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Wiggins JW, Sledd JE, Coolen LM. Spinal Cord Injury Causes Reduction of Galanin and Gastrin Releasing Peptide mRNA Expression in the Spinal Ejaculation Generator of Male Rats. Front Neurol 2021; 12:670536. [PMID: 34239493 PMCID: PMC8258150 DOI: 10.3389/fneur.2021.670536] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 05/21/2021] [Indexed: 01/23/2023] Open
Abstract
Spinal cord injury (SCI) in men is commonly associated with sexual dysfunction, including anejaculation, and chronic mid-thoracic contusion injury in male rats also impairs ejaculatory reflexes. Ejaculation is controlled by a spinal ejaculation generator consisting of a population of lumbar spinothalamic (LSt) neurons that control ejaculation through release of four neuropeptides including galanin and gastrin releasing peptide (GRP) onto lumbar and sacral autonomic and motor nuclei. It was recently demonstrated that spinal contusion injury in male rats caused reduction of GRP-immunoreactivity, but not galanin-immunoreactivity in LSt cells, indicative of reduced GRP peptide levels, but inconclusive results for galanin. The current study further tests the hypothesis that contusion injury causes a disruption of GRP and galanin mRNA in LSt cells. Male rats received mid-thoracic contusion injury and galanin and GRP mRNA were visualized 8 weeks later in the lumbar spinal cord using fluorescent in situ hybridization. Spinal cord injury significantly reduced GRP and galanin mRNA in LSt cells. Galanin expression was higher in LSt cells compared to GRP. However, expression of the two transcripts were positively correlated in LSt cells in both sham and SCI animals, suggesting that expression for the two neuropeptides may be co-regulated. Immunofluorescent visualization of galanin and GRP peptides demonstrated a significant reduction in GRP-immunoreactivity, but not galanin in LSt cells, confirming the previous observations. In conclusion, SCI reduced GRP and galanin expression in LSt cells with an apparent greater impact on GRP peptide levels. GRP and galanin are both essential for triggering ejaculation and thus such reduction may contribute to ejaculatory dysfunction following SCI in rats.
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Affiliation(s)
- James W Wiggins
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, MS, United States.,Graduate Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS, United States
| | - Jonathan E Sledd
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, MS, United States
| | - Lique M Coolen
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, MS, United States.,Department of Biological Sciences, Kent State University, Kent, OH, United States
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Spontaneous Ejaculation: A Focused Review for the Clinicians. Sex Med Rev 2020; 9:406-422. [PMID: 33262094 DOI: 10.1016/j.sxmr.2020.11.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 10/25/2020] [Accepted: 11/01/2020] [Indexed: 01/23/2023]
Abstract
INTRODUCTION The process of ejaculation has important meanings not only for its association with orgasm but also for the timing to ejaculate in the context of sexual activity. Spontaneous (involuntary) ejaculation (SE) without any sexual stimulation is a distressing symptom. Our understanding of SE is limited. Unfortunately, many physicians are not aware of these cases. OBJECTIVES The objective of this study is to describe the etiopathogenesis, clinical features, diagnosis, and treatment options for SE. METHODS We searched the literature for publications on "SE," "spontaneous emission" or "involuntary ejaculation," and factors influencing SE in the PUBMED/MEDLINE, Scopus, Cochrane Library, EMBASE, PsycINFO, ProQuest, Academic Search Complete database, Google Scholar, and CINAHL databases from inception to August 2020. RESULTS The literature search yielded 36 relevant publications reporting on 43 patients with SE. Attempts to explain the cause of pathologic SE have included 4 etiological groups (spinal cord lesions, psychological causes, rabies, and drug-induced). The underlying mechanisms responsible for induction of SE may include increased adrenergic activity, overactivity in dopaminergic system, decreased serotonergic activity, damage of descending inhibitory pathway, or penile hyperexcitability. SE may occur in the absence of an identifiable trigger or may be triggered by non-sexual circumstances (micturition, defecation, glans touch, anxiety, panic attack, or school examinations). Treatment options include psychoanalytic treatment, paroxetine, citalopram, sertraline, silodosin, and anxiolytics. In drug-induced SE, dose reduction and drug withdrawal with or without switching to another drug may relief SE. CONCLUSIONS SE is one of the least reported ejaculatory dysfunction. The key feature shared in common by these men is SE without any sexual thoughts or fantasies, may be triggered by non-sexual contexts, rarely associated with orgasm or erection. Treatment by psychoanalytic treatment and pharmacotherapy may be helpful. Further research might explore the definite underlying mechanisms. Abdel-Hamid IA, Ali OI. Spontaneous Ejaculation: A Focused Review for the Clinicians. Sex Med Rev 2021;9:406-422.
