scholarly journals Effects of tetraethylammonium chloride on the membrane activity of guinea-pig stomach smooth muscle

1970 ◽  
Vol 211 (2) ◽  
pp. 445-460 ◽  
Author(s):  
Y. Ito ◽  
H. Kuriyama ◽  
Y. Sakamoto
2004 ◽  
Vol 40 (3) ◽  
pp. 111-124 ◽  
Author(s):  
Eri Nakamura ◽  
Ayako Hashimoto ◽  
Yoshihiko Kito ◽  
Hikaru Hashitani ◽  
Toyoki Mori ◽  
...  

1995 ◽  
Vol 67 ◽  
pp. 206
Author(s):  
Sanae Nakamura ◽  
Tsuyoshi Isliibashi ◽  
Mitsuo Mita ◽  
Takao Hashimoto ◽  
Kazuhiko Oishi ◽  
...  

1994 ◽  
Vol 266 (5) ◽  
pp. G839-G845 ◽  
Author(s):  
Z. F. Gu ◽  
T. K. Pradhan ◽  
D. H. Coy ◽  
R. T. Jensen

Galanin-like immunoactivity occurs in nerves and plexi in muscle layers throughout gastrointestinal tract including the stomach. Galanin can affect gastric emptying and contraction or relaxation of gastric muscle in different species. The aim of this study was to investigate the direct effect of galanin on dispersed gastric smooth muscle cells and to characterize any galanin receptors that mediated any effect. Dispersed gastric smooth muscle cells were prepared from guinea pig stomach by collagenase digestion. Porcine galanin (p-galanin; 1 microM) did not stimulate contraction when present alone; however, p-galanin (1 microM) inhibited carbachol-induced contraction with a half-maximal effect at 7 nM. p-Galanin (1 microM) increased cellular adenosine 3',5'-cyclic monophosphate (cAMP) content by 10 s and caused a maximal increase of 80% over basal. 125I-galanin (porcine) bound to dispersed cells in a time- and temperature-dependent manner. Binding was saturable, reversible, and specific. Binding of 125I-galanin was inhibited almost equally by porcine and rat galanin (Ki = 6-8 nM) but was not inhibited by the galanin-associated peptide [preprogalanin-(108-123)]. The fragment galanin-(1-16) was equally potent to rat galanin; however, the fragment galanin-(9-29) was 56-fold less potent (Ki = 370 nM). Computer analysis demonstrated there were two binding sites for p-galanin on gastric smooth muscle cells, a high-affinity site (Kd = 2.6 nM) with low capacity (Bmax = 175 fmol/mg protein) and a low-affinity site (Kd = 150 nM) with large capacity (Bmax = 3,611 fmol/mg protein).(ABSTRACT TRUNCATED AT 250 WORDS)


1993 ◽  
Vol 109 (3) ◽  
pp. 661-666 ◽  
Author(s):  
Keiko Suzuki ◽  
Kaoru M. Ito ◽  
Yukie Minayoshi ◽  
Hikaru Suzuki ◽  
Masahisa Asano ◽  
...  

2005 ◽  
Vol 83 (8-9) ◽  
pp. 791-797 ◽  
Author(s):  
Yasushi Sakai ◽  
Hiroki Kinoshita ◽  
Keiichirou Saitou ◽  
Ikuo Homma ◽  
Koji Nobe ◽  
...  

The plasma membrane ATP-dependent Ca2+ pump and the Na+/Ca2+ exchanger (NCX) are the major means of Ca2+ extrusion in smooth muscle. However, little is known regarding distribution and function of the NCX in guinea pig gastric smooth muscle. The expression pattern and distribution of NCX isoforms suggest a role as a regulator of Ca2+ transport in cells. Na+ pump inhibition and the consequent to removal of K+ caused gradual contraction in fundus. In contrast, the response was significantly less in antrum. Western blotting analysis revealed that NCX1 and NCX2 are the predominant NCX isoforms expressed in stomach, the former was expressed strongly in antrum, whereas the latter displayed greater expression in fundus. Isolated plasma membrane fractions derived from gastric fundus smooth muscle were also investigated to clarify the relationship between NCX protein expression and function. Na+-dependent Ca2+ uptake increased directly with Ca2+ concentration. Ca2+ uptake in Na+-loaded vesicles was markedly elevated in comparison with K+-loaded vesicles. Additionally, Ca2+ uptake by the Na+- or K+-loaded vesicles was substantially higher in the presence of A23187 than in its absence. The result can be explained based on the assumption that Na+ gradients facilitate downhill movement of Ca2+. Na+-dependent Ca2+ uptake was abolished by the monovalent cationic ionophore, monensin. NaCl enhanced Ca2+ efflux from vesicles, and this efflux was significantly inhibited by gramicidin. Results documented evidence that NCX2 isoform functionally contributes to Ca2+ extrusion and maintenance of contraction-relaxation cycle in gastric fundus smooth muscle.Key words: stomach, smooth muscle, Na+/Ca2+ exchanger (NCX), NCX2.


Sign in / Sign up

Export Citation Format

Share Document