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Wilkins NL, Medina Aguinaga D, Hoey R, Fell J, Harkema SJ, Hubscher CH. Bladder responses to thoracolumbar epidural stimulation in female urethane-anesthetized rats with graded contusion spinal cord injuries. J Neurotrauma 2024. [PMID: 39264865 DOI: 10.1089/neu.2024.0209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/14/2024] Open
Abstract
Spinal cord epidural stimulation (scES) is a therapeutic option that promotes functional improvements in sensory, motor, and autonomic functions following spinal cord injury (SCI). Previous scES mapping studies targeting the lower urinary tract (LUT) in rats demonstrated functional response variability based upon lumbosacral level, parameters used, extent of injury (spinally intact versus chronic anatomically complete spinal transections), and sex. In the current study, female rats with clinically relevant graded incomplete T9 contusion injuries were mapped with scES at 60 days-post-injury at three spinal levels (T13, L3, L6) with a novel miniature 15-electrode array designed to deliver optimal specificity. The results obtained during bladder fill and void cycles conducted under urethane anesthesia indicate frequency dependent sub-motor threshold effects on LUT function with a single row of electrodes positioned across the full medio-lateral extent of the dorsal cord. The findings of improved storage and emptying, represented by significantly longer inter-contractile intervals with T13 scES and L3 scES and by a significantly increased estimated void efficiency with L6 scES, respectively, is consistent with previous studies using intact and chronic complete transected male and female rats. The data support the efficacy of selective spinal network stimulation to drive functionally relevant networks for storage versus emptying phases of the urinary cycle. The current findings further demonstrate the translational promise of scES for SCI individuals with LUT dysfunctions, regardless of injury severity.
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Affiliation(s)
- Natasha L Wilkins
- University of Louisville School of Medicine, Anatomical Sciences & Neurobiology, Louisville, Kentucky, United States;
| | - Daniel Medina Aguinaga
- University of Louisville School of Medicine, Anatomical Sciences & Neurobiology, Louisville, Kentucky, United States;
| | - Robert Hoey
- MetroHealth Medical Center, Physical Medicine and Rehabilitation , Cleveland, Ohio, United States;
| | - Jason Fell
- University of Louisville School of Medicine, Anatomical Sciences & Neurobiology, Louisville, Kentucky, United States;
| | - Susan J Harkema
- University of Louisville School of Medicine, Neurological Surgery, Louisville, Kentucky, United States;
| | - Charles H Hubscher
- University of Louisville School of Medicine, Anatomical Sciences & Neurobiology, Louisville, Kentucky, United States;
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Karnup S, Hashimoto M, Cho KJ, Beckel J, de Groat W, Yoshimura N. Sexual Dimorphism of Spinal Neural Circuits Controlling the Mouse External Urethral Sphincter With and Without Spinal Cord Injury. J Comp Neurol 2024; 532:e25658. [PMID: 38987904 PMCID: PMC11260501 DOI: 10.1002/cne.25658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 05/14/2024] [Accepted: 06/27/2024] [Indexed: 07/12/2024]
Abstract
Spinal cord injury (SCI) disrupts coordination between the bladder and the external urinary sphincter (EUS), leading to transient or permanent voiding impairment, which is more severe in males. Male versus female differences in spinal circuits related to the EUS as well as post-SCI rewiring are essential for understanding of sex-/gender-specific impairments and possible recovery mechanisms. To quantitatively assess differences between EUS circuits in males versus females and in spinal intact (SI) versus SCI animals, we retrogradely traced and counted EUS-related neurons. In transgenic ChAT-GFP mice, motoneurons (MNs), interneurons (INs), and propriospinal neurons (PPNs) were retrogradely trans-synaptically traced with PRV614-red fluorescent protein (RFP) injected into EUS. EUS-MNs in dorsolateral nucleus (DLN) were separated from other GFP+ MNs by tracing them with FluoroGold (FG). We found two morphologically distinct cell types in DLN: FG+ spindle-shaped bipolar (SB-MNs) and FG- rounded multipolar (RM-MNs) cholinergic cells. Number of MNs of both types in males was twice as large as in females. SCI caused a partial loss of MNs in all spinal nuclei. After SCI, males showed a fourfold rise in the number of RFP-labeled cells in retro-DLN (RDLN) innervating hind limbs. This suggests (a) an existence of direct synaptic interactions between spinal nuclei and (b) a post-SCI increase of non-specific inputs to EUS-MNs from other motor nuclei. Number of INs and PPNs deferred between males and females: In SI males, the numbers of INs and PPNs were ∼10 times larger than in SI females. SCI caused a twofold decrease of INs and PPNs in males but not in females.
