2000 Fiscal Year Final Research Report Summary
Effect of fatal hypoxia on ventilatory responses to hypoxia
| Project/Area Number |
11670058
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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 |
Environmental physiology (including Physical medicine and Nutritional physiology)
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| Research Institution | Chiba university |
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Principal Investigator |
HAYASHI Fumiaki Chiba University, School of Med., Associate Professor, 医学部, 助教授 (80173029)
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| Co-Investigator(Kenkyū-buntansha) |
MASUYAMA Shigeru Chiba University, School of Med., Assistant Professor, 医学部, 助手 (00219354)
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| Project Period (FY) |
1999 – 2000
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| Keywords | fetal hypoxia / high altitude acclimatization / high land native / hypoxic ventilatory response / developmental plasticity / neuronal circuit / rat |
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| Research Abstract |
The underlying mechanisms for the attenuated hypoxic ventilatory response observed in a highland native are still controversial. In addition two proposed mechanisms (e.g., genetic or acquired), the developmental plasticity for the neuronal circuits for the respiratory control has recently been noticed. We, therefore, hypothesized that the fetal hypoxia is the determinant factor on the attenuated hypoxic ventilatory response seen in highland natives.
The rat was exposed to 11% of hypoxia (corresponding to 4000-4500 meters altitude) for 14 days before birth and 4 weeks after birth. Thereafter, the animal was returned to normoxic chamber (21% O2). The ventilatory response to hypoxia (difference in the ventilation between air and 10% O2) was determined at 4,5,6,8 and 12 weeks after birth. The ventilatory parameters (VT, f and VE) were measured by a whole body plethysmograph.
The ventilatory response to hypoxia was significantly attenuated at 4 and 5 weeks after birth, but was returned to the control value after this period. The attenuated ventilatory response to hypoxia seen in rats exposed before and after birth, was considered to be due to a acclimatization to hypoxia, but not due to developmental plasticity of neuronal circuit controlling hypoxia ventilatory responses.
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