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Query: UMLS:C0403608 (ureter)
 9,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It is not clear how the increase in intraluminal pressure behind an obstructing ureteric calculus causes an increase in action potential frequency in ureteric sensory nerves so the pain messages are transmitted to the brain. It has been proposed that ureteric distension causes urothelial release of ATP, which activates purinoceptors on suburothelial nociceptive sensory nerves. The purpose of this study was to determine whether distension of the human ureter results in the release of ATP and whether the nociceptive P2 receptor, P2X(3), is expressed on suburothelial sensory nerves in the human ureter. Human ureter segments were perfused with Krebs solution and intermittently distended to a range of pressures. Samples of perfusate were collected throughout and the ATP concentration ([ATP]) was determined using a luciferin-luciferase assay. Sections of ureter were stained using antibodies against P2X(3) and capsaicin receptors (TRPV1). [ATP] rose to more than 10 times baseline levels after distension beyond a threshold of 25-30 cmH(2)O. Immunofluorescence studies on consecutive frozen sections showed that suburothelial nerves stained positively for P2X(3) and capsaicin receptors, with no staining in controls. These findings are consistent with the hypothesis that purinergic signalling is involved in human ureteric mechanosensory transduction, leading to nociception.
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PMID:ATP release from the human ureter on distension and P2X(3) receptor expression on suburothelial sensory nerves. 1881 20

The suppression of renal energy metabolism during ureteral obstruction is a well-known phenomenon; however, its exact responsible mechanism(s) and association with simultaneously induced renal oxidative stress have not been clarified. This study examined the improving effects of L: -carnitine, a facilitating cofactor for mitochondrial oxidation of fatty-acids as well as a scavenger of free-radicals, and alpha-tocopherol as the most potent antioxidant on renal metabolic defect and oxidative stress induced by acute unilateral ureteral obstruction (UUO). The left ureter was ligated in ether-anaesthetised rats, in which L: -carnitine, alpha-tocopherol or their vehicles were intraperitoneally injected in four different groups. After elapsing 24 h of UUO-induction, both kidneys were removed and stored at -80 degrees C. There were also two sham-operated and control groups. The kidney samples were assessed to measure the levels of ferric reducing/antioxidant power (FRAP) and malondialdehyde (MDA) for evaluating their redox state, as well as, their amounts of adenosine triphosphate (ATP) and adenosine diphosphate (ADP) by using luciferin-luciferase method. As much as 24 h of UUO in vehicle-treated groups caused increases in MDA and ADP, but decreases in FRAP, ATP, and ATP/ADP of the obstructed kidney with respect to those of the sham group. alpha-tocopherol normalised the levels of MDA and FRAP but did not affect the altered amounts of energy metabolic indices in the obstructed kidney, while L: -carnitine could ameliorate all of them. These findings suggest that oxidative stress may not involve in development of acute UUO-induced suppression of renal aerobic metabolism, and probably reduction of energy substrates is a responsible factor.
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PMID:Comparison of the effects of L: -carnitine and alpha-tocopherol on acute ureteral obstruction-induced renal oxidative imbalance and altered energy metabolism in rats. 1994 Sep 86