Effects of L-glutamic acid on acid secretion and mucosal blood flow in the rat stomach.
The effect of intravenous administration of L-glutamic acid (L-Glu) on gastric acid secretion and gastric mucosal blood flow (GMBF) in anesthetized rats were investigated. Infusion with synthetic L-Glu alone had no effect on spontaneous acid secretion. However, L-Glu reduced histamine- (2 mg/kg/hr) or oxotremorine- (1 microg/kg/hr) stimulated acid secretion, whereas L-Glu had no effect on acid secretion induced by pentagastrin (8 microg/kg/hr). Furthermore, this inhibitory effect of L-Glu on histamine- or oxotremorine-stimulated acid secretion was blocked by 6,7-dinitroquinoxaline-2,3-dione (DNQX), a non-NMDA receptor antagonist. The effect of L-Glu on gastric mucosal microcirculation in the anesthetized rats was evaluated by using Laser Doppler Flowmetry (LDF). The results showed that L-Glu did not significantly reduce both mucosal and serosal blood flow in stomach. No significant modulatory effect on histamine- or oxotremorine-stimulated increase in GMBF was noted after infusion with L-Glu. It is concluded that L-glutamic acid is capable of the modulating of gastric acid secretion via ionotropic non-NMDA receptors, but do not affect on GMBF. However, L-glutamic acid showed no effect on acid secretion by itself.
Tsai
L H
LH
Department of Physiology, School of Medicine, Taipei Medical College, Taiwan, ROC. lhtsai@mail.tmc.edu.tw
Huang
L R
LR
Chen
S H
SH
Liu
H J
HJ
Chou
L S
LS
D000758:Anesthesia; D000818:Animals; D018679:Cholinergic Agonists / Q000494:pharmacology; D017615:Enteric Nervous System / Q000737:chemistry / Q000502:physiology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005744:Gastric Acid / Q000378:metabolism*; D005753:Gastric Mucosa / Q000098:blood supply* / Q000187:drug effects* / Q000378:metabolism; D018698:Glutamic Acid / Q000494:pharmacology*; D006632:Histamine / Q000494:pharmacology; D007275:Injections, Intravenous; D017078:Laser-Doppler Flowmetry; D008297:Male; D018721:Muscarinic Agonists / Q000494:pharmacology; D010095:Oxotremorine / Q000494:pharmacology; D010418:Pentagastrin / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017470:Receptors, Glutamate / Q000502:physiology; D012039:Regional Blood Flow / Q000187:drug effects
D018679:Cholinergic Agonists; D018691:Excitatory Amino Acid Antagonists; D018721:Muscarinic Agonists; D011810:Quinoxalines; D017470:Receptors, Glutamate; D018698:Glutamic Acid; D010095:Oxotremorine; C056723:FG 9041; D006632:Histamine; D010418:Pentagastrin