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    Immunocytochemical characterization of delta-opioid and Mu-opioid receptor protein in the bovine pineal gland
    (2006-04-01) Pansiri Phansuwan-Pujito; Manuchair Ebadi; Piyarat Govitrapong; Srinakharinwirot University; The Institute of Science and Technology for Research and Development, Mahidol University; Mahidol University; University of North Dakota
    Opioidergic innervation has been identified in the mammalian pineal gland. Recently, opioid receptors in bovine pineal glands have been characterized; the activation of these receptors leads to the stimulation of melatonin synthesis. In this study..., the precise localization of opioid receptors in bovine pineal glands was determined by an immunohistochemical technique using antibodies raised against delta-opioid and mu-opioid receptors. Immunoreactivity of these two receptors was present at a moderate
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    The existence of opioid receptors in the cochlea of guinea pigs
    (2006-05-01) Nopporn Jongkamonwiwat; Pansiri Phansuwan-Pujito; Stefano O. Casalotti; Andrew Forge; Hilary Dodson; Piyarat Govitrapong; The Institute of Science and Technology for Research and Development, Mahidol University; Srinakharinwirot University; UCL; Mahidol University
    of opioid fibers remains to be investigated. In the present study the expression of opioid receptors and their peptides is demonstrated in young adult guinea pig cochlea. Opioid receptors are mainly expressed in hair cells of the organ of Corti and in inner... and outer spiral bundles with different characteristics for each type of receptor. Co-localization studies were employed to compare the distribution of mu-, delta- and kappa-opioid receptors and their respective peptides, β-endorphin, leu-enkephalin
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    The stimulatory effect of mu- and delta-opioid receptors on bovine pinealocyte melatonin synthesis
    (2004-11-01) Uayart Chuchuen; Manuchair Ebadi; Piyarat Govitrapong; Mahidol University; University of North Dakota
    Mammalian pinealocytes synthesize and secrete melatonin. The synthesis of melatonin is regulated by several biogenic amine, amino acid and peptide transmitters. In our previous study, the delta- and mu-opioid receptors have been identified... and characterized in bovine pinealocytes. In order to elaborate the function of different types of opioid receptors in regulating melatonin synthesis, we used a selective mu-opioid receptor agonist, Tyr-[D-Ala2, N-methyl-phe4, glycol5] (DAMGO), a selective delta
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    The presence and actions of opioid receptors in bovine pineal gland
    (1992-01-01) P. Govitrapong; M. Pariyanonth; M. Ebadi; Mahidol University; University of Nebraska at Omaha
    population of opioid receptors in the bovine pineal gland using [3H]‐diprenorphine and other ligands. The receptors have a dissociation equilibrium constant (Kd) of 1.36 ± 0.31 nM and a density (Bmax) of 17.93 ± 5.22 fmol/mg protein. In competitive.... In order to delineate the function of the opioid system in the pineal gland, the effects of both opioid receptor agonists and antagonists on the basal activity of N‐acetyltransferase were examined in the bovine pineal expiants in culture. Morphine
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    Melatonin exerts its analgesic actions not by binding to opioid receptor subtypes but by increasing the release of β-endorphin an endogenous opioid
    (2005-01-30) Shaik Shavali; Begonia Ho; Piyarat Govitrapong; Saiphon Sawlom; Amornpan Ajjimaporn; Sirirat Klongpanichapak; Manuchair Ebadi; UND School of Medicine & Health Sciences - Northeast Campus; Mahidol University
    -induced analgesia is blocked by naloxone or pinealectomy. By using selective radioligands [3H]-DAMGO, [3H]-DPDPE, [3-U69593, and 3H]-nociceptin, we have shown that the bovine pinealocytes contain delta and mu, but not kappa or ORL1 opioid receptor subtypes.... In the present study, by using melatonin receptor agonists (6-chloromelatonin or 2-iodo-N-butanoyl-5- methoxytryptamine) or melatonin receptor antagonist (2-phenylmelatonin), we have shown that these agents do not compete with opioid receptor subtypes. However
