소장 카할 사이질 세포에서 5-HT의 작용 및 기전

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Serotonin (5-hydroxytruptamine or 5-HT)는 위장관에 널리 분포하면 위장관의 생리학적 기능 수행에 있어 5-HT의 기능은 매우 중요한 것으로 알려져 있다. 따라서, 위장관내 존재하는 Ca^(2+) 사이질 세포에서 발생하는 전기적 현상에 대한 5-HT의 효과와 작용기전을 규명하고자 생쥐 작은 창자에서 배양된 Cajal 세포에서 세포막 전압 고정법 및 세포 내 Ca2+ 분석을 시행하였다. 정상상태에서의 세포막 전압 고정법 시행시 Cajal세포는 서파와 자발적인 내향성 전류(향도잡이 전류)를 발생하였고 5-HT의 투여는 일시적인 내향성 전류를 발생시키는 것을 알 수 있었다. 또한 5-HT₄와 5-HT_(7) 수용체 길항제인 SDZ 205557과 SB 269970은 5-HT의 효과를 부분적으로 억제하였다. 더불어 5-HT3 수용체 길항제인 3-TCM는 완벽하게 억제하는 것을 보여주었다. 하지만, GDPβS를 이용한 G 단백질 관여 실험에서는 5-HT효과에 영향을 주지 못하였다.
Ca^(2+)-free 용액을 전 처리는 ICC에서 발생하는 자발적 향도잡이 전류를 억제하였으며, 5-HT에 대한 효과도 억제하였다. 이와 더불어, 다양한 MAP kinases 길항제를 이용한 실험에서 JNK II 길항제만이 5-HT의 효과를 감소시켰으며, 수용체 tyrosine kinase 길항제인 genistein과 herbimycin A 또한 억제 효과를 보여주었다.
이와 같은 결과는 ICC에서 발생되는 향도잡이 전류에 대한 5-HT의 역할을 확인시켜주는 것으로 그 작용은 5-HT₃,₄,_(7)을 통하여 이루어 지는 것을 알 수 있었다. 또한 그 작용은 수용체 typrosine kinase와 MAP kinase 활성화를 통해 이루어 지는 것을 시사한다.|Serotonin (5-hydroxytruptamine or 5-HT) is present in abundance within the gut, most stored in enterochromaffin cell granules. It plays a critical physiological role in regulation of Gastrointestinal (GI) function which is related to the expression of multiple 5-HT receptor types and subtypes. The effects of 5-HT on electrical responses of the membrane were investigated in Interstitial Cells of Cajal (ICC) isolated from the murine small intestine. For the analysis, whole cell patch clamp technique, Confocal microscopy for change in intracellular Calcium oscillation and molecular studies were performed. On application of 5-HT (10 mol) on the spontaneous pacemaker current generating ICC, it showed the transient inward current. In presence of 5-HT4 and 5-HT7 receptor antagonists, SDZ 205557 and SB 269970, the effect was partially blocked but completely antagonized in the presence of mixture of both the antagonists. 5-HT₃ receptor antagonist 3-TCM also abolished the effect of 5-HT. There is has no involvement of G protein as GDP S, a nonhydrolyzable guanosine 5-diphosphate (GDP) analogue which permanently inactivates GTP-binding proteins, did not affect the 5-HT induced effect. The pretreatment with Ca^(2+) -free solution abolished the generation of pacemaker currents and suppressed the 5-HT -induced action. Moreover, MAP kinase is involved in 5-HT activity as JNK II Inhibitor, c-jun NH2-terminal kinase inhibitor, completely abolished the 5-HT effect where as PD 98059, a p44/42 MAPK inhibitor, and SB 203580, a p38 MAPK inhibitor, partially blocked and has no effect on 5-HT action respectively. In addition, Genistein and Herbimycin A, receptor tyrosine kinase inhibitors, also inhibited the 5-HT effect on ICC but Diadzein, an inactive analogue of Genistein failed to do so. These results suggest 5-HT when exogenously applied to pacemaker current generating ICC produces transient inward current through 5-HT₃, 5-HT₄ and 5-HT_(7) and this occur by the activation of receptor tyrosine kinase and MAP kinase activation.
Alternative Title
Receptor Tyrosine and MAP Kinase are involved in effects of 5-HT on interstitial Cells of Cajal in Murine Intestine
Alternative Author(s)
Pawan Kumar Shahi
조선대학교 의과대학 생리학교실
일반대학원 의학과
Awarded Date
Table Of Contents
□Introduction = 3
⊙Cellular Physiology of gastrointestinal Smooth Muscle = 03
⊙Interstitial Cells of Cajal (ICC) = 03
⊙Organization and Electrophysiology of Interstitial Cells of Cajal; and Smooth Muscle Cells in Gastrointestianl Tract = 06
⊙ICC and the peristalsis in GI tract. = 08
⊙The pacemaker apparatus = 10
⊙The pacemaker mechanism = 11
⊙Serotonin and Interstitial Cells of Cajal = 13
⊙5-HT and its Receptors = 15
⊙5-HT Receptors in the GI tract = 15
□Material and Methods = 22
⊙Animal = 22
⊙Cell Culture = 22
⊙Patch - Clamp Experiments = 23
⊙Solutions = 24
⊙Measurement of the Intracellular Ca^(2+) Concentration = 24
⊙Drugs and Chemicals = 25
⊙Statistical analysis = 26
□Result = 27
⊙Spontaneous membrane potential and pacemaker current generated by ICC at resting state. = 27
⊙Effect of 5-HT on membrane potential generated by ICC = 28
⊙Effect of 5-HT at different concentration on ICC = 29
⊙No involvement of G-protein in the action of 5-HT in cultured ICC = 31
⊙Effect of external Ca^(2+) in 5-HT induced inward current on ICC = 32
⊙Excitation of [Ca^(2+)]i oscillation by 5-HT = 33
⊙Identification of receptor subtypes of 5-HT in cultured ICC = 35
⊙Involvement of tyrosine kinase in the 5-HT induced inward current of pacemaker ICC. = 37
⊙Involvement of mitogen-activated protein kinases (MAPKs) in the 5-HT induced depolarization of pacemaker currents = 39
□Discussion = 41
□Summary = 45
□References = 47
조선대학교 대학원
파완쿠마샤히. (2008). 소장 카할 사이질 세포에서 5-HT의 작용 및 기전.
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General Graduate School > 3. Theses(Master)
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