Different antiarrhythmic effects of dalargin and β-endorphin in severe myocardial ischemia during stimulation of the sensorimotor cortex

The effects of the opiate receptor agonists dalargin and β-endorphin on the occurrence of idioventricular arrhythmias, including ventricular tachycardia and fibrillation, are studied in acute experiments on Nembutal-anesthetized cats. Dalargin administered in the dose crossing the blood-brain barrier produces a pronounced antiarrhythmic effect, while β-endorphin is effective only against ventricular fibrillation. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 7, pp. 28–31, July, 1997     

Correction of electrical instability of the heart with opiate receptor ligands

Peripheral injections of the μ-opiate receptor agonist DALDA,k-opiate receptor agonist spiradoline, and δ-opiate receptor blocker DuP734 significantly increased the ventricular fibrillation threshold in animals with modeled postinfarction cardiosclerosis or stress-induced damage to the heart. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 10, pp. 399–401, October, 1998     

Role of cholinergic regulation of the heart in the protective antiarrhythmic effect of adaptation to continuous moderate stress

Rats were adapted to the continuous action of moderate immobilization stress for 1, 5, and 15 days. Thereafter the threshold of ventricular fibrillation and the heart rate were compared with biochemical indexes of adrenergic and cholinergic regulation of the heart, namely, catecholamine, cAMP, and cGMP content, acetylcholinesterase and choline acetyltransferase activity, the number and affinity of cardiac muscarinic receptors, and the catecholamine content in the adrenals. The threshold of ventricular fibrillation fell on the 1st day due to a predominance of the adrenergic regulatory effect over the cholinergic. Adaptation for 5 days is attended by a rise of the threshold of ventricular fibrillation to the norm and by marked bradycardia, both these shifts being abolished by atropine. Elevation of the heart's resistance to arrhythmias stems from the prevalence of cholinergic regulation. Equilibrium between the cholinergic and adrenergic effects on the heart was found as a results of 15-day adaptation. The normal threshold of ventricular fibrillation and the increased cardiac resistance to arrhythmia were preserved and dictated largely by adaptive changes at the cardiomycyte level. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120. N ^o 7, pp. 36–39, July, 1995 Presented by G. N. Kryzhanovskii, Member of the Russian Academy of Medical Sciences     

Effect of befol on the electric threshold of ventricular fibrillation

Befol (20 mg/kg) rises electric threshold of ventricular fibrillation in cats. This effect is most pronounced in ischemized myocardium. It is shown that not only tricyclic but also monocyclic antidepressants exhibit antifibrillatory activity. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 123, No. 3, pp. 305–307, March, 1997     

Peculiarities of ischemic cardiac arrhythmias in cats against the background of stimulation of sensorimotor cortex and administration of selective opiate receptor agonists

In acute experiments on Nembutal-anesthetized cats, the effect of opiate receptor agonists DAGO, DSLET, and dinorphin A_1–13 on the incidence of idioventricular rhythm disturbances, including ventricular tachycardia and fibrillation, was studied under conditions of occlusion of circumflex branch of the left coronary artery and stimulation of the sensorimotor cortex. The most pronounced effects were observed with DSLET and dinorphin A_1–13. These preparations completely prevented ventricular fibrillation. DAGO produced a less pronounced protective effect probably because of parallel increase in plasma catecholamine concentration. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 5, pp. 504–506, May, 2000     

Antiarrhythmic activity of <Emphasis Type="Italic">n</Emphasis>-tyrosol during acute myocardial ischemia and reperfusion

Antiarrhythmic activity of n-tyrosol was demonstrated on the model of early occlusion and reperfusion arrhythmia. The preparation reduces the incidence of ventricular tachycardia and fibrillation, increases the percent of animals without ventricular arrhythmia, and moderates the severity of developing ventricular arrhythmias. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 143, No. 6, pp. 631–633, June, 2007     

The role of heart vegetative nerves in antiarrhythmic effect of β-endorphin in experimental myocardial ischemia

Acute experiments on narcotized cats showed that premedication with β-endorphin promotes the development of ventricular tachycardia and decreases the occurrence of ventricular fibrillation caused by myocardial ischemia. The antifibrillatory effect of β-endorphin is related to central nervous structures regulating the function of the cardiovascular system and is mediated through the vagus nerves. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 123, No. 5, pp. 509–511, May, 1997     

