| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1994: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1993: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Research Abstract |
Addition of KCl or ATP stimulated Ca influx and noradrenaline (NA) release in PC12 cells. The activation of protein kinase C by phorbol myristate acetate and increases of cAMP content by stimulants enhanced KCl- and ATP-stimulated NA releases. KCl- and ATP-stimulated NA releases from pertussis toxin-pretreated PC12 cells were same compared with those from control cells. Pretreatment with cholera toxin (CTX) showed stimulatory and inhibitory effects in PC12 cells, depending on pretreatment-time. After 1-2 h, KCl- and ATP-stimulated NA releases were enhanced by CTX.After 24 h, the NA releases were inhibited significantly by CTX,although the level of cAMP in PC12 cells was high.
Next we investigated the ADP-rebosylation of membrane proteins by CTX from KCl- and ATP-stimulated PC12 cells. CTX catalyzed [32-P] ADP-ribosylation of 45 kDa protein, alpha subunit of Gs, in membranes. The amounts of ADP-ribosylation of 45 kDa in membranes from KCl- and ATP-stimulated cells increased two-fold, compared with that in the control (non-stimulated) cells. The protein contents of alpha subunit in KCl- and ATP-stimulated cells were same as that in control cells, by immunoblotting analysis. The amount of atuto-ADP-ribosylation by CTX also increased in membranes from KCl- and ATP-stimulated cells. These data suggest that ADP-rebosylation factor (ARF), which was an activator protein of CTX-catalyzed ADP-ribosylation, increased in KCl- and ATP-stimulated cells.
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