1998 Fiscal Year Final Research Report Summary
Effect of magnesium on fetal circulatory responses to acute hypoxemia
| Project/Area Number |
09671700
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Obstetrics and gynecology
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| Research Institution | Miyazaki Medical College |
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Principal Investigator |
SAMESHIMA Hiroshi Miyazaki Medical College, Perinatal Center, Associate Professor, 医学部, 助教授 (50274775)
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| Co-Investigator(Kenkyū-buntansha) |
SAKAMOTO Hiroshi Kagoshima University, Department of Agriculture, Professor, 農学部, 教授 (20041650)
KANEKO Masatoki Miyazaki Medical College, Perinatal Center, Research Associate, 医学部, 助手 (40264387)
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| Project Period (FY) |
1997 – 1998
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| Keywords | magnesium / fetal circulation / catecholamines / neuroprotection / colored microspheres |
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| Research Abstract |
Effect of magnesium sulfate on fetal circulatory responses to acute hypoxemia was studied with a "chronic preparation" goat model.
Acute hypoxemia causes fetal heart rate (FHR) deceleration with an increase in fetal arterial blood pressure (BP). Hypoxemia with a continuous magnesium infusion masks these fetal responses and shows no changes in FHR or BP.Four-hours magnesium infusion decreases baseline FHR, incidence of acceleration of FHR, and baseline variabilities. Acute hypoxemia significantly increases FHR variabilities, which are not blunted by magnesium. Catecholamines are increased by hypoxemia as well as hypoxemia with magnesium.
Blood flow is measured by a colored microsphere method. From the pre-hypoxemic level, hypoxemia significantly increases blood flow to the cerebral cortex, midbrain, cerebellum, medulla, and heart. Magnesium further increases blood low to these organs, and this increase to the cerebral cortex achieves statistical significance.
To better understand magnesium neuroprotective effect, we use 7-day-old rats model (unilateral carotid artery ligation with 2 hours hypoxia). Pretreatment of magnesium before the hypoxic-ischemic insult shows neuroprotective effects in all the part of the brain, but statistical significance is limited to the cerebral cortex.
These results reveal that magnesium has neuroprotective effects on the fetus (and newborn), and that increases in blood flow to the brain and heart with magnesium may account for the neuroprotective effects.
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