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762Relaxation of porcine and human detrusor muscle by selective and non-selective beta-agonists
DECREASED B L A D D E R ' CAPACITY IN ANIMALS PRONE OVERACTIVE BLADDER: ARE THE BLADDERS TOO SMALL?
761
762
TO
RELAXATION OF PORCINE AND HUMAN DETRUSOR MUSCLE BY SELECTIVE AND NON-SELECTIVE BETA-AGON1STS
Schneider T.~, Michel M. 2
Badawi J.K), Uecelehan H. 1, Langbein S. 1, Hatzinger MJ, Michel M.S?, Haferkamp A.2, Bross S. 1
IUniversitfitsklinikum Essen, Dept. Urology, Essen, Germany, 2University of Amsterdam, Dept. Pharmacology & Pharmacotherapy, Amsterdam, The Netherlands
iUniversity Hospital Mannheim, Urology, Mannheim, Germany, 2University of Heidelberg, Urology, Heidelberg, Germany
INTRODUCTION & OBJECTIVES: Reduced bladder capacity is a hallmark of the overactive bladder (OAB) syndrome. This can be due to functional changes (e.g. altered muscarinic or adrenergic tone) or structural changes (e.g. fibrosis). Advanced age, female gender and hypertension are states which are associated with an increased likelihood to suffer from OAB and/or where the respective animal models show signs of OAB. We have tested whether changes in bladder size as a possible cause of reduced bladder capacity are present in aged, female or hypertensive rats. MATERIAL & METHODS: Young and old (3 vs. 23 months), male and female (12-14 weeks old), and normotensive and hypertensive rats (12-14 weeks old) were compared for body weight (BOW), bladder weight (BLW) and BLW/BOW ratio. Statistical significance of group differences was assessed by two-tailed t-test tests. RESULTS: Aged rats had greater BOW than young rats (642 ± 12 vs, 387 ± 12 g) and BLW (i19 ± 4 vs. i02 ± 5 rag) but BLW/BOW was reduced (0.19 ± 0.01 vs. 0.27 ± 0.01, n = 28-30, p < 0.0001). Female rats had smaller BOW than male rats (228 ~_2 vs. 341 ± 3 g) and BLW (65 ± 1 vs. 85 ± 1 mg) and also a reduced BLW/BOW (0.25 ~_ 0.01 vs. 0.29 =k0.01, n = 142, p < 0.0001). Hypertensive rats had similar BOW as normotensive rats (307 ± 6 vs. 303 ± 5 g), but smaller BLW (63 ± 2 vs. 78 ~: 3 rag) and also smaller BLW/BOW (0.21 ± 0.01 vs. 0.26 ± 0.01, n = 26, p = 0.0003). CONCLUSIONS: We conclude that three conditions with an increased likelihood of OAB symptoms are characterized by a BLW which is too small relative to BOW. This should lead to a reduced relative bladder capacity and hence may contribute to increased frequency in those states.
