1995 Fiscal Year Final Research Report Summary
Medullay newronal pathway meliating Hering -Bseuen reflex.
| Project/Area Number |
06670045
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
General physiology
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| Research Institution | Chiba Univ., School of Medicine |
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Principal Investigator |
HAYASHI Fumiaki Chiba University, School of Medicine, lecturer, 医学部, 講師 (80173029)
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| Co-Investigator(Kenkyū-buntansha) |
FUKUDA Yasuichirou Chiba University, School of Medicine professor, 医学部, 教授 (10009649)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Heving-Brewer raflex / Veutual rospirodorg group / Respiratory newron / Pulwouay shetch ncsptor / Vogus ueuo / Respiratory patteu / Control of braathing / Rat |
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| Research Abstract |
Ventral respiratory group (VRG) neuron responscs to vagus nerve stimulation and lung inflation were determined in urethane or Nembutal anesthetized, paralyzed rats. Vagus nerves were sectioned except in animals in which lung inflation was used to elicit the Breuer-Hering (BH) reflex consisting of inspiratory termination and expiratory prolongation. Intracellular recordings revealed 3 groups of inspiratoy (I) and expiratory 2 groups of (E) neurons similar to previous descriptions : I-augmenting (I-Aug) , I-decrementing (I-Dec) , I-plateau (I-All) , E-augmenting (E-Aug) , and E-decrementing (E-Dec) neurons. An additional subgroup (E-Decearly) discharged a brief burst of action potentials beginning at the inspiratory-expiratory phasetransition. The BH reflex was activated by lung inflation (7.5cmH20 ; n=33) or was mimicked by vagus nerve stimulation (50Hz ; n=30) . Either procedure inhibited E-Aug and I neurons. All E-Dec neurons tested were depolarized by vagal nerve stimulation (50Hz ; n=5) , and most were depolarized by lung inflation (13 of 17 neurons ), but some were inhibited (n=4). One E-Decearly cell was inhibited and a second excited by vagus nerve stimulation. Vagus nerve stimulation elicited EPSPs in all neuron group except I-Dec and E-Aug neurons. EPSPs were divided into two groups based on latency (2.8 <plus-minus> 0.1 msec, n=10 ; 4.0<plus-minus>0.1 msec, n=17). IPSPs were elicited in I-Aug and I-All neurons (4.8<plus-minus>0.1 msec, n=12). The findings are consistent with the hypothesis that subsets of E-Dec and E-Decearly have roles as inhibitory interneurons in the BH-reflex pa
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