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

1. A method of recording the peristaltic frequency and the rate of transport of fluid (perfusion rate) in the rat ureter in vivo is described.2. Acetylcholine and atropine did not alter ureteral activity. Histamine increased the rate of peristalsis by up to 15% and the rate of perfusion by up to 10%. Low doses of 5-hydroxytryptamine increased peristaltic frequency whereas high doses decreased peristaltic frequency; all doses reduced the rate of perfusion.3. Morphine reduced the rate of perfusion by 5-10% at all dose levels, but only the highest dose used reduced the frequency of ureteral peristalsis.4. (-)-Adrenaline, (-)-noradrenaline and (+/-)-isoprenaline reduced the frequency of peristalsis. The order of potency was isoprenaline>noradrenaline>adrenaline. The response was dose-related and blocked by propranolol, which itself did not affect ureteral activity.
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PMID:The pharmacology of the rat ureter in vivo. 504 47

The occurrence of histamine H1- and H2-receptors in the human ureter was studied by means of relatively selective agonists and antagonists of both kinds of receptors. Isolated preparations of small strips of human ureters removed during surgery were used. Histamine and the H1-agonist 2-aminoethylthiazole contracted the ureter in a dose-dependent fashion whereas the H2-agonists dimaprit and impromidine were ineffective. The H1-antagonist chlorpheniramine shifted to the right the dose-response curves to histamine and to 2-aminoethylthiazole with the kinetics of the competitive antagonism. Conversely the H2-antagonists cimetidine, metiamide and tiotidine potentiated the effect of histamine by a factor of 3 though high concentrations had to be used (25 - 30 micrograms/ml). Both H1 and H2-antagonists were not able to modify the basal tone and/or motility showed by ureteral strips. All the above data suggested that H1-receptors are predominant in the human ureteral muscle and the contraction induced by their stimulation completely mask the effect of the H2-receptors stimulation. Since H2-agonists were ineffective in basal conditions and H2-antagonists potentiated the effect of histamine which is spasmogenic, we may suggest that H2-receptors are less numerous than H1-receptors and their stimulation cause a slight relaxation of the ureteral muscle. This situation is not uncommon in other smooth muscle system (e.g. respiratory system and gastrointestinal tract).
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PMID:Histamine receptors in the human ureter. 622 45

We investigated the effects of histamine on the motility of isolated segments from canine ureters and characterized pharmacologically the histamine receptors involved. We also evaluated the effects of various autacoids (5-HT, carbachol, noradrenaline, thromboxane, prostaglandin F2alpha) on the motility of canine ureters. Histamine as well as the H1 receptor agonist 2-(2-pyridyl)ethylamine elicited a concentration-dependent contraction. This contractile response was antagonized by dimethindene, causing a rightward shift (pA2 8.30) and a reduction of the slope and the maximal effect (pD'2 6.01) of the concentration-response curve. The histamine H2 receptor antagonist cimetidine in a concentration of 10(-5) mol/l was ineffective concerning the concentration-response curve for histamine. After precontraction of the ureter segments (5-HT, carbachol, prostaglandin F2alpha), a concentration-dependent relaxant effect was evaluated in the presence of histamine or the histamine H2 receptor agonist impromidine. The histamine H2 receptor antagonist cimetidine attenuated the relaxant response, causing a rightward shift of the concentration-response curve. All autacoids except thromboxane were capable of increasing contractility in canine ureters. Comparing the absolute contractile force in the presence of prostaglandin F2alpha, 5-HT, carbachol, noradrenaline and potassium, we found that histamine exhibits the most marked effect on this parameter in the canine ureter. It is concluded that there are two types of histamine receptors modulating contractile activity in the canine ureter: histamine H1 receptors, which mediate contraction, and histamine H2 receptors, which mediate relaxation (in the precontracted tissue).
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PMID:Characterization of histamine receptors in the ureter of the dog. 901 30

Histamine increased the oscillation frequency of the slow-wave activity in the cat ureter and changed the characteristics of the AP plateau phase. A specific and sensitive to histamine electrogenic Na/Ca agent seems to take part in generation of the ureter spontaneous activity.
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PMID:[The action of histamine on the slow-wave and spike activities of the cat and guinea pig ureter]. 948 60

