Motility of the human ureter, with special reference to the effect of indomethacin

Current and emerging pharmacological targets for medical expulsive therapy

The primary goals of medical expulsive therapy are to increase the rate of stone expulsion along the ureter to avoid ureteral obstruction and reduce ureteral colic and thus avoid the need for surgical and more invasive interventions. This review focussed on the findings from in vivo and in vitro animal and human studies that have investigated the pharmacological mechanisms controlling ureteral motility and their translation to current and potentially new clinically used drugs for increasing the rate of stone expulsion along the ureter. The complicated contractility profile of the ureter, which alters with age, tissue segment region, orientation and species contributes to the difficulty of interpreting studies on ureteral pharmacology, which translates to the complexity of discovering ideal drug targets for medical expulsive therapy. Nevertheless, the current drug classes clinically used for patients with stone lodgement include α₁ -adrenoceptor antagonists, calcium channel blockers and NSAIDS, whilst there are promising targets for drug development that require further clinical investigations including the phosphodiesterase type 5 enzyme, β-adrenoceptors and 5-HT receptors.

Involvement of Rho-kinase in the contractile mechanism of human ureteral smooth muscle

AIM

Even though many agents have been implicated as modulators of ureteral contractile activity, the exact mechanisms that control human ureteral smooth muscle contractility have yet to be clearly defined. Recently, Rho-kinase has been reported to be involved in the contractile mechanism of smooth muscles in various organs. In the present study, we sought to investigate whether or not Rho-kinase is expressed in the human ureteral smooth muscle, and to study its role regarding human ureteral smooth muscle contractility.

METHODS

Ureteral samples were obtained from human adult subjects undergoing radical nephrectomy. Immunohistochemistry and Western blotting were performed to determine the presence of Rho-kinase in human ureter. Functional studies were performed with human ureteral strips suspended in organ bath, and the effects of Y-27632, a specific inhibitor of Rho-kinase, on baseline tensions, spontaneous contractions, and electrical field stimulation (EFS)-induced contractions were analyzed.

RESULTS

The results of immunohistochemistry and immunoblotting study indicated that Rho-kinase is present in human ureteral smooth muscle. In functional analysis, Y-27632 was shown to decrease the baseline tension. And, both spontaneous and EFS-induced contractile responses of human ureteral strips were attenuated by Y-27632 in dose-dependent manners.

CONCLUSIONS

For the first time, the results of the present study indicate that Rho-kinase is present in human ureteral smooth muscle and may play an important role in the intricate mechanism of human ureteral contractility and tone.

Systemic and topical drug administration in the pig ureter: effect of phosphodiesterase inhibitors alpha1, beta and beta2-adrenergic receptor agonists and antagonists on the frequency and amplitude of ureteral contractions

PURPOSE

We searched for compounds that are pharmacologically active on ureteral motility for treating ureteral colic to ease retrograde access into the ureter and improve the clearance of stones or stone particles from the ureter. The effects of the alpha1-adrenergic receptor agonist phenylephrine, the nonselective beta and beta2-adrenergic receptor agonists isoproterenol and fenoterol, and the phosphodiesterase inhibitors papaverine (nonspecific) and rolipram (type IV) on the frequency and amplitude of ureteral contractions when administered intravenously or topically were investigated in pigs.

MATERIALS AND METHODS

A total of 52 pigs were anesthetized. A double lumen 6Fr catheter was inserted through each renal pelvis and into the ureter, allowing perfusion of saline or drug solution into the renal pelvis and the recording of contractions from the mid portion of the ureter.

RESULTS

The alpha1 and beta-adrenergic receptors of the ureter are not tonically activated by endogenous epinephrine or norepinephrine. Phenylephrine administered intravenously at a dose of 0.01 to 3 mg./kg. and topically at 0.1 to 3 mg./ml. per minute increased contraction frequency 10 and 4-fold, respectively, and contraction amplitude 2-fold each in a dose dependent manner. Arterial blood pressure increased markedly during intravenous administration of phenylephrine but was minimally affected during topical application. The phenylephrine effects were reversed by the antagonist prazosin. Isoproterenol administered intravenously at a dose of 0.01 to 10 mg./kg. and topically at 0.1 to 200 microg./ml. per minute decreased contraction frequency to 13% and 31% of controls, respectively. Contraction amplitude was not affected by intravenous administration but decreased to 59% of controls when applied topically. These effects were also observed with a slight delay in the saline perfused contralateral ureter. The heart rate also increased, suggesting absorption of the drug by the urothelium. The isoproterenol effects were blocked by the antagonist propranolol. Fenoterol administered intravenously at a dose of 0.1 to 30 microg./kg. and topically at 0.003 to 1 mg./ml. per minute decreased contraction frequency to 14% and 10% of controls, and contraction amplitude to 84% and 65%, respectively. These effects on the drug perfused ureter were also observed on the contralateral saline perfused ureter but to a lesser extent. The fenoterol effects were blocked by the antagonist propranolol. Papaverine administered intravenously at a dose of 0.001 to 3 mg./kg. decreased contraction frequency to 33% of controls. Topically administered papaverine as well as intravenous and topically administered rolipram had no relevant effect on ureteral motility.