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Affiliation(s)
- Sergei Karnup
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Mamoru Hashimoto
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Kang Jun Cho
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Jonathan Beckel
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - William de Groat
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Naoki Yoshimura
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, PA
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Medina-Aguiñaga D, Hoey RF, Wilkins NL, Ugiliweneza B, Fell J, Harkema SJ, Hubscher CH. Mid-lumbar (L3) epidural stimulation effects on bladder and external urethral sphincter in non-injured and chronically transected urethane-anesthetized rats. Sci Rep 2023; 13:12258. [PMID: 37507456 PMCID: PMC10382500 DOI: 10.1038/s41598-023-39388-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 07/25/2023] [Indexed: 07/30/2023] Open
Abstract
Recent pre-clinical and clinical spinal cord epidural stimulation (scES) experiments specifically targeting the thoracolumbar and lumbosacral circuitries mediating lower urinary tract (LUT) function have shown improvements in storage, detrusor pressure, and emptying. With the existence of a lumbar spinal coordinating center in rats that is involved with external urethral sphincter (EUS) functionality during micturition, the mid-lumbar spinal cord (specifically L3) was targeted in the current study with scES to determine if the EUS and thus the void pattern could be modulated, using both intact and chronic complete spinal cord injured female rats under urethane anesthesia. L3 scES at select frequencies and intensities of stimulation produced a reduction in void volumes and EUS burst duration in intact rats. After chronic transection, three different subgroups of LUT dysfunction were identified and the response to L3 scES promoted different cystometry outcomes, including changes in EUS bursting. The current findings suggest that scES at the L3 level can generate functional neuromodulation of both the urinary bladder and the EUS in intact and SCI rats to enhance voiding in a variety of clinical scenarios.
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Affiliation(s)
- Daniel Medina-Aguiñaga
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, 511 S. Floyd St., MDR, Room 111, Louisville, KY, 40202, USA
| | - Robert F Hoey
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, 511 S. Floyd St., MDR, Room 111, Louisville, KY, 40202, USA
- Physical Medicine and Rehabilitation Department, MetroHealth Rehabilitation Institute of Ohio, Cleveland, OH, USA
- Physical Medicine and Rehabilitiation Department, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Natasha L Wilkins
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, 511 S. Floyd St., MDR, Room 111, Louisville, KY, 40202, USA
| | - Beatrice Ugiliweneza
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, KY, USA
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, USA
- Department of Health Management and Systems Science, School of Public Health and Information Science, University of Louisville, Louisville, KY, USA
| | - Jason Fell
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, 511 S. Floyd St., MDR, Room 111, Louisville, KY, 40202, USA
| | - Susan J Harkema
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, KY, USA
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, USA
| | - Charles H Hubscher
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, 511 S. Floyd St., MDR, Room 111, Louisville, KY, 40202, USA.
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, USA.
