| Project/Area Number |
06671844
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
Functional basic dentistry
|
|---|
| Research Institution | Hokkaido Univ. |
|---|
Principal Investigator |
YOSHIMURA Keiichi Hokkaido Univ. Sch. of Dent., Associate Prof., 歯学部, 助教授 (30000938)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
HIRAMATSU Yukiharu Hokkaido Univ. Sch. of Dent., Instructor, 歯学部, 助手 (90261312)
|
|---|
| Project Period (FY) |
1994 – 1995
|
| Project Status |
Completed (Fiscal Year 1995)
|
| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1995: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1994: ¥1,800,000 (Direct Cost: ¥1,800,000)
|
|---|
| Keywords | Potentiation of amylase secretion, / Isoproterenol / Substance P / Isolated parotid acinar cell / Cyclic AMP / Ca^<2+> / PDBu / 耳下腺アミラーゼ / イソプロテレノール / サブスタンスP / カルバコール / アゴニスト / 増強効果 |
|---|
| Research Abstract |
Potentiation of amylase secretion between isoproterenol (Isop) and substance P or carbachol was examined in perifused rat parotid acinar cells. Combined additions of Isop and substance P evoked biphasic changes in amylase secretion with an initial rapid and large peak and the following sustained plateau phase : The magnitudes of the both responses were potentiated. The time course of amylase secretion obtained by a combination of Isop and substance P was similar to that induced by substance P,but not by Isop. Dose-response of amylase secretion by substance P shows that Isop enhanced both the magnitude of the maximum response and the apparent affinity for substance P to evoke the initial peak response ; the EC_<50> in the presence and absence of Isop was about 0.6 nM and 10 nM,respectively. On the other hand, 1 nM substance P was sufficient for evoking the maximum potentiation of the sustained plateau response. Substance P,however, did not change the apparent affinity for the Isop-effec
… More
t. Similar results were observed when carbachol was used instead of substance P.The effect of Isop was able to be duplicated by dibutyryl cyclic AMP or the agents which increase parotid cyclic AMP.Omission of Ca^<2+> or addition of 5 mM NiCl_2 almost completely abolished the potentiation of the sustained plateau response, but did not affect that of the initial peak. Isop did not enhance the effect of substance P on [Ca^<2+>]_i. Switching to solutions containing higher concentrations of Ca^<2+> during the continuous stimulation with Isop or IBMX,evoked rapid and large peak in amylase secretion ; the magnitude of the response was increased when the permeability of plasma membrane to calcium was increased with ionomycin. The Ca^<2+>-effect was slightly augmented by PDBu, but the effect of PDBu was not augmented by Isop. These results suggest that the potentiation is mainly, if not completely, caused by an interaction between the cyclic AMP and calcium messenger systems at a step distal to the second messenger generation, probably by the cyclic AMP-induced modification of the intracellular events evoked by calcium signal. Less
|