CONCLUSIONS

Intravenous phenylephrine increases, and isoproterenol and fenoterol decrease the frequency and amplitude of ureteral contractions in the pig. The same effects are observed with the topical administration of phenylephrine, which causes a significant local but not systemic side effect. Topical administration of isoproterenol and fenoterol produced local as well as systemic effects, suggesting absorption by the urothelium. However, to our knowledge a drug that relaxes ureteral peristalsis in pigs without causing systemic side effects has not yet been identified.

Effects of selective inhibitors of cyclo-oxygenase-1 (COX-1) and cyclo-oxygenase-2 (COX-2) on the spontaneous myogenic contractions in the upper urinary tract of the guinea-pig and rat

The role of cyclo-oxygenase-1 (COX-1) and cyclo-oxygenase-2 (COX-2) in the upper urinary tract of the guinea-pig and rat was examined using simultaneous tension recordings of the proximal and distal regions of the renal pelvis and the ureter. The guinea-pig upper urinary tract contracted at a frequency (7.52+/-0.3 min(-1) at 35 degrees C) significantly lower than the frequency in the proximal renal pelvis (21.6+/-1.3 min(-1)) and in the distal renal pelvis and ureter (20.2+/-1.4 min(-1)) of the rat (at 30 degrees C). Indomethacin (>/=1 microM for 60 min), decreased the motility index (amplitudexfrequency) (MI) in all three regions of the guinea-pig upper urinary tract, an effect which mainly arose from a decrease in the frequency of contractions. In the rat, indomethacin (1 - 30 microM for 60 min) significantly decreased the MI calculated in the proximal renal pelvis (>/=30 microM indomethacin), and in the distal renal pelvis (>/=10 microM indomethacin), arising from a significant decrease in the amplitude of contractions. The COX-1 inhibitor, valeryl salicylate (VSA) (5 - 100 microM for 60 min), had no effect on either the amplitude or frequency of contractions in the guinea-pig upper urinary tract. In contrast, VSA increased the force of contractions in the proximal and distal renal pelvis of the rat, whilst having little effect on the frequency of contractions. The COX-2 inhibitor, NS-398 (10 - 100 nM for 60 min) reduced the MI in the guinea-pig upper urinary tract in a concentration-dependent manner. The MIs calculated for the proximal renal pelvis, distal renal pelvis and ureter, were decreased by 72, 64 and 72% respectively, in 100 nM NS-398. NS-398 (10 - 100 nM) had no effect on any of the three parameters measured in either the proximal or distal renal pelvis of the rat. These data suggest that endogenously-released prostaglandins (PGs) maintain the myogenic contractility of the upper urinary tract in both the guinea-pig and rat. Moreover COX-2 is the primary enzyme involved in synthesizing PGs in the guinea-pig upper urinary tract, while COX-1 appears to be the predominantly active enzyme in the rat.

NK-2 is the predominant tachykinin receptor subtype in the swine ureter

OBJECTIVE

To determine which of the known tachykinin receptor subtypes is predominant in the swine ureter.

MATERIALS AND METHODS

Ureters from adult pigs were harvested, cut into longitudinal strips and placed in 10 mL tissue baths containing Krebs buffer, under 4 g of initial tension. The magnitude and frequency of contractions were recorded. Tissues were incubated with 1 micromol/L solutions of peptidase inhibitors (phosphoramidon and captopril) for 1 h to inhibit degradation of peptides and treated with either CP 96,345 (NK-1 receptor antagonist), SR 48,968 (NK-2 receptor antagonist) or saline (control). Concentration-response curves to the tachykinins substance P (SP), neurokinin A (NKA) and neurokinin B (NKB) were determined.

