupled Receptors. Mol Pharmacol 2011; 81:154-65. [DOI: 10.1124/mol.111.075267] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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9
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Shieh JP, Cheng KC, Chung HH, Kerh YF, Yeh CH, Cheng JT. Plasma glucose lowering mechanisms of catalpol, an active principle from roots of Rehmannia glutinosa, in streptozotocin-induced diabetic rats. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:3747-53. [PMID: 21391677 DOI: 10.1021/jf200069t] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Catalpol is one of the active principles from roots of Rehmannia glutinosa Steud (Scrophulariaceae) that is widely used to treat diabetic disorders in Chinese traditional medicine using the name of Di-Huang, which is used to investigate the mechanisms for lowering of plasma glucose in streptozotocin-induced diabetic rats (STZ-diabetic rats). Catalpol decreased plasma glucose in a dose-related manner, and this action was reduced by pretreatment with naloxone or naloxonazine. An increase of plasma β-endorphin by catalpol was also observed in parallel. The plasma glucose lowering action of catalpol was deleted in bilateral adrenalectomized rats. Moreover, catalpol enhanced β-endorphin release from the isolated adrenal medulla of STZ-diabetic rats. Otherwise, plasma glucose lowering action of catalpol failed to produce in opioid μ-receptor knockout mice. Also, repeated administration of catalpol for 3 days in STZ-diabetic rats resulted in a marked reduction of phosphoenolpyruvate carboxykinase (PEPCK) expression in liver and an increased expression of glucose transporter subtype 4 (GLUT 4) in skeletal muscle. These effects were also reversed by blockade of opioid μ-receptors. Our results suggested that catalpol increased glucose utilization through increase of β-endorphin secretion from adrenal gland in STZ-diabetic rats.
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Affiliation(s)
- Ja-Ping Shieh
- Department of Anesthesiology, Chi-Mei Medical Center, Yong Kang, Tainan City, Taiwan, Republic of China
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Liu IM, Cheng JT. Mediation of Endogenous β-Endorphin in the Plasma Glucose-Lowering Action of Herbal Products Observed in Type 1-Like Diabetic Rats. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2010; 2011:987876. [PMID: 19095661 PMCID: PMC3147137 DOI: 10.1093/ecam/nen078] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Accepted: 11/14/2008] [Indexed: 01/01/2023]
Abstract
Recently, there have been advances in the development of new substances effective in managing diabetic disorders. Opioid receptors couple multiple systems to result in various biological effects, although opioids are best known for analgesia. In the present review, we used our recent data to describe the advance in plasma glucose-lowering action of herbal products, especially the mediation of β-endorphin in glucose homeostasis of insulin-deficient diabetes. In type 1-like streptozotocin-induced diabetic rats, we identified many products purified from herbs that show a dose-dependent plasma glucose-lowering action. Increase in β-endorphin secretion from the adrenal gland may activate peripheral opioid μ-receptors (MOR) to enhance the expression of muscle glucose transporters and/or to reduce hepatic gluconeogenesis at the gene level, thereby leading to improved glucose utilization in peripheral tissues for amelioration of severe hyperglycemia. It has also been observed that stimulation of α(1)-adrenoceptors (α(1)-ARs) in the adrenal gland by some herbal products is responsible for the increase in β-endorphin secretion via a phospholipase C-protein kinase dependent pathway. However, an increase in β-endorphin secretion from the adrenal gland by herbal products can function via another receptor. New insights into the mediation of endogenous β-endorphin activation of peripheral MOR by herbal products for regulation of glucose homeostasis without the presence of insulin have been established. Therefore, an increase in β-endorphin secretion and/or direct stimulation of peripheral MOR via an insulin-independent action might serve as the potential target for development of a therapeutic agent or promising adjuvant in intensive plasma glucose control.
