enkephalin--leucine-2-alanine and Myocardial-Infarction

A method for computed determination of death probability was used to examine the effects of various modalities of stress-limiting therapy on mortality rates within a month after myocardial infarction. The examination was made in 591 patients with large myocardial infarction. A significant decrease in mortality rates was seen in patients on finoptin and phosphocreatine (by 9.6 and 11.2, respectively) as compared to the expected drop. Other agents given within the first hours of myocardial infarction such as beta-blockers, opioid peptides, sodium oxybutyrate, piracetam, antioxidants were demonstrated to cause no reduction in mortality rates.

Topics: Aged; Antioxidants; Clinical Trials as Topic; Enkephalin, Leucine; Enkephalin, Leucine-2-Alanine; Female; Humans; Male; Myocardial Infarction; Phosphocreatine; Piracetam; Propranolol; Sodium Oxybate; Stress, Physiological; Verapamil

The synthetic opioid peptide dalargin was examined for its potency in 86 patients with primary transmural myocardial infarction. The agent was shown to contribute to a decrease in initially elevated plasma cortisol levels and an increase in beta-endorphine and leucine-enkephaline concentrations. Myocardial contractility became normal by reducing the hyperfunction of its intact segments. This was evidenced by antistressor effects of the drug. However, no substantial effect was found on the clinical course of the disease, evolution of myocardial infarction, plasma CPK MB. The left ventricular contractility showed severe depression.

Topics: Adult; Aged; beta-Endorphin; Clinical Enzyme Tests; Creatine Kinase; Electrocardiography; Enkephalin, Leucine-2-Alanine; Female; Humans; Hydrocortisone; Isoenzymes; Male; Middle Aged; Models, Cardiovascular; Myocardial Infarction; Sympatholytics

We previously reported that pharmacological preconditioning of rabbit hearts with acetylcholine involves activation of phosphatidylinositol 3-kinase (PI3-K) through transactivation of the epidermal growth factor receptor (EGFR). Transactivation is thought to be initiated by cleavage of membrane-bound pro-heparin-binding EGF-like growth factor (HB-EGF) by a membrane metalloproteinase thus releasing HB-EGF which binds to the EGFR. This pathway leads to redox signaling with the generation of reactive oxygen species (ROS) by mitochondria. We tested whether preconditioning's physiological triggers, bradykinin and opioid, also signal through the EGFR. Both bradykinin and the synthetic delta-opioid agonist DADLE increased ROS production in isolated cardiomyocytes by approximately 50%. DADLE's effect was abrogated by either metalloproteinase inhibitor III (MPI) or the diphtheria toxin mutant CRM-197 which blocks heparin-binding EGF shedding indicating that DADLE signals through EGFR transactivation. MPI also blocked DADLE's infarct-sparing effect in whole hearts. Additionally, blocking Src kinase (a component of the EGFR's signaling complex) with PP2 or PI3-K with wortmannin blocked DADLE's effect on cardiomyocyte ROS production and PP2 blocked DADLE's salvage of ischemic myocardium. Finally, DADLE increased phosphorylation of Akt and extracellular signal-regulated protein kinases (ERK) 1/2 in left ventricular myocardium, and this increase was blocked by the EGFR antagonist AG1478. On the other hand, neither MPI nor CRM-197 prevented bradykinin from increasing ROS production, and MPI did not affect bradykinin's infarct-sparing effect in intact hearts. Conversely, both PP2 and wortmannin blocked bradykinin's effect on ROS generation and also aborted bradykinin's cardioprotective effect in intact hearts. While bradykinin also increased phosphorylation of Akt and ERK in myocardium, that increase was not affected by AG1478. Hence bradykinin, unlike acetylcholine or opioid, does not transactivate EGFR, although all 3 agonists do signal through Src and PI3-K.