RESULTS

Ureteric segments showed a concentration-dependent response to all tachykinins; NKA stimulated increased contractions at a lower concentration than either SP or NKB (P<0.05). This was reflected by the difference in the effective concentration required to obtain half the maximal response (EC50 ) for each of the peptides. The mean (sd) EC50 values were (micromol/L): NKA, 0.2 (0.02); SP, 3.5 (0.7); and NKB, 4.5 (1.7). In addition, the selective NK-2 antagonist (SR 48,968) significantly reduced contractile responses to all peptides, as indicated by a 10-fold rightward shift of the concentration-response curves (P<0. 05), whereas the NK-1 antagonist (CP 96,345) had no significant effect.

CONCLUSION

These results indicate that NK-2 is the predominant tachykinin receptor subtype responsible for contraction of ureteric smooth muscle. The use of mediators which act on NK-2 receptors may have clinical applications for the treatment of ureteric disease.

Evaluation of ureteric contraction: a comparison among ring, spiral-cut and longitudinal segments

OBJECTIVE

To determine the optimal contractile response of isolated ureters to inflammatory mediators and neurotransmitters by evaluating four common methods of ureteric suspension.

MATERIALS AND METHODS

Ureters from adult domestic swine were placed immediately in Krebs buffer and cut into 4-5 mm segments. Four methods of suspension were compared: (i) an unopened ring segment suspended horizontally; (ii) a spirally cut segment (lumen cut open at a 45 degrees and suspended end-to-end); (iii) an open longitudinal segment; and (iv) a closed longitudinal segment. All segments were placed in individual water-jacketed tissue baths containing Krebs buffer, the frequency of contraction measured using a force transducer and registered on a polygraph. The sensitivity of all four segments was tested by measuring the tension and frequency in response to increasing frequencies of electric field stimulation, and by a cumulative concentration-response curve to carbachol.

RESULTS

Ureteric segments responded with an increased frequency of contraction depending on the intensity of stimulus to both electric field stimulation and carbachol. However, there were no significant differences in spontaneous levels of contraction, sensitivity or maximal response among the methods of suspension in response to electric field stimulation or carbachol.

CONCLUSION

These results indicate that all four methods of suspending the ureteric segments produce contractile responses sensitive enough to study the action of various neurotransmitters.

Effects of potassium channel modulators cromakalim, tetraethylammonium and glibenclamide on the contractility of the isolated human ureter

PURPOSE

Experiments were performed to assess the effect of the potassium channel modulators cromakalim, tetraethylammonium (TEA) and glibenclamide on the contractility of isolated human ureteric rings.

MATERIALS AND METHODS

Segments of human distal ureter obtained from kidney donors (leftovers) were cut into rings and suspended in an organ bath filled with modified Tyrode solution for measurement of isometric contractile force. The ureter was stimulated electrically or with KCl, and the contractile activity recorded on a polygraph.

RESULTS

The amplitude of the contraction induced by electrical stimulation was not changed by glibenclamide but was enhanced by tetraethylammonium. The resting tension of the ureter was not changed by either potassium channel inhibitor. Cromakalim did not change the resting tension of the human ureter per se but induced a concentration-dependent inhibition of the contractions induced by electrical stimulation. This inhibitory effect of cromakalim was not changed by tetraethylammonium but was inhibited by glibenclamide. A phasic and tonic contractile response in the isolated human ureteric ring was induced by 60 mM. KCl. The phasic contractions were abolished by cromakalim whereas the tonic contractions were unaffected. Following sustained contraction induced by 25 mM. KCl, the cumulative addition of cromakalim to the organ bath produced a concentration-dependent relaxation. However, in rings precontracted with 60 mM. KCl, cromakalim at a concentration as high as 10(-5) M. did not induce relaxation. The cromakalim-induced relaxation of rings precontracted with 25 mM. KCl was significantly inhibited by glibenclamide.

CONCLUSION

These results suggest that potassium channels are important in the control of human ureter contractility and that potassium channel openers may be an alternative therapeutic indication in the treatment of human ureteric colic.

