2011 Fiscal Year Final Research Report
Interaction of alpha-and beta-adrenergic activation in the calcium dynamics in mouse brown adipocyte
| Project/Area Number |
21790215
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
General physiology
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| Research Institution | Nagoya University of Arts and Sciences |
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Principal Investigator |
HAYATO Ryotaro 名古屋学芸大学, 管理栄養学部, 助教 (60440822)
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| Project Period (FY) |
2009 – 2011
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| Keywords | 褐色脂肪細胞 / アドレナリン受容体 / Ca^<2+> / 肥満 |
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| Research Abstract |
In brown adipocytes,-adrenergic activation evokes Ca^<2+> release from the endoplasmic reticulum(ER) and store-operated Ca^<2+> entry(SOC) in brown adipocytes, while.-adrenergic activation causes mitochondrial Ca^<2+> release via uncoupling of oxidative phosphorylation, which activates Ca^<2+>-induced Ca^<2+> release from the ER, SOC, and a novel uncoupling-linked Ca^<2+> entry. We studied how these two modes of adrenergic Ca^<2+> signaling pathways interact with each other by recording cytoplasmic Ca^<2+>([Ca^<2+>]_i), mitochondrial membrane potential and the Ca^<2+> concentration in the ER([Ca^<2+>]_<ER>) by fluorometry. The rise in [Ca^<2+>]_i and the reduction of [Ca^<2+>]_<ER> evoked by phenylephrine was depressed under the full effect of a-agonist, BRL37344, while they were enhanced under the weak action of BRL37344.On the other hand, the second and/or third components of the bi-or triphasic rises in [Ca^<2+>]_i induced by BRL37344 was depressed under the effect of the subthreshold concentration of phenylephrine. Thus, when the-action is strong enough to cause a large rise in [Ca^<2+>]_i, it was suppressed during the late phase of the-action for the decreased Ca^<2+> content in the ER. On the other hand, when the-action is weak not enough to release Ca^<2+> from the ER presumably due to an inadequate rise in IP_3 concentration, the rises in [Ca^<2+>]_i by mitochondrial Ca^<2+> release would boost the activation of IP_3 receptor at the ER membrane.
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