Topics: Animals; Bradykinin; Cells, Cultured; Enkephalin, Leucine-2-Alanine; ErbB Receptors; Extracellular Signal-Regulated MAP Kinases; Ischemic Preconditioning, Myocardial; Mitochondria, Heart; Molecular Mimicry; Myocardial Infarction; Myocytes, Cardiac; Phosphatidylinositol 3-Kinases; Phosphorylation; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins pp60(c-src); Rabbits; Reactive Oxygen Species; Signal Transduction; Vasodilator Agents

The specific delta-opioid receptor agonist [D-Ala(2)-D-Leu(5)]enkephalin (DADLE) protects against infarction in the heart when given before ischemia. In rabbit, this protection leads to phosphorylation of the pro-survival kinases Akt and extracellular signal-regulated kinase (ERK) and is dependent on transactivation of the epidermal growth factor receptor (EGFR). DADLE reportedly protects rat hearts at reperfusion. We therefore tested whether DADLE at reperfusion could protect isolated rabbit hearts subjected to 30 min of regional ischemia and 120 min of reperfusion and whether this protection is dependent on Akt, ERK, and EGFR. DADLE (40 nM) was infused for 1 h starting 5 min before reperfusion and reduced infarct size from 31.0 +/- 2.3% in the control group to 14.6 +/- 1.6% (P = 0.01). This protection was abolished by cotreatment of the metalloproteinase inhibitor (MPI) and the EGFR inhibitor AG1478. In contrast, 20 nM DADLE, although known to be protective before ischemia, failed to protect. Western blotting revealed that DADLE's protection was correlated to increase in phosphorylation of the kinases Akt and ERK1 and -2 in reperfused hearts (2.5 +/- 0.5, 1.6 +/- 0.2, and 2.3 +/- 0.7-fold of baseline levels, P < 0.05 vs. control). The DADLE-dependent increases in Akt and ERK1/2 phosphorylation were abolished by either MPI or AG1478, confirming a signaling through the EGFR pathway. Additionally, DADLE treatment increased phosphorylation of EGFR (1.4 +/- 0.2-fold, P = 0.03 vs. control). Thus the delta-opioid agonist DADLE protects rabbit hearts at reperfusion through activation of the pro-survival kinases Akt and ERK and is dependent on the transactivation of the EGFR.

Topics: Animals; Enkephalin, Leucine-2-Alanine; ErbB Receptors; Extracellular Signal-Regulated MAP Kinases; Male; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Myocardial Infarction; Oncogene Protein v-akt; Rabbits; Receptors, Opioid, delta; Reperfusion Injury; Transcriptional Activation

The aim of this study was to examine possible interactions of ERK and calcineurin in cardioprotection afforded by delta-opioid receptor stimulation. Infarction was induced in rat hearts by 20-min coronary occlusion and reperfusion. Tissue ERK level and calcienurin activity were determined by immunoblotting and an assay using a phosphopeptide substrate, respectively. Administration of a delta-opioid receptor agonist, D-Ala2-D-Leu5-enkephalin (DADLE, 1 mg/kg), before ischemia increased the phospho-ERK levels during ischemia and reduced infarct size (as percentage of risk area, %IS/AR) from 47.7 +/- 2.3% to 23.2 +/- 2.5%. This protection was abolished by 10 mg/kg of natrindole hydrochloride (NTI), a delta-opioid receptor antagonist. PD98059, a MEK1/2 inhibitor, abolished both ERK1/2 activation and infarct size limitation by DADLE. Calcineurin inhibitors, cyclosporine-A (5 mg/kg) and FK506 (3.5 mg/kg), reduced %IS/AR (27.4 +/- 4.4% and 29.9 +/- 3.4%, respectively). The protective effects of these calcineurin inhibitors were inhibited by PD98059, and the combination of DADLE with cyclosporine-A or FK506 did not afford further cardioprotection. DADLE significantly suppressed myocardial calcineurin activity, and this effect was inhibited by NTI. Suppression of calcineurin activity by FK506 was associated with modest activation of ERK1/2. These results suggest that suppression of calcineurin and activation of ERK1/2 are interacting mechanisms involved in cardioprotection by delta-opioid receptor activation.

