PHYSIOLOGICAL ROLE OF NEURONAL-GRIAL INTERACTION
| Project/Area Number |
10680744
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Neuroscience in general
|
|---|
| Research Institution | The University of Tokushima |
|---|
Principal Investigator |
INOUE Isao THE UNIVERSITY OF TOKUSHIMA, Institute for Enzyme Research, Associate Professor, 分子酵素学研究センター, 助教授 (80001973)
|
|---|
| Project Period (FY) |
1998 – 1999
|
| Project Status |
Completed (Fiscal Year 1999)
|
| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 1999: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1998: ¥2,500,000 (Direct Cost: ¥2,500,000)
|
|---|
| Keywords | NEURON / SQUID GAINT AXON / SHWANN CELL / SIGNALING / POTASSIUM CHANNEL / CALCIUM CHANNEL / GLUTAMIC ACID / INTRACELLULAR CALCIUMION / 神経系 / 神経細胞 / グリア細胞 / カリウムホメオスタシス / 不活性化 |
|---|
| Research Abstract |
Schwann cells were enzymatically isolated from squid giant axons. Macroscopic ionic currents were recorded using whole cell clamp and single channel currents using patch clamp. Two types of ionic currents were found with whole cell voltage clamp. One is voltage gated L-type calcium current sensitive to externally applied nifedipine or CoィイD12+ィエD1. This current is activated at >-40 mV. The other current is outwardly rectified potassium current. This current is blocked by externally applied nifedipine or COィイD12+ィエD1, but insensitive to externally applied caffeine, ryanodine or L-glutamate. Single potassium channel currents with a conductance of 40 pS were recorded from excised inside-out patches. The open probability (Po) was 0.05 at 3x10ィイD1-7ィエD1 M CaィイD12+ィエD1, increased transiently to 0.4 when the CaィイD12+ィエD1 concentration was elevated to 1×10ィイD1-6ィエD1 M, then ran down spontaneously at this CaィイD12+ィエD1 concentration. The channel activity was insensitive to externally applied L-glutamate, internally applied acetylcholine (ACh), or ATP. The results suggest that the calcium activated potassium channels play an essential role in generation of the Schwann cell membrane potential of -40 mV, and the membrane potential is controlled by the intracellular CaィイD12+ィエD1 level. Schwann cells were loaded fluo-3, a CaィイD12+ィエD1-sensitive dye. Externally applied K+ induced an increase in the internal CaィイD12+ィエD1 level only when external solution contained CaィイD12+ィエD1. Externally applied L-glutamate, ACh, and caffeine induced no detectable change in the internal CaィイD12+ィエD1level.
|
Report
(3 results)
Research Products
(17 results)
