Eiichiro Takaoka, Joonbeom Kwon, Pradeep Tyagi, Pittsburgh, PA; Motoaki Saito, Nankoku, Japan; Naoki Yoshimura, Pittsburgh, PA INTRODUCTION AND OBJECTIVES: Nerve growth factor (NGF) has been implicated as an important mediator to induce C-fiber bladder afferent hyperexcitability, which contributes to the emergence of neurogenic detrusor overactivity (NDO) following spinal cord injury (SCI). In this study, we examined whether NGF neutralization using anti-NGF antibody normalizes the SCI-induced changes in electro- physiological properties of capsaicin-sensitive C-fiber bladder afferent neurons in the mouse model. METHODS: In female C57BL/6 mice, the spinal cord was transected at the Th8/9 level. Two weeks later, an osmotic pump was placed subcutaneously to administer anti-NGF antibody at 10 mg/kg/h for 2 weeks. Bladder afferent neurons were labeled with axonal trans- port of Fast Blue (FB), a fluorescent retrograde tracer, injected into the bladder wall 3 weeks after SCI. Four weeks after SCI, freshly dissoci- ated L6-S1 dorsal root ganglion neurons were prepared. Whole cell patch clamp recordings were then performed in FB-labeled bladder afferent neurons, and the data were compared between SCI and spinal intact (SI) mice. After recording action potentials (AP) or voltage-gated K + (Kv) currents, the sensitivity of each neuron to capsaicin was evaluated. RESULTS: In capsaicin-sensitive bladder afferent neurons, the resting membrane potentials and the peak and duration of AP did not changed by SCI. On the other hand, the threshold for eliciting AP was significantly reduced in SCI vs. SI mice. Also, SCI increased the number of AP during 800 ms membrane depolarization. These SCI induced changes were reversed by NGF neutralization. SCI induced significant increases in the diameter and cell input capacitance of capsaicin-sen- sitive bladder afferent neurons, which were not reversed by NGF neutralization. Densities of slow decaying K A and sustained K DR cur- rents evoked by depolarization to 0 mV were significantly reduced by SCI. NGF neutralization reversed the SCI-induced reduction in the K A current density. CONCLUSIONS: In SCI mice, NGF plays an important role in hyperexcitability of capsaicin sensitive C-fiber bladder afferent neurons due to K A current reduction. Thus, NGF-targeting therapies could be effective for treatment of afferent hyperexcitability and NDO in SCI. Source of Funding: NIH P01 DK093424 MP42-04 CHARACTERIZING DEVELOPMENT OF THE HUMAN LOWER URINARY TRACT: ANATOMIC FEATURES AND MOLECULAR EXPRESSION OF THE URETERIC BUD AND CLOACA Alexander C Small*, Julia B Finkelstein, Alejandra Perez, Alessia Casale, Ekatherina Batourina, Cathy L Mendelsohn, New York, NY INTRODUCTION AND OBJECTIVES: Embryonic development of the lower urinary tract (LUT) occurs in a rapid and complex sequence where the bladder, urethra and ureters must connect in a stereotypical manner to assure proper form and function. Congenital anomalies of the kidney and urinary tract (CAKUT) are the most common human birth defects. There are limited studies of human developmental anatomy, with great reliance on animal models to infer human translation. This study examined human embryos to establish detailed information on LUT development with special focus on the ureteric bud and cloaca. METHODS: With institutional review board approval, 22 human embryos from Carnegie Stage (CS) 14 to 23 were serially sectioned at 5 mM. Representative sections were analyzed after staining with hema- toxylin and eosin (H&E) for histology and immunohistochemistry (IHC) for genetic expression. ICH used antibodies to Caspase-3, p63, uro- plakin, keratin 5, FoxA2, and E-cadherin. Because mouse develop- mental anatomy and genetic expression are well studied, we compared human embryos to equivalent stages in mouse development. RESULTS: We created a timeline of human LUT development (figure). Insertion of the nephric ducts (ND, also called wolffian ducts) into the cloaca occurs before CS 14 (approximately day 24), estab- lishing a connection between the upper tract and LUT. Shortly after, the ureteric bud emerges from the posterior aspect of the ND and the ureter is joined indirectly to the urogenital sinus via the posterior-most ND segment, the common nephric duct (CND). Contrary to the “Ureteral Bud Theory” (Mackie and Stephens, 1975), the CND does not differ- entiate into the bladder trigone but instead undergoes apoptosis (expressing Caspase-3 on IHC) between CS 15 to 18 (days 36 to 44). Apoptosis separates the ND and ureter in close proximity to the sinus ridge, an epithelial structure located at the dorsal urogenital sinus. Simultaneously, cloacal septation completes by CS 19 (day 48). These findings are consistent with previous mouse studies. CONCLUSIONS: This study provides an important basis for characterizing anatomic and molecular development of the human LUT. Defects in apoptosis and CND remodeling may contribute to reflux or obstruction. Further studies of human samples will be crucial to un- derstand the CAKUT spectrum of pathology. Source of Funding: Research funded by NIDDK U01 (DK110803). Specimens provided by the Joint MRC- Wellcome Trust Human Developmental Biology Resource (099175/Z/12/Z). MP42-05 CHRONIC ORAL ADMINISTRATION OF THE GUANYLATE CYCLASE-C AGONIST LINACLOTIDE ATTENUATES COLITIS INDUCED BLADDER AFFERENT AND DORSAL ROOT GANGLION HYPERACTIVITY Luke Grundy*, Sonia Garcia-Caraballo, Jessica Maddern, Grigori Rychkov, Adelaide, Australia; Pei Ge, Gerhard Hannig, Caroline Kurtz, Ada Silos-Santiago, Cambridge, MA; Stuart Brierley, Adelaide, Australia INTRODUCTION AND OBJECTIVES: Patients suffering from IBS frequently suffer from urological symptoms characteristic of over- active bladder and interstitial cystitis. Cross-organ sensitisation between the bowel and bladder has also been described in pre-clinical studies. Rodents with active colitis exhibit bladder afferent sensitisation and altered cystometry [1,2]. We have previously shown in a model of chronic colonic hypersensitivity (CCH) that bladder mechanical hypersensitivity Vol. 197, No. 4S, Supplement, Saturday, May 13, 2017 THE JOURNAL OF UROLOGY â e545