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A V Krylatov

Publications and source records attributed to A V Krylatov.

At least 19 recordsLinked to original sources
PubMed2006

[Paticipation of cannabinoid receptors in the regulation of cardiac rhythm and cardiac contractility].

It has been found that i. v. administration of cannabinoid receptor (CB) agonists (HU-210, ACPA, anandamide, methanandamide) induced a decrease in the heart rate (HR) in anesthetized rats. Pretreatment with CB1 receptor antagonist SR141716A completely abolished a negative chronotropic effect of CB receptor agonist HU-210. The CB2 receptor antagonist SRI 44528 did not prevent a HU-210-induced decrease in the HR. Pretreatment with the ganglion blocker hexamethonium had no effect on the negative chronotropic action of HU-210. Addition of HU-210 (100 nM) to perfusion solution induced a decrease in the HR, left ventricular development pressure, rate of contractility and relaxation of isolated perfused rate heart without change in end diastolic pressure. These data suggest that cardiac CBI receptor activation induces a decrease in the HR both in vivo and in vitro. An occupancy of the same receptors mediates a negative inotropic effects of cannabinoids.

Animals↗
PubMed2005

Cannabinoid receptor antagonists SR141716 and SR144528 exhibit properties of partial agonists in experiments on isolated perfused rat heart.

We studied the effect of selective cannabinoid receptor ligands on contractility of isolated Langendorff-perfused rat heart. It was found that 10-min perfusion of rat heart with a solution containing selective agonist of CB1 and CB2 receptors HU-210 (10 nM) decreased left ventricular developed pressure and maximum rates of contraction and relaxation. However, HU-210 had no effect on heart rate and end-diastolic pressure. Treatment with selective CB1 receptor antagonist SR141716 (1 microM) and selective CB2 receptor antagonist SR144528 (1 microM) decreased left ventricular developed pressure and maximum rates of contraction and relaxation, but had no effect on heart rate and end-diastolic pressure. Ten-minute perfusion of rat heart with a solution containing selective agonist of CB1 and CB2 receptors HU-210 (10 nM) decreased cAMP concentration in the heart. CB receptor antagonists had little effect on cAMP concentration in the heart. The negative inotropic effect of HU-210 and CB receptor antagonists is probably mediated by activation of CB1 receptors. It can be hypothesized that the decrease in heart cAMP concentration is related to stimulation of CB2 receptors. Our results suggest that selective CB receptor antagonists SR141716 and SR144528 in a final concentration of 1 microM exhibit properties of partial CB receptor agonists.

Animals↗
PubMed2004

Selective cannabinoid receptor agonist HU-210 decreases pump function of isolated perfused heart: role of cAMP and cGMP.

The rate and strength of heart contractions decreased after 10-min perfusion of rat myocardium with Krebs-Henseleit solution containing a selective cannabinoid receptor agonist HU-210 in a final concentration of 10 nM. HU-210 completely blocked the positive inotropic and chronotropic effect of beta-adrenoceptor agonist isoproterenol, decreased the basal level of cAMP, and abolished the isoproterenol-induced increase in myocardial cAMP concentration. cGMP concentration remained unchanged under these conditions. The decrease in myocardial cAMP concentration after activation of cannabinoid receptors did not correlate with changes in the strength and rate of heart contractions. Our results suggest that the negative inotropic and chronotropic effects of HU-210 are not associated with decreased cAMP concentration in the myocardium.

Adrenergic beta-Agonists↗
PubMed2003

Possible mechanism underlying the antiarrhythmic effect of peptides nociceptin and DALDA on the heart.

