RETURNYonago Acta medica 1991;34:37-52
Stress-Induced Gastric Mucosal Lesions and Changes in Amino Acid Metabolism due to the Activation of the Sympathetic Nervous System In Rats
Hiroki Omodani, Yoshinori Kamisaki and Tadao Itoh
Department of Clinical Pharmacology, Faculty of Medicine, Tottori University, Yonago 683, Japan
In order to investigate the effects of stress on amino acid metabolism through the sympathetic nervous system, Wistar rats were subjected to water-immersion restraint stress for 1, 2, 4 and 7 h. The stress produced gastric mucosal lesions in a time-dependent manner, associated with elevation of plasma catecholamine level. The stress induced significant increases in serum concentrations of valine, leucine, isoleucine, threonine, lysine, phenylalanine, cystine, histidine, arginine and tyrosine. At the same time, the stress induced decreases in serum concentrations of glutamic acid, aspartic acid, tryptophan and alanine. Similar stress-induced changes in amino acid concentration were also observed in stomach, liver, muscles , heart and kidneys. An intraperitoneal administration (10 µmol/kg) of prazosin, alpha-1 adrenergic antagonist, or clonidine, alpha-2 adrenergic agonist, significantly inhibited the gastric lesions which were induced by the 7-h stress. Simultaneously, these agents attenuated the stress-induced changes in serum amino acid levels. These results suggest that both the stress-induced gastric mucosal damage and the alteration of amino acid metabolism may be mediated by the hindrance of the peripheral circulation which results from increased sympathetic nervous activity, since prazosin and clonidine inhibit the effects of the increased activity.
Key words: amino acid metabolism; clonidine; prazosin; stress ulcer; sympathetic nervous system