Rino Sugiyama

Functional role of the transient receptor potential melastatin 8 (TRPM8) ion channel in the urinary bladder assessed by conscious cystometry and ex vivo measurements of single-unit mechanosensitive bladder afferent activities in the rat

To evaluate the role of the transient receptor potential melastatin 8 (TRPM8) channel on bladder mechanosensory function by using L‐menthol, a TRPM8 agonist, and RQ‐00203078 (RQ), a selective TRPM8 antagonist.

Influence of urethane‐anesthesia on the effect of resiniferatoxin treatment on bladder function in rats with spinal cord injury

We investigated the effect of resiniferatoxin (RTX)‐treatment on cystometric parameters in the spinal cord injury (SCI) rats in both conscious and urethane‐anesthetized conditions and evaluated the influence of urethane‐anesthesia on the effect of RTX on lower urinary tract (LUT) function in SCI rats.

Selective inhibitory effect of imidafenacin and 5-hydroxymethyl tolterodine on capsaicin sensitive C fibers of the primary bladder mechanosensitive afferent nerves in the rat.

PURPOSE Imidafenacin and fesoterodine are used to treat overactive bladder. Imidafenacin, fesoterodine and its active metabolite 5-hydroxymethyl tolterodine are muscarinic receptor antagonists. It is believed that these agents act on afferent nerves in addition to smooth muscle. We investigated the effects of imidafenacin and 5-hydroxymethyl tolterodine on single unit afferent activity of mechanosensitive capsaicin sensitive and insensitive primary bladder afferent nerve fibers in rats. MATERIALS AND METHODS Female Sprague Dawley® rats were anesthetized. Single unit afferent activity was recorded from the L6 dorsal roots and classified by conduction velocity as that of Aδ or C fibers. After measuring control single afferent activity during constant filling cystometry the procedure was repeated with intravenous administration of imidafenacin (0.3 to 30 μg/kg) or 5-hydroxymethyl tolterodine (0.01 to 1 mg/kg) at cumulative doses with or without intravesical capsaicin or oxotremorine-M instillation. RESULTS A total of 139 single unit afferent fibers were isolated from 111 rats, including 19 Aδ and 120 C fibers. Neither imidafenacin nor 5-hydroxymethyl tolterodine significantly affected the overall single unit afferent activity of Aδ or C fibers. Based on capsaicin sensitivity C fibers were divided into capsaicin sensitive and insensitive groups. Each antimuscarinic inhibited the single unit afferent activity of capsaicin sensitive C fibers but not of capsaicin insensitive C fibers at the highest dose. Moreover, oxotremorine-M facilitated single unit afferent activity in a proportion of C fibers. The facilitated single unit afferent activity was significantly attenuated by the highest dose of imidafenacin. CONCLUSIONS These findings demonstrate that imidafenacin and 5-hydroxymethyl tolterodine can selectively inhibit capsaicin sensitive C fibers among mechanosensitive bladder afferents by antagonizing bladder muscarinic receptors.

Functional roles of bladder α1-adrenoceptors in the activation of single-unit primary bladder afferent activity in rats.

To clarify the involvement of bladder α1‐adrenoceptors (α1‐ARs) in afferent pathways by investigating the effects of silodosin and BMY7378, selective α1A‐ or α1D‐AR antagonists, respectively, on single‐unit afferent nerve fibre activity (SAA) of the primary bladder afferent nerves and their relationship with bladder microcontractions in rats.

Synergic Suppressive Effect of Silodosin and Imidafenacin on Non‐Voiding Bladder Contractions in Male Rats with Subacute Bladder Outlet Obstruction

To investigate single or combined effect of silodosin, an α1A‐adrenoceptor antagonist, and imidafenacin, an antimuscarinic agent, on bladder function in a subacute bladder outlet obstruction (BOO) model of male rats.

Effects of Sildenafil, a Phosphodiesterase Type 5 Inhibitor, on the Primary Single Afferent Activity of the Rat Bladder

We investigated the direct effects of sildenafil, a phosphodiesterase type 5 inhibitor, on the single‐unit mechanosensitive afferent activities (SAAs) primarily originated from the bladder in the rat.

MP8-06 PREVENTIVE EFFECTS OF CALORIC RESTRICTION ON AGING-ASSOCIATED BIOLOGICAL AND MOLECULAR CHANGES IN THE RAT BLADDER AND DORSAL ROOT GANGLIA

