1
|
Zimmerman LL, Mentzelopoulos G, Parrish H, Marcu VI, Luma BD, Becker JB, Bruns TM. Immediate and Long-Term Effects of Tibial Nerve Stimulation on the Sexual Behavior of Female Rats. Neuromodulation 2024; 27:343-352. [PMID: 36609088 DOI: 10.1016/j.neurom.2022.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 11/07/2022] [Accepted: 11/08/2022] [Indexed: 01/06/2023]
Abstract
OBJECTIVES There are limited treatment options for female sexual dysfunction (FSD). Percutaneous tibial nerve stimulation (PTNS) has shown improvements in FSD symptoms in neuromodulation clinical studies, but the direct effects on sexual function are not understood. This study evaluated the immediate and long-term effects of PTNS on sexual motivation and receptivity in a rat model of menopausal women. Our primary hypothesis was that long-term PTNS would yield greater changes in sexual behavior than short-term stimulation. MATERIALS AND METHODS In two experiments, after receiving treatment, we placed ovariectomized female rats in an operant chamber in which the female controls access to a male by nose poking. We used five treatment conditions, which were with or without PTNS and no, partial, or full hormone priming. In experiment 1, we rotated rats through each condition twice with behavioral testing immediately following treatment for ten weeks. In experiment 2, we committed rats to one condition for six weeks and tracked sexual behavior over time. We quantified sexual motivation and sexual receptivity with standard measures. RESULTS No primary comparisons were significant in this study. In experiment 1, we observed increased sexual motivation but not receptivity immediately following PTNS with partial hormone priming, as compared with priming without PTNS (linear mixed effect models; initial latency [p = 0.34], inter-interval latency [p = 0.77], nose poke frequency [p = 0.084]; eight rats). In experiment 2, we observed trends of increased sexual receptivity (linear correlation for weekly group means; mounts [p = 0.094 for trendline], intromissions [p = 0.073], lordosis quotient [p = 0.58], percent time spent with a male [p = 0.39], decreased percent time alone [p = 0.024]; four rats per condition), and some sexual motivation metrics (linear correlation for weekly group means; nose pokes per interval [p = 0.050], nose poke frequency [p = 0.039], decreased initial latency [p = 0.11]; four rats per condition) when PTNS was applied long-term with partial hormone priming, as compared with hormone-primed rats without stimulation. CONCLUSIONS PTNS combined with hormone priming shows potential for increasing sexual motivation in the short-term and sexual receptivity in the long-term in rats. Further studies are needed to examine variability in rat behavior and to investigate PTNS as a treatment for FSD in menopausal women.
Collapse
Affiliation(s)
- Lauren L Zimmerman
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA; Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
| | - Georgios Mentzelopoulos
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA; Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA; Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, USA
| | - Hannah Parrish
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA; Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, USA
| | - Vlad I Marcu
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA; Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, USA; Department of Engineering Physics, University of Michigan, Ann Arbor, MI, USA
| | - Brandon D Luma
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA
| | - Jill B Becker
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA; Department of Psychology, University of Michigan, Ann Arbor, MI, USA
| | - Tim M Bruns
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA; Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA.
| |
Collapse
|
2
|
Zhou Z, Wang X, Li X, Liao L. Transdermal tibial nerve optogenetic stimulation targeting C-fibers. Front Physiol 2023; 14:1224088. [PMID: 37492642 PMCID: PMC10365128 DOI: 10.3389/fphys.2023.1224088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 06/19/2023] [Indexed: 07/27/2023] Open
Abstract
Purpose: To explore whether stimulation of C-fibers in tibial nerves can induce bladder inhibition by optogenetic transdermal illumination. Methods: Ten rats were injected with AAV2/6-hSyn-ChR2(H134R)-EYFP into the tibial nerves. Transurethral cystometry was performed 4 weeks after the virus injection. Illumination (473-nm blue light at 100 mW) was performed with the fiber positioned above the right hind paw near the ankle. The light transmission efficiency was examined with a laser power meter. The effects on cystometry were compared before and after illumination with the bladder infused with normal saline and acetic acid, respectively. Result: Upon transdermal delivery of 473-nm light at a peak power of 100 mW, the irradiance value of 0.653 mW/mm2 at the target region was detected, which is sufficient to activate opsins. The photothermal effect of 473-nm light is unremarkable. Acute inhibitory responses were not observed during stimulation regarding any of the bladder parameters; whereas, after laser illumination for 30 min, a statistically significant increase in bladder capacity with the bladder infused with normal saline (from 0.53 ± 0.04 mL to 0.72 ± 0.05 mL, p < 0.001) and acetic acid (from 0.25 ± 0.02 mL to 0.37 ± 0.04 mL, p < 0.001) was detected. A similar inhibitory response was observed with pulsed illumination at both 10Hz and 50Hz. However, illumination did not significantly influence base pressure, threshold pressure, or peak pressure. Conclusion: In this preliminary study, it can be inferred that the prolonged bladder inhibition is mediated by the stimulation of C-fibers in the tibial nerves, with no frequency-dependent characteristics. Although the 473-nm blue light has limited penetration efficacy, it is sufficient to modulate bladder functions through transdermal illumination on the superficial peripheral nervous system.