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Affiliation(s)
- I M Liu
- Department of Pharmacy, Tajen University, Yen-Pou, Ping Tung Shien, Taiwan
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Merlin J, Evans BA, Csikasz RI, Bengtsson T, Summers RJ, Hutchinson DS. The M3-muscarinic acetylcholine receptor stimulates glucose uptake in L6 skeletal muscle cells by a CaMKK-AMPK-dependent mechanism. Cell Signal 2010; 22:1104-13. [PMID: 20206685 DOI: 10.1016/j.cellsig.2010.03.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Revised: 02/23/2010] [Accepted: 03/01/2010] [Indexed: 11/15/2022]
Abstract
The role of muscarinic acetylcholine receptors (mAChRs) in regulating glucose uptake in L6 skeletal muscle cells was investigated. [(3)H]-2-Deoxyglucose uptake was increased in differentiated L6 cells by insulin, acetylcholine, oxotremorine-M and carbachol. mAChR-mediated glucose uptake was inhibited by the AMPK inhibitor Compound C. Whole cell radioligand binding using [(3)H]-N-methyl scopolamine chloride identified mAChRs in differentiated but not undifferentiated L6 cells and M(3) mAChR mRNA was detected only in differentiated cells. M(3) mAChRs are Gq-coupled, and cholinergic stimulation by the mAChR agonists acetylcholine, oxotremorine-M and carbachol increased Ca(2+) in differentiated but not undifferentiated L6 cells. This was due to muscarinic but not nicotinic activation as responses were antagonised by the muscarinic antagonist atropine but not the nicotinic antagonist tubocurarine. Western blotting showed that both carbachol and the AMPK activator AICAR increased phosphorylation of the AMPKalpha subunit at Thr172, with responses to carbachol blocked by Compound C and the CaMKK inhibitor STO609 but not by the PI3K inhibitor wortmannin. AICAR-stimulated AMPK phosphorylation was not sensitive to STO-609, confirming that this compound inhibits CaMKK but not the classical AMPK kinase LKB1. The TAK1 inhibitor (5Z)-7-oxozeaenol and the G(i) inhibitor pertussis toxin both failed to block AMPK phosphorylation in response to carbachol. Using CHO-K1 cells stably expressing each of the mAChR subtypes (M(1)-M(4)), it was determined that only the M(1) and M(3) mAChRs phosphorylate AMPK, confirming a G(q)-dependent mechanism. This study demonstrates that activation of M(3) mAChRs in L6 skeletal muscle cells stimulates glucose uptake via a CaMKK-AMPK-dependent mechanism, independent of the insulin-stimulated pathway.
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Affiliation(s)
- Jon Merlin
- Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Victoria, 3800, Australia
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Yu BC, Chang CK, Su CF, Cheng JT. Mediation of beta-endorphin in andrographolide-induced plasma glucose-lowering action in type I diabetes-like animals. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2007; 377:529-40. [PMID: 18080810 DOI: 10.1007/s00210-007-0240-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Accepted: 11/26/2007] [Indexed: 11/29/2022]
Abstract
In the present study, we investigated the mechanism(s) for glucose-lowering action of andrographolide in streptozotocin-induced diabetic rats (STZ-diabetic rats). Andrographolide lowered plasma glucose concentrations in a dose-dependent manner and increased plasma beta-endorphin-like immunoreactivity (BER) dose-dependently in diabetic rats. Both of these responses to andrographolide were abolished by the pretreatment of animals with prazosin or N-(2-(2-cyclopropylmethoxy) ethyl) 5-choro-alpha-dimethyl-1H-indole-3-thylamine (RS17053) at doses sufficient to block alpha1-adrenoceptors (ARs). Also, andrographolide enhanced BER release from isolated rat adrenal medulla in a concentration-related manner that could be abolished by alpha1-ARs antagonists. Bilateral adrenalectomy in STZ-diabetic rats eliminated the activities of andrographolide, including the plasma glucose-lowering effect and the plasma BER-elevating effect. Andrographolide failed to lower plasma glucose in the presence of opioid micro-receptor antagonists and in the opioid micro-receptor knockout diabetic mice. Treatment of STZ-diabetic rats with andrographolide resulted in the reduced expression of phosphoenolpyruvate carboxykinase (PEPCK) in liver and an increased expression of the glucose transporter subtype 4 (GLUT 4) in soleus muscle. These effects were also blocked by opioid micro-receptor antagonists. In conclusion, our results suggest that andrographolide may activate alpha1-ARs to enhance the secretion of beta-endorphin which can stimulate the opioid micro-receptors to reduce hepatic gluconeogenesis and to enhance the glucose uptake in soleus muscle, resulting in a decrease of plasma glucose in STZ-diabetic rats. However, the roles of other endogenous opioid peptides or the mixture of several opioid peptides in the activation of opioid micro-receptors associated with the plasma glucose-lowering action of andrographolide, should be considered and need more investigation in the future.