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Wiggins JW, Kozyrev N, Sledd JE, Wilson GG, Coolen LM. Chronic Spinal Cord Injury Reduces Gastrin-Releasing Peptide in the Spinal Ejaculation Generator in Male Rats. J Neurotrauma 2019; 36:3378-3393. [PMID: 31111794 DOI: 10.1089/neu.2019.6509] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Spinal cord injury (SCI) causes sexual dysfunction, including anejaculation in men. Likewise, chronic mid-thoracic contusion injury impairs ejaculatory reflexes in male rats. Ejaculation is controlled by a spinal ejaculation generator (SEG) comprised of a population of lumbar spinothalamic (LSt) neurons. LSt neurons co-express four neuropeptides, including gastrin-releasing peptide (GRP) and galanin and control ejaculation via release of these peptides in lumbar and sacral autonomic and motor nuclei. Here, we tested the hypothesis that contusion injury causes a disruption of the neuropeptides that are expressed in LSt cell bodies and axon terminals, thereby causing ejaculatory dysfunction. Male Sprague Dawley rats received contusion or sham surgery at spinal levels T6-7. Five to six weeks later, animals were perfused and spinal cords were immunoprocessed for galanin and GRP. Results showed that numbers of cells immunoreactive for galanin were not altered by SCI, suggesting that LSt cells are not ablated by SCI. In contrast, GRP immunoreactivity was decreased in LSt cells following SCI, evidenced by fewer GRP and galanin/GRP dual labeled cells. However, SCI did not affect efferent connections of LSt, cells as axon terminals containing galanin or GRP in contact with autonomic cells were not reduced following SCI. Finally, no changes in testosterone plasma levels or androgen receptor expression were noted after SCI. In conclusion, chronic contusion injury decreased immunoreactivity for GRP in LSt cell soma, but did not affect LSt neurons per se or LSt connections within the SEG. Since GRP is essential for triggering ejaculation, such loss may contribute to ejaculatory dysfunction following SCI.
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Affiliation(s)
- J Walker Wiggins
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi.,Graduate Program in Neuroscience, University of Mississippi Medical Center, Jackson, Mississippi
| | - Natalie Kozyrev
- Robarts Institute, Western University, London, Ontario, Canada
| | - Jonathan E Sledd
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi
| | - George G Wilson
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi
| | - Lique M Coolen
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi.,Department of Biological Sciences, Kent State University, Kent, Ohio
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Chéhensse C, Clément P, Joussain C, Bernabé J, Giuliano F. The spinal generator of ejaculation: Functional consequences of chronic spinalization and effect of substance P in anesthetized rats. Neuroscience 2016; 336:12-19. [DOI: 10.1016/j.neuroscience.2016.08.044] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 08/22/2016] [Accepted: 08/25/2016] [Indexed: 01/23/2023]
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Safron A. What is orgasm? A model of sexual trance and climax via rhythmic entrainment. SOCIOAFFECTIVE NEUROSCIENCE & PSYCHOLOGY 2016; 6:31763. [PMID: 27799079 PMCID: PMC5087698 DOI: 10.3402/snp.v6.31763] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 08/04/2016] [Accepted: 08/05/2016] [Indexed: 01/07/2023]
Abstract
Orgasm is one of the most intense pleasures attainable to an organism, yet its underlying mechanisms remain poorly understood. On the basis of existing literatures, this article introduces a novel mechanistic model of sexual stimulation and orgasm. In doing so, it characterizes the neurophenomenology of sexual trance and climax, describes parallels in dynamics between orgasms and seizures, speculates on possible evolutionary origins of sex differences in orgasmic responding, and proposes avenues for future experimentation. Here, a model is introduced wherein sexual stimulation induces entrainment of coupling mechanical and neuronal oscillatory systems, thus creating synchronized functional networks within which multiple positive feedback processes intersect synergistically to contribute to sexual experience. These processes generate states of deepening sensory absorption and trance, potentially culminating in climax if critical thresholds are surpassed. The centrality of rhythmic stimulation (and its modulation by salience) for surpassing these thresholds suggests ways in which differential orgasmic responding between individuals-or with different partners-may serve as a mechanism for ensuring adaptive mate choice. Because the production of rhythmic stimulation combines honest indicators of fitness with cues relating to potential for investment, differential orgasmic response may serve to influence the probability of continued sexual encounters with specific mates.
