1993 Fiscal Year Final Research Report Summary
Intracelluar signal transduction of relaxin : comparative study with beta-adrenergic action
| Project/Area Number |
04670049
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
General physiology
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| Research Institution | Yamaguchi University |
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Principal Investigator |
OSA Takuro Yamaguchi University school of Medicine, Professor, 医学部, 教授 (40038691)
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| Co-Investigator(Kenkyū-buntansha) |
TODOROKI Natsuko Yamaguchi University school of Medicine, Research Associate, 医学部, 助手 (90253153)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Mg / Mn / relaxin / isoprenaline / db cAMP / 8-Br cGMP / myometrium |
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| Research Abstract |
It was aimed how the relaxin action resembles and differs from cAMP-and cGMP-mediated effects. The longitudinal myometrium was taken from ovariectomized rat 72h after the injection of estradiol-benzoate. Phasic contractions were evoked in Mg-free Krebs solution by electrical stimulation. The [Mg]i was increased from 380muM in the control solution to 420muM, when the tissue was exposed to Ca-free 40mX K solution containing 15mM Mg. It was assumed that muscle cells were loaded with Mn, when exposed to 0.6mM Mn. Contractile responses to relaxin, isoprenaline, forskolin and cyclic nucleotide derivatives were compared before and after the intracellular load with Mg or Mn. Results are summarized in the table shown below.
Influence of the elevation of intracellular Mg(b) of Mu(c) on the contractile inhibition caused by db cAMP and 8-bromo cGMP in comparison with that by isoprenaline, forskolin and relaxin. Upward and downward arrows indicate augmentation and attenuation of the inhibitory effects, respectively.
The activation of protein kinase A is thought to be a common pathway of relaxin and adrenergic beta-action (Hsu and Sanborn, 1986). The questions are raised, how and why relaxin and db cAMP behabed differently from isoprenaline and forskolin under the influence of intracellular load with Mn.
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