Glycine receptors contribute to cytoprotection of glycine in myocardial cells
| Autor: | Ren-bin Qi, Chu-jie Li, Hua-dong Wang, Jun-yan Zhang, Da-xiang Lu, Hai-hua Wang |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Lipopolysaccharides
Male Lipopolysaccharide Blotting Western Glycine Blood Pressure Rats Sprague-Dawley chemistry.chemical_compound Receptors Glycine Heart Rate Lactate dehydrogenase medicine Animals Glycine receptor L-Lactate Dehydrogenase Chemistry Cardiac muscle Heart General Medicine Hypoxia (medical) Immunohistochemistry Cytoprotection Molecular biology Rats Blot medicine.anatomical_structure Biochemistry Calcium medicine.symptom |
| Zdroj: | Chinese Medical Journal. 120:915-921 |
| ISSN: | 0366-6999 |
| DOI: | 10.1097/00029330-200705020-00012 |
| Popis: | BACKGROUND The classic glycine receptor (GlyR) in the central nervous system is a ligand-gated membrane-spanning ion channel. Recent studies have provided evidence for the existence of GlyR in endothelial cells, renal proximal tubular cells and most leukocytes. In contrast, no evidence for GlyR in myocardial cells has been found so far. Our recent researches have showed that glycine could protect myocardial cells from the damage induced by lipopolysaccharide (LPS). Further studies suggest that myocardial cells could contain GlyR or binding site of glycine. METHODS In isolated rat heart damaged by LPS, the myocardial monophasic action potential (MAP), the heart rate (HR), the myocardial tension and the activities of lactate dehydrogenase (LDH) from the coronary effluent were determined. The concentration of intracellular free calcium ([Ca(2+)](i)) was measured in cardiomyocytes injured by LPS and by hypoxia/reoxygenation (H/R), which excludes the possibility that reduced calcium influx because of LPS neutralized by glycine. Immunohistochemistry was used to detect the GlyR in myocardial tissue. GlyR and its subunit in the purified cultured cardiomyocytes were identified by Western blotting. RESULTS Although significant improvement in the MAP/MAPD(20), HR, and reduction in LDH release were observed in glycine + LPS hearts, myocardial tension did not recover. Further studies demonstrated that glycine could prevent rat mycordial cells from LPS and hypoxia/reoxygenation injury (no endotoxin) by attenuating calcium influx. Immunohistochemistry exhibited a positive green-fluorescence signaling along the cardiac muscle fibers. Western blotting shows that the purified cultured cardiomyocytes express GlyR beta subunit, but GlyR alpha1 subunit could not be detected. CONCLUSIONS The results suggest that glycine receptor is expressed in cardiomyocytes and participates in cytoprotection from LPS and hypoxia/reoxygenation injury. Glycine could directly activate GlyR on the cardiomyocytes and prevent calcium influx into the cardiomyocytes. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|