enkephalin-leu--ala(2)-arg(6)- and Myocardial-Ischemia

Effects of intravenous dalargin daily administered in a dose of 28 micrograms/kg during 7 days on hemodynamics, oxygen balance, lipid spectrum were studied in patients with coronary heart disease. The results of the treatment show that dalargin decreases incidence of anginal attacks, peripheral vascular resistance, venous tonicity, increases exercise tolerance, peripheral blood flow and venous flow. In addition, such treatment reduces oxygen consumption, levels of total cholesterol, triglycerides, low density lipoprotein cholesterol.

Topics: Adrenergic beta-Agonists; Anti-Arrhythmia Agents; Enkephalin, Leucine-2-Alanine; Enkephalins; Female; Hemodynamics; Humans; Injections, Intravenous; Lipoproteins; Male; Middle Aged; Myocardial Ischemia; Receptors, Opioid; Receptors, Opioid, mu

Perfusion of the isolated intact rat heart with Krebs-Henseleit solution containing agonists ((-)-TAN-67, DPDPE, and dalargin) or antagonists of delta-opioid receptors (naltrindole, TIPP[psi], and ICI 174,864) in a final concentration of 0.1 mg/liter was followed by a decrease in the heart rate, end-diastolic pressure, contraction rate, relaxation rate, and left ventricular developed pressure. Perfusion with a solution containing the delta-opioid receptor agonist DPDPE or delta-antagonists naltrindole, TIPP[psi], and ICI 174,864 before modeling of global ischemia increased the severity of reperfusion-induced contractile dysfunction in the myocardium. Our results suggest that delta-opioid receptor antagonists in vitro exhibit properties of partial delta-receptor agonists.

Topics: Animals; Enkephalin, D-Penicillamine (2,5)-; Enkephalin, Leucine; Enkephalin, Leucine-2-Alanine; Heart; In Vitro Techniques; Male; Myocardial Contraction; Myocardial Ischemia; Naltrexone; Oligopeptides; Perfusion; Quinolines; Rats; Rats, Wistar; Receptors, Opioid, delta

Electrostimulation of the central gray matter in the sylvian aqueduct and nucleus raphe magnus produced an antiarrhythmic effect during acute myocardial ischemia. Stimulation and blockade of opiate receptors in the central amygdaloid nucleus and lateral hypothalamus with dalargin and naloxone induced the same effect. Destruction of the central gray matter in the sylvian aqueduct and nucleus raphe magnus decreased electrical stability of ischemic myocardium.

Topics: Amygdala; Animals; Anti-Arrhythmia Agents; Enkephalin, Leucine-2-Alanine; Heart; Hypothalamus; Male; Myocardial Contraction; Myocardial Ischemia; Naloxone; Narcotic Antagonists; Narcotics; Rats; Serotonin

Topics: Animals; Anti-Arrhythmia Agents; Arrhythmias, Cardiac; Cats; Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; Enkephalin, Leucine; Enkephalin, Leucine-2-Alanine; Enkephalins; Female; Heart; Lasers; Male; Myocardial Ischemia; Myocardium; Opioid Peptides; Receptors, Opioid; Sympathectomy

Topics: Animals; Anti-Arrhythmia Agents; beta-Endorphin; Cats; Enkephalin, Leucine-2-Alanine; Female; Male; Motor Cortex; Myocardial Ischemia; Somatosensory Cortex; Tachycardia, Ventricular; Ventricular Fibrillation

Topics: Animals; Anti-Arrhythmia Agents; Blood Pressure; Cats; Enkephalin, Leucine-2-Alanine; Female; Heart Rate; Male; Myocardial Ischemia; Sympathectomy; Sympatholytics; Ventricular Fibrillation

We studied antiarrhythmic action of D-Ala 2, Leu 5, Arg 6-enkephalin (dalargin) in experiments on male rats. Dalargin is reported to prevent heart rhythm disturbance and heart electrical stability decrease in experimental coronary occlusion, postinfarction, cardiosclerosis and emotional stress. Dalargin prevents acute myocardial ischaemia-induced increase of cAMP content in blood serum and cardiac muscle, as an indirect feature of its antiadrenergic activity. D-Ala 2, Leu 5, Arg 6-enkephalin leads to a decrease of cAMP content in myocardium and blood plasma, which presumably indicates a decrease of sympathetic tone. The data strongly suggest that cGMP content increase and somatostatin level decrease in cardiac muscle play a significant role in antiarrhythmic action of dalargin.

Topics: Animals; Anti-Arrhythmia Agents; Arrhythmias, Cardiac; Chi-Square Distribution; Enkephalin, Leucine-2-Alanine; Male; Myocardial Ischemia; Rats

It has been established that preliminary administration of D-Ala2-Leu5-Arg6-enkephalin, D-Met2-Pro5-enkephalinamide, and D-phenylalanine to experimental animals prevents a stress-induced increase of the content of thromboxane in the blood plasma and myocardium and induces a rise of the level of prostacyclin, PGF2 and PGE in the heart and blood plasma. The authors hold that the changes in the level of prostanoids may mediate cardioprotective and anti-stressor rather than antiarrhythmic effects of enkephalins.

Topics: Animals; Anti-Arrhythmia Agents; Disease Models, Animal; Drug Evaluation, Preclinical; Enkephalin, Leucine-2-Alanine; Enkephalin, Methionine; Heart; Myocardial Ischemia; Myocardium; Prostaglandins; Stress, Physiological; Ventricular Fibrillation

In acute experiments on cats it has been shown that dalargin possess antiarrhythmic affect in myocardial ischemia. Antiarrythmic effect of dalagrig may be connected both with reflex and with direct action of dalargin on neurons structure, which

Topics: Animals; Anti-Arrhythmia Agents; Cats; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Enkephalin, Leucine-2-Alanine; Female; Heart; Heart Rate; Male; Myocardial Ischemia; Vagotomy; Ventricular Fibrillation

Adaptation of rats to cold and physical exercise prevented ventricular fibrillation (VF) caused by the occlusion of the left anterior coronary artery. In the heart of adapted rats with acute myocardial ischemia, myocardial enkephalins increased whereas the level of cAMP declined as compared to nonadapted animals. Injection of dalargin before the occlusion of the coronary artery in rats prevented both VF and a decrease of VF threshold. The peptide averted the rise of cAMP content in the heart during acute myocardial ischemia. The data obtained suggest that the rise of endogenous myocardial enkephalins may have an important role in antiarrhythmic action of adaptation. It is assumed that antiarrhythmic effect of enkephalins may be related to the restriction of sympathetic influence on the heart.

Topics: Acute Disease; Adaptation, Physiological; Animals; Cold Temperature; Enkephalin, Leucine-2-Alanine; Enkephalins; Exercise; Heart; Male; Myocardial Ischemia; Myocardium; Nucleotides, Cyclic; Rats; Rats, Wistar; Sympatholytics; Ventricular Fibrillation