Toshia Obata

Summary

Affiliation: Oita Medical University
Country: Japan

Publications

  1. ncbi request reprint Nitric oxide and depolarization induce hydroxyl radical generation
    Toshio Obata
    Department of Pharmacology, Oita Medical University, Japan
    Jpn J Pharmacol 88:1-5. 2002
  2. ncbi request reprint Glibenclamide, an antagonist of ATP sensitive K+ channels, blocks free radical generation in the rat myocardium
    T Obata
    Department of Pharmacology, Oita Medical University, Japan
    Neurosci Lett 257:57-9. 1998
  3. ncbi request reprint Semicarbazide-sensitive amine oxidase (SSAO) in the brain
    Toshio Obata
    Department of Pharmacology, Oita Medical University, Hasama, Japan
    Neurochem Res 27:263-8. 2002
  4. ncbi request reprint Iron (III) attenuates hydroxyl radical generation accompanying non-enzymatic oxidation of noradrenaline in the rat heart
    Toshio Obata
    Department of Pharmacology, Oita Medical University, Hasama machi, Oita 879 5593, Japan
    Naunyn Schmiedebergs Arch Pharmacol 365:158-63. 2002
  5. ncbi request reprint Protective effect of histidine on para-nonylphenol-enhanced hydroxyl free radical generation induced by 1-methyl-4-phenylpyridinium ion (MPP+) in rat striatum
    T Obata
    Department of Pharmacology, Oita Medical University, 1 1, Hasama machi, Oita 879 5593, Japan
    Biochim Biophys Acta 1568:171-5. 2001
  6. ncbi request reprint Nitric oxide induces hydroxyl radical generation in rat hearts via depolarization-induced nitric oxide synthase activation
    T Obata
    Department of Pharmacology, Oita Medical University, Japan
    Naunyn Schmiedebergs Arch Pharmacol 364:59-65. 2001
  7. ncbi request reprint Release of dopamine by perfusion with 1-methyl-4-phenylpyridinium ion (MPP(+)) into the striatum is associated with hydroxyl free radical generation
    T Obata
    Department of Pharmacology, Oita Medical University, 1 1, Hasama machi, Oita 879 5593, Japan
    Brain Res 906:170-5. 2001
  8. ncbi request reprint Histamine increases interstitial adenosine concentration via activation of ecto-5'-nucleotidase in rat hearts in vivo
    T Obata
    Department of Pharmacology, Oita Medical University, Hasama machi, Oita, Japan
    J Pharmacol Exp Ther 298:71-6. 2001
  9. ncbi request reprint Allopurinol suppresses para-nonylphenol and 1-methyl-4-phenylpyridinium ion (MPP(+))-induced hydroxyl radical generation in rat striatum
    T Obata
    Department of Pharmacology, Oita Medical University, Hasama machi, 879 5593, Oita, Japan
    Neurosci Lett 306:9-12. 2001
  10. ncbi request reprint Role of hydroxyl radical formation in neurotoxicity as revealed by in vivo free radical trapping
    Toshio Obata
    Department of Pharmacology, Oita Medical University, 1 1, Hasama machi, Oita 879 5593, Japan
    Toxicol Lett 132:83-93. 2002

Collaborators

Detail Information

Publications40

  1. ncbi request reprint Nitric oxide and depolarization induce hydroxyl radical generation
    Toshio Obata
    Department of Pharmacology, Oita Medical University, Japan
    Jpn J Pharmacol 88:1-5. 2002
    ..Depolarization enhances the formation of *OH products via NOS activation...
  2. ncbi request reprint Glibenclamide, an antagonist of ATP sensitive K+ channels, blocks free radical generation in the rat myocardium
    T Obata
    Department of Pharmacology, Oita Medical University, Japan
    Neurosci Lett 257:57-9. 1998
    ..v. injection, the elevation of DHBA was not observed. These results suggest that openings of cardiac K(ATP) channel by depolarization evokes .OH generation via xanthine oxidase reaction...
  3. ncbi request reprint Semicarbazide-sensitive amine oxidase (SSAO) in the brain
    Toshio Obata
    Department of Pharmacology, Oita Medical University, Hasama, Japan
    Neurochem Res 27:263-8. 2002
    ..The precise physiological functions of SSAO could play an important role in the control of energy balance in adipose tissue. SSAO could play an important role in the regulation of adipocyte homeostasis...
