Abstract
Excitatory amino acids (EAAs), in particular, L-aspartate (L-Asp) neurons and their processes, were localized in the rat stomach using a immunohistochemical method with specific antibodies against either L-Asp or its synthesizing enzyme, aspartate aminotransferase (AAT). Myenteric ganglia and nerve bundles in the circular muscle and in the longitudinal muscle were found to be AAT-or L-Asp-positive. In addition, AAT or L-Asp-positive cells were also found in the muscle layer and the deep mucosal layer. The distribution of AAT- or L-Asp-positive cells in both the mucosal and muscle layers was heterogeneous in the stomach. In addition, L-Asp at 10-6 M negligibly influenced acid secretion in an everted preparation of isolated rat stomach. However, according to our results, L-Asp markedly inhibited the histamine-stimulated acid secretion, but not the oxotremorine- or the pentagastrin-stimulated acid secretion. Furthermore, L-Asp also inhibited histamine-induced elevation of cAMP. L-Asp itself did not affect the cAMP level although it elevated the cGMP level in the stomach. Moreover, either (+)2-amino-5-phosphonovaleric acid or (±)3-(2-carboxypiperazin-4- yl)prophyl-1-phosphonic acid, i.e. two specific antagonists for N-methyl-D- aspartic acid (NMDA) receptors, blocked the inhibitory effect of L-Asp on histamine-stimulated acid secretion or histamine-induced elevation of cAMP. Since cAMP has been strongly implicated as the second messenger involved in histamine-induced acid secretion, we believe that L-Asp regulates acid secretion in the stomach by inhibiting histamine release through the NMDA receptors, subsequently lowering the level of cAMP and ultimately reducing acid secretion.
| Original language | English |
|---|---|
| Pages (from-to) | 36-44 |
| Number of pages | 9 |
| Journal | Journal of Biomedical Science |
| Volume | 6 |
| Issue number | 1 |
| Publication status | Published - Jan 1999 |
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Keywords
- Acid secretion
- cAMP
- cGMP
- Excitatory amino acids
- Histamine
- L-Aspartic acid
- NMDA receptor
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
Cite this
Effect of excitatory amino acid neurotransmitters on acid secretion in the rat stomach. / Tsai, Li Hsueh; Lee, Yih Jing; Wu, Jang Yen.
In: Journal of Biomedical Science, Vol. 6, No. 1, 01.1999, p. 36-44.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Effect of excitatory amino acid neurotransmitters on acid secretion in the rat stomach
AU - Tsai, Li Hsueh
AU - Lee, Yih Jing
AU - Wu, Jang Yen
PY - 1999/1
Y1 - 1999/1
N2 - Excitatory amino acids (EAAs), in particular, L-aspartate (L-Asp) neurons and their processes, were localized in the rat stomach using a immunohistochemical method with specific antibodies against either L-Asp or its synthesizing enzyme, aspartate aminotransferase (AAT). Myenteric ganglia and nerve bundles in the circular muscle and in the longitudinal muscle were found to be AAT-or L-Asp-positive. In addition, AAT or L-Asp-positive cells were also found in the muscle layer and the deep mucosal layer. The distribution of AAT- or L-Asp-positive cells in both the mucosal and muscle layers was heterogeneous in the stomach. In addition, L-Asp at 10-6 M negligibly influenced acid secretion in an everted preparation of isolated rat stomach. However, according to our results, L-Asp markedly inhibited the histamine-stimulated acid secretion, but not the oxotremorine- or the pentagastrin-stimulated acid secretion. Furthermore, L-Asp also inhibited histamine-induced elevation of cAMP. L-Asp itself did not affect the cAMP level although it elevated the cGMP level in the stomach. Moreover, either (+)2-amino-5-phosphonovaleric acid or (±)3-(2-carboxypiperazin-4- yl)prophyl-1-phosphonic acid, i.e. two specific antagonists for N-methyl-D- aspartic acid (NMDA) receptors, blocked the inhibitory effect of L-Asp on histamine-stimulated acid secretion or histamine-induced elevation of cAMP. Since cAMP has been strongly implicated as the second messenger involved in histamine-induced acid secretion, we believe that L-Asp regulates acid secretion in the stomach by inhibiting histamine release through the NMDA receptors, subsequently lowering the level of cAMP and ultimately reducing acid secretion.
AB - Excitatory amino acids (EAAs), in particular, L-aspartate (L-Asp) neurons and their processes, were localized in the rat stomach using a immunohistochemical method with specific antibodies against either L-Asp or its synthesizing enzyme, aspartate aminotransferase (AAT). Myenteric ganglia and nerve bundles in the circular muscle and in the longitudinal muscle were found to be AAT-or L-Asp-positive. In addition, AAT or L-Asp-positive cells were also found in the muscle layer and the deep mucosal layer. The distribution of AAT- or L-Asp-positive cells in both the mucosal and muscle layers was heterogeneous in the stomach. In addition, L-Asp at 10-6 M negligibly influenced acid secretion in an everted preparation of isolated rat stomach. However, according to our results, L-Asp markedly inhibited the histamine-stimulated acid secretion, but not the oxotremorine- or the pentagastrin-stimulated acid secretion. Furthermore, L-Asp also inhibited histamine-induced elevation of cAMP. L-Asp itself did not affect the cAMP level although it elevated the cGMP level in the stomach. Moreover, either (+)2-amino-5-phosphonovaleric acid or (±)3-(2-carboxypiperazin-4- yl)prophyl-1-phosphonic acid, i.e. two specific antagonists for N-methyl-D- aspartic acid (NMDA) receptors, blocked the inhibitory effect of L-Asp on histamine-stimulated acid secretion or histamine-induced elevation of cAMP. Since cAMP has been strongly implicated as the second messenger involved in histamine-induced acid secretion, we believe that L-Asp regulates acid secretion in the stomach by inhibiting histamine release through the NMDA receptors, subsequently lowering the level of cAMP and ultimately reducing acid secretion.
KW - Acid secretion
KW - cAMP
KW - cGMP
KW - Excitatory amino acids
KW - Histamine
KW - L-Aspartic acid
KW - NMDA receptor
UR - http://www.scopus.com/inward/record.url?scp=0344286484&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0344286484&partnerID=8YFLogxK
M3 - Article
C2 - 9933741
AN - SCOPUS:0344286484
VL - 6
SP - 36
EP - 44
JO - Journal of Biomedical Science
JF - Journal of Biomedical Science
SN - 1021-7770
IS - 1
ER -