INTRODUCTION & OBJECTIVES: Urinary bladder dysfunction associated with urinary incontinence is a widely spread disease found in all age groups. One type of urinary incontinence is based on a hyperactive bladder or unstable bladder. In an aging population the urinary incontinence is not only a medical, but also a social and economic problem. At present, antimuscarinic drugs are the therapeutic agents mainly used for detmsor instability and other urinary bladder dysfunctions. Unfortunately, use is limited by different adverse effects and patients have to discontinue the therapy. Therefore, drugs with other mechanisms of action are needed. An interesting therapeutic approach is the use of [3-adrenoceptor-agonists. [3-receptorsplay an important role in the relaxation of detrusor muscle. In this study, the relaxant effects of different [3-adrenoceptor agonists on porcine and human detrusor were examined. Thus, the [3-adrenoceptor subtype mainly responsible for the relaxation in the detrusor muscle of pigs was characterized. Additionally, the relaxant effects of different selective and nonselective [3-agonists in both species were shown. MATERIAL & METHODS: Experiments were performed on porcine detrusor muscle obtained from the abattoir and human detmsor muscle obtained from patients undergoing cystectomy. Muscle strips were suspended in a tissue bath. Examined were the non-selective [3-agonist isoprenaline, the selective [32-agonists procaterol and salbutamol and the selective [33-agonists BRL 37344, CL 316 243 and CGP 12177. Concentration-relaxation curves of this substance were performed on porcine and hmnan detrusor muscle. Additionally, the rank order of potency for endogenous catecholamines was determined in pigs. RESULTS: In pigs the concentration-response experiments showed that the maximum relaxation induced by procaterol arid salbutamol was more than 90%, which was not significantly different from isoprenaline, whereas the maximum relaxations of CL 316 243, BRL 37344 and CGP 12177 amounted to 68%, 70% or 30%, respectively. The rank order of potencies for endogenous catecholamines was isoprenaline >/- adrenaline > noradrenaline in porcine detrusor muscle. In humans isoprenaline, procaterol, salbutamol and CL 316 243 showed a mean maximum relaxation of 80%, 41%, 24% and 35% and pD2 values of 6.24, 5.65, 5.48 and 5.55, respectively. CONCLUSIONS: The [32-adrenoceptor appears to be the most functionally important [3-adrenoceptor in the pig bladder, while both the [32- and the [33-adrenoceptors appear to be equally important in mediating human detrusor smooth muscle relaxation.
763
764
MODULATION OF THE MICTURITION REFLEX IN AN ANESTHETIZED CAT M O D E L T H R O U G H PERCUTANEOUS STIMULATION OF THE T1BIAL NERVE
ACCURACY OF TRANSURETHRAL ENDOSCOPIC AND ULTRASOUND GUIDED INJECTIONS OF BULKING AGENTS
Van der Pal F., Heesakkers J., DebruyneF., Bemelmans B.
Strasser H,, Pinggera G.M., Mitterberger M., Rehder R, Bartsch G.
UMC St. Radboud, Dept. of Urology, Nijmegen, The Netherlands
University of Innsbruck, Department of Urology, Innsbruck, Austria
INTRODUCTION & OBJECTIVES: The tibial nerve is a mixed (sensoryand motor) nerve that originates from the spinal level L4 to S3. Percutaneous stimulation of this nerve has been successfully applied in the treatment of patients with overactive bladder syndrome. The physiological mechanismis still unknown, but it is presumed that signals from and towards the bladder are modulated by retrograde afferent stimulation through the sacral plexus. The present study was designed to investigate whether the concept of bladder inhibition through tibial nerve stimulation cau be confirmedin an anesthetized female cat model.
INTRODUCTION & OBJECTIVES: Transurethral injections of a variety of bulking agents under endoscopic view are widely used to treat urinary incontinence. In an experimental study the precision of endoscopic and ultrasound guided injections was investigated.
MATERIAL & METHODS: 4 female cats (mean 2.9 kg, range 2.5-4) were anesthetized with xylazine (0,5 mg/kg/hour i.v.) and ketamine (5 mg/kg/hour i.v.). A transurethral double lumen micro-tipcatheter (5F) was placed intravesically for pressuremeasurementand bladder filling. A similar single lumen micro-tip catheter was placed transanally for abdominal pressure measurement. The pressure signals were recorded on standard urodynamic equipment. In each animal the baseline micturition reflex volume (MRV) was determined. After emptying of the bladder it was filled with body warm saline (39 °C) at a filling rate of 1 ml/miaute until a clear bladder contraction occurred. This was repeated 2 times. After a resting period of 60 minutes an acupuncture needle was placed near both the left and right tibial nerve. Both needles were connected to a battery driven stimulator. Flexion of the toes on activation of the stimulator confirmed correct needle placement. The MRV was detelrnined again with continuoustibial nerve stimulation (1-4 mA, 100 ~tsec., 10 Hz) at the level of the motor response. Stimulation and bladder filling were stopped immediately when the micturition reflex occurred and cystometrywas continued until baseline values were reached. This was repeated two times. Between the cystometries was a resting period up 5 minutes. Statistically analyses were performedwith the Wilcoxon signed Ranks Test. RESULTS: In one cat MVR could not be determined because of absent bladder reflexes. In the other 3 cats a clear bladder contraction could be observed on filling and mean MRV at baseline was 38 ml (SD 13, range 21-55). On tibial nerve stimulation mean MRV changed to 50 ml (SD 14, range 30-66; p<0.05). The MRV after tibial nerve stimulation returned to baselines values; mean 36 ml (SD 16, range 17-55; p<0.05). In one cat subsequent cystometries after cessation of tibial nerve stimulation showed a carry over effect of 103 minutes. CONCLUSIONS: In this anesthetized cat model it could be proven that acute stimulation of the tibial nerve modulates the volume at which the micturition reflex occurs. The effect of tibial nerve stimulation on the bladder is reversible and in one animal a clear carry over effect could be observed.
