The Influences of G Proteins, Ca2+ and K+ Channels on Electrical Field Stimulation in Cat Esophageal Smooth Muscle
- Authors
- Park, Jun Hong; Kim, Hyun Sik; Park, Sun Young; Im, Chaeuk; Jeong, Ji Hoon; Kim, In Kyeom; Sohn, Uy Dong
- Issue Date
- Oct-2009
- Publisher
- KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY
- Keywords
- EFS; Cat esophageal; Circular smooth muscle; NO; L-type Ca2+ channel
- Citation
- KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY, v.13, no.5, pp 393 - 400
- Pages
- 8
- Journal Title
- KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY
- Volume
- 13
- Number
- 5
- Start Page
- 393
- End Page
- 400
- URI
- https://scholarworks.bwise.kr/cau/handle/2019.sw.cau/22970
- DOI
- 10.4196/kjpp.2009.13.5.393
- ISSN
- 1226-4512
2093-3827
- Abstract
- NO released by myenteric neurons controls the off contraction induced by electrical field stimulation (EFS) in distal esophageal smooth muscle, but in the presence of nitric oxide synthase (NOS) inbibitor, L-NAME, contraction by EFS occurs at the same time. The authors investigated the intracellular signaling pathways related with G protein and ionic channel EFS-induced contraction using cat esophageal muscles. EFS-induced contractions were significantly suppressed by tetrodotoxin (1 mu M) and atropine (1 mu M). Furthermore, nimodipine inhibited both on and off contractions by EFS in a concentration dependent meaner. The characteristics of 'on' and 'off' contraction and the effects of G-proteins, phospholipase, and K+ channel on EFS-induced contraction in smooth muscle were also investigated. Pertussis toxin (PTX, a G(i) inactivator) attenuated both EFS-induced contractions. Cholera toxin (CTX, G(s) inactivator) also decreased the amplitudes of EFS-induced off and on contractions. However, phospholipase inhibitors did not affect these contractions. Pinacidil (a K+ channel opener) decreased these contractions, and tetraethylammonium (TEA, K-Ca(+) channel blocker) increased them. These results suggest that EFS-induced on and off contractions ran be mediated by the activations Gi or Gs proteins, and that L-type Ca2+ channel may be activated by G-protein alpha subunits. Furthermore, K-Ca-(+) channel involve in the depolarization of esophageal smooth muscle. Further studies are required to characterize the physiological regulation of Ca2+ channel and to investigate the effects of other K+ channels on EFS-induced on and off contractions.
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Collections - College of Medicine > College of Medicine > 1. Journal Articles
- College of Pharmacy > School of Pharmacy > 1. Journal Articles
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