Topics: Animals; Blood Pressure; Calcineurin Inhibitors; Enkephalin, Leucine-2-Alanine; Enzyme Activation; Extracellular Signal-Regulated MAP Kinases; Heart; Heart Rate; Male; Myocardial Infarction; Phosphorylation; Rats; Rats, Sprague-Dawley; Receptors, Opioid, delta; Tacrolimus

Pharmacological preconditioning with kappa-opioid receptor agonists is proarrhythmic and exerts antipreconditioning effects in rats. In swine, it is unknown whether kappa-opioid receptor stimulation plays a role in pharmacological preconditioning. Swine were preconditioned with 1) saline (controls), 2) [d-Ala(2),d-Leu(5)]enkephalin (DADLE), 3) morphine, 4) pentazocine, 5) norbinaltorphimine (nor-BNI), 6) DADLE + nor-BNI, 7) morphine + nor-BNI, or 8) pentazocine + nor-BNI before occlusion (45 min) and reperfusion (180 min) of the left anterior descending coronary artery. Infarct size to area at risk (IS), regional (systolic shortening) and global (pressures and flows) myocardial function, and arrhythmia occurrence were assessed. Only DADLE + nor-BNI preconditioning significantly decreased infarct size compared with controls (47 +/- 13 vs. 65 +/- 5%, P < 0.05); morphine preconditioning was not cardioprotective with or without kappa-opioid receptor blockade (nor-BNI). DADLE preconditioning significantly increased ischemia-induced arrhythmias relative to controls, whereas pentazocine-preconditioned animals (n = 2) experienced intractable ventricular fibrillation during ischemia. kappa-Opioid receptor blockade with DADLE or pentazocine preconditioning alleviated proarrhythmic effects. These results suggest that kappa-opioid receptor activation during pharmacological preconditioning is proarrhythmic in swine.

Topics: Animals; Arrhythmias, Cardiac; Coronary Circulation; Enkephalin, Leucine-2-Alanine; Hemodynamics; Ischemic Preconditioning, Myocardial; Morphine; Myocardial Infarction; Myocardial Ischemia; Naltrexone; Narcotic Antagonists; Narcotics; Pentazocine; Receptors, Opioid, kappa; Swine

Opioids are involved in cardiac ischemic preconditioning. Important species differences in cellular signaling mechanisms, antiarrhythmic, and antistunning effects have been described. The role of the delta-opioid receptor activation in swine remains unknown. Forty minutes before a 45-min occlusion and 180-min reperfusion of the left anterior descending coronary artery, open-chest, pentobarbital-anesthetized swine received either 1) saline (controls); 2) [D-Ala(2),D-Leu(5)]enkephalin (DADLE); 3) [D-Pen(2,5)]enkephalin (DPDPE); 4) deltorphin-D, a novel delta(2)-opioid agonist; or 5) ischemic preconditioning (IP). Assessed were 1) infarct size to area at risk (IS, triphenyltetrazolium staining), 2) regional and global myocardial function (sonomicrometry, ventricular pressure catheters), and 3) arrhythmias (electrocardiogram analyses). It was found that DPDPE and deltorphin-D pretreatment reduced IS from 64.7 +/- 5 to 36.5 +/- 6% and 27.4 +/- 11% (P < 0.01), respectively, whereas DADLE had no effect (66.8 +/- 3%). Both IP and DADLE had a proarrhythmic effect (P < 0.01). However, no differences in global or regional myocardial function or arrhythmia scores were observed between groups. This suggests that delta-receptor-specific opioids provide cardioprotection in swine.

Topics: Animals; Arrhythmias, Cardiac; Cardiotonic Agents; Electrocardiography; Enkephalin, D-Penicillamine (2,5)-; Enkephalin, Leucine-2-Alanine; Hemodynamics; Ischemic Preconditioning, Myocardial; Myocardial Infarction; Myocardial Ischemia; Myocardial Reperfusion; Oligopeptides; Receptors, Opioid, delta; Species Specificity; Swine; Ventricular Pressure

