Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0403608 (ureter)
 9,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The spontaneous activity of guinea-pig renal pelvis-ureter is regulated by the adrenergic system. Spontaneous rhythmic contractions, and contractions induced by Noradrenaline are inhibited by Dihidroergotamine and Phentolamine. Alpha-adrenergic blocking agents block also contractions induced by histamine, angiotensin and barium chloride, but not contractions induced by electric stimulation. The Authors suggest an hypothetical model for the activation of the adrenergic receptor: Noradrenaline (NE) recognition sites are activated only by NE, whereas complementary sites can be activated by NE or other agonists. Both sites are blocked by alpha-adrenergic blocking agents.
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PMID:[Sympathetic mediation of induced and spontaneous activity of the pelvis-ureter in vitro]. 4 5

1. The mechanism responsible for ipsilateral renal vasoconstriction resulting from mechanical stimulation of the ureter was examined using the pharmacological antagonists saralasin, SQ20881, indomethacin, atropine and phentolamine. 2. A segment of PE tubing was implanted in the left ureter, patency being well maintained. Three to four days later renal blood flow was measured bilaterally and antagonists administered intravenously. 3. The mechanism responsible for vasoconstriction could not be attributed to either increased intrarenal noradrenaline or angiotensin, nor to a decreased activity of prostaglandins, kinins or acetylcholine. 4. Histological and bacteriological examination also proved negative. 5. Thus, additional evidence of an unidentified intrarenal mechanism causing vasoconstriction is presented.
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PMID:Intrarenal mechanism for renal vasoconstriction resulting from stimulation of the ureter in the dog. 63 61

To determine the precise localization of the pacemaker in the renal pelvis of the unicalyceal rabbit kidney, the spontaneous activity of muscle strip preparations was investigated in vitro. (1) The highest frequency of spontaneous contractions was found in the most intrarenal part of the renal pelvis. (2) The frequency diminished from the most intrarenal parts to the pyeloureteral junction. (3) No spontaneous activity was observed in ureter preparations; even adrenaline, noradrenaline, acetylcholine and oxytocin did not start any contraction. In the pyeloureteral system the cells with the highest spontaneous frequency will act as a pacemaker. Cells with a less frequent activity can only work as secondary or latent pacemakers.
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PMID:Pacemaker localization in the renal pelvis of the unicalyceal kidney. In vitro study in the rabbit. 65 74

Measurements were taken for the acetylcholine content of animal and human pelviureteral muscle and for the release of acetylcholine at rest and during field stimulation of the isolated renal pelvis and ureter. Release was frequency-dependent, with the maximum output obtained at 10 Hz. The release of acetylcholine from reserpine-pretreated and piperoxan-treated tissues remained unchanged, but tetrodotoxin (1.10(-6) g/ml) and noradrenaline (2.10(-6) g/ml) significantly reduced the output.
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PMID:Acetylcholine content of and release from isolated pelviureteral tract. 66 26

Smooth muscle preparations of the urethra, bladder, and ureter were obtained from patients undergoing operations for various urological disorders. The urethral preparations were contracted by noradrenaline (0.1-3 microgram . ml-1), prostaglandin F2alpha (1-10 microgram . ml-1), and potassium (127 mM), the bladder preparations by carbacholine (0.004-1 microgram . ml-1), prostaglandin F2alpha (1-10 microgram . ml-1), potassium (127 mM), and barium chloride (3 mM), and the ureter preparations by potassium (127 mM), and barium chloride (3 mM). Irrespective of the mode of activation, pretreatment with nifedipine (0.1 microgram . ml-1) for 10 min. reduced the responses. Nifedipine also relaxed preparations contracted by the contractile agents used. In 19 female patients, aged 20 to 73 years, undergoing investigation because of urgency and/or urge incontinence, simultaneous urethrocystometry at rest was performed before and after oral administration of 20 to 40 mg nifedipine. Bladder capacity and residual urine were also determined. Nifedipine did not affect the pressures within the bladder and urethra, nor did it increase the bladder capacity. However, after nifedipine intake there was a statistically significant increase in residual urine. The results suggest that nifedipine can inhibit contractile activity induced by drugs with different modes of action; the drug does not affect the tone in bladder and urethra.
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PMID:Effects of nifedipine on the smooth muscle of the human urinary tract in vitro and in vivo. 69 40

The relation between the inhibitory action of prostaglandin (E1 (PGE1) and external Ca concentration was investigated using the guinea-pig isolated ureter and the perfused central artery of the rabbit isolated ear. PGE1 20 ng/ml reduced the ureteral contraction evoked by a single electrical stimulation. This inhibitory action of PGE1 was enhanced with a decreased external Ca concentration. PGE1 100 ng/ml also reduced Ca-induced contracture of the ureter depolarized in Ca-free K(80 mM)-Krebs' solution. Furthermore, PGE1 50 ng/ml inhibited the responses of peripheral vascular resistance to noradrenaline, and this effect increased with a reduced external Ca concentration.
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PMID:Inhibitory action of prostaglandin E1 on smooth muscle contraction and calcium responses. 70 5

