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

There have been only a few reports of the measurement of autonomic receptors in ureteral smooth muscle. Furthermore, it is so difficult to maintain stable spontaneous contractions in the ureter, that either electrical field stimulation or KCl at high concentrations are utilized to induce ureteral contractions in many in vitro ureteral pharmacologic examinations. We used the spiral ureteral strips which generate spontaneous contractions in the ureter in present experiments. Norepinephrine, phenylephrine, clonidine, carbachol, and prostaglandin F2 alpha enhanced the spontaneous contractile force and/or increased the contractile frequency of spontaneous rhythmic contractions in spirally-incised muscle strips from isolated canine ureters. In contrast, isoproterenol, terbutaline, a beta 2-adrenergic agonist, and prostaglandin E2 reduced the spontaneous contractile force and/or decreased the contractile frequency of spontaneous rhythmic contractions. Dobutamine, a beta 1-adrenergic agonist, did not affect significantly the spontaneous rhythmic contractions. The effects of the prostaglandins were not influenced by autonomic antagonists or tetrodotoxin. The existence of alpha 1-, alpha 2-, and beta-adrenoceptors and muscarinic cholinergic receptors were demonstrated in the canine ureter using radioligand techniques. The density of alpha 1-receptors binding sites was significantly greater than that of the other receptors examined. Our data show that the sympathetic nervous system is more involved than the para-sympathetic nervous system in canine ureteral contractile activities, and that alpha- and beta-receptors contained in canine ureteral smooth muscle are comprised mainly of the alpha 1- and beta 2-subtypes. It is also suggested that prostaglandins directly affect canine ureteral contraction.
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PMID:Function and distribution of autonomic receptors in canine ureteral smooth muscle. 792 Jun 88

Integrins are thought to be essential adhesion receptors for the maintenance of tissue histioarchitecture. The purpose of this study was to determine integrin expression patterns in the human stratified transitional epithelium of the urinary tract (urothelium). In situ expression patterns were compared with in vitro expression, using a normal cell culture model system in which the effects of cell stratification can be studied independently of differentiation. By immunohistological criteria, the urothelia of bladder, ureter and renal pelvis expressed alpha 2 beta 1 and alpha 3 beta 1 integrins in all layers at intercellular junctions, and cytoplasmically in the lower strata. By contrast, alpha 6 beta 4 and occasionally alpha v beta 4 were expressed only by basal cells and localised to the basal lamina. These expression patterns were unaltered in specimens where an inflammatory cell infiltrate was present. In long-term cultures of normal urothelial cells maintained in a low-Ca++ serum-free medium, the monolayer cultures expressed alpha 2 beta 1, alpha 3 beta 1 and alpha 5 beta 1 integrins at intercellular junctions and in cytoplasmic inclusions, whereas alpha 6 beta 4 was distributed in a random pattern over the substratum. Increasing exogenous Ca++ concentrations induced cell stratification and desmosome formation, but not cytodifferentiation. Under these conditions, alpha 6 beta 4 became cell-, rather than substratum-associated, localising particularly to filopodia and lamellipodia. Quantitation of integrin expression by flow cytometry confirmed increased surface expression of alpha 6 beta 4 in high Ca++ media, and also of alpha 3 and alpha 5, but not alpha 2, subunits. These results suggest that alpha 2 beta 1 and alpha 3 beta 1 integrins, although differentially regulated, are mainly involved in homotypic cell-cell interactions and the maintenance of a stratified morphology, whereas alpha 6 beta 4 is the principal integrin involved in substratum adhesion.
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PMID:Expression and in vitro regulation of integrins by normal human urothelial cells. 884 24


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