Collapse
Affiliation(s)
- Zhonghan Zhou
- Shandong University, Jinan, Shandong, China
- Department of Urology, China Rehabilitation Research Center, Beijing, China
- University of Health and Rehabilitation Sciences, Qingdao, Shandong, China
- China Rehabilitation Science Institute, Beijing, China
- Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Xuesheng Wang
- Department of Urology, China Rehabilitation Research Center, Beijing, China
- University of Health and Rehabilitation Sciences, Qingdao, Shandong, China
- School of Rehabilitation, Capital Medical University, Beijing, China
- China Rehabilitation Science Institute, Beijing, China
- Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Xunhua Li
- Department of Urology, China Rehabilitation Research Center, Beijing, China
- University of Health and Rehabilitation Sciences, Qingdao, Shandong, China
- School of Rehabilitation, Capital Medical University, Beijing, China
- China Rehabilitation Science Institute, Beijing, China
- Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Limin Liao
- Shandong University, Jinan, Shandong, China
- Department of Urology, China Rehabilitation Research Center, Beijing, China
- University of Health and Rehabilitation Sciences, Qingdao, Shandong, China
- School of Rehabilitation, Capital Medical University, Beijing, China
- China Rehabilitation Science Institute, Beijing, China
- Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| |
Collapse
|
3
|
Paquette JP, Yoo PB. Recruitment of unmyelinated C-fibers mediates the bladder-inhibitory effects of tibial nerve stimulation in a continuous-fill anesthetized rat model. Am J Physiol Renal Physiol 2019; 317:F163-F171. [PMID: 31141398 DOI: 10.1152/ajprenal.00502.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Although percutaneous tibial nerve stimulation is considered a clinically effective therapy for treating overactive bladder, the mechanism by which overactive bladder symptoms are suppressed remains unclear. The goal of the present study was to better understand the role of specific neural inputs (i.e., fiber types) on the bladder-inhibitory effects of tibial nerve stimulation (TNS). In 24 urethane-anesthetized rats, a continuous suprapubic saline infusion model was used to achieve repeated filling and emptying of the bladder. A total of 4 TNS trials (pulse frequency: 5 Hz) were applied in randomized order, where each trial used different amplitude settings: 1) no stimulation (control), 2) Aβ-fiber activation, 3) Aδ-fiber activation, and 4) C-fiber activation. Each stimulation trial was 30 min in duration, with an intertrial washout period of 60-90 min. Our findings showed that TNS evoked statistically significant changes in bladder function (e.g., bladder capacity, residual volume, voiding efficiency, and basal pressure) only at stimulation amplitudes that electrically recruited unmyelinated C-fibers. In a subset of experiments, TNS also resulted in transient episodes of overflow incontinence. It is noted that changes in bladder function occurred only during the poststimulation period. The bladder-inhibitory effects of TNS in a continuous bladder filling model suggests that electrical recruitment of unmyelinated C-fibers has important functional significance. The implications of these findings in percutaneous tibial nerve stimulation therapy should be further investigated.