Modulation by stereoselective inhibition of cyclo-oxygenase of electromechanical coupling in the guinea-pig isolated renal pelvis

1. The effects of the (S)- and (R)-enantiomers of the cyclo-oxygenase (COX) inhibitor, ketoprofen, have been investigated on the spontaneous activity of the guinea-pig isolated renal pelvis and on electrical field stimulation-(EFS) induced contractions of the guinea-pig ureter in comparison with the effects of the achiral COX inhibitor, indomethacin. 2. (S)-ketoprofen (0.1-100 microM) produced a concentration- and time-dependent inhibition of the spontaneous myogenic activity of the renal pelvis. The maximal inhibitory effect (% inhibition of motility index) averaged 29, 42, 47 and 56% inhibition of control values at 0.1, 1, 10 and 100 microM. The (R)-enantiomer was ineffective up to 10 microM. 3. Indomethacin (0.1-100 microM) likewise produced a concentration- and time-dependent inhibition of spontaneous motility of the isolated renal pelvis: its maximal inhibitory effect was larger than that produced by (S)-ketoprofen and averaged 21, 40, 69 and 95% inhibition of motility index at 0.1, 1, 10 and 100 microM respectively. In the presence of a maximally effective (100 microM) concentration of (S)-ketoprofen, 100 microM indomethacin produced > 90% inhibition of residual motility. 4. In the guinea-pig isolated ureter, phasic contractions were induced by EFS (5 ms pulse width, 60 V): (S)-ketoprofen (100-500 microM) had no effect on the EFS-evoked contractions. Indomethacin (100-500 microM) produced a concentration-dependent inhibition and/or suppression of the EFS-evoked contractions. When contraction of the ureter was evoked by 80 mM KCl, indomethacin produced about 30 and 80% inhibition at 100 and 300 microM, respectively, while (S)-ketoprofen (300 microM) was ineffective. 5. The effect of (S)-ketoprofen or indomethacin (10 microM each) on the propagation of myogenic impulses along the ureter was determined by use of a three chamber organ bath. The renal end of the ureter was electrically stimulated while recording the mechanical activity of the renal and bladder ends of the ureter: addition of either (S)-ketoprofen or indomethacin (10 microM) did not effect propagation of impulses from the renal to the bladder end of the ureter, while nifedipine (10 microM) promptly blocked the propagated contractions. 6. In sucrose gap experiments, (S)-ketoprofen (10-100 microM) produced a time-dependent shortening of spontaneous action potentials of the guinea-pig renal pelvis and reduced the amplitude and duration of the accompanying phasic contractions. Indomethacin (10 microM) produced comparable effects on the same parameters and significantly reduced the maximal amplitude of depolarization of the pacemaker potential. In the presence of 100 microM (S)-ketoprofen, 100 microM indomethacin promptly suppressed the residual pacemaker potential and contraction.7. Neither (S)-ketoprofen nor indomethacin (10 microM each for 60 min) affected the parameters of action potential and contraction of the guinea-pig ureter evoked by EFS. Both drugs produced a sustained membrane depolarization.8. The present findings demonstrate that stereoselective COX inhibition affects pacemaker potentials and contractility (electromechanical coupling) in the guinea-pig renal pelvis. The modulatory role of endogenous prostanoids involves an amplification of electromechanical coupling in the renal pelvis while excitability, contractility or propagation of impulses along the ureter appear almost independent of prostanoid generation. Previous reports of a total suppression of pyeloureteral motility by indomethacin may reflect a combination of COX inhibition and nonspecific effect on electromechanical coupling.

Effects of intrinsic prostaglandins on the spontaneous contractile and electrical activity of the proximal renal pelvis of the guinea-pig

1. The effects of blocking prostaglandin biosynthesis with indomethacin on the spontaneous electrical and contractile activity recorded in smooth muscle strips of the guinea-pig renal pelvis were examined using standard tension and membrane potential recording techniques. 2. Circumferentially cut strips of proximal renal pelvis contracted more frequently (4.5 +/- 0.2 min-1) than strips cut from the mid region (1.3 +/- 0.2; P < 0.05, n = 5) of the renal pelvis. 3. Indomethacin (1 nM-10 microM) reduced the amplitude and frequency of the contractions of the renal pelvis in a concentration- and time-dependent manner. Contractions were completely abolished in the presence of 30 microM indomethacin. 4. After indomethacin blockade, activation of prostaglandin F2 alpha (PGF2 alpha) receptors with dinoprost (1-100 nM) restored the amplitude and frequency of the spontaneous contractions of renal pelvis. Higher concentrations of dinoprost (> 100 nM-3 microM) increased the contraction amplitude of the proximal and mid renal pelvis 1.9 and 1.6 times respectively. The contraction frequency of the mid renal pelvis, but not the proximal pelvis, was also raised above its pre-indomethacin frequency. 5. The spontaneous electrical activity recorded in proximal strips of the renal pelvis was designated to come from three cell types: (i), pacemaker cells (10% of cells recorded), with simple action potentials comprising relatively slow rising and repolarizing phases triggered on top of a slowly-developing pre-potential; (ii), driven cells (75% of cells), with complex action potentials comprising a rapid initial spike, followed by a period of membrane oscillation and a plateau of 0.2-2 s duration; and (iii), intermediate cells (15%) which fired action potentials with an initial rapid and a long plateau phase. 6. Indomethacin (10-30 micro M) decreased the amplitude and frequency of the action potentials recorded in driven and intermediate cells. The membrane potential of these cells also depolarized 5mV to-51.2 +/-2.6mV (n=5).7. Dinoprost (300 nM-1.5 micro M) increased the rate of action potential discharge, without affecting the membrane potential of driven cells previously exposed to indomethacin (30 micro M).8. These data suggest that the endogenous release of prostaglandins is necessary for the in vitro spontaneous contractile activity recorded in the guinea-pig renal pelvis. Blockade of the synthesis of these prostaglandins appears either to modify the ability of the driven regions of the renal pelvis to fire action potentials or to reduce the coupling of these driven regions to their pacemaker cells.