Two series of experiments were performed in the isolated perfused rat heart to determine the role of kappa- and delta-opioid receptors (OR) in cardioprotection of ischemic preconditioning (IP). In the first series of experiments, it was found that IP with two cycles of 5-min regional ischemia followed by 5-min reperfusion each reduced infarct size induced by 30-min ischemia, and the ameliorating effect of IP on infarct was attenuated with blockade of either 5 x 10(-6) mol/l nor-binaltorphimine (nor-BNI), a selective kappa-OR antagonist, or 5 x 10(-6) mol/l naltrindole (NTD), a selective delta-OR antagonist. The second series showed that U50,488H, a selective kappa-OR agonist, or D-Ala(2)-D-leu(5)-enkephalin (DADLE), a selective delta-OR agonist, dose dependently reduced the infarct size induced by ischemia, which mimicked the effects of IP. The effect of 10(-5) mol/l U50,488H on infarct was significantly attenuated by blockade of protein kinase C (PKC) with specific PKC inhibitors, 5 x 10(-6) mol/l chelerythrine or 8 x 10(-7) mol/l calphostin C, as well as by blockade of ATP-sensitive K(+) (K(ATP)) channels with blockers of the channel, 10(-5) mol/l glibenclamide or 10(-4) mol/l 5-hydroxydecanoate. IP also reduced arrhythmia induced by ischemia. Nor-BNI, but not NTD, attenuated, while U50,488H, but not DADLE, mimicked the antiarrhythmic action of IP. In conclusion, the present study has provided first evidence that kappa-OR mediates the ameliorating effects of IP on infarct and arrhythmia induced by ischemia, whereas delta-OR mediates the effects only on infarct. Both PKC and K(ATP) channels mediate the effect of activation of kappa-OR on infarct.

Topics: 3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; Animals; Arrhythmias, Cardiac; Coronary Circulation; Enkephalin, Leucine-2-Alanine; Enzyme Inhibitors; Hemodynamics; In Vitro Techniques; Ischemic Preconditioning, Myocardial; Male; Myocardial Infarction; Potassium Channel Blockers; Protein Kinase C; Rats; Rats, Sprague-Dawley; Receptors, Opioid, delta; Receptors, Opioid, kappa; Signal Transduction

Stimulation of the delta(1)-opioid receptor confers cardioprotection to the ischemic myocardium. We examined the role of protein kinase C (PKC) after delta-opioid receptor stimulation with TAN-67 or D-Ala(2)-D-Leu(5)-enkephalin (DADLE) in a rat model of myocardial infarction induced by a 30-min coronary artery occlusion and 2-h reperfusion. Infarct size (IS) was determined by tetrazolium staining and expressed as a percentage of the area at risk (IS/AAR). Control animals, subjected to ischemia and reperfusion, had an IS/AAR of 59.9 +/- 1.8. DADLE and TAN-67 administered before ischemia significantly reduced IS/AAR (36.9 +/- 3.9 and 36.7 +/- 4.7, respectively). The delta(1)-selective opioid antagonist 7-benzylidenenaltrexone (BNTX) abolished TAN-67-induced cardioprotection (54.4 +/- 1.3). Treatment with the PKC antagonist chelerythrine completely abolished DADLE- (61.8 +/- 3.2) and TAN-67-induced cardioprotection (55.4 +/- 4.0). Similarly, the PKC antagonist GF 109203X completely abolished TAN-67-induced cardioprotection (54.6 +/- 6.6). Immunofluorescent staining with antibodies directed against specific PKC isoforms was performed in myocardial biopsies obtained after 15 min of treatment with saline, chelerythrine, BNTX, or TAN-67 and chelerythrine or BNTX in the presence of TAN-67. TAN-67 induced the translocation of PKC-alpha to the sarcolemma, PKC-beta(1) to the nucleus, PKC-delta to the mitochondria, and PKC-epsilon to the intercalated disk and mitochondria. PKC translocation was abolished by chelerythrine and BNTX in TAN-67-treated rats. To more closely examine the role of these isoforms in cardioprotection, we utilized the PKC-delta selective antagonist rottlerin. Rottlerin abolished opioid-induced cardioprotection (48.9 +/- 4.8) and PKC-delta translocation without affecting the translocation of PKC-alpha, -beta(1), or -epsilon. These results suggest that PKC-delta is a key second messenger in the cardioprotective effects of delta(1)-opioid receptor stimulation in rats.