Effect of KLN-93 on ventricular fibrillation induced by reperfusion and electrical stimulation in cats

In experiments devoted to modeling of reperfusion ventricular fibrillation and determination of the electric threshold of fibrillation, a protective effect of KLN-93 (a para-aminobenzoic acid ester derivative) is compared with that of lidocaine. It is shown that KLN-93 in doses stopping reperfusion fibrillation is 2-4-fold less toxic than the isoeffective doses of lidocaine. In a dose of 0,4 mg/kg (2.5% LD₅₀) KLN-93 increases the fibrillation threshold 4.5-fold, while isotoxic dose of lidocaine increases this parameters apparoximately 2-fold. These data suggest that KLN-93 is an effective antifibrillatory agent. Translated fromByulleten' Eksperimental'noi i Meditsiny, Vol. 124, No. 8, pp. 135–137, August, 1997     

Role of sympathetic nervous system in protective effects of selectivek-opiate receptor agonist dynorphin A1–13 on the incidence of cardiac arrhythmia during myocardial ischemia

Preliminary administration of dynorphin A_1–13 to narcotized cats with myocardial ischemia attenuated cardiac fibrillation, but increased the incidence of ventricular tachycardia. Protective effect of dynorphin A_1–13 was observed only under conditions of intact sympathetic cardiac innervation. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 1, pp. 34–37, January, 2000     

Opiatergic mechanisms of the cardiotropic effect of acute cooling

Changes in myocardial contractility after an acute cold exposure following intracerebroventricular administration of opiate receptor agonists were studied in rat hearts isolated after Langendorff. Cold exposures were carried out individually for each animal in chambers at −10°C for 4 h. Thirty min before being exposed to cold the animals were administered in a brain ventricle 10 μl of μ- or δ-opiate receptor agonists (DAGO or DADLE, respectively). Isolation and perfusion of the hearts were performed directly after the cold exposure was over. The mechanism of reduction of myocardial contractility and coronary flow induced by an acute cold exposure is believed to include stimulation of μ-opiate receptors as one of its main components, and the effect of intracerebral hypertension on hemodynamic parameters is partially mediated through activation of δ-opiate receptors. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 12, pp. 582–584, December, 1994 Presented by R. S. Karpov, Member of the Russian Academy of Medical Sciences     

Central and peripheral actions of delta sleep-inducing peptide on electrical stability of the heart

In rabbits under nembutal anesthesia delta sleep-inducing peptide injected intravenously or directly into a ventricle of the brain raised the threshold for ventricular fibrillation. Its effect on the electrical stability of the heart after central administration developed later than after systemic administration. Bilateral vagotomy did not alter the central effects of this peptide. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, N ^o 6, pp. 566–568, June, 1994 Presented by K. V. Sudakov, Member of the Russian Academy of Medical Sciences     

The role of α<Subscript>1</Subscript>-and β-adrenoceptors in initiation and development of thermoregulatory reactions during fast and slow cooling

Ionophoretic application of α₁-and β-adrenoceptor blockers into the skin produces no effect on the parameters of thermal homeostasis under thermoneutral conditions. α₁-Adrenoblocker verapamil inhibits cold shivering during fast and slow cold exposure; it elevates the temperature threshold and moderates the vasoconstrictor response during rapid cooling. These changes are accompanied by a compensatory decrease in the threshold and stimulation of non-shivering thermogenesis. Application of non-selective β-blocker propranolol had no effect on the temperature thresholds of the thermoregulatory reactions, but augmented the maximum amplitude of shivering during both cooling protocols, thereby compensating the decrease in non-shivering thermogenesis. In the whole organism, block of one type adrenoceptors during cold exposure is accompanied by activation of the compensatory mechanisms mediated by adrenoceptors of the other type. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 145, No. 3, pp. 259–262, March, 2008     

Effect of NO-synthase inhibitor L-NAME on occlusion and reperfusion arrhythmias in cats

On the model of occlusion/reperfusion arrhythmia in cats it was shown that repeated injections of the NO-synthase inhibitor L-NAME decreased the incidence of occlusion arrhythmias (to 40%), eliminated reperfusion-induced ventricular fibrillation, and drastically reduced the latency of occlusion arrhythmias. A single injection of L-NAME (20 mg/kg) immediately before ligation of the coronary artery did not decrease the incidence of occlusion and reperfusion arrhythmias. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 5, pp. 509–511, May, 1999     

