Carvacrol is the major compound of essential oils of many plants, ethnomedically used for centuries but there were no detailed investigations on its action on the cardiovascular system. The aim of our study was to investigate the role of carvacrol on the cardiovascular functions of anesthetized rats and in vitro of isolated rat aorta. Carvacrol (100 microg/kg, I. P.) decreased heart rate, mean arterial pressure and systolic and diastolic blood pressures of the anesthetized rats whereas there were no effects at 1, 10 and 20 microg/kg. Carvacrol was observed to exhibit hypotension and to inhibit N((omega))-nitro- L-arginine methyl ester ( L-NAME)-induced hypertension. The lack of inhibitory action of carvacrol (10 (-4) M) on the CaCl (2)- and phenylephrine-induced contractions of isolated rat aorta showed that neither adrenergic receptors nor voltage-dependent vascular L-type calcium channels were involved. But, based on previous investigations, the involvement of cardiac L-type calcium channel blocking actions are suggested for the hypotensive actions of carvacrol was assumed.

Tumor necrosis factor-alpha (TNF-alpha) has been established as an important mediator in renal ischemia-reperfusion (I/R) injury. Leptin, a product of the ob gene, has been known to exhibit cytoprotective effects on renal tissue, but its effect on renal tissue TNF-alpha level after renal I/R injury in rats remains unknown. The purpose of the study was to evaluate the effects of leptin on renal tissue TNF-alpha, malondialdehyde (MDA), protein carbonyls (PCs) and total sulfydryl group (SH) levels, and plasma nitrite levels after renal I/R injury in rats. The animals were divided into three groups: control, I/R and I/R+leptin. Rats were subjected to renal ischemia by clamping the left pedicle for 45 min, and then reperfused for 1 h. The I/R+leptin group was pretreated intraperitoneally with leptin (10 microg/kg) 30 min before the induction of ischemia. Our results indicate that MDA, TNF-alpha levels, and PCs were significantly higher in the I/R group than those in the control group (p < 0.05). The administration of leptin decreased these parameters (p < 0.05) significantly. The SH level was observed to significantly decrease after I/R injury when compared to the control group (p < 0.05). Leptin treatment significantly increased tissue SH and plasma nitrite levels when compared to the I/R group (p < 0.05). Plasma nitrite levels did not change significantly in I/R when compared to the control. These results suggest that leptin could exert a protective effect on I/R induced renal damage by decreasing TNF-alpha levels and increasing nitrite level.

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