  4. ncbi request reprint Iron (III) attenuates hydroxyl radical generation accompanying non-enzymatic oxidation of noradrenaline in the rat heart
    Toshio Obata
    Department of Pharmacology, Oita Medical University, Hasama machi, Oita 879 5593, Japan
    Naunyn Schmiedebergs Arch Pharmacol 365:158-63. 2002
    ..The present study demonstrates that the suppression of *OH formation by iron (III) may play a key role in the cardioprotective effect of iron (III) in the rat heart...
  5. ncbi request reprint Protective effect of histidine on para-nonylphenol-enhanced hydroxyl free radical generation induced by 1-methyl-4-phenylpyridinium ion (MPP+) in rat striatum
    T Obata
    Department of Pharmacology, Oita Medical University, 1 1, Hasama machi, Oita 879 5593, Japan
    Biochim Biophys Acta 1568:171-5. 2001
    ..These results indicate that para-nonylphenol and MPP+ -enhanced.OH generation was based on 1O(2) production, and histidine may have a preventive effect on para-nonylphenol and MPP+ -induced.OH generation in rat striatum...
  6. ncbi request reprint Nitric oxide induces hydroxyl radical generation in rat hearts via depolarization-induced nitric oxide synthase activation
    T Obata
    Department of Pharmacology, Oita Medical University, Japan
    Naunyn Schmiedebergs Arch Pharmacol 364:59-65. 2001
    ..However, L-NAME attenuated .OH generation by ischemic/reperfused rat heart. These results suggest that NOS inhibition is associated with a cardioprotective effect due to the suppression of [K+]o depolarization-induced .OH generation...
  7. ncbi request reprint Release of dopamine by perfusion with 1-methyl-4-phenylpyridinium ion (MPP(+)) into the striatum is associated with hydroxyl free radical generation
    T Obata
    Department of Pharmacology, Oita Medical University, 1 1, Hasama machi, Oita 879 5593, Japan
    Brain Res 906:170-5. 2001
    ..OH free radicals. These events may contribute, at least in part, to the nigrostriatal neurons cell death after MPP(+)...
  8. ncbi request reprint Histamine increases interstitial adenosine concentration via activation of ecto-5'-nucleotidase in rat hearts in vivo
    T Obata
    Department of Pharmacology, Oita Medical University, Hasama machi, Oita, Japan
    J Pharmacol Exp Ther 298:71-6. 2001
    ..Taken together, the results demonstrate that histamine-released norepinephrine activates both alpha1-adrenoceptors and PKC, which increased ecto-5'-nucleotidase activity and augmented release of adenosine in rat hearts...
  9. ncbi request reprint Allopurinol suppresses para-nonylphenol and 1-methyl-4-phenylpyridinium ion (MPP(+))-induced hydroxyl radical generation in rat striatum
    T Obata
    Department of Pharmacology, Oita Medical University, Hasama machi, 879 5593, Oita, Japan
    Neurosci Lett 306:9-12. 2001
    ..The results indicate that para-nonylphenol enhanced *OH generation based on superoxide anion production, and allopurinol may have preventive effect on para-nonylphenol and MPP(+)-induced *OH generation...
  10. ncbi request reprint Role of hydroxyl radical formation in neurotoxicity as revealed by in vivo free radical trapping
    Toshio Obata
    Department of Pharmacology, Oita Medical University, 1 1, Hasama machi, Oita 879 5593, Japan
    Toxicol Lett 132:83-93. 2002
    ....
  11. ncbi request reprint [Adenosine production and its role in protection against ischemic and reperfusion injury of the myocardium]
    Toshio Obata
    Department of Pharmacology, Oita Medical University, 1 1, Hasama machi, Oita 879 5593, Japan
    Nihon Yakurigaku Zasshi 119:273-9. 2002
    ..Adenosine plays an important role as a modulator of ischemic reperfusion injury. The production and action of adenosine are intimately linked to the release of NE...
  12. ncbi request reprint Norepinephrine evoked by potassium depolarization increases interstitial adenosine concentration via activation of ecto-5'-nucleotidase in rat hearts
    Toshio Obata
    Department of Pharmacology and Therapeutics, Oita Medical University, 1 1, Idaigaoka, Hasama, Oita 879 5593, Japan
    J Pharmacol Exp Ther 305:719-24. 2003
    ..We conclude that high [K(+)](o)-induced NE release from sympathetic nerve terminals increases adenosine by stimulating the PKC-ecto-5'-nucleotidase cascade through alpha(1)-adrenoceptors...