maintained on regular diet for 30 weeks. Animals were subjected to the assessment of body weight (BW), body length (BL), waist circumference (WC), body mass index (BMI), blood glucose (BG), plasma insulin (INS), plasma leptin (LEP), total cholesterol (CHO), free fatty acid (FFA) and evaluated for urinary voiding functions. Total body fat measurement, prostate and bladder volumes were analyzed by MRI followed by histological evaluation of the organs. These parameters were used to examine the associations between MS and LUTS. RESULTS: Obesity parameters such as BW, WC, and BMI were significantly higher in B6.V-Lepob/J mice compared to C57BL/6N mice (p<0.01). Higher levels of total CHO and FFA were noted in B6.V-Lepob/ J mice than C57BL/6N mice (p<0.05). These results were concurrent with frequency, lower average urine volume and other urinary voiding dysfunctions inB6.V-Lepob/Jmice.MRIassessmentdemonstratemarked increase in body fat and prostate volume in these mice. Histology of prostate in B6.V-Lepob/J mice showed increased gland crowding and infiltration of immune cells in the stroma, compared to C57BL/6N mice. The regression and correlation analysis indicate that peritoneal fat (R1⁄40.831; p<0.002), BG (R1⁄40.712; p<0.01) and prostate volume (R1⁄40.706; p<0.05) strongly correlate with LUTS whereas BMI, WC, BMI, INS, CHO and FFA moderately correlate with the prevalence of voiding dysfunctions. CONCLUSIONS: Our findings suggests that LUTS may be attributable in part to obesity and MS. Further examination of our in vivo model may lead to understand the underlying pathophysiological mechanisms of obesity-induced LUTS in humans.

MP4-07 VOIDING BEHAVIOR AND TRANSIENT RECEPTOR POTENTIAL (TRP) CHANNEL EXPRESSIONS IN A NOVEL RAT MODEL OF CYSTITIS INDUCED BY HYDROGEN PEROXIDE (H2O2)

METHODS: Thirty female rats were submitted to subcutaneous implant of five PP fragments following the protocol: sham (without mesh); uncoated PP (control); PP coated only with PVA; or PP coated with GSNO+PVA in threeconcentrations: 1, 10and70mMol.Gama irradiation was used to sterilize meshes. Animals were divided into 2 groups (15 each) andwere euthanized at 4 days (group 1) and 30 days (group 2). Abdominal wall was excised en bloc for microscopic analyses. The immunohistochemical analysis was done in order to assess: (a) immunologic response (Interleukin 1IL-1); (b) collagen metabolism (metalloproteinases 2 MMP-2); (c) angiogenesis (surface antigen CD-31). Objective analysis of immunoreactive expression (percent reactive area, total reaction tissue area and vessels concentration) was performed with AxioVision Microscope Software (Karl Zeiss-Germany). RESULTS: It was observed higher vessel density in the PVA and 1mM GSNO+PVA group (p1⁄40,0025 e p1⁄4 0,0081, respectively). There werehigher IL-1averagedensity inall groups in relation to shamat4and30 days (p1⁄40,0056 and p1⁄4 0,0109, respectively). There were no difference among treatments along the time. The total reaction tissue area is higher at 30 than at 4 days for all groups with mesh (p< 0,0001) and higher than the sham in any time of euthansia (p< 0,0001 for 4 days and 30 days). CONCLUSIONS: For this experimental model, in proper concentrations, GSNO coating can increase angiogenesis and change immunologic response to mesh implant There was a increase of IL1 expression, without signicant changes in collagen metabolism. The total reaction tissue increases after mesh implant and over time.

MP1-06 IN VIVO AND IN VITRO BLADDER DYSFUNCTION IN AGED MICE AND ITS SEX DIFFERENCES

INTRODUCTION AND OBJECTIVES: Precise pathophysiology of age-related bladder dysfunction has not been fully clarified yet. In the present study, we aimed to investigate age-related changes in the bladder function of the mouse by using precise frequency volume (FV) measurements, in vitro contractile studies and histological examination of detrusor strips. Gender differences in the age-related changes were also determined. METHODS: C57/BL6 male and female mice were divided into two groups: control (CONT: 12 months-old; n1⁄48 of each sex) and aged (AGED: 27-30 months-old; male: n1⁄46, female: n1⁄47). After FV measurements, in vitro organ bath studies using detrusor strips were carried out to evaluate their contractile responses to high K+ (KCl: 62 mM), carbachol (CCh: 10-3-10-8 M), and to electrical field stimulation (EFS; 2-20 Hz) in the absence and presence of atropine (10-6 M), a,b-methylene ATP (M-ATP: 10-5 M x 5 times). In separate detrusor strips, the muscle/collagen ratio was evaluated by using Masson-trichrome staining. RESULTS: In the FV measurement, there were no significant differences in mean voided volume per micturition between CONT and AGED in either sex, although AGED of both sexes had larger total voided volume per day. Female AGED showed a decreased mean uroflow rate. The contractile responses to high K+ were weaker in AGED of both sexes (Fig.). In addition, those to CCh and EFS were decreased with aging in both sexes, but when standardized by the high K+-induced contraction, the contractile responses to CCh were stronger in AGED of both sexes (Fig.), and those to EFS were stronger only in female AGED. Moreover, AGED of both sexes showed a decreased atropine-sensitive component and an increased M-ATP-sensitive component of the EFS-induced contractions. The muscle/collagen ratio in the muscle layer did not change significantly with aging in either gender. CONCLUSIONS: The current in vitro functional studies with analysis of muscle/collagen ratio indicate the intrinsic contractile property of detrusor smooth muscle in both sexes is potentially impaired with aging. The findings that the contractile responses standardized by the high K+ -induced contraction to CCh and EFS were increased in the aged bladder, suggest a compensatory mechanism for the myogenic impairment. This compensatory mechanism may make the impairment of in vivo bladder function minimal. Source of Funding: none