During aconitine-induced arrhythmias the antiarrhythmic effect of DALDA (Tyr-D-Arg-Phe-Lys-NH2) and nociceptin (orphanin FQ) administered intravenously depended on activation of nitric oxide synthase. K(ATP) channels were not involved in the realization of this effect. Endogenous prostanoids played a minor role in the antiarrhythmic effect of nociceptin and did not contribute to the protective influence of DALDA. The antiarrhythmic effect of orphanin FQ administered intravenously did not depend on functional activity of the autonomic nervous system. However, the effect of orphanin FQ after intracerebroventricular infusion was determined by changes in the state of this system.

Aconitine↗
PubMed2003

[Role of ORL1 receptors in the regulation of cardiac resistance to arrhythmogenic effects ].

It has been found that intravenous administration of nociceptin (0.4 mg/kg) prevents development of aconitine-induced arrhythmias but has no effect on the incidence of occlusion, reperfusion, CaCl2-induced arrhythmias, and exacerbates epinephrine-evoked dysrhythmias. Pretreatment with hexamethonium, atropine, guanethidine and naloxone did not abolish the arrhythmic effect of nociceptin. Intracerebroventricular infusion of orphanin FQ was shown to increase cardiac tolerance of arrhythmogenic influence of aconitine, but this effect is completely abolished by hexamethonium administration. It has been suggested that stimulation of both central and peripheral ORL1 receptors increases cardiac resistance against arrhythmogenic effect of aconitine via different mechanisms.

Aconitine↗
PubMed2003

[Changes in cardiac resistance to arrhythmogenic effects during ATP-dependent K+ channel activation].

It has been found that pretreatment with ATP-dependent potassium channel (KATP-channel) opener, BMS 180448 (3 mg/kg, intravenously), increases cardiac resistance against arrhythmogenic action of coronary artery occlusion and reperfusion in anaesthetized rats. However, BMS 180448 induced a decrease in ventricular fibrillation threshold in rats postinfarction cardiac fibrosis. This effect was completely abolished by administration of the KATP-channel inhibitor, glibenclamide. By contrast, coadministration of BMS 180448 and selective sarcolemmal KATP-channel inhibitor, HMR 1098, promoted an increase in ventricular fibrillation threshold in rats with postinfarction cardiac fibrosis before normal value. The selective mitochondrial KATP-channel opener, diazoxide, also exacerbated a decrease in ventricular fibrillation threshold induced by postinfarction cardiac sclerosis. But after depletion of endogenous catecholamine storage by pretreatment with guanthidine, diazoxide, on the contrary, elevated the ventricular fibrillation threshold. It has been suggested that stimulation of mitochondrial ATP-sensitive potassium channels promotes an elevation in electrical stability of the heart, whereas opening of sarcolemmal KATP-channel increases a possibility of ventricular arrhythmias.

Adenosine Triphosphate↗
PubMed2003

[Alterations of inotropic function of isolated heart and extent of injury of cardiomyocytes after cannabinoid receptor activation during ischemia and reperfusion].

It was found that CB1- and CB2-receptor activation by intravenous administration of the selective CB-agonist HU-210 at a dose 0.1 mg/kg prompts an increase of myocardial resistance to the pathogenic action of ischemia and reperfusion in vitro. The revealed effects of HU-210 do not depend on the activation of CB-receptors in the myocardium.

Animals↗
PubMed2002

Activation of cannabinoid receptors decreases the area of ischemic myocardial necrosis.

We studied the possibility of decreasing the area of ischemic necrosis during myocardial infarction with HU-210, a selective cannabinoid receptor agonist. Activation of cannabinoid receptors with HU-210 had practically no effect on collateral blood flow in the myocardium, but considerably decreased the area of necrosis. There results indicate that cannabinoid receptor agonist HU-210 possesses cardioprotective activity and delays the formation of necrotic zones during coronary occlusion and reperfusion.

Animals↗
PubMed2002

Endogenous cannabinoids improve myocardial resistance to arrhythmogenic effects of coronary occlusion and reperfusion: a possible mechanism.