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Affiliation(s)
- Adam Safron
- Department of Psychology, Northwestern University, Evanston, IL, USA;
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Kozyrev N, Staudt MD, Brown A, Coolen LM. Chronic Contusion Spinal Cord Injury Impairs Ejaculatory Reflexes in Male Rats: Partial Recovery by Systemic Infusions of Dopamine D3 Receptor Agonist 7OHDPAT. J Neurotrauma 2016; 33:943-53. [DOI: 10.1089/neu.2015.4232] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Natalie Kozyrev
- Department of Anatomy and Cell Biology, Western University, London, Ontario, Canada
- Department of Physiology, University of Michigan, Ann Arbor, Michigan
| | - Michael D. Staudt
- Department of Anatomy and Cell Biology, Western University, London, Ontario, Canada
| | - Arthur Brown
- Department of Anatomy and Cell Biology, Western University, London, Ontario, Canada
- Robarts Research Institute, Western University, London, Ontario, Canada
| | - Lique M. Coolen
- Department of Anatomy and Cell Biology, Western University, London, Ontario, Canada
- Department of Physiology, University of Michigan, Ann Arbor, Michigan
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
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Pakpour AH, Rahnama P, Saberi H, Saffari M, Rahimi-movaghar V, Burri A, Hajiaghababaei M. The relationship between anxiety, depression and religious coping strategies and erectile dysfunction in Iranian patients with spinal cord injury. Spinal Cord 2016; 54:1053-1057. [DOI: 10.1038/sc.2016.7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 12/16/2015] [Accepted: 01/05/2016] [Indexed: 11/09/2022]
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Waldinger MD, van Coevorden RS, Schweitzer DH, Georgiadis J. Penile anesthesia in Post SSRI Sexual Dysfunction (PSSD) responds to low-power laser irradiation: A case study and hypothesis about the role of transient receptor potential (TRP) ion channels. Eur J Pharmacol 2015; 753:263-8. [PMID: 25483212 DOI: 10.1016/j.ejphar.2014.11.031] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 11/24/2014] [Accepted: 11/26/2014] [Indexed: 11/28/2022]
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Ferrero SL, Brady TD, Dugan VP, Armstrong JE, Hubscher CH, Johnson RD. Effects of lateral funiculus sparing, spinal lesion level, and gender on recovery of bladder voiding reflexes and hematuria in rats. J Neurotrauma 2014; 32:200-8. [PMID: 25137571 DOI: 10.1089/neu.2013.3247] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Deficits in bladder function are complications following spinal cord injury (SCI), severely affecting quality of life. Normal voiding function requires coordinated contraction of bladder and urethral sphincter muscles dependent upon intact lumbosacral reflex arcs and integration of descending and ascending spinal pathways. We previously reported, in electrophysiological recordings, that segmental reflex circuit neurons in anesthetized male rats were modulated by a bilateral spino-bulbo-spinal pathway in the mid-thoracic lateral funiculus. In the present study, behavioral measures of bladder voiding reflexes and hematuria (hemorrhagic cystitis) were obtained to assess the correlation of plasticity-dependent recovery to the degree of lateral funiculus sparing and mid-thoracic lesion level. Adult rats received mid-thoracic-level lesions at one of the following severities: complete spinal transection; bilateral dorsal column lesion; unilateral hemisection; bilateral dorsal hemisection; a bilateral lesion of the lateral funiculi and dorsal columns; or a severe contusion. Voiding function and hematuria were evaluated by determining whether the bladder was areflexic (requiring manual expression, i.e., "crede maneuver"), reflexive (voiding initiated by perineal stroking), or "automatic" (spontaneous voiding without caretaker assistance). Rats with one or both lateral funiculi spared (i.e., bilateral dorsal column lesion or unilateral hemisection) recovered significantly faster than animals with bilateral lateral funiculus lesions, severe contusion, or complete transection. Bladder reflex recovery time was significantly slower the closer a transection lesion was to T10, suggesting that proximity to the segmental sensory and sympathetic innervation of the upper urinary tract (kidney, ureter) should be avoided in the choice of lesion level for SCI studies of micturition pathways. In addition, hematuria duration was significantly longer in males, compared to females, despite similar bladder reflex onset times. We conclude that the sparing of the mid-thoracic lateral funiculus on one side is required for early recovery of bladder reflex voiding function and resolution of hematuria.