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Wada N, Karnup S, Kadekawa K, Shimizu N, Kwon J, Shimizu T, Gotoh D, Kakizaki H, de Groat W, Yoshimura N. Current knowledge and novel frontiers in lower urinary tract dysfunction after spinal cord injury: Basic research perspectives. UROLOGICAL SCIENCE 2022; 33:101-113. [PMID: 36177249 PMCID: PMC9518811 DOI: 10.4103/uros.uros_31_22] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
This review article aims to summarize the recent advancement in basic research on lower urinary tract dysfunction (LUTD) following spinal cord injury (SCI) above the sacral level. We particularly focused on the neurophysiologic mechanisms controlling the lower urinary tract (LUT) function and the SCI-induced changes in micturition control in animal models of SCI. The LUT has two main functions, the storage and voiding of urine, that are regulated by a complex neural control system. This neural system coordinates the activity of two functional units in the LUT: the urinary bladder and an outlet including bladder neck, urethra, and striated muscles of the pelvic floor. During the storage phase, the outlet is closed and the bladder is quiescent to maintain a low intravesical pressure and continence, and during the voiding phase, the outlet relaxes and the bladder contracts to promote efficient release of urine. SCI impairs voluntary control of voiding as well as the normal reflex pathways that coordinate bladder and sphincter function. Following SCI, the bladder is initially areflexic but then becomes hyperreflexic due to the emergence of a spinal micturition reflex pathway. However, the bladder does not empty efficiently because coordination between the bladder and urethral sphincter is lost. In animal models of SCI, hyperexcitability of silent C-fiber bladder afferents is a major pathophysiological basis of neurogenic LUTD, especially detrusor overactivity. Reflex plasticity is associated with changes in the properties of neuropeptides, neurotrophic factors, or chemical receptors of afferent neurons. Not only C-fiber but also Aδ-fiber could be involved in the emergence of neurogenic LUTD such as detrusor sphincter dyssynergia following SCI. Animal research using disease models helps us to detect the different contributing factors for LUTD due to SCI and to find potential targets for new treatments.
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Fortino TA, Randelman ML, Hall AA, Singh J, Bloom DC, Engel E, Hoh DJ, Hou S, Zholudeva LV, Lane MA. Transneuronal tracing to map connectivity in injured and transplanted spinal networks. Exp Neurol 2022; 351:113990. [DOI: 10.1016/j.expneurol.2022.113990] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 12/09/2021] [Accepted: 01/20/2022] [Indexed: 11/24/2022]
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Kawatani M, deGroat W, Itoi K, Uchida K, Sakimura K, Yamanaka A, Yamashita T, Kawatani M. Downstream projection of Barrington's nucleus to the spinal cord in mice. J Neurophysiol 2021; 126:1959-1977. [PMID: 34731061 DOI: 10.1152/jn.00026.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Barrington's nucleus (Bar) which controls micturition behavior through downstream projections to the spinal cord contains two types of projection neurons BarCRH and BarESR1 that have different functions and target different spinal circuitry. Both types of neurons project to the L6-S1 spinal intermediolateral (IML) nucleus while BarESR1 neurons also project to the dorsal commissural nucleus (DCN). To obtain more information about the spinal circuits targeted by Bar, we used patch-clamp recording in spinal slices from adult mice in combination with optogenetic stimulation of Bar terminals. Recording of opto-evoked excitatory post synaptic currents (oEPSCs) in DiI-labeled lumbosacral preganglionic neurons (LS-PGN) revealed that both Bar neuronal populations make strong glutamatergic monosynaptic connections with LS-PGN, while BarESR1 neurons also elicited smaller amplitude glutamatergic polysynaptic oEPSCs or polysynaptic inhibitory post synaptic currents (oIPSCs) in some LS-PGN. Optical stimulation of BarCRH and BarESR1 terminals also elicited monosynaptic oEPSCs and polysynaptic oIPSCs in sacral DCN neurons, some of which must include interneurons projecting either to the IML or ventral horn. Application of capsaicin increased opto-evoked firing during repetitive stimulation of Bar terminals through the modulation of spontaneous post synaptic currents in LS-PGN. In conclusion, our experiments have provided insights into the synaptic mechanisms underlying the integration of inputs from Bar to autonomic circuitry in the lumbosacral spinal cord that may control micturition.
