Clinical and experimental pharmacology & physiology
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Clin. Exp. Pharmacol. Physiol. · Mar 2008
Alpha-lipoic acid protects against renal ischaemia-reperfusion injury in rats.
1. Oxygen free radicals are important components involved in the pathophysiological processes observed during ischaemia-reperfusion (I/R). The present study was designed to assess the possible protective effect of alpha-lipoic acid (ALA) on renal I/R injury. 2. ⋯ Conversely, ALA treatment reversed all these biochemical indices, as well as histopathological alterations induced by I/R. 5. In conclusion, these data suggest that ALA reverses I/R-induced oxidant responses and improves microscopic damage and renal function. Thus, it seems likely that ALA protects kidney tissues by inhibiting neutrophil infiltration, balancing the oxidant-anti-oxidant status and regulating the generation of inflammatory mediators.
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Clin. Exp. Pharmacol. Physiol. · Feb 2008
Comparative StudyProtection of ischaemic-reperfused rat heart by dimethylamiloride is associated with inhibition of mitochondrial permeability transition.
1. The aim of the present study was to assess whether protection afforded by the Na(+)/H(+) exchanger blocker dimethylamiloride (DMA) is associated with inhibition of mitochondrial permeability transition (MPT). The effects of DMA were compared with those of cyclosporine (Cs) A, an inhibitor of MPT. 2. ⋯ In conclusion, DMA protects against the noxious effects of ischaemia-reperfusion and inhibits MPT, coinciding with present and previous findings concerning the effects of CsA. Dimethylamiloride also diminished lactate accumulation, although it did not exhibit any direct effect on glycolysis. These data suggest that blockade of Na(+)/H(+) exchange by DMA attenuates the extent of MPT in ischaemic-reperfused rat heart.
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Clin. Exp. Pharmacol. Physiol. · Feb 2008
Evidence that hydroxysafflor yellow A protects the heart against ischaemia-reperfusion injury by inhibiting mitochondrial permeability transition pore opening.
1. The present study was conducted to investigate whether hydroxysafflor yellow A (HSYA) has a protective effect against heart injury after ischaemia-reperfusion and to determine the possible mechanism involved. 2. Hearts isolated from male Sprague-Dawley rats were perfused on a Langendorff apparatus and subjected to 30 min global ischaemia, followed by 120 min reperfusion. ⋯ Levels of phosphorylated eNOS protein were significantly enhanced in the HSYA-treated group. 4. The findings of the present study indicate that HSYA protects the myocardium against ischaemia-reperfusion injury by inhibiting mitochondrial permeability transition pore opening. The effect of HSYA on mitochondrial permeability transition pore opening may be mediated through enhanced nitric oxide production by eNOS activation.
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Clin. Exp. Pharmacol. Physiol. · Jan 2008
Comparative StudyEffects of dipeptidyl peptidase iv inhibition on arterial blood pressure.
1. The aim of the present study was to determine whether inhibition of dipeptidyl peptidase IV (DPP IV) elevates arterial blood pressure and whether any such effect is dependent on genetic background, the sympathetic nervous system and Y(1) receptors. The rationale behind this study was that: (i) neuropeptide (NP) Y(1-36) and peptide YY(1-36) (PYY(1-36)) are endogenous Y(1) receptor agonists and are metabolised by DPP IV to NPY(3-36) and PYY(3-36), which are not Y(1) but rather selective Y(2) receptor agonists; (ii) Y(1) receptors mediate vasoconstriction, whereas Y(2) receptors have little effect on vascular tone; (iii) vaso-constrictor effect of the Y(1) receptor is enhanced in spontaneously hypertensive rats (SHR) compared with normotensive Wistar-Kyoto (WKY) rats; and (iv) NPY(1-36) is released from sympathetic nerve terminals. 2. ⋯ Unlike the results in genetically hypertensive animals, in normotensive WKY rats pretreated with captopril (30 mg/kg, i.v.; MABP = 81 +/- 4 mmHg; n = 6), or hydralazine (5 mg/kg, i.p.; MABP = 63 +/- 4 mmHg; n = 4) or chlorisondamine (10 mg/kg, s.c.; MABP = 63 +/- 4 mmHg; n = 5), P32/98 did not affect arterial blood pressure. 8. We conclude that, in genetically susceptible animals, inhibition of DPP IV increases arterial blood pressure via Y(1) receptors when elevated blood pressure is reduced with antihypertensive drugs provided that the sympathetic nervous system is functional. The results suggest vigilance because DPP IV inhibitors are used more widely in hypertensive patients treated with antihypertensive drugs.
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Clin. Exp. Pharmacol. Physiol. · Jan 2008
Hyperoxia confers myocardial protection in mechanically ventilated rats through the generation of free radicals and opening of mitochondrial ATP-sensitive potassium channels.
1. One hour exposure to hyperoxia has been shown previously to limit a subsequent ischaemia-reperfusion injury in spontaneously breathing rats. We tested the cardioprotective effect of a shorter period of hyperoxia during mechanical ventilation and the possible contribution of reactive oxygen species (ROS) and mitochondrial ATP-sensitive potassium (mitoK(ATP)) channels. 2. ⋯ When rats were pretreated either with NAC before hyperoxic ventilation or with K(ATP) channel blockers before ischaemia, myocardial protection was abolished. 4. Hyperoxic mechanical ventilation, prior to ischaemia, reduces myocardial reperfusion injury. This is likely to occur through the induction of oxidative stress, which leads to myocyte mitoKATP channel opening.