  13. ncbi request reprint Calcium overload enhances hydroxyl radical generation by 1-methyl-4 phenylpyridinium ion (MPP+) in rat striatum
    Toshio Obata
    Department of Pharmacology and Therapeutics, Oita Medical University, 1 1 Idaigaoka, Hasama, Oita 879 5593, Japan
    Brain Res 965:287-9. 2003
    ..These results suggests that Ca(2+) overload might enhance *OH generation by MPP(+) in rat striatum...
  14. ncbi request reprint Protective effect of diltiazem, a L-type calcium channel antagonist, on bisphenol A-enhanced hydroxyl radical generation by 1-methyl-4-phenylpyridinium ion in rat striatum
    Toshio Obata
    Department of Pharmacology and Therapeutics, Oita Medical University, 1 1 Idaigaoka, Hasama, Oita 879 5593, Japan
    Neurosci Lett 334:211-3. 2002
    ..OH generation. The results indicate bisphenol A augmented *OH generation, and diltiazem may have preventive effect on bisphenol A and MPP+-induced.OH generation...
  15. ncbi request reprint Effect of imipramine on 1-methyl-4-phenylpyridinium ion-induced hydroxyl radical generation in rat striatum
    Toshio Obata
    Department of Pharmacology and Therapeutics, Oita Medical University, 1 1 Idaigaoka, Hasama machi, Oita 879 5593, Japan
    Biochim Biophys Acta 1588:173-8. 2002
    ..A positive linear correlation was observed between iron (II) and DHBA (R(2)=0.985) in the dialysate. These results indicate that imipramine enhances generation of.OH induced by MPP(+) during enhanced DA overflow...
  16. ncbi request reprint Nicotine suppresses 1-methyl-4-phenylpyridinium ion-induced hydroxyl radical generation in rat striatum
    Toshio Obata
    Department of Pharmacology and Therapeutics, Oita Medical University, 1 1 Idaigaoka, Hasama, Oita 879 5593, Japan
    Neurosci Lett 330:122-4. 2002
    ..However, in the presence of nicotine (100 microM), the effect of nicotine was suppressed. These results suggest that nicotine has a preventive effect on.OH generation by MPP(+) in rat striatum...
  17. ncbi request reprint Adenosine production and its interaction with protection of ischemic and reperfusion injury of the myocardium
    Toshio Obata
    Department of Pharmacology and Therapeutics, Oita Medical University, 1 1 Idaigaoka, Hasama, Oita 879 5593, Japan
    Life Sci 71:2083-103. 2002
    ..Adenosine plays an important role as a modulator of ischemic reperfusion injury, and that the production and mechanism of action of adenosine are linked with NE release...
  18. ncbi request reprint Dopamine efflux by MPTP and hydroxyl radical generation
    T Obata
    Department of Pharmacology, Oita Medical University, Oita, Japan
    J Neural Transm 109:1159-80. 2002
    ..This review describes the free radicals mechanisms involved in MPTP toxicity and their possible involvement in the the pathogenesis of Parkinson's disease...
  19. ncbi request reprint Environmental estrogen-like chemicals and hydroxyl radicals induced by MPTP in the striatum: a review
    Toshia Obata
    Department of Pharmacology, Oita Medical University, Japan
    Neurochem Res 27:423-31. 2002
    ..Such findings may be useful in elucidating the actual mechanism of free radical formation in the pathogenesis of neurodegenerative brain disorders, including Parkinson's disease and traumatic brain injuries...
  20. ncbi request reprint Levetiracetam inhibits the high-voltage-activated Ca(2+) current in pyramidal neurones of rat hippocampal slices
    I Niespodziany
    UCB S A Pharma Sector, Preclinical CNS Research, B 1420, Braine l Alleud, Belgium
    Neurosci Lett 306:5-8. 2001
    ..The limited, but significant depression of the neuronal HVA Ca(2+) current, produced by LEV at a clinically relevant concentration, might contribute to the antiepileptic action of the drug...
  21. ncbi request reprint Nitric oxide enhances MPP(+)-induced hydroxyl radical generation via depolarization activated nitric oxide synthase in rat striatum
    T Obata
    Department of Pharmacology, Oita Medical University, Hasama machi, 879 5593, Oita, Japan
    Brain Res 902:223-8. 2001
    ..OH generation. The present results suggest that [K(+)](o)-induced depolarization augmented MPP(+)-induced.OH formation by enhancing NO synthesis...
