Roles of Na+/Ca2+ exchanger isoforms NCX1 and NCX2 in motility in mouse ileum

Roles of Na+/Ca2+exchanger 1 in digestive system physiology and pathophysiology

“…These results suggest that NCX1 and its mediated Ca 2+ influx play a critical and extensive role in regulating the secretion of HCO 3 - in the duodenal mucosa. Other studies have shown that NCX1 and NCX2 are also involved in ileal smooth muscle contraction and ileal motility regulation[71]. Nishiyama et al found that NCX2 regulates ileal motility primarily by controlling the sensitivity of acetylcholine (AchE) and substance P (SP) in smooth muscle[71].…”

“…Other studies have shown that NCX1 and NCX2 are also involved in ileal smooth muscle contraction and ileal motility regulation[71]. Nishiyama et al found that NCX2 regulates ileal motility primarily by controlling the sensitivity of acetylcholine (AchE) and substance P (SP) in smooth muscle[71]. Compared with that in the wild-type model, the contraction amplitude induced by AchE and SP after NCX2 knockout was significantly reduced; although NCX1 also plays a role in the regulation of ileal contraction, this decline was not evident in the NCX1 knockout model[71].…”

“…Nishiyama et al found that NCX2 regulates ileal motility primarily by controlling the sensitivity of acetylcholine (AchE) and substance P (SP) in smooth muscle[71]. Compared with that in the wild-type model, the contraction amplitude induced by AchE and SP after NCX2 knockout was significantly reduced; although NCX1 also plays a role in the regulation of ileal contraction, this decline was not evident in the NCX1 knockout model[71]. This finding suggests that NCX2 plays a more important role than NCX1 in ileal movement.…”

Na⁺/Ca²⁺ exchanger contributes to stool transport in mice with experimental diarrhea

“…The functional roles by which NCX influences gastrointestinal motility including contraction and relaxation are incompletely understood and vary by tissue, although its role in cardiac muscle and brain neurons is well understood. Our group is showing to reveal the functional role of NCX on gastrointestinal motility, because Ca 2+ homeostasis is central to the regulation of gastrointestinal smooth muscle functions [ 1 , 4 , 7 , 12 , 13 , 14 ]. To specifically assess the physiological role of NCX, we used NCX1 heterozygote knockout mice (NCX1 HET) and NCX2 HET.…”

“…To improve the understanding of NCX action on gastrointestinal motility, we examined to characterize the motilities in gastrointestinal segments from the gastric fundus, ileum and distal colon in NCX1 HET and NCX2 HET using an organ tissue bath system. In these previous articles, we found that NCX1 and NCX2 play important roles in the motility in the gastric fundus [ 4 ], ileum [ 14 ] and distal colon [ 1 , 13 ], although NCX1 HET and NCX2 HET appeared outwardly healthy and displayed normal growth established by body weight changes, amount of drinking, food intake, fecal weights and fecal numbers. Therefore, we believed that NCX1 and NCX2 play an important role in transport of intestinal contents.…”