Stimulation of cannabinoid receptors with endogenous cannabinoid anandamide and its enzyme-resistant analogue R-(+)-methanandamide improved cardiac resistance to arrhythmias induced by coronary occlusion and reperfusion. This antiarrhythmic effect was not associated with activation of NO synthase, since pretreatment with NG-nitro-L-arginine methyl ester had no effect on the incidence of ischemia/reperfusion-induced arrhythmias. Blockade of ATP-dependent K+ channels with glybenclamide did not abolish the antiarrhythmic effect of R-(+)-methanandamide. Antiarrhythmic activity of endogenous cannabinoids is probably associated with their direct effects on the myocardium.

Animals↗
PubMed2002

Effect of in vivo and in vitro stimulation of delta1-opioid receptors on myocardial resistance to arrhythmogenic action of ischemia and reperfusion.

Preliminary intravenous injection of peptide agonist of delta1-opioid receptors DPDPE (0.5 mg/kg) decreased the incidence of occlusion (10 min) and reperfusion (10 min) arrhythmias in rats. By contrast, delta2-opioid receptor agonist DSLET produced no effect on the incidence of arrhythmias provoked by coronary occlusion and reperfusion. Preliminary injection of selective delta-receptor antagonist ICI 174,864 (2.5 mg/kg) or TIPP[y] (0.5 mg/kg) completely abolished the antiarrhythmic effect of DPDPE. Stimulation of cardiac delta1-opioid receptors with DPDPE added to perfusion saline in concentrations of 0.1 and 0.5 mg/liter decreased the incidence of reperfusion arrhythmias. Addition of DPDPE to perfusion saline in a concentration of 0.1 mg/liter prevented reoxygenation destruction of cardiomyocytes. By contrast, no cardioprotective effect of this peptide was observed at a concentration of 0.5 mg/liter in perfusion saline or when it was injected intravenously. It is concluded that the cardioprotective and antiarrhythmic effects of DPDPE are caused by activation of cardiac delta1-opioid receptors.

Animals↗
PubMed2002

[Increase of the heart arrhythmogenic resistance and decrease of the myocardial necrosis zone during activation of cannabinoid receptors].

We have found that intravenous administration of cannabinoid receptor (CB) agonist HU-210 (0.05 mg/kg), increases cardiac resistance against arrhythmogenic effect of epinephrine, aconitine, coronary artery occlusion and reperfusion in rats. Pretreatment with CB2-receptor antagonist, SR144528 (1 mg/kg), completely abolished the antiarrhythmic effect of HU-210. However this effect of HU-210 was not attenuated by pretreatment with CB1-receptor antagonist, SR141716A (3 mg/kg). We also found that HU-210 (0.05 mg/kg) decreased the relationship between infarction size and area of ischemia. It is concluded that CB2 receptor stimulation promotes an increase in the cardiac resistance against arrhythmogenic influences and probably increases myocardial tolerance of both ischemic and reperfusion damages in rats.

Aconitine↗
PubMed2002

[Interactions of peripheral mu-opioid receptors and K(ATP)-channels in regulation of cardiac electrical stability in ischemia, reperfusion, and postinfarction cardiosclerosis].

It has been shown that mu-opioid receptor stimulation by intravenous administration of the selective mu receptor agonist DALDA in a dose of 0.1 mg/kg prevented ischemic and reperfusion arrhythmias in rats subjected to coronary artery occlusion (10 min) and reperfusion (10 min), and also increased the ventricular fibrillation threshold in rats with postinfarction cardiac fibrosis. These effects were abolished by pre-treatment with the selective mu receptor antagonist CTAP in a dose of 0.5 mg/kg or by prior injection of the opioid receptor antagonist naloxone methiodide (2 mg/kg) which does not penetrate the blood-braib barrier. Both antagonists by themselves had no effect on the incidence of occlusion or reperfusion-induced arrhythmias or on the ventricular fibrillation threshold. Pre-treatment with ATP-sensitive K+ channel (KATP channel) blocker glibenclamide in a dose of 0.3 mg/kg completely abolished the antiarrhythmic effect of DALDA. We believe that DALDA prevents occurrence of electrical instability during ischemia and reperfusion and increases the ventricular fibrillation threshold in rats with postinfarction cardiac fibrosis via stimulation of peripheral mu-opioid receptor which appear to be coupled to the KATP channel.