  22. ncbi request reprint Protective effect of fluvastatin, a new inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, on MPP(+)-induced hydroxyl radical in the rat striatum
    T Obata
    Department of Pharmacology, Oita Medical University, 1 1, Hasama machi, Oita, Japan
    Brain Res 860:166-9. 2000
    ..OH formation. However, fluvastatin (100 microM) reduced the.OH formation by the action of MPP(+). These results indicated that fluvastatin, a potent inhibitor of LDL oxidation, may resist the formation of.OH products of MPP(+)...
  23. ncbi request reprint Reserpine attenuates interstitial adenosine-mediated activation of ecto-5'-nucleotidase in rat hearts in vivo
    T Obata
    Department of Pharmacology, Oita Medical University, 1 1, Hasama machi, Oita, 879 5593, Japan
    Arch Biochem Biophys 375:333-9. 2000
    ..These results suggest that reserpine attenuates NE-induced adenosine via stimulation of alpha(1)-adrenoceptor and protein kinase C mediated activation of ecto-5'-nucleotidase in rat heart...
  24. ncbi request reprint Potassium chloride depolarization enhances MPP+-induced hydroxyl radical generation in the rat striatum
    T Obata
    Department of Pharmacology, Oita Medical University, Japan
    Brain Res 852:488-91. 2000
    ..988) in the dialysate. These results suggest that [K+]o-induced depolarization enhances the formation of *OH products of efflux/oxidation due to MPP+...
  25. ncbi request reprint Protective effect of imidaprilat, an angiotensin-converting enzyme inhibitor on *OH generation in rat myocardium
    T Obata
    Department of Pharmacology, Oita Medical University, Japan
    Biochim Biophys Acta 1472:62-70. 1999
    ..These results suggest that imidaprilat, an ACE inhibitor, is associated with cardioprotective effect due to the suppression of NE-induced *OH generation...
  26. ncbi request reprint Prazosin attenuates hydroxyl radical generation in the rat myocardium
    T Obata
    Department of Pharmacology, Oita Medical University, Hasama machi, Japan
    Eur J Pharmacol 379:161-6. 1999
    ..These results suggest that tyramine-induced noradrenaline causes *OH generation, an effect which is inhibited by prazosin as Na+ channel blocker, but not through its alpha1-adrenoceptor antagonistic action of prazosin...
  27. ncbi request reprint Protective effect of imidaprilat, a new angiotensin-converting enzyme inhibitor against 1-methyl-4-phenylpyridinium ion-induced *OH generation in rat striatum
    T Obata
    Department of Pharmacology, Oita Medical University, Japan
    Eur J Pharmacol 378:39-45. 1999
    ..These results suggested that angiotensin-converting enzyme inhibitors may protect against MPP+ -induced *OH formation in the rat striatum...
  28. ncbi request reprint Tyramine produces interstitial adenosine-mediated activation of ecto-5'-nucleotidase in rat heart in vivo
    T Obata
    Department of Pharmacology, Oita Medical University, Japan
    Eur J Pharmacol 374:25-31. 1999
    ..The results suggest that tyramine elevates adenosine via stimulation of alpha1-adrenoceptors and protein kinase C-mediated activation of ecto-5'-nucleotidase in rat heart...
  29. ncbi request reprint Reserpine prevents hydroxyl radical formation by MPP+ in rat striatum
    T Obata
    Department of Pharmacology, Oita Medical University, Hasama machi, Oita 879 5593, Japan
    Brain Res 828:68-73. 1999
    ..989) in the dialysate. These results indicated that reserpine-induced DA depletion may reduce MPP+-induced r22. OH formation...
  30. ncbi request reprint Fluvastatin, a new inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, resists hydroxyl radical generation in the rat myocardium
    T Obata
    Department of Pharmacology, Oita Medical University, Japan
    J Pharm Pharmacol 52:425-30. 2000
    ..The results show that iron (II) against LDL oxidation may be insensitive compared with Cu (II). Cu (II)-induced *OH formation may be reduced by inhibiting LDL with fluvastatin...
  31. ncbi request reprint Inhibition of monkey brain semicarbazide-sensitive amine oxidase by various antidepressants
    T Obata
    Department of Pharmacology, Oita Medical University, Hasama machi, Oita, 879 5593, Japan
    Neurosci Lett 286:131-3. 2000
    ..We found the tricyclic antidepressant drug to be the most selective inhibitors of SSAO activity in monkey brain, as compared with other type of antidepressant drugs...