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    Opioid modulation of GABA release in the rat inferior colliculus
    (2004) Walaiporn Tongjaroenbungam; Nopporn Jongkamonwiwat; Joanna Cunningham; Pansiri Phansuwan-Pujito; Hilary C Dodson; Andrew Forge; Piyarat Govitrapong; Stefano O Casalotti
    indicating that micro rather than delta or kappa opioid receptors mediate this action. [3H]GABA release was diminished by 16%, and this was not altered by the protein kinase C inhibitor bisindolylmaleimide I. Immunostaining of inferior colliculus cryosections... shows extensive staining for glutamic acid decarboxylase, more limited staining for micro opiate receptors and relatively few neurons co-stained for both proteins. CONCLUSION: The results suggest that micro-opioid receptor ligands can modify
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    Alteration of lymphocyte opioid receptors in methadone maintenance subjects
    (2010-01-01) Tipa Toskulkao; Ruchee Pornchai; Varaporn Akkarapatumwong; Smith Vatanatunyakum; Piyarat Govitrapong; Mahidol University; Thanyarak hospital
    of opiates with lymphocyte opioid receptors. In order to test this hypothesis, the levels of opioid receptors on immune cells obtained from heroin users were determined using saturation binding, and it was found that former heroin addicts on methadone... maintenance treatment had a significantly reduced maximum number (Bmax) of [3H]naloxone binding. The Bmaxvalues were 51.3±7.6fmol/mg protein for the non-addicted group and 25.3±3.1fmol/mg protein for the methadone maintenance group. Opioid receptor gene
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    Gene expressions of opioid receptors and G-proteins in pineal glands
    (1999-09-07) Banthit Chetsawang; Stefano O. Casalotti; Pansiri Phansuwan-Pujito; Naiphinich Kotchabhakdi; Piyarat Govitrapong; Mahidol University; Faculty of Medicine, Thammasat University
    In our previous studies, the opioid receptors located on pinealocytes have been identified and characterized, and these receptors have been found to play a stimulatory role in melatonin synthesis by activating the rate limiting enzyme, N...-acetyltransferase (NAT). In the present study, by using reverse transcriptase polymerase chain reaction (RT-PCR) followed by nested-PCR, segments of delta and mu opioid receptors have been amplified from mRNA of rat pineal gland and cerebral cortex. In addition
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    Down-regulation of opoid receptor gene expressions in T-lymphocytes of heroin users
    (2000-02-01) P. Govitrapong; T. Toskulkao; T. Suttitum; V. Akkarapatumwong; N. Kotchabhakdi; S. Vatanatunyakum; The Institute of Science and Technology for Research and Development, Mahidol University; Mahidol University; Thanyarak hospital
    receptors on T-cells. Opioid receptor gene expressions on the immune cells of heroin abusers were determined by using a semiquantitative reverse-transcriptase polymerase chain reaction (RT-PCR) technique with specific pairs of primers to amplify mu...- and delta-opioid receptor mRNAs. Both types of mRNAs were significantly decreased in T-cells of heroin abusers. The levels were normal in those heroin-withdrawal subjects. The present data indicates that gene expressions of opioid receptors were down
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    The presence of opioid receptors in rat inner ear
    (2003-01-01) Nopporn Jongkamonwiwat; Pansiri Phansuwan-Pujito; Puangkeaw Sarapoke; Banthit Chetsawang; Stefano O. Casalotti; Andrew Forge; Hilary Dodson; Piyarat Govitrapong; The Institute of Science and Technology for Research and Development, Mahidol University; Srinakharinwirot University; UCL
    Opioid peptides have been identified in the inner ear but relatively little information is available about the expression and distribution of their receptors. The aim of the present study was therefore to identify and localize the μ (MOR), δ (DOR...) and κ (KOR) opioid receptor subtypes within the rat cochlea. The expression of these opioid receptor subtypes was determined by reverse transcriptase-polymerase chain reaction followed by nested polymerase chain reaction analysis. Amplification of RNAs