MATERIAL & METHODS: Bovine collagen was marked with Indian ink and injected into the lower urinary tract in 20 dead female pigs. In each pig 5 depots of marked collagen were injected. In 5 pigs collagen was injected into the urethral wall under endoscopic control (group I). In the second group collagen depots were injected periurethrally under endosocopic control. In 5 pigs collagen was injected into the urethral wall under sonographic control (group III). In the fourth group collagen depots were injected periurethrally under sonographic control. A transurethral ultrasound probe (23 F) and injection device were used for transurethral ultrasound guided injections. In all pigs the urethra and the periurethral tissue were removed after injection and investigated by means of anatomical preparations and histological sections. RESULTS: In 2 pigs of group I only 2 depots were actually located in the urethral wall (2 out of 25 depots, 8%). In 2 pigs of group II 5 depots could be found in the urethral wall (5 out of 25 depots, 20%). The periurethral collagen depots were found to spread out in the loose connective and fat tissue around the urethra. In group III all ultrasound guided injections of collagen were situated in the urethral wall, in group IV all were located periurethrally. CONCLUSIONS: The present study demonstrates that endoscopic injection of bulking agents is an inaccurate technique. Ultrasound guided injection of bulking agents is much more precise. This technique enables excellent control of the therapeutic procedure.
European Urology Supplements 4 (2005) No. 3, pp. 193
761
762
TO
RELAXATION OF PORCINE AND HUMAN DETRUSOR MUSCLE BY SELECTIVE AND NON-SELECTIVE BETA-AGON1STS
Schneider T.~, Michel M. 2
Badawi J.K), Uecelehan H. 1, Langbein S. 1, Hatzinger MJ, Michel M.S?, Haferkamp A.2, Bross S. 1
IUniversitfitsklinikum Essen, Dept. Urology, Essen, Germany, 2University of Amsterdam, Dept. Pharmacology & Pharmacotherapy, Amsterdam, The Netherlands
iUniversity Hospital Mannheim, Urology, Mannheim, Germany, 2University of Heidelberg, Urology, Heidelberg, Germany
INTRODUCTION & OBJECTIVES: Reduced bladder capacity is a hallmark of the overactive bladder (OAB) syndrome. This can be due to functional changes (e.g. altered muscarinic or adrenergic tone) or structural changes (e.g. fibrosis). Advanced age, female gender and hypertension are states which are associated with an increased likelihood to suffer from OAB and/or where the respective animal models show signs of OAB. We have tested whether changes in bladder size as a possible cause of reduced bladder capacity are present in aged, female or hypertensive rats. MATERIAL & METHODS: Young and old (3 vs. 23 months), male and female (12-14 weeks old), and normotensive and hypertensive rats (12-14 weeks old) were compared for body weight (BOW), bladder weight (BLW) and BLW/BOW ratio. Statistical significance of group differences was assessed by two-tailed t-test tests. RESULTS: Aged rats had greater BOW than young rats (642 ± 12 vs, 387 ± 12 g) and BLW (i19 ± 4 vs. i02 ± 5 rag) but BLW/BOW was reduced (0.19 ± 0.01 vs. 0.27 ± 0.01, n = 28-30, p < 0.0001). Female rats had smaller BOW than male rats (228 ~_2 vs. 341 ± 3 g) and BLW (65 ± 1 vs. 85 ± 1 mg) and also a reduced BLW/BOW (0.25 ~_ 0.01 vs. 0.29 =k0.01, n = 142, p < 0.0001). Hypertensive rats had similar BOW as normotensive rats (307 ± 6 vs. 303 ± 5 g), but smaller BLW (63 ± 2 vs. 78 ~: 3 rag) and also smaller BLW/BOW (0.21 ± 0.01 vs. 0.26 ± 0.01, n = 26, p = 0.0003). CONCLUSIONS: We conclude that three conditions with an increased likelihood of OAB symptoms are characterized by a BLW which is too small relative to BOW. This should lead to a reduced relative bladder capacity and hence may contribute to increased frequency in those states.