To determine whether the ureter is innervated by the autonomic nervous system, isolated canine ureters were superfused with modified Tyrode solution, and force developed in response to 100-msec duration stimuli at a rate of 3 per min was monitored. Norepinephrine and phenylephrine significantly increased developed force; the latter more than the former. These increases in developed force were blocked by phentolamine, and propranolol enhanced the stimulatory effect of norepinephrine. In the presence of phentolamine, norepinephrine significantly decreased developed force. Isoproterenol significantly decreased developed force and this significant decrease in contractility was not observed in the presence of propranolol. High intensity, high frequency, short duration stimuli which in themselves were unable to excite quiescent rabbit and canine ureteral segments potentiated contractile force of segments contracting at the basal rate of 3 per min in response to long duration stimuli. When these same high intensity, high frequency, short duration stimuli were applied to ureteral segments pretreated with phentolamine, the developed force of the basally driven preparations decreased. These data suggest the presence of alpha-stimulatory and beta-inhibitory adrenergic receptors in canine and rabbit ureter and provide evidence for adrenergic tissue within the wall of the ureter that can influence contractile force.
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PMID:Adrenergic innervation of the ureter. 71 4

The innervation of the male genital tract and kidney in three anuran species was studied by the fluorescence histochemical method of Falck-Hillarp for the demonstration of monoamines whose identity was secured by thin-layer chromatography, and by electron microscopy including administration of 5- or 6- hydroxydopamine (5- and 6-ODHA). The genital tract comprises testis, intra- and extratesticular and intrarenal seminal efferent ducts, Bidder's canal, renal dorsal transverse ducts, and ureter. In addition--depending on the species studied--renal corpuscles and the various portions of uriniferous tubules may be involved in sperm transport. 1. Adrenaline is the main transmitter in nerves supplying the male genital tract and kidney. Only in Xenopus is it possible to demonstrate the presence of noradrenaline, which was confirmed in the chromatographic analysis. No obvious changes are observed with regard to the distribution, amount, and fluorescence intensity of adrenergic fibers and their susceptibility towards 5- and 6-OHDA when comparing animals killed in late autumn and winter, or in late spring, respectively. Non-adrenergic nerve fibers have not been observed. 2. The adrenergic innervation in the testis is only scarce and confined to blood vessels. Neuro-endocrine contacts on Leydig cells are not established. The gonadal ducts and the specific (i.e. non-vascular) are intratesticular smooth muscle cells in Xenopus are not innervated. 3. Apart from the uriniferous tubules (see below), only the ureter receives an adrenergic innervation which, however, is scarce even around the time of spermiation. Bundles of non-terminal and terminal axons are seen running contiguous to the superficial bundles of smooth muscle or smooth muscle-like cells. Neuromuscular relationships comprise synapses at distances of 2000-5--- A, but no close contacts. In the seminal vesicle of Rana the same mode of apposition of adrenergic terminals to muscle cells is observed. In addition, a direct innervation of the epithelium is seen in a few instances. 4. In the kidney the renal arteries, afferent arterioles, and the main branches of the kidney the renal arteries, afferent arterioles, and the main branches of the portal veins are supplied by a dense plexus of adrenergic nerves. Small groups of intensely fluorescent cells are found in the walls of the renal portal veins and veins proper. The density of the arteriolar plexus is more pronounced in Rana and Bufo than in Xenopus. In Rana and Bufo the arteriolar innervation comprises terminals at "ordinary" smooth musculature with membrane-to-membrane appositions, as well as contacts at a distance of 800 to 4000 A on juxtaglomerular epitheloid cells...
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PMID:Innervation of the male genital tract and kidney in the amphibia, Xenopus laevis Daudin, Rana temporaria L., and Bufo bufo L. 80 32

1. The ionic mechanism of the excitatory action of catecholamines and histamine on the smooth muscle cells of guinea-pig ureter was studied with the double sucrose-gap method. 2. In normal conditions adrenaline and noradrenaline in a concentration of 10(-5) g/ml., and histamine in a concentration of 10(-6) g/ml., prolonged the duration of the plateau of the action potential and increased the amplitude and duration of the phasic contraction. Sometimes these changes were accompanied by a slight depolarization of the muscle membrane and by a small increase (with noradrenaline) or decrease (with histamine) of the membrane resistance. The amplitude and duration of the fast spike component of the action potential were not changed. 3. Isoprenaline in a concentration of 10(-5) g/ml. either caused no change or it decreased the duration of the plateau, reduced the amplitude of contractions and reduced excitability. 4. Tetraethyl ammonium (TEA; 5 mM), which blocks the delayed outward K current, did not prevent the increase in the duration of the plateau nor the increase of the amplitude and duration of the contractions by noradrenaline and histamine. 5. In Na-free or in K-free solution or in the presence of ouabain, i.e. in conditions in which the Na-gradient across the membrane was reduced, noradrenaline and histamine were unable to increase the duration of the plateau and the amplitude and duration of the contraction. 6. In the presence of Mn2+ (2 mM) which suppressed the spike component of tha action potential and the phasic contraction, theeffects of noradrenaline and histamine were almost abolished. 7. The results suggest a dual ionic mechanism of the alpha-action of catecholamines and of the action of histamine on the smooth muscle of ureter: (1) these drugs affect the passive ionic permeability of the membrane in a manner that results in depolarization; (2) they specifically activate the potential-dependent conductance of the slow Na channels, thereby increasing the plateau duration. The increased amplitude and duration of the contraction is the result of their primary effect on the plateau of the action potential.
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PMID:The mechanism of the excitatory action of catecholamines and histamine on the smooth muscle of guinea-pig ureter. 84 27

The effects of various drugs on the partially obstructed ureter were investigated in a new model experiment which permitted the calculation of peripheral resistance. After the administration of noradrenaline, the local spasm of the ureter in the region of the obstruction was increased and the urinary flow fell. After administration of the alpha-blocker phentolamine and of the beta-receptor stimulant orciprenaline there was a reduction of the peripheral resistance and an increase in urinary flow due to spasmolysis. Because of its lower side-effect rate, phentolamine is worth investigating in further clinical studies.
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PMID:Possible pharmacological means of treating renal colic. 116 99


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