| Project/Area Number |
14571771
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Functional basic dentistry
|
|---|
| Research Institution | Iwate Medical University |
|---|
Principal Investigator |
KITADA Yasuyuki Iwate Medical University, Dental School, Professor, 歯学部, 教授 (80018423)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
AKABANE Kazuhisa Iwate Medical University, Dental School, Assistant Professor, 歯学部, 助手 (70160801)
NARITA Kinya Iwate Medical University, Dental School, Lecturer, 歯学部, 講師 (40291083)
|
|---|
| Project Period (FY) |
2002 – 2003
|
| Project Status |
Completed (Fiscal Year 2003)
|
| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2003: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2002: ¥2,500,000 (Direct Cost: ¥2,500,000)
|
|---|
| Keywords | taste cell / mechanism of taste reception / TTX-resistant voltage gated Na^+ currents / voltage gated Ca^<2+> currents / gustatory physiology |
|---|
| Research Abstract |
To investigate the mechanism of salt taste reception in taste cells, we used patch-clamp and Ca^<2+> technique. Membrane currents were recorded from taste cells in vertical slices of the bullfrog (Rana catesbeiana) taste disc. Cell types were identified by staining with Lucifer yellow in a pipette after recording their physiological properties. The following results were obtained. 1. Type lb and type II cells exhibited TTX-sensitive voltage-gated Na^+ currents. Type III cells showed TTX-resistant voltage-gated Na^+ currents. TTX-resistant voltage-gated Na~ currents in taste cells are reported for the first time here. 2. Only type III cells possess the voltage-gated Ca^<2+> channels. 3. The time constant for the inactivating portion of the voltage-gated inward Na^+ currents of type III cells was much larger than that of type lb and type II cells. Therefore, slow inactivation of inward Na^+ currents characterizes type III cells. 4. Ni^<2+> has been reported to enhance the response of the frog glossopharyngeal nerve. In this study, Ni^<2+> at 1 mM prolonged inactivation of inward Na^+ currents in three types of cells. The type III cells showed much stronger Ni^<2+> effec than other types of cells. 5. We could not load the calcium indicator into taste cells except several preparations. Further study will be needed to clarify changes in intracellular Ca^<2+> in taste cells during stimulation with salt tastants. In this study, we showed a possibility that type III cells are salt taste receptor cells.
|