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Affiliation(s)
- Bu Chin Yu
- Institute of Basic Medical Science, and Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan City, Taiwan, 70101, Republic of China
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Developmental expression and distribution of opioid receptors in zebrafish. Neuroscience 2007; 151:129-37. [PMID: 18082336 DOI: 10.1016/j.neuroscience.2007.09.086] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Revised: 09/24/2007] [Accepted: 10/27/2007] [Indexed: 11/22/2022]
Abstract
Zebrafish is a novel experimental model that has been used in developmental studies as well as in the study of pathological processes involved in human diseases. It has been demonstrated that the endogenous opioid system is involved in developmental mechanisms. We have studied the relationship between the different embryonic stages and opioid receptor expression for the four known opioid receptors in zebrafish (mu, delta 1, delta 2 and kappa). The mu opioid receptor is detected at higher levels than the other opioid receptors before the midblastula transition and during the segmentation period. The delta duplicate 2 exhibits only one peak of expression at 21 h postfertilization (hpf), when the motor nervous system is forming. The kappa receptor is expressed at very low levels. In situ hybridization studies at 24 hpf show that the opioid receptors are widely distributed in zebrafish CNS and at 48 hpf their localization is detected in more defined structures. Our results support specific implications of the opioid receptors in developmental processes such as morphogenesis of the CNS, neurogenesis, neuroprotection and development of neuromuscular and digestive system. Pain-related alterations can be a consequence of changes in the endogenous opioid system during development, hence we provide important information that might help to solve pain-related pathological situations.
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Duval RA, Allmon RL, Lever JR. Indium-Labeled Macrocyclic Conjugates of Naltrindole: High-Affinity Radioligands for In Vivo Studies of Peripheral δ Opioid Receptors. J Med Chem 2007; 50:2144-56. [PMID: 17402725 DOI: 10.1021/jm0700013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have identified a series of hydrophilic indium-labeled DOTA and DO3A conjugates of naltrindole (NTI) that are suited to in vivo studies of peripheral delta opioid receptors. Indium(III) complexes, linked to the indole nitrogen of NTI by six- to nine-atom spacers, display high affinities (0.1-0.2 nM) and excellent selectivities for binding to delta sites in vitro. The [111In]-labeled complexes can be prepared in good isolated yields ( approximately 65%) with high specific radioactivities (>3300 mCi/mumol). The spacers serve as pharmacokinetic modifiers, and log D7.4 values range from -2.74 to -1.79. These radioligands exhibit a high level of specific binding (75-94%) to delta opioid receptors in mouse gut, heart, spleen, and pancreas in vivo. Uptakes of radioactivity are saturable by the non-radioactive complexes, inhibited by naltrexone, and blocked by NTI. Thus, these radiometal-labeled NTI analogues warrant further study by single-photon emission computed tomography.
