Activation of μ-opiate receptors as a factor of regulation of heart resistance to ischemia-reperfusion and oxidative stress

Intravenous injection of the selective μ-opiate receptor agonist DAMGO (0.1 mg/kg, 15 min before isolation of the heart) improved resistance of isolated perfused rat heart to ischemia (45 min) and reperfusion (60 min) damages.In vivo administration of DAMGO prevented reperfusion-induced damages to cardiomyocytes and decreased the content of conjugated dienes in the myocardium during ischemia-reperfusionin vitro. Furthermore, stimulation of μ-opiate receptors promoted recovery of myocardial contractility during reoxygenation, but had no effect on heart resistance to free radical-induced damages during perfusion of isolated heart with a solution containing Fe²⁺ and ascorbic acid. Translated fromByulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 130, No. 8, pp. 163–167, August, 2000     

Some biochemical characteristics and water exchange in human articular cartilage in osteoarthrosis

Rearrangement of intra- and intermolecular bonds in collagen molecule, disaggregation of proteoglycans and their elimination from cartilage involved in osteoarthrosis are responsible for water accumulation and its increased mobility in cartilage.     

Acute disorders of cerebral circulation: prognostic factors in essential hypertension

AIM: To study subclinical signs of cerebrovascular pathology as prognostic factors of development of acute disorders of cerebral circulation (ADCC) in essential hypertension (EH). MATERIAL AND METHODS: A prospective (10-13 years) cohort trial of prognostic significance of subclinical forms of cerebral pathology in EH in relation to ADCC development covered 111 men aged 45-55 years who had undergone a unified neurological and cardiological examination in 1992-1993. RESULTS: Such factors as disordered circulation along major arteries of the head (a relative risk 3.1 [1.2; 10.3]), thick intima-media complex of the common carotid artery (a relative risk: 5.2 [2.1; 14.3]), the presence of asymptomatic lacunar brain infarctions (a relative risk: 6.6 [2.3; 13.5]) were revealed to be of unfavourable prognostic significance in respect to development of ADCC in EH. CONCLUSION: Some subclinical risk factors may have prognostic value in relation to development of ADCC in EH.     

Comparative analysis of the cardioprotective effect of antioxidant dibunol and agonists of mu- and delta-opioid receptors during oxidative stress

Upon intravenous injection of the delta-opioid receptor agonists, the isolated perfused rat heart became resistant to free radical damage. The cardioprotector activity of the delta-receptor agonists is more pronounced than that of the antioxidant dibunol. Both dibunol and the delta-receptor agonists favored a decrease in the level of diene conjugates in myocardium. Stimulation of the mu-opioid receptors did not change the resistance of rat heart to the oxidative stress.     

The use of delta-receptor antagonist DuP 734 for correction of the contractile diastolic cardiac dysfunction in reperfusion injury and oxidative stress

Intraperitoneal administration of the sigma-receptor antagonist DuP 734 (1 mg/kg) 15 min before heart excision produces a decrease in the reperfusion heart contractility and prevented from the reperfusion induced cardiac cell lesion upon global ischemia of the isolated perfused rat heart. At the same time, a preliminary treatment with DuP 734 potentiated the reperfusion induced suppression of the cardiac pump function, while affecting neither the cardiac contractility dysfunction nor the cardiac cell injury during the oxidative stress. It is concluded that DuP 734 is not effective in preventing the myocardial stunning. The cardio-protector effect of DuP 734 during reperfusion is not related to inhibition of the free radical cell damage.