Abstract
Background & Aims: The physiologic significance of the M3 muscarinic receptor is unclear due to an absence of specific ligand. In the present study, M3 receptor knock-out (KO) mice were used to elucidate the role of M3 receptors in gastric acid secretion and gastric mucosal integrity. Methods: M3 KO versus wild-type mice aged 1 month to 2 years were included. Gastric acid secretion was assessed by both direct intragastric pH measurement and pylorus ligation. Serum gastrin and gastric mucosal histamine levels were determined by radioimmunoassay and enzyme-linked immunosorbent assay, respectively. Morphologic analysis was performed by both immunohistochemistry and transmission electron microscopy. Results: Fasted M3 KO mice exhibited higher intragastric pH, lower acid output after pylorus ligation, a lower proportion of active parietal cells, and higher serum gastrin levels than fasted wild-type mice. Acid secretion in response to carbachol, histamine, gastrin 17, and 2-deoxy-D-glucose was impaired in the mutant mice. Although carbachol was still able to cause ∼30% acid output in M3 KO mice, the acid secretion was inhibited by pirenzepine or famotidine. Despite remarkable hypergastrinemia in M 3 KO mice, there were no trophic responses in the oxyntic mucosa with respect to the mucosal thickness, proliferation rate, and numbers of parietal and enterochromaffin-like cells. Cholecystokinin type 2 receptor antagonist YM022 was without the effect in M3 KO mice. Conclusions: The present study shows that M3 receptors are essential for basal acid secretion, a fully acid secretory response to histamine and gastrin, and the trophic responses of oxyntic mucosa to gastrin.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1774-1784 |
| Number of pages | 11 |
| Journal | Gastroenterology |
| Volume | 125 |
| Issue number | 6 |
| DOIs | |
| State | Published - Jan 1 2003 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Gastroenterology
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Impaired Gastric Secretion and Lack of Trophic Responses to Hypergastrinemia in M3 Muscarinic Receptor Knockout Mice. / Aihara, Takeshi; Fujishita, Teruaki; Kanatani, Keiko; Furutani, Kazuharu; Nakamura, Eiji; Taketo, Makoto M.; Matsui, Minoru; Chen, Duan; Okabe, Susumu.
In: Gastroenterology, Vol. 125, No. 6, 01.01.2003, p. 1774-1784.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Impaired Gastric Secretion and Lack of Trophic Responses to Hypergastrinemia in M3 Muscarinic Receptor Knockout Mice
AU - Aihara, Takeshi
AU - Fujishita, Teruaki
AU - Kanatani, Keiko
AU - Furutani, Kazuharu
AU - Nakamura, Eiji
AU - Taketo, Makoto M.
AU - Matsui, Minoru
AU - Chen, Duan
AU - Okabe, Susumu
PY - 2003/1/1
Y1 - 2003/1/1
N2 - Background & Aims: The physiologic significance of the M3 muscarinic receptor is unclear due to an absence of specific ligand. In the present study, M3 receptor knock-out (KO) mice were used to elucidate the role of M3 receptors in gastric acid secretion and gastric mucosal integrity. Methods: M3 KO versus wild-type mice aged 1 month to 2 years were included. Gastric acid secretion was assessed by both direct intragastric pH measurement and pylorus ligation. Serum gastrin and gastric mucosal histamine levels were determined by radioimmunoassay and enzyme-linked immunosorbent assay, respectively. Morphologic analysis was performed by both immunohistochemistry and transmission electron microscopy. Results: Fasted M3 KO mice exhibited higher intragastric pH, lower acid output after pylorus ligation, a lower proportion of active parietal cells, and higher serum gastrin levels than fasted wild-type mice. Acid secretion in response to carbachol, histamine, gastrin 17, and 2-deoxy-D-glucose was impaired in the mutant mice. Although carbachol was still able to cause ∼30% acid output in M3 KO mice, the acid secretion was inhibited by pirenzepine or famotidine. Despite remarkable hypergastrinemia in M 3 KO mice, there were no trophic responses in the oxyntic mucosa with respect to the mucosal thickness, proliferation rate, and numbers of parietal and enterochromaffin-like cells. Cholecystokinin type 2 receptor antagonist YM022 was without the effect in M3 KO mice. Conclusions: The present study shows that M3 receptors are essential for basal acid secretion, a fully acid secretory response to histamine and gastrin, and the trophic responses of oxyntic mucosa to gastrin.
AB - Background & Aims: The physiologic significance of the M3 muscarinic receptor is unclear due to an absence of specific ligand. In the present study, M3 receptor knock-out (KO) mice were used to elucidate the role of M3 receptors in gastric acid secretion and gastric mucosal integrity. Methods: M3 KO versus wild-type mice aged 1 month to 2 years were included. Gastric acid secretion was assessed by both direct intragastric pH measurement and pylorus ligation. Serum gastrin and gastric mucosal histamine levels were determined by radioimmunoassay and enzyme-linked immunosorbent assay, respectively. Morphologic analysis was performed by both immunohistochemistry and transmission electron microscopy. Results: Fasted M3 KO mice exhibited higher intragastric pH, lower acid output after pylorus ligation, a lower proportion of active parietal cells, and higher serum gastrin levels than fasted wild-type mice. Acid secretion in response to carbachol, histamine, gastrin 17, and 2-deoxy-D-glucose was impaired in the mutant mice. Although carbachol was still able to cause ∼30% acid output in M3 KO mice, the acid secretion was inhibited by pirenzepine or famotidine. Despite remarkable hypergastrinemia in M 3 KO mice, there were no trophic responses in the oxyntic mucosa with respect to the mucosal thickness, proliferation rate, and numbers of parietal and enterochromaffin-like cells. Cholecystokinin type 2 receptor antagonist YM022 was without the effect in M3 KO mice. Conclusions: The present study shows that M3 receptors are essential for basal acid secretion, a fully acid secretory response to histamine and gastrin, and the trophic responses of oxyntic mucosa to gastrin.
UR - http://www.scopus.com/inward/record.url?scp=0344628817&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0344628817&partnerID=8YFLogxK
U2 - 10.1053/j.gastro.2003.09.018
DO - 10.1053/j.gastro.2003.09.018
M3 - Article
C2 - 14724830
AN - SCOPUS:0344628817
VL - 125
SP - 1774
EP - 1784
JO - Gastroenterology
JF - Gastroenterology
SN - 0016-5085
IS - 6
ER -