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Affiliation(s)
- Romain A Duval
- Departments of Radiology and the Radiopharmaceutical Sciences Institute, and Medical Pharmacology and Physiology, University of Missouri-Columbia, Columbia, Missouri 65212, USA
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15
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Liou SS, Liu IM, Lai MC. The plasma glucose lowering action of Hei-Shug-Pian, the fire-processed product of the root of Aconitum (Aconitum carmichaeli), in streptozotocin-induced diabetic rats. JOURNAL OF ETHNOPHARMACOLOGY 2006; 106:256-62. [PMID: 16443340 DOI: 10.1016/j.jep.2006.01.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2005] [Revised: 12/24/2005] [Accepted: 01/02/2006] [Indexed: 05/06/2023]
Abstract
The anti-hyperglycemic action of Hei-Shug-Pian, the fire-processed product of the root of Aconitum (Aconitum carmichaeli), was investigated in streptozotocin-induced diabetic (STZ-diabetic) rats. At 120 min following oral administration of Hei-Shug-Pian at doses ranging from 12.5 to 50 mg/kg, plasma glucose of STZ-diabetic rats was found to be decreased in a dose-dependent manner. Under treatment conditions wherein plasma glucose was lowered, the uptake of glucose into soleus muscle was increased and the incorporation of glucose into glycogen of hepatocytes was enhanced. The plasma glucose-lowering effect of Hei-Shug-Pian was eliminated by blockade of opioid mu-receptors. Moreover, Hei-Shug-Pian treatment failed to lower plasma glucose in opioid mu-receptor knockout diabetic mice. The findings obtained in this study support the conclusion that Hei-Shug-Pian lowers the plasma glucose concentrations of STZ-diabetic rats through activation of opioid mu-receptors of peripheral tissues, resulting in enhanced glucose utilization.
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MESH Headings
- Aconitum
- Animals
- Blood Glucose/drug effects
- Diabetes Mellitus, Experimental/blood
- Diabetes Mellitus, Experimental/drug therapy
- Diabetes Mellitus, Experimental/metabolism
- Dose-Response Relationship, Drug
- Drugs, Chinese Herbal/pharmacology
- Drugs, Chinese Herbal/therapeutic use
- Glucose/metabolism
- Glycogen/metabolism
- Hepatocytes/drug effects
- Hepatocytes/metabolism
- Hot Temperature
- Hypoglycemic Agents/pharmacology
- Hypoglycemic Agents/therapeutic use
- Male
- Mice
- Mice, Knockout
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Naloxone/pharmacology
- Naphthalenes/pharmacology
- Naphthalenes/therapeutic use
- Narcotic Antagonists/pharmacology
- Plant Roots
- Rats
- Rats, Wistar
- Receptors, Opioid, mu/drug effects
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/metabolism
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Affiliation(s)
- Shorong-Shii Liou
- Department of Pharmacy, Tajen University, Yen-Pou, Ping Tung Shien, Taiwan, ROC.
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16
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Tabarin A, Diz-Chaves Y, Chaves YD, Carmona MDC, Catargi B, Zorrilla EP, Roberts AJ, Coscina DV, Rousset S, Redonnet A, Parker GC, Inoue K, Ricquier D, Pénicaud L, Kieffer BL, Koob GF. Resistance to diet-induced obesity in mu-opioid receptor-deficient mice: evidence for a "thrifty gene". Diabetes 2005; 54:3510-6. [PMID: 16306369 DOI: 10.2337/diabetes.54.12.3510] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Using pharmacological tools, a role for opioid receptors in the regulation of food intake has been documented. However, the involvement of specific receptor subtypes remains questionable, and little information is available regarding a role for opioid receptors in energy metabolism. Using adult male mice lacking the mu-opioid receptor (MOR) gene (MOR-/-), we show that the MOR is not essential for the maintenance of normal levels of ad libitum food intake but does modulate the efficiency of energy storage during high-fat diets through the regulation of energy partitioning. When fed a regular diet, MOR-/- mice displayed only subtle alterations in energy homeostasis, suggesting a relative overuse of fat as a fuel source in the fed state. When fed a high-fat diet, MOR-/- mice were resistant to obesity and impaired glucose tolerance, despite having similar energy intake to wild-type mice. This resistance to obesity was associated with a strong induction of the expression of key mitochondrial enzymes involved in fatty acid oxidation within skeletal muscle. This metabolic role of the MOR, which is consistent with the properties of a "thrifty gene," suggests that the MOR pathway is a potential target for pharmacological intervention in the treatment of obesity associated with the intake of fatty diets.