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Affiliation(s)
- Sunny L Ferrero
- 1 Department of Physiological Sciences, University of Florida College of Veterinary Medicine , Gainesville, Florida
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10
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Facchinetti P, Giuliano F, Laurin M, Bernabé J, Clément P. Direct brain projections onto the spinal generator of ejaculation in the rat. Neuroscience 2014; 272:207-16. [DOI: 10.1016/j.neuroscience.2014.04.064] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 04/26/2014] [Indexed: 11/16/2022]
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Rau KK, Petruska JC, Cooper BY, Johnson RD. Distinct subclassification of DRG neurons innervating the distal colon and glans penis/distal urethra based on the electrophysiological current signature. J Neurophysiol 2014; 112:1392-408. [PMID: 24872531 DOI: 10.1152/jn.00560.2013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Spinal sensory neurons innervating visceral and mucocutaneous tissues have unique microanatomic distribution, peripheral modality, and physiological, pharmacological, and biophysical characteristics compared with those neurons that innervate muscle and cutaneous tissues. In previous patch-clamp electrophysiological studies, we have demonstrated that small- and medium-diameter dorsal root ganglion (DRG) neurons can be subclassified on the basis of their patterns of voltage-activated currents (VAC). These VAC-based subclasses were highly consistent in their action potential characteristics, responses to algesic compounds, immunocytochemical expression patterns, and responses to thermal stimuli. For this study, we examined the VAC of neurons retrogradely traced from the distal colon and the glans penis/distal urethra in the adult male rat. The afferent population from the distal colon contained at least two previously characterized cell types observed in somatic tissues (types 5 and 8), as well as four novel cell types (types 15, 16, 17, and 18). In the glans penis/distal urethra, two previously described cell types (types 6 and 8) and three novel cell types (types 7, 14, and 15) were identified. Other characteristics, including action potential profiles, responses to algesic compounds (acetylcholine, capsaicin, ATP, and pH 5.0 solution), and neurochemistry (expression of substance P, CGRP, neurofilament, TRPV1, TRPV2, and isolectin B4 binding) were consistent for each VAC-defined subgroup. With identification of distinct DRG cell types that innervate the distal colon and glans penis/distal urethra, future in vitro studies related to the gastrointestinal and urogenital sensory function in normal as well as abnormal/pathological conditions may be benefitted.
