1999 Fiscal Year Final Research Report Summary
CaィイD12+ィエD1-Metabolism and Membrane Functions in Hypertension
| Project/Area Number |
10670674
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Circulatory organs internal medicine
|
|---|
| Research Institution | Wakayama Medical College |
|---|
Principal Investigator |
TSUDA Kazushi Wakayama Medical College, Division of Cardiology, Department of Medicine, Assistant Professor, 医学部, 講師 (90217315)
|
|---|
| Project Period (FY) |
1998 – 1999
|
| Keywords | Hypertension / β-Endorphin / Norepinephrine / Acetylcholine / Membrane fluidity / Adrenomedullin / Calcium / Dual energy X-ray Absorptiometry |
|---|
| Research Abstract |
The purpose of the present study was to determine the role of Ca and other intrinsic factors in the pathogenesis if hypertension.β-Endorphin significantly inhibited the stimulation-evoked norepinephrine (NE) release in rat medulla oblongata. The effect of β-endorphin was more attenuated in spontaneously hypertensive rats (SHR) than in normotensive Wistar-Kyoto(WKY) rats. The finding shows that β-endorphin might actively participate in the regulation of sympathetic nerve activity in hypertension. Additionally, we examined the of dopamine D2 receptors in acetylcholine (ACh) release in the central nervous system. Exogenously applied dopamine and apomorpine reduced the simulation-evoked ACh release. The activity of the dopamine D2 receptors in SHR was significantly more attenuated that in WKY rats. The results showed that the dopamine D2 receptors might have a potential role in the regulation of cholinergic nerve activity in hypertension.
In the next series of the experiments, we studied th
… More
e changes in membrane fluidity of erythrocytes in patients with essential hypertension (EH) by means of an electron paramagnetic resonance (EPR) method. The erythrocyte membrane fluidity was lower in EH than in normotensive subjects. Adrenomedullin(AM) significantly increased the membrane fluidity of erythrocytes. The effect of AM was potentiated by prostaglandin E1and dibutyryl cAMP. Furthermore, AM increased the membrane fluidity to a greater extent in EH than in normotensive subjects. The results showed that AM might be involved in the regulation of cell function in hypertension.
Recent studies have documenbted abnormalities in Ca-metabolism at systemic level in human hypertension as well as in experimental hypertension. Since bone is the largest store of Ca in the body, we investigated the bone mineral density (BMD) in patients with EH by means of the dual energy X-ray absorptiometric (DXA) method. DXA analysis showed a significant decrease in BMD in female EH compared with age-matched normotensive subjects. In addition , the BMD was inversely correlated with systolic blood pressure. Furthermore, the greater the urinary Ca-excretion, the lower the BMD in females. The results of the present study demonstrate the DXA provided an index of whole Ca-balance, and suggest that hypertension might be associated with reduced BMD in female EH. Less
|