Acute pain management

Analgesic regimens should be based on sound clinical data and tailored to the individual patient's needs. The combination of specific agents for selected syndromes and traditional analgesics allows safe pain relief to be achieved for most emergency patients.

Aqueous extracts of garlic (Allium sativum) inhibit prostaglandin synthesis in the ovine ureter

The prostaglandins (PGs) synthesized from C14-arachidonic acid by the homogenized sheep ureter were identified as being prostacyclin (PGI2), PGF2 alpha and thromboxane B2 (TXB2). The radioimmunoassay (RIA) estimation of 6-keto-PGF1 alpha, a stable metabolite of PGI2, confirms that it was the major metabolite of arachidonic acid. Aqueous extracts of fresh garlic (5, 12.5, 25 and 50 mg/ml) were shown to inhibit the synthesis of the prostanoids in a dose dependent manner. Fresh garlic extracts (1, 2.5, 5 and 10 mg/ml) also dose dependently inhibited spontaneous rhythmic contractions of the isolated ureter. Boiled garlic (5, 12.5, 25 and 50 mg/ml) had no effect on either ureteral motility or the PG synthesizing capacity of the sheep ureter.

The effect of nifedipine and verapamil on rhythmic contractions of human isolated ureter

The effect of calcium antagonists nifedipine and verapamil on spontaneous rhythmic contractions of human isolated ureter obtained from donor subjects undergoing kidney transplantation was investigated in comparison with a nonsteroidal antiinflammatory drug indomethacin. Stop-times i.e. the time elapsing from application, were determined for each drug. The rank order of potency at 10(-8) and 10(-7) M concentrations of the drugs was: nifedipine > verapamil > or = indomethacin. However, no significant difference of the stop-times was observed at 10(-6) M concentration of the drugs tested. The rhythmic contractions were re-activated by PGF2 alpha after stoppage with indomethacin but not with nifedipine or verapamil. These results suggest that not only endogenous PG synthesis but also an influx of calcium from the extracellular space is responsible for the spontaneous rhythmic activity of human ureter. The beneficial effects of using calcium antagonists in the treatment of ureteric colic is discussed.

Extracorporeal shock wave lithotripsy induces the release of prostaglandins which increase ureteric peristalsis

The aim of this study was to identify the changes in secretion of prostaglandins into the urinary tract as a result of treatment by extracorporeal shock wave lithotripsy (ESWL) and to determine their effects on ureteric motility. Sixteen patients with renal or upper ureteric calculi were studied. A peripheral blood and urine sample was collected immediately before and after ESWL, with further samples taken 24 h later. The following variables were assessed by radioimmunoassay:prostaglandin E2 (PGE2), prostaglandin F1 alpha (PGF1 alpha), and thromboxane B2 (TXB2). An in vitro canine study was then designed to study the activity of TXB2, PGF1 alpha and PGE2 on an isolated intact canine ureter model. Significant elevations of TXB2 were found immediately after ESWL in both serum and urine, which fell almost to pre-treatment levels by 24 h. PGF1 alpha levels showed significant elevations at 24 h but no immediate increase as seen with TXB2. In contrast, PGE2 levels were unchanged in the urine but significantly decreased in the serum. In vitro studies showed that both TXB2 and PGF1 alpha repeatedly produced an increased frequency of ureteric contraction. ESWL results in the release of prostaglandins from the urinary tract which are shown to cause increased ureteric peristalsis.