Topics: Acetophenones; Alkaloids; Analgesics; Animals; Benzophenanthridines; Benzopyrans; Benzylidene Compounds; Enkephalin, Leucine-2-Alanine; Enzyme Activation; Enzyme Inhibitors; Heart Rate; Indoles; Ischemic Preconditioning, Myocardial; Isoenzymes; Male; Maleimides; Myocardial Infarction; Myocardial Ischemia; Myocardial Reperfusion Injury; Myocardium; Naltrexone; Narcotic Antagonists; Phenanthridines; Protein Kinase C; Protein Kinase C-delta; Quinolines; Rats; Rats, Wistar; Receptors, Opioid, delta

The effects of the extremely selective mu-opioid receptor agonist, [D-Arg2,Lys4]-dermorphin-(1-4)-amide (DALDA), the mu-opioid receptor agonist morphine, the mu/delta agonist D-Ala2, Leu5, Arg6-enkephalin (dalargin), the kappa-opioid receptor agonist spiradoline, and the sigma1-receptor antagonist DuP 734 on ventricular fibrillation threshold (VFT) was investigated in an experimental post-infarction cardiosclerosis model and an immobilization stress-induced model in rats. Both models produced a significant decrease in VFT. The postinfarction cardiosclerosis-induced decrease in VFT was significantly reversed by intravenous administration of dalargin (0.1 mg/kg), DALDA (0.1 mg/kg), or morphine HCl (1.5 mg/kg). Pretreatment with naloxone (0.2 mg/kg) completely eliminated the increase in cardiac electrical stability produced by DALDA. Both spiradoline (8 mg/kg, i.p.) and DuP 734 (1 mg/kg, i.p.) produced a significant increase in VFT in rats with post-infarction cardiosclerosis. This effect of spiradoline was blocked by nor-binaltorphimine. The immobilization stress-induced decrease in VFT was significantly reversed by administration of either DALDA, spiradoline or DuP 734. In conclusion, activation of either mu- or kappa1-opioid receptors or blockade of sigma1-receptors reversed the decrease in VFT in both cardiac compromised models. Since DALDA and dalargin essentially do not cross blood brain barriers, their effects on VFT may be mediated through peripheral mu-opioid receptors.

Topics: Animals; Anti-Arrhythmia Agents; beta-Endorphin; Disease Models, Animal; Dynorphins; Enkephalin, Leucine-2-Alanine; Heart; Immobilization; Ligands; Morphine; Myocardial Infarction; Myocardium; Naloxone; Naltrexone; Narcotic Antagonists; Oligopeptides; Piperidines; Pyrrolidines; Rats; Receptors, Opioid; Receptors, Opioid, delta; Stress, Physiological; Ventricular Fibrillation

It was found, that injection of delta-receptors agonist dalargin before the occlusion of left anterior coronary artery in rats prevented the decrease of ventricular fibrillation threshold (VFT). An injection of naloxone in dose 0.5 mg/kg (for the blockade of mu-receptors only) had no influence on the VFT. Naloxone in dose 1 mg/kg (for the blockade peripheric mu- and delta-receptors) decreased VFT. An intraventricular infusion of dalargin (10 mkg) induced bradycardia and an increase of VFT. It was assumed that anti-arrhythmic effects of enkephalins in acute myocardial ischemia could be realized by an activation of peripheric delta-receptors and central mu-receptors.

Topics: Animals; Anti-Arrhythmia Agents; Arrhythmias, Cardiac; Enkephalin, Leucine-2-Alanine; Enkephalins; Male; Myocardial Infarction; Naloxone; Rats; Receptors, Opioid; Receptors, Opioid, delta; Receptors, Opioid, mu; Ventricular Fibrillation

A histofluorescence study was made of catecholamine saturation of the adrenergic nervous plexuses of the intact zone of rabbit left ventricles and adrenal medullas on days 3 and 7 of experimental myocardial infarction induced by ligation of the anterior branch of the left coronary artery when dalargrin, a leucine-enkephalin analogue, was administered. Dalargin was shown to decrease catecholamine saturation of myocardial nervous plexuses and to reduce detection rates of mediator accumulation in the sympathetic axons of nervous fascicles. In addition, the agent caused a decrease in the hormone content in chromaffinocytes on day 3 of the experiment and contributed to recovery of their functional homogeneity.