  32. ncbi request reprint Effect of fluvastatin, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, on nitric oxide-induced hydroxyl radical generation in the rat heart
    T Obata
    Department of Pharmacology, Oita Medical University, Hasama machi, Japan
    Biochim Biophys Acta 1536:55-63. 2001
    ..These results suggest that fluvastatin is associated with a cardioprotective effect due to the suppression of noradrenaline-induced *OH generation by inhibiting LDL oxidation in the heart...
  33. ncbi request reprint Adenosine deaminase activity in rat intestine: assay with a microdialysis technique
    T Obata
    Department of Pharmacology, Oita Medical University, Japan
    Comp Biochem Physiol A Mol Integr Physiol 119:309-13. 1998
    ..The dialysis technique makes it possible to measure adenosine deaminase activity in intestinal mucosa...
  34. ncbi request reprint [Parkinsonism induced by MPTP and free radical generation]
    T Obata
    Department of Pharmacology, Oita Medical University, 1 1, Hasama machi, Oita 879 5593, Japan
    Nihon Yakurigaku Zasshi 117:105-10. 2001
    ..OH formation. The inhibitory effect on the susceptibility of LDL oxidation can reduce .OH generation. These drugs may be applied as antiparkinsonian agents. Further clinical investigation is necessary in the future...
  35. ncbi request reprint Protective effect of histidine on potassium chloride depolarization enhances 1-methyl-4-phenylpyridinium ion-induced hydroxyl radical generation in the rat striatum
    T Obata
    Department of Pharmacology, Oita Medical University, Japan
    Life Sci 68:689-97. 2000
    ..However, in the presence of histidine (25 mM), the effect of [K+]o was abolished. These results indicated that histidine may reduce the [K+]o-induced depolarization enhanced *OH formation by the action of MPP+ in the rat striatum...
  36. ncbi request reprint Evidence for existence of immobilization stress-inducible semicarbazide-sensitive amine oxidase inhibitor in rat brain cytosol
    T Obata
    Department of Pharmacology, Oita Medical University, Hasama machi, 879 5593, Oita, Japan
    Neurosci Lett 296:58-60. 2000
    ..This inhibitor was proved to be heat-stable resistant to protease treatment. These results suggest that this inhibitor is induced by IMMO. SSAO activity in rat brain might be regulated by the level of this inhibitor...
  37. ncbi request reprint Methamphetamine enhances 1-methyl-4-phenylpyridinium ion-induced hydroxyl radical generation in the rat striatum
    T Obata
    Department of Pharmacology, Oita Medical University, Hasama machi, 879 5593, Oita, Japan
    Neurosci Lett 292:54-6. 2000
    ..OH formation trapped as DHBA (R(2)=0.985) in the dialysate. These results suggest that MA enhances the &z.rad;OH products of efflux/oxidation due to MPP(+)...
  38. ncbi request reprint Block of cardiac ATP-sensitive K(+) channels reduces hydroxyl radicals in the rat myocardium
    T Obata
    Department of Pharmacology, Oita Medical University, Hasama machi, Oita, 879 5593, Japan
    Arch Biochem Biophys 378:195-200. 2000
    ..When corresponding experiments were performed with 5-HD (100 microM) pretreated animals, the same results were obtained. These results suggest that opening of cardiac K(ATP) channels may cause (*)OH generation...
  39. ncbi request reprint An increase of the native interstitial adenosine concentration during histidine application
    T Obata
    Department of Pharmacology, Oita Medical University, Japan
    Naunyn Schmiedebergs Arch Pharmacol 361:529-34. 2000
    ..These results indicate that histidine increases interstitial adenosine concentration via NA release-mediated activation of ecto-5'-nucleotidase...
  40. ncbi request reprint Phytic acid suppresses 1-methyl-4-phenylpyridinium ion-induced hydroxyl radical generation in rat striatum
    Toshio Obata
    Department of Pharmacology and Therapeutics, Oita Medical University, 1 1 Idaigaoka, Hasama, Oita 879 5593, Japan
    Brain Res 978:241-4. 2003
    ..05). These results suggest that the antiradical effect of phytic acid occurs by chelating iron required for the MPP(+)-enhanced *OH generation via the Fenton-type reaction...