Local motor responses to bradykinin and bacterial chemotactic peptide formyl-methionyl-leucyl-phenylalanine (FMLP) in the guinea-pig isolated renal pelvis and ureter

The local motor response to bradykinin and the bacterial chemotactic peptide, formyl-methionyl-leucyl-phenylalanine (FMLP) was investigated in the guinea-pig isolated renal pelvis and ureter in relation to possible activation of capsaicin-sensitive primary afferent nerves and release of sensory neuropeptides. Both bradykinin (1 nM-10 microM) and FMLP (10 nM-10 microM) produced a concentration-dependent positive inotropic effect in the isolated renal pelvis which was unaffected by in vitro capsaicin desensitization. The response to bradykinin was antagonized by HOE 140, a bradykinin receptor antagonist, while it was unaffected by MEN 10,376, a tachykinin receptor antagonist, hCGRP(8-37) a calcitonin gene-related peptide (CGRP) receptor antagonist and N-t-BOC-Phe-DLeu-Phe-DLeu-Phe (BPLPLP), an FMLP antagonist. The response to FMLP was blocked by BPLPLP while it was unaffected by HOE 140, MEN 10,376 or hCGRP(8-37). Indomethacin (10 microM) enhanced the response to both bradykinin and FMLP. Bradykinin transiently activated rhythmic contractions in the isolated ureter. The response to bradykinin was blocked by HOE 140 and was unaffected by in vitro capsaicin desensitization, indomethacin, MEN 10,376 or BPLPLP. FMLP had no motor effect on the resting ureter but when rhythmic background contractions were evoked by the addition of 100 nM endothelin 1, it produced a transient suppression of ureteral motility. This inhibitory effect was unchanged by in vitro capsaicin desensitization or HOE 140 while it was abolished by indomethacin or BPLPLP pretreatment. Both bradykinin and FMLP evoked the release of CGRP-like immunoreactivity in the renal pelvis. The effect of bradykinin but not that of FMLP was abolished by indomethacin. By contrast neither bradykinin nor FMLP did evoke a significant CGRP-LI release in the ureter. It is concluded that bradykinin and FMLP affect pyeloureteral motility through specific and independent pathways. The local motor responses produced by these chemical stimulants are independent from the release of sensory neuropeptides from capsaicin-sensitive primary afferent neurons. Direct neurochemical evidence was obtained for activation of capsaicin-sensitive primary afferents in the renal pelvis: such a mechanism could be involved in the genesis of ureteral pain whenever bradykinin or FMLP come into contact with sensory nerves in the pyeloureteral wall.

Eicosanoid synthesis in the isolated human renal pelvis, ureter and bladder

Prostaglandin synthetase inhibitors are used for the treatment of ureteric colic. However, there is controversy regarding the mechanism of action of these drugs. In this study, differential prostaglandin synthesis in the human renal pelvis, ureter and bladder was measured using specific radioimmunoassays and gas chromatography/mass spectrometry. There was a significant quantitative predominance of the smooth muscle constrictor eicosanoids, PGF2 alpha and TXA2 over the dilatory PGE2 in tissue from all sites--renal pelvis, ureter and bladder. The results indicate that prostaglandins play a direct role in smooth muscle activity of the upper urinary tract and the inhibition of this activity with indomethacin indicates a further mode of its action in pain relief in ureteric colic.

Oral indomethacin for acute renal colic

A number of studies have suggested that nonsteroidal antiinflammatory agents can relieve renal colic by a mechanism of action different from that of narcotics, offering the potential advantage of avoiding narcotic side-effects such as alteration of mental status. The authors prospectively administered oral indomethacin, 50 mg, to 25 nonvomiting patients with acute renal colic due to a documented stone. Eleven patients group (I) received the drug in an unblinded, nonrandomized fashion after failure of oral or parenteral narcotics to provide satisfactory pain relief, either at home or in the emergency department. In 14 additional patients group (II) indomethacin was given as the only initial treatment. Pain intensity before and after treatment was reported using a 1-to-10 scale. In group I, pain decreased from 5.8 +/- 2.7 to 3.6 +/- 3.8 (P less than .02). Six of the 11 patients reported a decrease in pain intensity of 50% or more, which occurred within 25 +/- 11 minutes, and in 5 of these 6, pain decreased to a 0 or 1 level. In group II, pain decreased from 7.6 +/- 1.5 to 4.6 +/- 4.0 (P less than .008). Eight of the 14 patients reported a decrease in pain intensity of 50% or more, which occurred within 40 +/- 14 minutes, and in 5 of these 8 pain decreased to a 0 or 1 level. Among all 25 patients who received indomethacin, pain relief was not significantly associated with the duration of pain before treatment or with patient age or sex. There was a trend for pretreatment pain intensity to be higher among nonresponders (P = .07).(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of indomethacin and metamizole on ureteral motility and urine flow in sheep