Correction of biotransformation of xenobiotics by α-tocopherol in combination with nicotinamide and methionine in the liver damaged by ultrasound

Six day after rat liver sonication, the content of cytochrome P-450, rate of NADPH oxidation, activity of NADPH—cytochrome P-450 reductase, and rate of aniline hydroxylation in the microsomal fraction decrease. After 12 days, the rate of ethylmorphine N-demethylation also decreases. Intragastral administration of methionine, nicotinamide, and vitamin E for 6 and 12 days activates these enzymes and uridine 5′-diphosphate glucuronyl transferase. Translated fromByulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 123, No. 4, pp. 420–423, April, 1997     

Delayed behavioral effects of β-casomorphin-7 depend on age and gender of albino rat pups

Systemic administration of β-casein heptapeptide β-casomorphin-7 (YPFPGPI, 1 mg/kg daily) to 10–23-day-old albino rat pups produced delayed anxiolytic effects, which were more pronounced in female than in male rats. Experimental findings confirm our assumption on the important role of nutritional opioids in brain development in newborn mammals. Translated fromByulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 130, No. 11, pp. 488–492, November, 2000     

Effects of β-carotene and aspartame on clustogenic activity of cyclophosphamide and dioxidine in mice

Antimutagenic effects of combination of aspartame (0.4 and 4 mg/kg) and β-carotene (0.15–15 mg/kg) were studied by estimation of chromosome aberrations in bone marrow cells of C57Bl/6 mice. Single and 5-day treatment with this combination decreased the clastogenic effects of dioxidine and cyclophosphamide and produced a more potent and universal antimutagenic effect than its constituents. Translated fromByulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 130, No. 11, pp. 570–573, November, 2000     

Clinical and experimental study of antiarrhythmic and antianginal effects of quaternidine

High antiarrhythmic activity of a new Russian antiarrhythmic drug quaternidine in ventricular arrhythmia was studied in 96 coronary patients by Holter monitoring, bicycle ergometry, and echocardiography. The drug had a positive impact on local kinetics in left-ventricular ischemic myocardium and some parameters of bicycle exercise test. The preparation possesses no arrhythmogenic effect. Experiments on 30 random-bred rats showed that the drug reduced the necrotic zone under conditions of experimental coronary occlusion. Experiments on 14 intact cats demonstrated that quaternidine had no effect on coronary bloodflow. Translated fromByulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 130, No. 11, pp. 581–584, November, 2000     

Mechanism of protective effect of dalargin against ischemic arrhythmias

Acute tests on cats with altered sympathetic innervation of the heart show that the protective action exerted by dalargin against the development of ischemic ventricular fibrillation is due to a modulating influence of this leu-enkephalin analog on both the sympathetic and parasympathetic regulation of cardiac activity. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 122, No. 8, pp. 176–178, August, 1996     

Delta sleep-inducing peptide and flunitrazepam acting jointly increase cardiac electrical stability

In experiments on rabbits under Nembutal anesthesia, intravenous injection of flunitrazepam in a single dose of 0.125 mg/kg in combination with delta sleep-inducing peptide in a single dose of 60 nmol/kg raised the threshold of ventricular fibrillation to a level that was significantly higher than that after injection of flunitrazepam alone in the same dose and comparable to that after injection of this benzodiazepine alone in twice as high a dose (0.25 mg/kg), but without the side effects (persistent hypotension and transient bradycardia) produced by the latter dose. It is concluded that the ability of jointly acting delta sleep-inducing peptide and flunitrazepam to increase the electrical stability of the heart may have practical relevance to the prevention of ventricular arrhythmias occurring under conditions of emotional stress and myocardial ischemia. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 4, pp. 342–345, April, 1995 Presented by K. V. Sudakov, Member of the Russian Academy of Medical Sciences     

Modifying effect of pineal peptide hormones on the reactivity of rat thyroid gland to cooling

The study explores the effect of pineal peptide hormones (epitalamin) on the pituitarythyroid system in cold exposure. It is shown that pineal hormones block hyperreactivity of the thyroid to acute cold stress, while in chronic cooling they modulate the adaptive reaction of the thyroid gland to cold. Thus, pineal peptides can modulate the thyroid reaction to cooling. Epitalamin modulates the intensity of peripheral deiodination of thyroxine. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 12, pp. 652–654, December, 1997