naltrindole and chelerythrine

The purpose of this study is to determine 1) whether morphine post condition (MPostC) can attenuate the intercellular adhesion molecules-1 (ICAM-1) expression after reoxygenation injury and 2) the subtype(s) of the opioid receptors (ORs) that are involved with MPostC. Human umbilical vein endothelial cells (HUVECs) were subjected to 6 hr anoxia followed by 12 hr reoxygenation. Three morphine concentrations (0.3, 3, 30 µM) were used to evaluate the protective effect of MPostC. We also investigated blockading the OR subtypes' effects on MPostC by using three antagonists (a µ-OR antagonist naloxone, a κ-OR antagonist nor-binaltorphimine, and a δ-OR antagonist naltrindole) and the inhibitor of protein kinase C (PKC) chelerythrine. As results, the ICAM-1 expression was significantly reduced in the MPostC (3, 30 µM) groups compared to the control group at 1, 6, 9, and 12 hours reoxygenation time. As a consequence, neutrophil adhesion was also decreased after MPostC. These effects were abolished by co administering chelerythrine, nor-binaltorphimine or naltrindole, but not with naloxone. In conclusion, it is assumed that MPostC could attenuate the expression of ICAM-1 on endothelial cells during reoxygenation via the κ and δ-OR (opioid receptor)-specific pathway, and this also involves a PKC-dependent pathway.

Topics: Animals; Benzophenanthridines; Endothelial Cells; Endothelium, Vascular; Humans; Intercellular Adhesion Molecule-1; Morphine; Naloxone; Naltrexone; Narcotic Antagonists; Narcotics; Protein Isoforms; Protein Kinase C; Receptors, Opioid; Reperfusion Injury; Signal Transduction; Umbilical Veins

Opioid preconditioning protects the myocardium against ischemia/reperfusion (IR) injury. By enhancing cardiomyocyte viability, opioids can enhance cardiac function and recovery from IR injury during acute cardiac care. The myocyte model HL-1 is an immortalized, mouse atrial cell line that expresses functional delta-opioid receptors. The HL-1 myocyte may be useful for IR injury research exploring opioid cardioprotection.. In study I, microplates of HL-1 were subjected to 10 min pre-treatment with either basal media, delta-opioid agonist DADLE(10uM), or DADLE(10uM) + delta-antagonist naltrindole (10uM). Study II treatment groups included PKC inhibitor chelerythrine (2uM), K(ATP) channel closer glybenclamide (100uM), or mitochondrial K(ATP) channel opener diazoxide (100uM) administered in various combinations followed by DADLE (10uM) or control. Microplates were subjected to normal oxygen/substrate conditions or ischemic (<1% 0(2)) and substrate deficient (10 uM 2-Deoxyglucose versus 10 mM glucose) conditions, then reperfused with normal oxygen and glucose-containing media. Microplate supernatants were subjected to lactate dehydrogenase (LDH) assay.. Compared to untreated control, the LDH assay showed significant reduction in opioid-only pretreated groups at all time points. These effects were attenuated with delta-opioid antagonist co-administration. Co-administration of non-selective K(ATP) channel closer glybenclamide and DADLE abolished DADLE cytoprotection, while selective mitochondrial K(ATP) opener diazoxide mimicked DADLE cytoprotection Co-administration of chelerythrine and DADLE significantly reduced chelerythrine cytotoxicity.. Delta-opioid preconditioning of HL-1 myocytes significantly decreased necrosis from in vitro simulated ischemia/reperfusion as measured by LDH release; this effect was reversed by delta-antagonist naltrindole. Cytoprotection was PKC and K(ATP) channel-dependent. HL-1 myocytes exhibit opioid-induced cytoprotection from IR injury, and present a novel model of pharmacologic preconditioning.

Topics: Alkaloids; Animals; Benzophenanthridines; Cell Line; Enkephalin, Leucine-2-Alanine; Enzyme Inhibitors; Heart; Ischemic Preconditioning, Myocardial; Kinetics; Membrane Proteins; Muscle Cells; Myocardial Reperfusion; Myocardium; Naltrexone; Phenanthridines; Potassium Channels; Protein Kinase C; Receptors, Opioid, delta