기니픽의 회장평활근에서 NANC 신경전달 물질의 작용기건 = Action Mechanisms of NANC Neurotransmitters in Smooth Muscle of Guinea Pig Ileum

다국어 초록 (Multilingual Abstract)

The relaxation induced by stimulation of the inhibitory non-adrenergic, non-cholinergic (iNANC) nerve is mediated by the release of iNANC neurotransmitters such as nitric oxide (NO)m vasoactive intestinal peptide (VIP) and adenosine triphosphate(ATP). The mechanismsof NO, VIP or ATP-induced relaxation have been partly deterinined in previous studies, but the detailed inechanism remains unknown. We tried ti identify the nature of iNANC neurotransmitters in the smooth muscle of guinea pig ileum and to deterinine the mechanism of the inhibitory effect of nitric oxide. We measured the effect of NO-donors, VIP and ATP on the intracellular Ca^2+ concentration([Ca^2+]_1), by means of a fluorescence dye(fura 2) and tension simultaneously in the isolated guinea pig ileal smooth muscle. Following are the results obtained.
1. Sodium mtroprusside (SNP:10^-5 M) or S-mitro-N-acetyl-penicillamine(SNAP:^-5 M) decreased resting [Ca^2+]_1 and tension of muscle. SNP or SNAP also inhibited rhythmic oscillation of [Ca^2+]_1 and tension. In 40mM K^+ solution or carbachol(CCh:10^-6 M) induced precontracted muscle, SNP decreased muscle tension. VIP did not change[Ca^2+]_1 and tension in the resting or precontracted muscle, but ATP increased resting[Ca^2+]_1 and tension in the resting muscle.
2. IH-[1,2,4]oxadiazol[4,3-alquinoxalin-1-one(ODQ:1 μM), a specific inhibitor of soluble guanylate cyclase, limited the inhibotory effect of SNP.
3. Glibenclamide (10 μM),a blocker of K_ATP channel, and 4-aminophridine(4-AP:5 mM), a bloker of delayed rectifier K channel, apamin(0.1 μM), a blocker of small conductance K_Ca channel, significantly increased the resting [Ca^2+]_1,and tension, and limited the inhibitory effect of SNP.
4. Nifedipine (1 μM) or elimination of external Ca^2+ decreased not only resting [Ca^2+]_1 and tension but also oscillation of [Ca^2+]_1 and tension. Ryanodine (5 μM) and cyclopiazonic acid(10 μM) decreased iscillation of [Ca^2+]_1 and tension.
5. SNP decreased Ca²?? sensitivity of contractile protein.
In conclusion, these results suggest that 1) No is an inhibitory neuritransmitter in the guinea pig ileum, 2) the inhibotory effect of SNP on the [Ca^2+]^1 and tension of the musele is due to a decrease in [Ca^2+]_1 by activation of the large conductance K_Ca channel and decrease in the sensitivity of contractile elements to Ca^2+ through activation of G-kinase.

목차 (Table of Contents)

• 서론
• 방법
• 결과분석
• 결과
• 고찰
• 참고문헌