l -Glutamine in vitro regulates rat aortic glutamate content and modulates nitric oxide formation and contractility responses
| Autor: | David Schachter |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Male
Endothelium Physiology Glutamine Glutamic Acid Aorta Thoracic In Vitro Techniques Nitric Oxide Muscle Smooth Vascular 3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide) Nitric oxide Rats Sprague-Dawley Contractility chemistry.chemical_compound Leucine medicine.artery medicine Animals Nitric Oxide Donors Enzyme Inhibitors Aorta Dose-Response Relationship Drug biology Glutamate receptor Cell Biology Glutamic acid Rats Vasodilation Nitric oxide synthase NG-Nitroarginine Methyl Ester medicine.anatomical_structure Biochemistry chemistry biology.protein Biophysics Endothelium Vascular Nitric Oxide Synthase Triazenes |
| Zdroj: | American Journal of Physiology-Cell Physiology. 293:C142-C151 |
| ISSN: | 1522-1563 0363-6143 |
| DOI: | 10.1152/ajpcell.00589.2006 |
| Popis: | These studies test the hypothesis that l-glutamine at its physiological plasma concentration, approximately 0.5 mM, can increase tissue content and net synthesis of glutamate in rat aortic segments in vitro, thereby mediating relaxation of the underlying smooth muscle in the elastic reservoir region of the thoracic aorta. Aortic segments were incubated in an isotonic medium with and without 21 amino acids at their normal plasma concentrations. Of these amino acids only L-glutamine and L-leucine at their plasma concentrations increased glutamate synthesis and content. Tissue glutamate content resulting from increasing concentrations of each precursor reached an upper level of approximately 1.3-1.6 micromol/g wet wt. Regulation of the tissue glutamate content involves an interaction of the synthetic pathways in which L-glutamine inhibits the endothelial leucine-to-glutamate pathway. L-glutamine increases nitric oxide (NO) formation, and NO inhibits the controlling enzyme of the endothelial leucine-to-glutamate pathway, the branched-chain alpha-ketoacid dehydrogenase complex. Treatment of precontracted aortic rings with 0.5 mM L-glutamine elicits smooth muscle relaxation, a response that requires endothelial nitric oxide synthase activity and an intact endothelium. The results demonstrate that in vitro L-glutamine at its normal concentration in plasma can regulate rat aortic glutamate content and modulate NO formation and contractility responses of the thoracic aortic wall. |
| Databáze: | OpenAIRE |
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