The present study shows that VitD may prevent endothelial cell death through modulation of the interplay between apoptosis and autophagy. This effect is obtained by inhibiting superoxide anion generation, maintaining mitochondria function and cell viability, activating survival kinases, and inducing NO production.
Background: Recently, 1α,25-dihydroxycholecalciferol (vitD) has received increasing interest for its effects on many tissues and organs other than bone. A number of experimental studies have shown that vitD may have an important role in modifying risk for cardiovascular disease. Aims: This study was planned to test the effects of vitD on endothelial nitric oxide (NO) production and to study the intracellular pathways leading to NO release. Methods: In human umbilical vein endothelial cells (HUVEC) cultures the effects of vitD on NO production and p38, Akt, ERK and eNOS phosphorylations were examined in absence or in presence of the NO synthase inhibitor L-NAME and protein kinases specific inhibitors SB203580, wortmannin and UO126. Results: VitD caused a concentration-dependent increase in NO production. The maximum effect was observed at a concentration of 1 nM and the optimal time of stimulation was 1 min. Effects induced by vitD were abolished by L-NAME and by pre-treatment with protein kinases inhibitors. To verify the effective involvement of vitD receptor (VDR) in the action mechanism of vitD, experiments were repeated in presence of the specific VDR ligands ZK159222 and ZK191784. Conclusions: The results of this study demonstrate that vitD can induce a significant increase in endothelial NO production. VitD interaction with VDR caused the phosphorylation of p38, AKT and ERK leading to eNOS activation.
Administration of WIN 55,212-2 and CP 55,940 promoted voluntary ethanol intake in sP rats. This effect was mediated by stimulation of the cannabinoid CB1 receptor and required the activation of the endogenous opioid system. The results of the present study add further support to the hypothesis that the cannabinoid CB1 receptor is part of the neural substrate regulating ethanol intake. These results are also discussed in terms of WIN 55,212-2 and CP 55,940 administration possibly fixing to a higher level the hedonic set-point mechanism regulating ethanol drinking behavior in sP rats.
These results suggest that baclofen may specifically reduce the motivational properties of alcohol; further, these results are in agreement with the recently reported anti-craving potential of baclofen in alcoholics.
Ischemia/reperfusion (I/R) injury is an important cause of acute renal failure because of oxidative, inflammatory, and apoptotic mechanisms. The aim of the present study was to examine any possible protective effects of levosimendan in an in vivo pig model of renal I/R injury. In 40 anesthetized pigs (eight groups of five pigs each), I/R was induced by clamping-reopening the left renal artery. During ischemia, in three groups of pigs, levosimendan and the multiorgan preservation solution Custodiol, alone or in combination with levosimendan, were infused in the renal artery. In two other groups of animals, levosimendan in combination with Custodiol was administered after the intrarenal nitric-oxide (NO) synthase blocker N -nitro-L-arginine methyl ester (L-NAME) or the mitochondrial ATP-sensitive K ϩ channel (K ATP channel) inhibitor 5-hydroxydecanoate (5-HD). In the other animals, saline, L-NAME, or 5-HD were administered alone. Throughout the experiments, urinary N-acetyl--glucosaminidase (NAG) release was measured, and renal function was assessed. Moreover, renal biopsy samples were taken for the detection of apoptosis and tissue peroxidation. In pigs treated with levosimendan or the combination of levosimendan and Custodiol, NAG, peroxidation, and apoptotic markers were lower than in animals treated with Custodiol alone. In addition, renal function was better preserved, and cell survival and antioxidant systems were more activated. All beneficial effects were prevented by L-NAME and 5-HD. In conclusion, levosimendan alone or in combination with Custodiol exerted better protection against renal I/R injuries than Custodiol alone through antioxidant, antiapoptotic, and prosurvival actions depending on mitochondrial K ATP channels and NO-related mechanisms.
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