U-46619, a Selective Thromboxane A_2 Mimetic, Inhibits the Release of Endogenous Noradrenaline From the Rat Hippocampus In Vitro

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Author(s)

Abstract

Possible roles of thromboxane A<SUB>2</SUB>(TXA<SUB>2</SUB>)in the release mechanism of hippocampal noradrenaline(NA)were examined in vitro.Slices or crude synaptosomes prepared from the rat hippocampus were superfused with modified Krebs-Ringer solution.Application of 20mM KCl for 5min increase the release of NA from the slices, and this release was consistently reproduced.Application of U-46619(9, 11-dideoxy-9α, 11α-methanoepoxy prostaglandin F<SUB>2α</SUB>), a specific TXA<SUB>2</SUB> mimetic, just before the second KCl(20mM)stimulation decreased the KCl-evoked NA release in a concentration-dependent manner(10-100μM).This U-46619(50μM)-induced inhibition of NA release was abolished by 10μM SQ29548, a specific TXA<SUB>2</SUB> receptor antagonist.In experiments with hippocampal crude synaptosomes, however, KCl(20 and 40mM)-evoked release of NA was not attenuated by U-46619(100μM).Furthermore, the inhibitory effect of U-46619(50μM)in the sliced preparations was not modified by 100μM(−)-bicuculline, a GABA<SUB>A</SUB>-receptor antagonist.The present results indicate that U-46619 inhibits the release of NA from the rat hippocampus by activation of TXA<SUB>2</SUB> receptors.Activation of TXA<SUB>2</SUB> receptors probably excites an unidentified but not GABAergic neuron system, thereby inhibiting the NA release from the rat hippocampus.

Journal

  • The Japanese Journal of Pharmacology

    The Japanese Journal of Pharmacology 82(3), 226-231, 2000-03-01

    The Japanese Pharmacological Society

References:  28

Codes

  • NII Article ID (NAID)
    10008183513
  • NII NACSIS-CAT ID (NCID)
    AA00691188
  • Text Lang
    ENG
  • Article Type
    ART
  • ISSN
    00215198
  • NDL Article ID
    5321034
  • NDL Source Classification
    ZS51(科学技術--薬学)
  • NDL Call No.
    Z53-D199
  • Data Source
    CJP  NDL  J-STAGE 
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