Animals↗
PubMed2001

Activation of type II cannabinoid receptors improves myocardial tolerance to arrhythmogenic effects of coronary occlusion and reperfusion.

Preliminary intravenous injection of cannabinoid receptor agonist HU-210 (0.05 mg/kg) reduced the incidence of ventricular arrhythmias during 10-min coronary occlusion and 10-min reperfusion in chloralose-anesthetized rats. Preliminary injection of type I cannabinoid receptor antagonist SR 141716A (3 mg/kg) had no effect on the antiarrhythmic effect of HU-210, while type II cannabinoid receptor antagonist SR 144528 (1 mg/kg) completely abolished the effect of HU-210. Preconditioning with glibenclamide (0.3 mg/kg), an inhibitor of ATP-dependent K(+)-channels, did not affect the antiarrhythmic activity of HU-210. These findings suggest that antiarrhythmic effect of HU-210 is mediated through activation of type II cannabinoid receptors rather than activation of K(+)-channels.

Animals↗
PubMed2001

[Role of delta opioid receptors and their ligands in the development of adaptive heart protection against arrhythmogenesis].

It has been found that stimulation of delta-1 opioid receptors by intravenous administration of DPDPE (0.5 mg/kg) decreases the incidence of ischemic and reperfusion-induced arrhythmias and also increases myocardial tolerance to the arrhythmogenic action of epinephrine in rats. Pretreatment with a selective delta-2 agonist, DSLET, had no antiarrhythmic effect. The inhibition of the enzymatic breakdown of endogenous enkephalins by intravenous administration of acetorphan decreased the incidence of epinephrine-induced arrhythmias. Pretreatment with a selective delta opioid receptor antagonist, ICI-174.868, completely abolished this antiarrhythmic effect. Adaptation of rats to repeated immobilization stress during 12 days increased myocardial tolerance to the arrhythmogenic action of coronary artery occlusion (10 min) and reperfusion (10 min). Pretreatment with a selective delta opioid receptor antagonist, TIPP(Psy), did not abolish the antiarrhythmic effect of adaptation to immobilization stress. It seems that endogenous agonists of delta opioid receptors are not involved in the antiarrhythmic effect resulting from adaptation to stress.

Adaptation, Physiological↗
PubMed1998

[Delta-opiate receptors and heart resistance to arrhythmogenic factors].

Stimulation of peripheral delta-opioid receptors exerted no effect on arrhythmias, whereas that central delta 1- and delta 2-receptor activation decrease the heart susceptibility to arrhythmogenic action of epinephrine. Pre-treatment with the delta-opioid receptor antagonist ICI 174 prevented the antiarrhythmic effect of the central delta-receptors stimulation. The findings suggest that the heart decreased vulnerability to epinephrine-induced arrhythmias following the central delta-receptors stimulation is mediated by an enhanced vagal activity.

Animals↗
PubMed1998

[Modulation of the antiarrhythmic effect by endogenous opioids during adaptation to hypoxia in rats].

Adaptation of rats to hypoxia increased the heart resistance against arrhythmogenic effects. The Met-enkephaline-Arg6-Phe7 contant increased in the hypothalamus of the adapted animals. The blockers of mu- and delta-opioid receptors reduced the antiarrhythmic effect of the adaptation, whereas chi-receptor inhibitor, nor-binaltorphimine, completely abolished it. The findings suggest the antiarrhythmic effect depends on an increase of the endogenous opioids level and modulated effect of these peptides upon autonomous nervous system.

Adaptation, Physiological↗