Cardioprotective Effect of Selective μ-Opioid Receptor Agonist Endomorphin-1 in Cardiac Reperfusion In Vivo and In Vitro.

The effect of the selective μ-opioid receptor agonist endomorphin-1 in reperfusion injury in male Wistar rats was studied in vivo and in vitro. The in vivo experiment included coronary artery occlusion (45 min) and reperfusion (120 min); in in vitro experiments, 45-min global ischemia of the isolated rat heart was followed by 30-min reperfusion. Endomorphin-1 was administered intravenously 5 min before in vivo reperfusion (at a dose 50 μg/kg) or added to the perfusion solution at the onset of reperfusion of the isolated heart (in a concentration of 152 nmol/liter).

The β-adrenergic receptor agonist formoterol attenuates necrosis and apoptosis in the rat myocardium under experimental stress-induced cardiac injury.

Background: Currently, there is no effective therapy for takotsubo syndrome (stress-induced cardiac injury in humans) in the clinics. It has previously been shown that β-adrenergic receptor (β-AR) agonist formoterol reduces cardiomyocyte injury in experimental takotsubo syndrome.

Objectives: The aim of this study was to investigate whether formoterol prevents apoptosis and necrosis of cardiomyocytes and endothelial cells in stress-induced cardiomyopathy.

Synthesis and crystal structures of 5,17-di-bromo-26,28-dihy-droxy-25,27-dipropynyloxycalix[4]arene, 5,17-di-bromo-26,28-dipropoxy-25,27-dipropynyloxycalix[4]arene and 25,27-bis-(2-azido-eth-oxy)-5,17-di-bromo-26,28-di-hydroxy-calix[4]arene.

The calixarenes, 5,17-di-bromo-26,28-dihy-droxy-25,27-dipropynyloxycalix[4]arene (CHBrO, ), 5,17-di-bromo-26,28-dipropoxy-25,27-dipropynyloxycalix[4]arene (CHBrO, ) and 25,27-bis-(2-azido-eth-oxy)-5,17-di-bromo-26,28-di-hydroxy-calix[4]arene (CHBrNO, ) possess a pinched cone mol-ecular shape for and , and a 1,3-alternate shape for compound . In calixarenes and , the cone conformations are additionally stabilized by intra-molecular O-H⋯O hydrogen bonds, while in calixarene intra-molecular Br⋯Br inter-actions consolidate the 1,3-alternate mol-ecular conformation. The dense crystal packing of the cone dialkyne is a consequence of π-π, C-H⋯π and C-H⋯O inter-actions.

Activation of Cardiac δ-Opioid Receptors Increases Heart Tolerance to Reperfusion.

Coronary occlusion (45 min) and reperfusion (120 min) in male Wistar rats in vivo, as well as total ischemia (45 min) of an isolated rat heart followed by reperfusion (30 min) were reproduced. The selective δ-opioid receptor agonist deltorphin II (0.12 mg/kg and 152 nmol/liter) was administered intravenously 5 min before reperfusion in vivo or added to the perfusion solution at the beginning of reperfusion of the isolated heart.