Collapse
Affiliation(s)
- Jason P Paquette
- Institute of Biomaterials and Biomedical Engineering, University of Toronto , Toronto, Ontario , Canada
| | - Paul B Yoo
- Institute of Biomaterials and Biomedical Engineering, University of Toronto , Toronto, Ontario , Canada.,Department of Electrical and Computer Engineering, University of Toronto , Toronto, Ontario , Canada
| |
Collapse
|
4
|
Hotta H, Watanabe N. Gentle Perineal Skin Stimulation for Control of Nocturia. Anat Rec (Hoboken) 2019; 302:1824-1836. [PMID: 30980505 DOI: 10.1002/ar.24135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 10/30/2018] [Accepted: 11/18/2018] [Indexed: 11/06/2022]
Abstract
One of the major causes of nocturia is overactive bladder (OAB). Somatic afferent nerve stimuli are used for treating OAB. However, clinical evidence for the efficacy of this treatment is insufficient due to the lack of appropriate control stimuli. Studies on anesthetized animals, which eliminate emotional factors and placebo effects, have demonstrated an influence of somatic stimuli on urinary bladder functions and elucidated the underlying mechanisms. In general, the effects of somatic stimuli are dependent on the modality, location, and physical characteristics of the stimulus. Recently we showed that gentle stimuli applied to the perineal skin using a soft elastomer roller inhibited micturition contractions to a greater extent than a roller with a hard surface. Studies aiming to elucidate the neural mechanisms of gentle stimulation-induced inhibition reported that 1-10 Hz discharges of low-threshold cutaneous mechanoreceptive Aβ, Aδ, and C fibers evoked during stimulation with an elastomer roller inhibited the micturition reflex by activating the spinal cord opioid system, thereby reducing both ascending and descending transmission between bladder and pontine micturition center. The present review will provide a brief summary of (1) the effect of somatic electrical stimulation on the micturition reflex, (2) the effect of gentle mechanical skin stimulation on the micturition reflex, (3) the afferent, efferent, and central mechanisms underlying the effects of gentle stimulation, and (4) a translational clinical study demonstrating the efficacy of gentle skin stimuli for treating nocturia in the elderly with OAB by using the two roller types inducing distinct effects on rat micturition contractions. Anat Rec, 302:1824-1836, 2019. © 2019 American Association for Anatomy.
Collapse
Affiliation(s)
- Harumi Hotta
- Department of Autonomic Neuroscience, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Nobuhiro Watanabe
- Department of Autonomic Neuroscience, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| |
Collapse
|
5
|
Casella DP, Dudley AG, Clayton DB, Pope JC, Tanaka ST, Thomas J, Adams MC, Brock JW, Caskey CF. Modulation of the rat micturition reflex with transcutaneous ultrasound. Neurourol Urodyn 2017; 36:1996-2002. [DOI: 10.1002/nau.23241] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 01/18/2017] [Accepted: 01/23/2017] [Indexed: 02/04/2023]
Affiliation(s)
| | - Anne G. Dudley
- Vanderbilt University Medical Center; Nashville Tennessee
| | | | - John C. Pope
- Vanderbilt University Medical Center; Nashville Tennessee
| | | | - John Thomas
- Vanderbilt University Medical Center; Nashville Tennessee
| | - Mark C. Adams
- Vanderbilt University Medical Center; Nashville Tennessee
| | - John W. Brock
- Vanderbilt University Medical Center; Nashville Tennessee
| | | |
Collapse
|
6
|
Inhibitory effects of tibial nerve stimulation on bladder neurophysiology in rats. SPRINGERPLUS 2016; 5:35. [PMID: 26835217 PMCID: PMC4713404 DOI: 10.1186/s40064-016-1687-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 01/06/2016] [Indexed: 11/10/2022]
Abstract
Tibial nerve stimulation (TNS) is a form of peripheral neuromodulation which has been found effective in treating overactive bladder symptoms, with lesser side effects than first line pharmacotherapy. Despite its widespread clinical use, the underlying mechanism of action is not fully understood. Our aim was to study its effect on the bladder neurophysiology and the trigger mechanism of voiding in the overactive detrusor, simulated by acetic acid (AA) instillation. In urethane anaesthetized male Wistar rats, the tibial nerve was stimulated for 30 min at 5 Hz, pulse width 200 µs and amplitude approximately three times the threshold to induce a slight toe movement. The pressure at which a voiding contraction was triggered (pthres) did not change significantly between the pre- and post-TNS measurements in AA induced detrusor overactivity. It was found that TNS significantly reversed the effects of AA irritation by increasing the bladder compliance and the bladder volume at pthres, as well as suppressed the threshold afferent nerve activity. The slope of the linear relationship between pressure and the afferent activity increased after AA instillation and decreased significantly after stimulation. In addition to its well-known central inhibitory mechanisms, this study has demonstrated that TNS improves bladder storage capacity by delaying the onset of voiding, via an inhibitory effect on the bladder afferent signaling at the peripheral level.