INTRODUCTION & OBJECTIVES: Urinary bladder dysfunction associated with urinary incontinence is a widely spread disease found in all age groups. One type of urinary incontinence is based on a hyperactive bladder or unstable bladder. In an aging population the urinary incontinence is not only a medical, but also a social and economic problem. At present, antimuscarinic drugs are the therapeutic agents mainly used for detmsor instability and other urinary bladder dysfunctions. Unfortunately, use is limited by different adverse effects and patients have to discontinue the therapy. Therefore, drugs with other mechanisms of action are needed. An interesting therapeutic approach is the use of [3-adrenoceptor-agonists. [3-receptorsplay an important role in the relaxation of detrusor muscle. In this study, the relaxant effects of different [3-adrenoceptor agonists on porcine and human detrusor were examined. Thus, the [3-adrenoceptor subtype mainly responsible for the relaxation in the detrusor muscle of pigs was characterized. Additionally, the relaxant effects of different selective and nonselective [3-agonists in both species were shown. MATERIAL & METHODS: Experiments were performed on porcine detrusor muscle obtained from the abattoir and human detmsor muscle obtained from patients undergoing cystectomy. Muscle strips were suspended in a tissue bath. Examined were the non-selective [3-agonist isoprenaline, the selective [32-agonists procaterol and salbutamol and the selective [33-agonists BRL 37344, CL 316 243 and CGP 12177. Concentration-relaxation curves of this substance were performed on porcine and hmnan detrusor muscle. Additionally, the rank order of potency for endogenous catecholamines was determined in pigs. RESULTS: In pigs the concentration-response experiments showed that the maximum relaxation induced by procaterol arid salbutamol was more than 90%, which was not significantly different from isoprenaline, whereas the maximum relaxations of CL 316 243, BRL 37344 and CGP 12177 amounted to 68%, 70% or 30%, respectively. The rank order of potencies for endogenous catecholamines was isoprenaline >/- adrenaline > noradrenaline in porcine detrusor muscle. In humans isoprenaline, procaterol, salbutamol and CL 316 243 showed a mean maximum relaxation of 80%, 41%, 24% and 35% and pD2 values of 6.24, 5.65, 5.48 and 5.55, respectively. CONCLUSIONS: The [32-adrenoceptor appears to be the most functionally important [3-adrenoceptor in the pig bladder, while both the [32- and the [33-adrenoceptors appear to be equally important in mediating human detrusor smooth muscle relaxation.
763
764
MODULATION OF THE MICTURITION REFLEX IN AN ANESTHETIZED CAT M O D E L T H R O U G H PERCUTANEOUS STIMULATION OF THE T1BIAL NERVE
ACCURACY OF TRANSURETHRAL ENDOSCOPIC AND ULTRASOUND GUIDED INJECTIONS OF BULKING AGENTS
Van der Pal F., Heesakkers J., DebruyneF., Bemelmans B.
Strasser H,, Pinggera G.M., Mitterberger M., Rehder R, Bartsch G.