The objective of this study was to evaluate the effect of two non-steroid anti-inflammatory drugs, indomethacin and metamizole, on ureteral peristalsis during acute occlusion similar to the situation in renal colic. In 12 pentobarbital anesthetized sheep, both ureters were cannulated and the frequency of ureteral contractions, urine flow, mean ureteral pressure and blood pressure were recorded during 10-min control and i.v. drug administration periods. Both indomethacin (1-2 mg/kg) and metamizole (60-120 mg/kg) showed a dose dependent reduction in peristaltic frequency without reduction of the mean pressure. In addition, the pressure amplitude of the peristaltic waves was also lowered, particularly with indomethacin. Only indomethacin reduced the urine flow. Arterial blood pressure was elevated by both drugs, particularly after the first dose of indomethacin. It can be concluded that indomethacin and metamizole reduce ureteral peristaltic frequency, probably blocking the impulse transmission at the ureteropelvic junction.

Indomethacin suppository to treat primary nocturnal enuresis: double-blind study

The prostaglandin synthesis inhibitor indomethacin (used as a suppository) was compared to placebo in the treatment of primary nocturnal enuresis in a double-blind crossover study. There were 12 girls and 7 boys between 6 and 15 years old. Indomethacin (50 to 100 mg.) was significantly more effective than placebo in the treatment of primary enuresis.

The effect of ureteral distension on peristalsis. Studies on human and sheep ureters

Isolated sheep and human ureteral preparations (from patients with bilharzia) were subjected in-vitro to graded elongation and the effect on tension and spontaneous peristaltic frequency was assessed. Sheep specimens were obtained from three locations: the intra- and extrarenal portion of the pelvis and distal ureter. Elongation (stretch) induced an increase in spontaneous frequency only in pelvic ureteric specimens, but not in the distal ureter. Basal tension increased exponentially with stretch and most markedly in the distal sheep ureter and also in human preparations. Active tension (amplitude of phasic contractions) increased with stretch in specimens from all locations and reached a maximum at 110-115% elongation. These data suggest that acute distension of the ureter increases frequency of peristaltic waves only in the intrarenal parts of the ureter. Acute obstruction in renal colic can induce hypermotility in terms of increased frequency and force of contraction.

The effects of urine on mast cells and smooth muscle of the human ureter

Electron microscopy was performed on normal human ureteral rings before and after incubation in human urine for 30 minutes. A large number of mast cells was detected subepithelially and in close proximity to smooth muscle fibres. Treatment with urine (346 mOsm/l) induced various degrees of degranulation in the majority of mast cells. Some membrane bound granules were found free in the surrounding connective tissue and near smooth muscle cells indicating rupture of the cell membrane. In the functional study frequency and amplitude of peristaltic contractions were studied in-vitro. Addition of urine increased frequency and amplitude of peristaltic contractions and addition of the histamine-1-blocker mepyramine (10(-6) M) partially reversed these changes. It can be concluded that in a situation with urothelial damage such as ureteral calculus, urine can penetrate subepithelially and induce degranulation of mast cells with release of mediators. This is followed by forceful peristaltic contractions which are induced by histamine and other newly formed mediators such as prostaglandins. The process is likely to occur in renal colic with impacted kidney stones.

The effect of urothelial damage on ureteric motility. An ultrastructural and functional study

Evidence of a leaky urothelial barrier in bilharzial uropathy is presented. The ultrastructural basis of this concept is demonstrated together with its functional consequences. The study was conducted on 4 ureters obtained at surgery from patients with non-functioning kidneys due to chronic bilharzial infections. Six normal ureters from kidney donors served as controls. Light and electron microscopic studies showed a reduced thickness of the transitional epithelium together with localised disruption of intercellular junctions and infiltration of red blood cells. The functional studies involved in vitro demonstration of stable phasic peristaltic contractions which were fundamentally altered by the addition of urine. The changes in motility included increase in contractile frequency and elevation of basal tone, inducing a state of hypermotility which could be equated with ureteric spasm. These changes were partly reversible upon administration of the histamine l-blocker, mepyramine. Evidence is presented to show that these changes might be induced in vivo by histamine released from mast cells triggered by urine leaking through a damaged urothelial barrier. The functional consequences (pain, spasm) are discussed.

