Eur Urol Suppl 2011;10(2):256 Amplitude before GA (mg) 533±406 666±493 864±427 1072±613 Amplitude after GA (mg) 458±401 524±427 410±186 541±339 Frequency before Oxy (sec) 0.34±0.041 0.48±0.15 0.69±0.24 0.80±0.24 Frequency after Oxy (sec) 0.46±0.072 0.59±0.20 0.83±0.27 0.91±0.26 Frequency before GA (sec) 0.35±0.054 0.36±0.08 0.46±0.19 0.69±0.25 Frequency after GA (sec) 0.37±0.053 0.41±0.10 0.55±0.21 0.76±0.24 Connexin 43 release (density/ mm 2 ) 99.11±44.33 109.69±25.42 167.08±35.57 127.39±50.80 Oxy: Oxybutinin, GA: 18 alpha GA, BOO: Bladder Outlet Obstruction Conclusions: Although previous studies have shown the effects of estrogen on uterine gap junctions and connexin-43 levels, oophorectomy had no effect in the expression of connexin-43, gap junctions in bladder and bladder overactivity, as well. Therefore obstruction, as the main factor increases the amount of gap junctions so gap junction blockers are more effective in the obstruction groups. 808 2-aMinoethoxydiPhenyl borate inhibits CalCiuM sensitization induCed by CarbaChol in ContraCtion of huMan urinary bladder sMooth MusCle Shahab N., Kajioka S., Seki N., Naito S. Kyushu University, Dept. of Urology, Fukuoka, Japan introduction & objectives: We investigated the effect of 2-aminoethoxydiphenyl borate (2-APB) in Ca 2+ sensitization using α-toxin permeabilized strips obtained from human detrusor smooth muscle (DSM). Materials & Methods: Tissue specimens were obtained from the bladder in males undergoing cystectomy due to bladder cancer. After removing mucosa and connective tissues, the smooth muscle was dissected into small strips (300-400 μM in diameter, 3-4 mm in length) and then mounted between 2 tungsten wires, one of which was attached to a force transducer in a Perspex block with 100 μl physiological saline solution buffered by HEPES-Tris under a resting of 100 mg. Permeabilization was done in relaxing solution containing 5,000 U/ml α-toxin for 1 hour. The effect of 2-APB in carbachol (CCh)-induced Ca 2+ sensitization was studied by the application of 100μM 2-APB during sustained contraction induced by 1 μM Ca 2+ , 100 μM GTP and 10 μM CCh. The relative predominant effect of 2-APB on Rho-kinase (ROK) pathway and protein kinase C (PKC) pathway was further investigated using specifc inhibitor of PKC, bisindolylmaleimide I (GF109203X; 5μM) and specifc inhibitor of ROK (Y-27632; 5μM). Low molecular weight of IP-3 inhibitor, heparin (5 mg/ml) was used to confrmed the Ca 2+ independent effect of 2-APB. The experiment was carried out with cyclopiazonic acid (CPA; 1μM) present in all solutions after permeabilization at room temperature. results: The application of 100 μM 2-APB during sustained contraction-induced by 10 μM CCh in the presence of 100 μM GTP at constant 1 μM [Ca 2+ ]i caused marked relaxation (40.9 ± 2.5%; n=4) compared to time matched control (16.3 ± 0.9%; n=3) with P<0.001 (Fig.1A). This relaxation was decreased by 5 μM GF- 109203X or 5 μM Y-27632 (Fig 1B). The relaxation effect of 100 μM 2-APB after pre-application with 5 μM Y-27632 was signifcantly smaller (3.5 ± 0.5%; n=5) than that after pre-application with 5 μM GF-109203X (10.1% ± 0.4%; n=3) with P<0.001. The effect of 2-APB still exist after pre-application of 5 mg/ml heparin. There was no inhibitory effect of 2-APB in the absence of CCh (Fig.1D). Conclusions: 2-APB can relax the CCh-induced DSM contraction of human by decreasing the Ca 2+ sensitivity through both PKC and ROK pathway but predominantly through ROK pathway. The inhibition of Ca 2+ sensitization pathways might represent an alternative target in the treatment of overactive bladder. 