| Co-Investigator(Kenkyū-buntansha) |
OTANI Hitomi Kansai Medical University, Department of Pharmacolgy, Assistant Professor, 医学部, 講師 (40140272)
HARA Mitsuyoshi Kansai Medical University, Department of Pharmacolgy, Assistant Professor, 医学部, 講師 (50192282)
OMORI Kyoko Kansai Medical University, Department of Pharmacolgy, Associate Professor, 医学部, 助教授 (90152256)
KITAGAWA Kaori Kansai Medical University, Department of Pharmacolgy, Research Associate, 医学部, 助手 (10165813)
HATTORI Naoki Kansai Medical University, Department of Pharmacolgy, Assistant Professor, 医学部, 講師 (80288828)
|
|---|
| Research Abstract |
(1) Intraneuronal ClィイD1=ィエD1 concentrations ([ClィイD1=ィエD1]i) and immediately early gene (c-fos) expression
Intracerebroventricular administration of a ClィイD1-ィエD1 pump inhibitor, ethacrynic acid, caused convulsions in mice. Expression of c-fos was stimulated biphasically with the peaks at 60min and 10-14 days after the convulsion. Expression of nerve growth factor, damage of GABAergic neurons and development of seizure susceptibility were also observed. A transient increase in neuronal [ClィイD1-ィエD1]i thus appeared to cause biphasic increases in c-fos expression and related modulation of neuronal functions.
(2) Mechanisms of ammonia-induced increases in neuronal [ClィイD1=ィエD1]i
A neurotoxic factor in hepatic encephalopathy, ammonia (2 mM, 48 hr), increased [ClィイD1-ィエD1]i in cultured rat hippocampal neurons. The increase was found to be due to enhanced expression of anion exchanger (AE3) mediated by protein kinase C activation.
(3) ClィイD1=ィエD1 transport in hypoxia/reoxygenaion-induced changes in pHi and {CaィイD12+ィエD1]i in myocytes
Under hypoxia/reoxygenaion conditions, pHi decreased and [CaィイD12+ィエD1]i increased during hypoxia and reoxygenation, respectively. Inhibitors of anion exchanger (SITS and DIDS) and removal of medium ClィイD1-ィエD1 or HCOィイD23ィエD2 attenuated such changes in pHi and [CaィイD12+ィエD1]i. Inhibitors of protein kinase C slightly reduced the changes in pHi. Involvement of anion exchanger in hypoxia-induced pHi changes was first demonstrated with the resulting inhibitory effects on reoxygenation-induced increases in [CaィイD12+ィエD1]i.
(4) Subunits and cDNA cloning of neuronal ClィイD1=ィエD1 pump
A new ClィイD1-ィエD1 transporter, ClィイD1-ィエD1 pump, was isolated as 520 kDa protein complex from the rat brain. SDS-PAGE analyses yielded 4 subunits (51, 55, 60 and 62kDa), and 51kDa protein appeared to be a catalytic subunit. cDNA for 55 kDa protein was cloned from the rat brain cDNA library, and its primary structure was assumed to be a new peptide with 475 amino acids.
|