Mast cells and histamine responses of the ureter, ultrastructural features of cell-to-cell associations and functional implications

In this study of normal adult human and ovine ureters, a characteristic distribution of a large population of typical mast cells was described by light and electron microscopy. Pharmacological studies were used to ascribe a functional role for these cells in normal and pathological states. In the structural investigations typical mast cells with their cytoplasm packed with characteristic electron dense granules were found in close vicinity to smooth muscle cells. A close association between mast cells and a fibroblast like La-cell and non myelinated nerve fibers was noted. The prevalence of mast cells was higher in human ureters. Human and sheep ureteral ring preparations exhibited spontaneous rhythmical contractions in vitro. Addition of histamine (10(-6)-10(-5) M) induced an increase in the frequency of contractions and enhanced the basal tone particularly in human samples. It is likely that histamine under pathological conditions such as renal colic and inflammatory reactions is released from mast cells within the ureter and induces a state of forceful contractions and pain fibre stimulation.

The action of the prostaglandins on isolated human ureteric smooth muscle

A study has been carried out on the actions of the prostaglandins E2 and F2 alpha and their synthesis inhibitors, indomethacin and diclofenac sodium, upon isolated human ureteric smooth muscle, using the technique of microsuperfusion designed to ensure good tissue viability. Indomethacin and diclofenac sodium were shown to abolish almost completely the contractile response of ureteric muscle to electrical field stimulation. Contractile activity, in the presence of the inhibitors, could be restored by prostaglandin E2 or F2 alpha or by increasing the external potassium concentration, [K+]O, of the superfusate. Prostaglandin E2 or F2 alpha alone were shown to increase dramatically both the phasic and tonic component of the electrically stimulated contractions, on occasions inducing spontaneous activity. A possible mechanism of action was elucidated with an electrophysiological technique using intracellular microelectrodes. The mean membrane potential recorded was 54.7 mV (SD +/- 10 mV, n = 15). The depolarising action of raising [K+]O was demonstrated and prostaglandin F2 alpha (3 x 10(-6) M) was shown to produce a small depolarisation of the ureteric muscle cell membrane.

The effect of prostaglandin synthesis inhibition on motility of the sheep ureter

To determine the effect of prostaglandin-synthesis inhibition on ureteral motility, isolated rings of sheep ureters were suspended for recording isometric tension in organ baths filled with Krebs-Henseleit solution. The non-steroidal anti-inflammatory drugs (NSAIDs) indomethacin and diclofenac sodium (10(-5) M) inhibited rhythmic ureteral motility by reducing frequency, amplitude and finally stopping contractions. Prostaglandin F2 alpha, 6-keto-prostaglandin F1 alpha and thromboxane B2 were determined by radioimmunoassay in the bathing solution before and after addition of NSAIDs. Peak contractile activity at 100 min of suspension was associated with increased concentration of all three prostanoids and 50 min after addition of indomethacin and diclofenac sodium when rhythmic contractions stopped, concentration dropped to low levels. The concentration of prostaglandins released into the organ bath were not quantitatively related to the frequency of contractions and therefore do not seem to affect pacemaker activity within ureteral smooth muscle but rather intercellular recruitment of myo-genically active fibres. These findings indicate that prostaglandins play a role in the motor control of the ureter, and that non-steroidal anti-inflammatory drugs exert an inhibitory action.

Generation and transmission of ovine ureteral contractions, with special reference to prostaglandins

The pattern of spontaneous rhythmic contractions was studied in isolated preparations from calyx, pelvic, middle and distal parts of the sheep ureter. The frequency of contractions was highest in intrarenal specimens (13.3 +/- 0.8 contractions min-I). The regional difference in contractions is consistent with proximal dominant pacemaker cells. In isolated rings, indomethacin (10(-5) M) inhibited and finally stopped rhythmic motility. After stoppage prostaglandin PGF2 alpha (10(-6)-10(-5) M) promptly re-established contractions in a manner characteristic of each specimen, apparently according to the pre-existent dominant pacemaker (frequency and pattern). This was demonstrated in a frequency analysis which showed a highly significant correlation of pacemaker frequencies before and after indomethacin. Experiments using dual recordings from both ends of a longitudinal preparation (tandem mode) showed that co-ordinated contractile waves travelling from one end to the other could be initiated with PGF2 alpha. These results have been interpreted to indicate that prostaglandins in ureteral smooth muscle play a predominant role in co-ordinating intercellular impulse transmission for which gap junctions could be responsible. The presence of such structures, as clearly demonstrated by an ultrastructural study, lends support to this hypothesis.