UMC St. Radboud, Dept. of Urology, Nijmegen, The Netherlands
University of Innsbruck, Department of Urology, Innsbruck, Austria
INTRODUCTION & OBJECTIVES: The tibial nerve is a mixed (sensoryand motor) nerve that originates from the spinal level L4 to S3. Percutaneous stimulation of this nerve has been successfully applied in the treatment of patients with overactive bladder syndrome. The physiological mechanismis still unknown, but it is presumed that signals from and towards the bladder are modulated by retrograde afferent stimulation through the sacral plexus. The present study was designed to investigate whether the concept of bladder inhibition through tibial nerve stimulation cau be confirmedin an anesthetized female cat model.
INTRODUCTION & OBJECTIVES: Transurethral injections of a variety of bulking agents under endoscopic view are widely used to treat urinary incontinence. In an experimental study the precision of endoscopic and ultrasound guided injections was investigated.
MATERIAL & METHODS: 4 female cats (mean 2.9 kg, range 2.5-4) were anesthetized with xylazine (0,5 mg/kg/hour i.v.) and ketamine (5 mg/kg/hour i.v.). A transurethral double lumen micro-tipcatheter (5F) was placed intravesically for pressuremeasurementand bladder filling. A similar single lumen micro-tip catheter was placed transanally for abdominal pressure measurement. The pressure signals were recorded on standard urodynamic equipment. In each animal the baseline micturition reflex volume (MRV) was determined. After emptying of the bladder it was filled with body warm saline (39 °C) at a filling rate of 1 ml/miaute until a clear bladder contraction occurred. This was repeated 2 times. After a resting period of 60 minutes an acupuncture needle was placed near both the left and right tibial nerve. Both needles were connected to a battery driven stimulator. Flexion of the toes on activation of the stimulator confirmed correct needle placement. The MRV was detelrnined again with continuoustibial nerve stimulation (1-4 mA, 100 ~tsec., 10 Hz) at the level of the motor response. Stimulation and bladder filling were stopped immediately when the micturition reflex occurred and cystometrywas continued until baseline values were reached. This was repeated two times. Between the cystometries was a resting period up 5 minutes. Statistically analyses were performedwith the Wilcoxon signed Ranks Test. RESULTS: In one cat MVR could not be determined because of absent bladder reflexes. In the other 3 cats a clear bladder contraction could be observed on filling and mean MRV at baseline was 38 ml (SD 13, range 21-55). On tibial nerve stimulation mean MRV changed to 50 ml (SD 14, range 30-66; p<0.05). The MRV after tibial nerve stimulation returned to baselines values; mean 36 ml (SD 16, range 17-55; p<0.05). In one cat subsequent cystometries after cessation of tibial nerve stimulation showed a carry over effect of 103 minutes. CONCLUSIONS: In this anesthetized cat model it could be proven that acute stimulation of the tibial nerve modulates the volume at which the micturition reflex occurs. The effect of tibial nerve stimulation on the bladder is reversible and in one animal a clear carry over effect could be observed.
MATERIAL & METHODS: Bovine collagen was marked with Indian ink and injected into the lower urinary tract in 20 dead female pigs. In each pig 5 depots of marked collagen were injected. In 5 pigs collagen was injected into the urethral wall under endoscopic control (group I). In the second group collagen depots were injected periurethrally under endosocopic control. In 5 pigs collagen was injected into the urethral wall under sonographic control (group III). In the fourth group collagen depots were injected periurethrally under sonographic control. A transurethral ultrasound probe (23 F) and injection device were used for transurethral ultrasound guided injections. In all pigs the urethra and the periurethral tissue were removed after injection and investigated by means of anatomical preparations and histological sections. RESULTS: In 2 pigs of group I only 2 depots were actually located in the urethral wall (2 out of 25 depots, 8%). In 2 pigs of group II 5 depots could be found in the urethral wall (5 out of 25 depots, 20%). The periurethral collagen depots were found to spread out in the loose connective and fat tissue around the urethra. In group III all ultrasound guided injections of collagen were situated in the urethral wall, in group IV all were located periurethrally. CONCLUSIONS: The present study demonstrates that endoscopic injection of bulking agents is an inaccurate technique. Ultrasound guided injection of bulking agents is much more precise. This technique enables excellent control of the therapeutic procedure.
European Urology Supplements 4 (2005) No. 3, pp. 193