Collapse
|
7
|
Su X, Nickles A, Nelson DE. Optimization of Neuromodulation for Bladder Control in a Rat Cystitis Model. Neuromodulation 2015; 19:101-7. [PMID: 26517575 DOI: 10.1111/ner.12360] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 09/09/2015] [Accepted: 09/15/2015] [Indexed: 11/26/2022]
Abstract
OBJECTIVES In a bladder overactivity model of cystitis induced by intravesical infusion of acetic acid (a.a.), several parameters of spinal nerve stimulation (SNS) were optimized using continuous infusion cystometry. The optimal stimulation was further characterized through measurements of urodynamic function using single-fill cystometry. MATERIALS AND METHODS In anesthetized male rats, a cannula was placed into the bladder dome for saline or 0.3% a.a. infusion and intravesical pressure monitoring. For SNS, two teflon-coated stainless steel electrodes were placed bilaterally under each of the L6 spinal nerves, and current stimulation was controlled independently using two Grass stimulators. RESULTS Stimulation of 1 Hz or 50 Hz at motor threshold (Tmot ) was ineffective for altering bladder activities, but 10-Hz SNS increased the infused volume (IV) in a stimulation intensity-dependent fashion (P < 0.01, mixed model repeated analysis). Pairwise comparisons of IV differences to each stimulation intensity show that IV during 1 × Tmot stimulation was significantly larger than 0 × Tmot (no stim, P = 0.001), while the IV during 2 × Tmot stimulation was significantly larger than other intensities tested (P < 0.01). The mean IV (±SEM) during 0 × Tmot (no stim), 0.5 × Tmot , 1 × Tmot , and 2 × Tmot were 0.23 ± 0.04 mL, 0.25 ± 0.03 mL, 0.26 ± 0.03 mL, and 0.40 ± 0.04 mL, respectively. In single-fill cystometry, 10-Hz SNS at 1 × Tmot and 2 × Tmot stimulation increased the IV, or voiding duration and threshold pressure. SNS did not produce significant effects on basal pressure and micturition pressure. CONCLUSIONS SNS significantly attenuates hypersensitive micturition reflex; 10 Hz and high-intensity stimulation are mostly effective. Acute peripheral nerve activation increases the functional bladder capacity, which may be via mechanisms on the afferent arm of the bladder micturition reflex.
Collapse
Affiliation(s)
- Xin Su
- Neuromodulation Research, Medtronic, Inc, Minneapolis, MN, USA
| | - Angela Nickles
- Physiological Research Laboratories, Medtronic, Inc, Minneapolis, MN, USA
| | - Dwight E Nelson
- Neuromodulation Research, Medtronic, Inc, Minneapolis, MN, USA
| |
Collapse
|
8
|
Su X, Nickles A, Nelson DE. Preclinical assessment of potential interactions between botulinum toxin and neuromodulation for bladder micturition reflex. BMC Urol 2015; 15:50. [PMID: 26055982 PMCID: PMC4460855 DOI: 10.1186/s12894-015-0048-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 06/03/2015] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND While botulinum toxin A (BoNT-A) has become a more commonly used second-line treatment for patients with detrusor overactivity, it remains unknown whether the impacts of this therapy may persist to influence other therapies such as sacral neuromodulation. In this preclinical study we have evaluated urodynamic functions to intradetrusor injection of BoNT-A and the bladder inhibitory effects of spinal nerve stimulation (SNS) following BoNT-A treatment. METHODS Female rats were anesthetized with 3 % isoflurane. BoNT-A (2 units, 0.2 ml) or saline were injected into the detrusor. Rats then were housed for 2 days to 1 month before neuromodulation study. Monopolar electrodes were placed under each of the L6 spinal nerve bilaterally under urethane anesthesia. A bladder cannula was inserted via the urethra for saline infusion and intravesical pressure recording. RESULTS Intradetrusor injection of BoNT-A for 1-2 weeks or 1 month significantly increased bladder capacity compared with saline injection (p < 0.05, two-way ANOVA). Following BoNT-A, SNS attenuated the frequency of bladder contractions, either eliminating bladder contractions or reducing the contraction frequency during electrical stimulation. Inhibition of the contraction frequency by SNS following BoNT-A treated rats was not different from that measured following saline injection. CONCLUSIONS BoNT-A increased the bladder capacity, but compensating for additional saline infusion to the enlarged urinary bladder in BoNT-A pretreated rats, the bladder contractions induced by bladder filling were attenuated by SNS. BoNT-A did not alter the ability of SNS to inhibit bladder contraction following intradetrusor injection of BoNT-A for 2 days, 1-2 weeks or 1 month. These results support further pre-clinical and clinical studies to evaluate potential interactions or combination therapy with neuromodulation and intradetrusor BoNT-A therapeutic approaches.