Topics: Adrenal Medulla; Adrenergic Fibers; Animals; Catecholamines; Depression, Chemical; Enkephalin, Leucine; Enkephalin, Leucine-2-Alanine; Heart; Male; Myocardial Infarction; Rabbits

It has been established that in lesion of the myocardium accumulation of huge amount of algesic compounds may cause limitation of the level of cardiac afferentation. Use of naloxone, buterfanol tartrate and D-ala-2-lei-enkephalin prevent the development of the reaction. The possibility of participation of the endogenic cardiac opioids in anti-nociceptive reactions of heart during its lesion is considered.

Topics: Animals; Bradykinin; Butorphanol; Cats; Electrocardiography; Endorphins; Enkephalin, Leucine; Enkephalin, Leucine-2-Alanine; Heart; Heart Conduction System; Myocardial Infarction; Naloxone; Neurons, Afferent; Receptors, Opioid

The experiments on white rats with induced myocardial infarction have studied the influence of dalargin on the infarction size and peri-infarction zone ultrastructure. 24 hours later the decrease in the infarction zone size was detected in rats who had received dalargin in a dose of 50 and 100 micrograms/kg. In the peri-infarction zone the increase in glycogen quantity, the lower degree of lipid infiltration, the increase in mitochondrial number and mitochondrial energy effectiveness coefficient were noted, as compared to control animals. Sarcolemma of cardiomyocytes from the peri-infarction zone in rats on dalargin was impermeable for colloidal lanthanum. The decrease in the infarction size under the effect of dalargin is explained by its influence on the survival of cardiomyocytes in the peri-infarction zone.

Topics: Animals; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Enkephalin, Leucine; Enkephalin, Leucine-2-Alanine; Heart; Microscopy, Electron; Mitochondria, Heart; Myocardial Infarction; Myocardium; Rats

Topics: Adult; Aged; Blood Glucose; Calcium; Enkephalin, Leucine; Enkephalin, Leucine-2-Alanine; Humans; Lactates; Magnesium; Male; Metabolism; Middle Aged; Myocardial Infarction; Triglycerides; Urea

Topics: Adenine Nucleotides; Animals; Drug Evaluation, Preclinical; Enkephalin, Leucine; Enkephalin, Leucine-2-Alanine; Heart; Liver; Male; Myocardial Infarction; Myocardium; Rats

Topics: Adrenal Cortex Hormones; Adult; Aged; Drug Evaluation; Enkephalin, Leucine; Enkephalin, Leucine-2-Alanine; Humans; Middle Aged; Myocardial Infarction; Pituitary Hormones

Topics: Animals; Dogs; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Enkephalin, Leucine; Enkephalin, Leucine-2-Alanine; Myocardial Infarction; Nitroglycerin; Propranolol; Rats

The effect of an opioid hormone (Leu-enkephalin analog Tyr-Dala-Gly-Phe-Leu-Arg) on the healing of myocardial infarction caused by the ligation of the descending branch of the rabbit left coronary artery has been investigated. The peptide was injected intraperitoneally at a dose of 10 micrograms/kg daily. Using light and electron microscopy, the peptide has been shown to exert a pronounced stimulating effect on the healing of the necrotic zone on days 3 and 7 of the experiment. Opioid peptides are suggested to take part in the healing of various disorders.

Topics: Animals; Drug Evaluation, Preclinical; Enkephalin, Leucine; Enkephalin, Leucine-2-Alanine; Male; Microscopy, Electron; Myocardial Infarction; Myocardium; Necrosis; Rabbits; Time Factors; Wound Healing

An experimental study in rats demonstrated that myocardial infarction, induced by the ligation of the descending branch of the left coronary artery, led to marked metabolic disorders, such as increased lactate and glucose levels and decreased levels of blood calcium and magnesium and hepatic glycogen. A stable analogue of leu-enkephalin administered to the animals normalized metabolic parameters and improved the course of experimental myocardial infarction in rats.

Topics: Animals; Blood Glucose; Calcium; Diuresis; Enkephalin, Leucine; Enkephalin, Leucine-2-Alanine; Lactates; Liver Glycogen; Magnesium; Male; Myocardial Infarction; Rats