1 The localization of protease-activated receptor-2 (PAR2) and the effects of PAR2 activators were investigated in the mouse isolated ureter in order to test the hypothesis that PAR2 activation may initiate neuropeptide release from sensory nerve fibres and hence contribute to inflammation. 2 PAR2 was localized by fluorescence immunohistochemistry to both the smooth muscle and epithelium of the ureter. Macrophage-like cells in the adventitia of the ureter were also PAR2-immunoreactive. PAR2-immunoreactivity was not observed in mast cells or nerve fibres. 3 In circular muscle preparations of the ureter in which continuous rhythmic beating was induced by KCl (20 mM) and the thromboxane A2 mimetic U46619 (0.3 microM), trypsin (0.3 U ml-1) reduced beat frequency to 84.6+/-2.0% of control rates. The PAR2-selective peptide agonist SLIGRL-NH2 concentration-dependently (0.1-3.0 microM) slowed beat frequency to a maximum of 72.7+/-2.0%. 4 Histamine (1-300 microM) was more efficacious than SLIGRL-NH2 in inhibiting ureter beat frequency in a concentration-dependent manner to a maximum (at 300 microM) of 7.9+/-2.5% of the control rate. 5 Pretreatment of preparations with capsaicin (10 microM for 30 min) markedly attenuated the inhibitory effect of histamine, but not that of SLIGRL-NH2, indicating a role for sensory nerves in the inhibitory effect of histamine only. 6 The inhibitory effect of SLIGRL-NH2 on ureter beat frequency was unaffected by the nitric oxide (NO) synthase inhibitor, L-NOARG (100 microM) or the cyclo-oxygenase inhibitor, indomethacin (3 microM). 7 In conclusion, PAR2 activation causes inhibition of beating in the mouse ureter that is not mediated by axon reflex release of inhibitory neuropeptides. This inhibitory effect of PAR2 appears to be mediated directly on smooth muscle cells, although the contribution of non-NO, non-prostanoid epithelium-derived factors cannot be ruled out.
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PMID:The role of protease-activated receptor-2 (PAR2) in the modulation of beating of the mouse isolated ureter: lack of involvement of mast cells or sensory nerves. 1055 19

Histamine changed characteristics of the perinephric spontaneous spike activity and of the spreading electrical wave. It was shown that histamine could activate latent pacemakers of the ureter's middle area. Morphological picture of the histamine effect was also shown.
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PMID:[Effect of histamine on spontaneous rhythmogenesis of the guinea pig ureter]. 1271 Jan 90

Heterogeneity of the cGMP-dependent contractility effects of the smooth cells (SMC) was shown in guinea pig ureter by the methods of the double sucrose gap junction. Sodium nitroprusside (SN, 0.1-100 microM) relaxed the high-K+ depolarisationprecontracted SMC but strengthened the SMC constriction triggered by electrical stimulation. In taenia coli, SN or nitroglycerin in the same concentration ranges depressed the electrical or mechanical activity of the SMC and relaxed the SMC, precontracted by depolarization in high-K+ medium. The inhibitor of the phosphodiesterases vinpocetine (1 microM) contributed to the activating effect of SN; the inhibitor of the soluble guanilatcyclase Methilen Blue (10 microM) depressed it. Histamine and mesotone (1-10 microM) increased the action potential and constriction of the SMC triggered by electrical stimulation but decreased the effect of SN. The activator of the protein kinase C (PK-C) phorbol miristoyl-13-acetyl (0.5 microM) changed direction of the SN effects inhibiting both the parameters of an action potential and of the SMC constriction. The pre-treatment with the inhibitor of PK-C calphostin C (0.1 microM) additionally depressed the effects of SN, increasing SMC constriction, especially in the presence of histamine and mesatone. We suggest that c-GMP depressed activity of the PK-C by independent mechanisms operating in SMC.
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PMID:[Myogenic effects of cyclic guanosine monophosphate in smooth muscle cells. Role of protein kinase C]. 1296 21