809 ChroniC hyPerliPideMia Causes detrusor overaCtivity and inCrease in urinary Prostaglandin e2 release in rabbits Yoshida M. 1 , Masunaga K. 2 , Nagata T. 3 , Miyamoto Y. 1 , Haba T. 1 , Kudoh J. 1 1 Kumamoto Rosai Hospital of Japan Labor Health and Welfare Organization, Dept. of Urology, Kumamoto, Japan, 2 Tokyo Metropolitan Geriatric Hospital, Dept. of Urology, Tokyo, Japan, 3 Social Insurance Saitama Hospital, Dept. of Urology, Saitama, Japan introduction & objectives: Life style diseases and bladder ischemia has been suggested as important etiological factors in overactive bladder. Hyperlipidemia is a well known risk factor for development and progression for cardiovascular diseases. Recently, we demonstrated that chronic hyperlipidemia caused bladder dysfunction including detrusor overactivity in heritable hyperlipidemic rabbits (myocardial infarction-prone Watanabe Heritable Hyperlipidemic rabbits: WHHLMI rabbits). Prostaglandins are synthesized locally in both bladder smooth muscle and mucosa and the synthesis is initiated by various pathologic conditions. In the present study, to evaluate the effects of hyperlipidemia on lower urinary tract function, we examined the relationship between hyperlipidemia-induced bladder dysfunction and urinary prostaglandin E2 (PGE2) level in WHHLMI rabbits. Materials & Methods: WHHLMI rabbits and the age and sex-matched Japanese white rabbits (control group) were prepared. All rabbits were housed in metabolic cage, and the volume and the frequency of micturition was recorded for three days, and 24-h urine samples of all rabbits were collected. Cystometrograms were performed under anaesthesia using constant infusion of saline into the bladder to elicit voiding, and voided volume, residual urine, micturition pressure, and micturition interval were evaluated. 24-h urinary PGE2 levels were assayed by enzyme immunoassay (EIA) by using PGE2 EIA kit-Monoclonal (Cayman Chemical). In addition, immunohistochemical staining of COX-2 of bladder tissue of WHHLMI and control rabbits was performed, using mouse monoclonal anti- COX-2 antibody. results: The number of micturition per day was higher in WHHLMI rabbits (4.24±1.07 times/day) than in control rabbits (1.8±0.3 times/day), and the voided volume was lower in WHHLMI rabbits (14.81±4.60 ml) than in control rabbits (43.8±5.1 ml). In cystometrograms, WHHLMI rabbits showed detrusor overactivity, higher frequency of micturition (7.55±1.25 times/20 min) and lower voided volume (6.92±1.5 ml) than in control rabbits (1.44±2.51 times/20 min and 20.8±3.2 ml, respectively). The urinary excretion of PGE2 was signifcantly higher in WHHL rabbits (6.44±1.87 ng/ml) than in control rabbits (0.91±0.14 ng/ml). Analysis of relationship between parameters of bladder function and urinary PGE2 level in WHHLMI rabbits indicated a signifcantly negative correlation (r=0.81) between urinary PGE2 level and voided volume, and a signifcant positive correlation between urinary PGE2 level and the number of micturition (r=0.86). Immunohistochemical staining of COX-2 showed a signifcant higher immunoreactivity in bladder mucosa of WHHLMI rabbits, as compared to control. Conclusions: The present study suggested that chronic hyperlipidemia caused increase of COX-2 activity in bladder mucosa, which might cause the enhanced PGE2 release, resulting in activation of sensory input and detrusor overactivity. 810 effeCts by the gnrh antagonist ganirelix on norMal MiCturition and Pge2-induCed detrusor overaCtivity in ConsCious feMale rats Russo A. 1 , Castiglione F. 1 , Salonia A. 1 , Benigni F. 1 , Andersson K.E. 2 , Hedlund P. 1 1 Urological Research Institute, Dept. of Urology, Milan, Italy, 2 Wake Forest University, Dept. of Regenerative Medicine, Winston Salem, United States of America introduction & objectives: The gonadotropin-releasing hormone (GnRH) may be involved in the control of micturition. The aim was to study effects of ganirelix, a GnRH receptor antagonist, on bladder function and experimental detrusor overactivity (DO) in female rats. Materials & Methods: After ethical approval, Sprague-Dawley rats were given ganirelix (0.1 mg/kg; n=12) or saline vehicle (controls; n=9) subcutaneously once daily. At two weeks, bladder function and responses to intravesical (ives) PGE2 (50µM) were studied with cystometry in conscious rats (Table). Separately, 5 rats were given ganirelix (1.2mg/L) ives. Effects by carbachol (0.01µM-100µM), ganirelix (1nm-1µM) or activation of nerves were studied in isolated detrusor.