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Affiliation(s)
- Antoine Tabarin
- Laboratoire Homéostasie-Allostasie-Pathologie, EA 3666, University of Bordeaux 2, 146 Rue Leo Saignat, 33076 Bordeaux, France.
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17
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Khan S, Evans AAL, Hughes S, Smith ME. Beta-endorphin decreases fatigue and increases glucose uptake independently in normal and dystrophic mice. Muscle Nerve 2005; 31:481-6. [PMID: 15704144 DOI: 10.1002/mus.20286] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
beta-Endorphin and a C-terminal analogue have been shown to decrease muscle fatigue and increase glucose uptake in muscles of normal mice. In order to provide evidence whether these peptides might be useful in muscle-wasting conditions and whether the two actions of the peptides are interdependent, the effect of beta-endorphin on muscle fatigue and glucose uptake was studied using isolated hemidiaphragm preparations of dystrophic mice as well as normal mice. Muscle contractions were elicited by high-frequency stimulation of the phrenic nerve. Glucose uptake was measured using (nonmetabolizable) 2-deoxy-D-[1-(3)H]glucose. beta-Endorphin and the C-terminal analogue reduced fatigue in normal muscles of males but not females. Insulin had no effect in either sex. The peptides increased 2-deoxyglucose uptake in contracting and noncontracting muscles of normal males and females. beta-Endorphin reduced fatigue and increased deoxyglucose uptake in dystrophic muscles. The effect on fatigue was not due to increased glucose uptake, as the energy substrate present was pyruvate. Nerve stimulation released beta-endorphin immunoreactivity from intramuscular nerves of dystrophic mice. It is hypothesized that beta-endorphin released from motor nerves as well as from the pituitary could be responsible for improving muscle function during exercise. beta-Endorphin or analogues could have therapeutic use in muscle-wasting disease.
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Affiliation(s)
- Salim Khan
- Department of Physiology, Medical School, University of Birmingham, Birmingham B15 2TT, United Kingdom
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18
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Evans AAL, Smith ME. Opioid receptors in fast and slow skeletal muscles of normal and dystrophic mice. Neurosci Lett 2004; 366:339-41. [PMID: 15288447 DOI: 10.1016/j.neulet.2004.05.064] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2004] [Revised: 05/21/2004] [Accepted: 05/22/2004] [Indexed: 10/26/2022]
Abstract
The density of beta-endorphin receptors and the proportions of fibres that expressed the receptors was assessed in fast extensor digitorum longus muscle and slow soleus muscles of normal and dystrophic mice using [125I]beta-endorphin and autoradiography. In the EDL the density was approximately 3.5 times higher and the proportion of labelled fibres approximately 2.6 times higher in dystrophic mice than normal mice. In the soleus the density was approximately 6.4 times higher and the proportion of labelled fibres approximately 1.5 times higher in the dystrophic mice than the normal mice. The receptors were of the delta-opioid subtype.
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MESH Headings
- Analysis of Variance
- Animals
- Autoradiography/methods
- Benzeneacetamides/pharmacology
- Binding Sites/drug effects
- Binding Sites/physiology
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/pharmacology
- Enkephalin, D-Penicillamine (2,5)-/pharmacology
- Iodine Isotopes/pharmacokinetics
- Mice
- Mice, Inbred C57BL
- Muscle Fibers, Fast-Twitch/metabolism
- Muscle Fibers, Slow-Twitch/metabolism
- Muscle, Skeletal/metabolism
- Muscular Dystrophy, Animal/metabolism
- Pyrrolidines/pharmacology
- Receptors, Opioid/metabolism
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, kappa/agonists
- Receptors, Opioid, mu/agonists
- beta-Endorphin/pharmacokinetics
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Affiliation(s)
- Anthony A L Evans
- Department of Physiology, Medical School, University of Birmingham, Birmingham B15 2TT, UK
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Abstract
This paper is the twenty-fourth installment of the annual review of research concerning the opiate system. It summarizes papers published during 2001 that studied the behavioral effects of the opiate peptides and antagonists. The particular topics covered this year include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology(Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, CUNY, 65-30 Kissena Blvd., Flushing, NY 11367, USA.
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