Collapse
Affiliation(s)
- Xin Su
- Medtronic plc, Neuromodulation Research, 7000 Central Avenue, Minneapolis, MN, 55432, USA.
| | - Angela Nickles
- Physiological Research Laboratories, 7000 Central Avenue, Minneapolis, MN, 55432, USA.
| | - Dwight E Nelson
- Medtronic plc, Neuromodulation Research, 7000 Central Avenue, Minneapolis, MN, 55432, USA.
| |
Collapse
|
9
|
Gajewski JB, Kanai AJ, Cardozo L, Ikeda Y, Zabbarova IV. Does our limited knowledge of the mechanisms of neural stimulation limit its benefits for patients with overactive bladder? ICI-RS 2013. Neurourol Urodyn 2014; 33:618-21. [PMID: 24838593 DOI: 10.1002/nau.22610] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 03/14/2014] [Indexed: 11/08/2022]
Abstract
INTRODUCTION Neural stimulation has become an established minimally invasive treatment for various lower urinary tract symptoms. The results both short- and long-term are encouraging, however, there is still a lack of knowledge of obvious risk factors, which may affect the outcome of treatment. Although neural stimulation has been embraced by healthcare professionals and patients, the exact mechanism by which neural stimulation works is still unclear. DISCUSSION A condense review of knowledge available on this topic is presented. Several research questions are raised. Outlines of research studies, both clinical and basic science, are suggested. CONCLUSIONS Further studies are necessary to understand mechanism of action of neural stimulation and its implications on treatment outcomes.
Collapse
|
10
|
Matsuta Y, Roppolo JR, de Groat WC, Tai C. Poststimulation inhibition of the micturition reflex induced by tibial nerve stimulation in rats. Physiol Rep 2014; 2:e00205. [PMID: 24744884 PMCID: PMC3967688 DOI: 10.1002/phy2.205] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 12/25/2013] [Accepted: 01/06/2014] [Indexed: 11/16/2022] Open
Abstract
The purpose of this study was to determine the effect of tibial nerve stimulation (TNS) on the micturition reflex. Experiments were conducted in 24 rats under urethane anesthesia. A catheter was inserted into the bladder via the bladder dome for saline infusion. A cuff electrode was placed around right tibial nerve for stimulation. TNS (5 Hz, 0.2 msec pulse width) at 2–4 times the threshold (T) intensity for inducing a toe movement was applied either during slow (0.08 mL/min) infusion of the bladder or for 30 min with an empty bladder. TNS had no effect on the micturition reflex when it was applied during slow bladder infusion. However, the 30‐min TNS applied with an empty bladder induced poststimulation inhibition and significantly (P < 0.05) increased the bladder capacity to about 140% of prestimulation level in a 50‐min period following the termination of stimulation. The bladder compliance was also significantly (P < 0.05) increased after the 30‐min TNS. These results suggest that different mechanisms might exist in acute‐ and post‐TNS inhibition of micturition reflex. The animal model developed in this study will be very useful for further investigations of the neurotransmitter mechanisms underlying tibial neuromodulation of bladder function. This study suggests that different mechanisms might exist in acute‐ and poststimulation tibial inhibition of the micturition reflex. The animal model developed in this study is very useful for further investigations of the neurotransmitter mechanisms underlying tibial neuromodulation of bladder function.
Collapse
Affiliation(s)
- Yosuke Matsuta
- Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - James R Roppolo
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - William C de Groat
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Changfeng Tai
- Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania ; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| |
Collapse
|