Overexpression of Na + /Ca 2+ exchanger 1 display enhanced relaxation in the gastric fundus

In gastric smooth muscles, the released Ca activates the contractile proteins and Ca taken up from the cytosol cause relaxation. The Na /Ca exchanger (NCX) is an antiporter membrane protein that controls Ca influx and efflux across the membrane. However, the possible relation of NCX in gastric fundu...

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Bibliographic Details
Published in:Journal of pharmacological sciences 2016-11, Vol.132 (3), p.181
Main Authors: Fujimoto, Yasuyuki, Hayashi, Satomi, Azuma, Yasu-Taka, Mukai, Kazunori, Nishiyama, Kazuhiro, Kita, Satomi, Morioka, Ai, Nakajima, Hidemitsu, Iwamoto, Takahiro, Takeuchi, Tadayoshi
Format: Article
Language:English
Subjects:
Animals
Electric Stimulation
Gastric Fundus - metabolism
Gastric Fundus - physiology
In Vitro Techniques
Mice
Mice, Inbred C57BL
Mice, Transgenic
Muscle Relaxation - physiology
Muscle, Smooth - metabolism
Muscle, Smooth - physiology
Sodium-Calcium Exchanger - biosynthesis
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Summary:In gastric smooth muscles, the released Ca activates the contractile proteins and Ca taken up from the cytosol cause relaxation. The Na /Ca exchanger (NCX) is an antiporter membrane protein that controls Ca influx and efflux across the membrane. However, the possible relation of NCX in gastric fundus motility is largely unknown. Here, we investigated electric field stimulation (EFS)-induced relaxations in the circular muscles of the gastric fundus in smooth muscle-specific NCX1 transgenic mice (Tg). EFS caused a bi-phasic response, transient and sustained relaxation. The sustained relaxation prolonged for an extended period after the end of the stimulus. EFS-induced transient relaxation and sustained relaxation were greater in Tg than in wild-type mice (WT). Disruption of nitric oxide component by N-nitro-l-arginine, EFS-induced transient and sustained relaxations caused still marked in Tg compared to WT. Inhibition of PACAP by antagonist, EFS-induced sustained relaxation in Tg was not seen, similar to WT. Nevertheless, transient relaxation remained more pronounced in Tg than in WT. Next, we examined responses to NO and PACAP in smooth muscles. The magnitudes of NOR-1, which generates NO, and PACAP-induced relaxations were greater in Tg than in WT. In this study, we demonstrate that NCX1 regulates gastric fundus motility.
ISSN:1347-8648