1996 Fiscal Year Final Research Report Summary
Mechanism of nitric oxide-mediated relaxation of gatrointestinal smooth muscle.
| Project/Area Number |
07660406
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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 |
Basic veterinary science/Basic zootechnical science
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| Research Institution | Osaka Prefecture University |
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Principal Investigator |
HATA Fumiaki Osaka Prefecture University, College of Agriculture, Professor, 農学部, 教授 (60028363)
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| Project Period (FY) |
1995 – 1996
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| Keywords | Rat gastrointestine / NANC relaxation / Proximal colon / Distal colon / Nitric oxide / cyclic GMP / Rectum |
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| Research Abstract |
Mechanism of nitric oxide-mediated relaxation of smooth muscle was studied in the longitudinal muscle of proximal and distal colon, and the jejunum of rats. Results obtained newly are as follows. In the proximal colon : Dimethylphenylpiperazinium (DMPP) and electrical field stimulation (EFS) induced nitric oxide-mediated relaxation of the segments with a conconitant increase in cydic GMP content. Soluble guanylyl cyclase inhibitors significanthy inhibited stimulatory effects of DMPP and EFS on the cyclic GMP content, but did not attect the relaxant responses of the segments to DMPP and EFS.It was strongly suggested that intric oxide-mediated relaxation of the rat proximal colon is not associated with change in cyclic GMP content of the tissue. In the distal colon : Any participation of nitric oxide in NANC relaxation was not found. It was suggested that VIP and PACAP are involved in NANC inhibitory responses of longitudinal muscle of the rat distal colon via activation of charybdotoxin-and apamin-sensitive K^+ channels, respectively. In the jejunum NANC relaxation in longitudinal muscle of rat jejunum involves two independent components : one is a nitric oxide-mediated minor component, and the other is an unknown substance-mediated apamin-sensitive major component that is inhibited by alpha-chymotrypsin treatment.
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