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Affiliation(s)
- Masahiro Kawatani
- Department of Neurophysiology, Graduate School of Medicine, Akita University, Akita, Japan.,Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Aichi, Japan.,Department of Physiology, School of Medicine, Fujita Health University, Aichi, Japan
| | - William deGroat
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, United States
| | - Keiichi Itoi
- Department of Neuroendocrinology, Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - Katsuya Uchida
- Department of Neuroendocrinology, Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - Kenji Sakimura
- Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata, Japan
| | - Akihiro Yamanaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Aichi, Japan
| | - Takayuki Yamashita
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Aichi, Japan.,Department of Physiology, School of Medicine, Fujita Health University, Aichi, Japan
| | - Masahito Kawatani
- Department of Neurophysiology, Graduate School of Medicine, Akita University, Akita, Japan
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Karnup S. Spinal interneurons of the lower urinary tract circuits. Auton Neurosci 2021; 235:102861. [PMID: 34391124 DOI: 10.1016/j.autneu.2021.102861] [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: 04/01/2021] [Revised: 07/17/2021] [Accepted: 07/21/2021] [Indexed: 10/20/2022]
Abstract
The storage and elimination of urine requires coordinated activity between muscles of the bladder and the urethra. This coordination is orchestrated by a complex system containing spinal, midbrain and forebrain networks. Normally there is a reciprocity between patterns of activity in urinary bladder sacral parasympathetic efferents and somatic motoneurons innervating the striatal external urethral sphincter muscle. At the spinal level this reciprocity is mediated by ensembles of excitatory and inhibitory interneurons located in the lumbar-sacral segments. In this review I will present an overview of currently identified spinal interneurons and circuits relevant to the lower urinary tract and will discuss their established or hypothetical roles in the cycle of micturition. In addition, a recently discovered auxiliary spinal neuronal ensemble named lumbar spinal coordinating center will be described. Sexual dimorphism and developmental features of the lower urinary tract which may play a significant role in designing treatments for patients with urine storage and voiding dysfunctions are also considered. Spinal cord injuries seriously damage or even eliminate the ability to urinate. Treatment of this abnormality requires detailed knowledge of supporting neural mechanisms, therefore various experiments in normal and spinalized animals will be discussed. Finally, a possible intraspinal mechanism will be proposed for organization of external urethral sphincter (EUS) bursting which represents a form of intermittent EUS relaxation in rats and mice.
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Affiliation(s)
- Sergei Karnup
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, 200 Lothrop St. BST, R.1303, Pittsburgh, 15213, PA, United States.
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Deciphering Spinal Endogenous Dopaminergic Mechanisms That Modulate Micturition Reflexes in Rats with Spinal Cord Injury. eNeuro 2021; 8:ENEURO.0157-21.2021. [PMID: 34244339 PMCID: PMC8328273 DOI: 10.1523/eneuro.0157-21.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 06/03/2021] [Accepted: 06/30/2021] [Indexed: 01/23/2023] Open
Abstract
Spinal neuronal mechanisms regulate recovered involuntary micturition after spinal cord injury (SCI). It was recently discovered that dopamine (DA) is synthesized in the rat injured spinal cord and is involved in lower urinary tract (LUT) activity. To fully understand the role of spinal DAergic machinery in micturition, we examined urodynamic responses in female rats during pharmacological modulation of the DA pathway. Three to four weeks after complete thoracic SCI, the DA precursor L-DOPA administered intravenously during bladder cystometrogram (CMG) and external urethral sphincter (EUS) electromyography (EMG) reduced bladder overactivity and increased the duration of EUS bursting, leading to remarkably improved voiding efficiency. Apomorphine (APO), a non-selective DA receptor (DR) agonist, or quinpirole, a selective DR2 agonist, induced similar responses, whereas a specific DR2 antagonist remoxipride alone had only minimal effects. Meanwhile, administration of SCH 23390, a DR1 antagonist, reduced voiding efficiency by increasing tonic EUS activity and shortening the EUS bursting period. Unexpectedly, SKF 38393, a selective DR1 agonist, increased EUS tonic activity, implying a complicated role of DR1 in LUT function. In metabolic cage assays, subcutaneous administration of quinpirole decreased spontaneous voiding frequency and increased voiding volume; L-DOPA and APO were inactive possibly because of slow entry into the CNS. Collectively, tonically active DR1 in SCI rats inhibit urine storage and enhance voiding by differentially modulating EUS tonic and bursting patterns, respectively, while pharmacologic activation of DR2, which are normally silent, improves voiding by enhancing EUS bursting. Thus, enhancing DA signaling achieves better detrusor-sphincter coordination to facilitate micturition function in SCI rats.
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