1996 Fiscal Year Final Research Report Summary
EFFECTS OF HYPOXIA OR HYPERCAPNIA DURING PERINATAL PERIODS ON THE RESPIRATORY CONTROL OF THE CONSCIOUS NEWBORNRAT
| Project/Area Number |
07671273
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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 |
Embryonic/Neonatal medicine
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| Research Institution | SHINSHU UNIVERSITY |
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Principal Investigator |
MATUSOKA Takafumi SHINSHU UNIVERSITY SCHOOL OF MEDICINE ASSISTANT PROFESSOR, 医学部, 講師 (70270965)
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| Project Period (FY) |
1995 – 1996
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| Keywords | newborn / respiratory control / respiratory output / Hering-Breuer reflex / acute repeated hypoxia / acute repeated hypercapnia / chronic sustained hypoxia / sudden infant death syndrome (SIDS) |
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| Research Abstract |
I asked whether hypoxic or hypercapnic exposures during the fetal and/or the early neonatal periods can affect the lung volume-dependent ventilatory inhibition (Hering-Breuer inflation inhibitory reflex, HBR). At 5 day after birth, measurements of respiratory pattern were done by flow-plethysmography on each rat pup, while, conscious, it was breathing normoxia (NMX), 10% hypoxia (HPX) or 3% hypercapnia (HPC). The HBR was triggered by lung inflation via negative body surface pressure ; it was quantified as a ratio of TE_<inf>l to TE_c, i. e., IR=TE_<infl>/TE_c. Results were as follows : 1) effects of acute repeated 6% hypoxia [ARHo, 30min, twice a day, from postnatal day 1 to 4] : in HPX,IR was increased above the NMX value ; 2) effects of acute repeated 6% hypercapnia [ARH_c, 30min, twice a day, from postnatal day 1 to 4] : no effects ; 3) effects of CSHN [14% sustained hypoxia from postnatal day 1 to 4], CSHF [14% sustained hypoxia from pregnant week 1 to postnatal day 1], or CSHT [14% sustained hypoxia from pregnant week 1 to postnatal day 4] : in HPX,IR was increased above the NMX value. I conclude that in rat pups repeated and sustained hypoxic episodes can modify the HBR,namely prolong duration of apnea in HPX.The findings are in agreement with the view that hypoxic exposures in the fetal and/or the early neonatal periods may interfere with maturation of the respiratory control, and may be involved in the mechanisms of SIDS.
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Research Products
(2 results)