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Affiliation(s)
- Kristofer K Rau
- Department of Anesthesiology, Department of Anatomical Sciences and Neurobiology, and Kentucky Spinal Cord Injury Research Center, University of Louisville College of Medicine, Louisville, Kentucky; Department of Physiological Sciences, University of Florida College of Veterinary Medicine and McKnight Brain Institute, Gainesville, Florida
| | - Jeffrey C Petruska
- Department of Anatomical Sciences and Neurobiology, Department of Neurological Surgery, Kentucky Spinal Cord Injury Research Center, University of Louisville College of Medicine, Louisville, Kentucky
| | - Brian Y Cooper
- Department of Oral and Maxillofacial Surgery, Division of Neuroscience, J. Hillis Miller Health Center, University of Florida College of Dentistry and McKnight Brain Institute, Gainesville, Florida; and
| | - Richard D Johnson
- Department of Physiological Sciences, University of Florida College of Veterinary Medicine and McKnight Brain Institute, Gainesville, Florida
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Dobberfuhl AD, Oti T, Sakamoto H, Marson L. Identification of CNS neurons innervating the levator ani and ventral bulbospongiosus muscles in male rats. J Sex Med 2013; 11:664-77. [PMID: 24373488 DOI: 10.1111/jsm.12418] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
INTRODUCTION The pelvic striated muscles play an important role in mediating erections and ejaculation, and together these muscles compose a tightly coordinated neuromuscular system that is androgen sensitive and sexually dimorphic. AIM To identify spinal and brains neurons involved in the control of the levator ani (LA) and bulbospongiosus (BS) in the male adult and preadolescent rat. METHODS Rats were anesthetized, and the transsynaptic retrograde tracer pseudorabies virus (PRV) was injected into the LA muscle of adults or the ventral BS muscle in 30-day-old rats. After 3-5 days rats were sacrificed, and PRV-labeled neurons in the spinal cords and brains were identified using immunohistochemistry. The presence of gastrin-releasing peptide (GRP) in the lumbar spinal neurons was examined. MAIN OUTCOMES MEASURES The location and number of PRV-labeled neurons in the spinal cord and brain and GRP colocalization in the lumbar spinal cord. RESULTS PRV-labeled spinal interneurons were found distributed throughout T11-S1 of the spinal cord, subsequent to dorsal medial motoneuron infection. The majority of spinal interneurons were found in the lumbosacral spinal cord in the region of the dorsal gray commissure and parasympathetic preganglionic neurons. Preadolescent rats had more PRV-labeled spinal interneurons at L5-S1 where the motoneurons were located but relatively less spread rostrally in the spinal cord compared with adults. Lumbar spinothalmic neurons in medial gray of L3-L4 co-localized PRV and GRP. In the brain consistent labeling was seen in areas known to be involved in male sexual behavior including the ventrolateral medulla, hypothalamic paraventricular nucleus, and medial preoptic area. CONCLUSION Common spinal and brain pathways project to the LA and BS muscles in the rat suggesting that these muscles act together to coordinate male sexual reflexes. Differences may exist in the amount of synaptic connections/neuronal pathways in adolescents compared with adults.
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Affiliation(s)
- Amy D Dobberfuhl
- Division of Urology, Department of Surgery, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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Huynh HK, Willemsen AT, Lovick TA, Holstege G. Pontine Control of Ejaculation and Female Orgasm. J Sex Med 2013; 10:3038-48. [DOI: 10.1111/jsm.12300] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Hubscher CH, Gupta DS, Brink TS. Convergence and cross talk in urogenital neural circuitries. J Neurophysiol 2013; 110:1997-2005. [DOI: 10.1152/jn.00297.2013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Despite common comorbidity of sexual and urinary dysfunctions, the interrelationships between the neural control of these functions are poorly understood. The medullary reticular formation (MRF) contributes to both mating/arousal functions and micturition, making it a good site to test circuitry interactions. Urethane-anesthetized adult Wistar rats were used to examine the impact of electrically stimulating different nerve targets [dorsal nerve of the penis (DNP) or clitoris (DNC); L6/S1 trunk] on responses of individual extracellularly recorded MRF neurons. The effect of bladder filling on MRF neurons was also examined, as was stimulation of DNP on bladder reflexes via cystometry. In total, 236 MRF neurons responded to neurostimulation: 102 to DNP stimulation (12 males), 64 to DNC stimulation (12 females), and 70 to L6/S1 trunk stimulation (12 males). Amplitude thresholds were significantly different at DNP (15.0 ± 0.6 μA), DNC (10.5 ± 0.7 μA), and L6/S1 trunk (54.2 ± 4.6 μA), whereas similar frequency responses were found (max responses near 30–40 Hz). In five males, filling/voiding cycles were lengthened with DNP stimulation (11.0 ± 0.9 μA), with a maximal effective frequency plateau beginning at 30 Hz. Bladder effects lasted ∼2 min after DNP stimulus offset. Many MRF neurons receiving DNP/DNC input responded to bladder filling (35.0% and 68.3%, respectively), either just before (43%) or simultaneously with (57%) the voiding reflex. Taken together, MRF-evoked responses with neurostimulation of multiple nerve targets along with different responses to bladder infusion have implications for the role of MRF in multiple aspects of urogenital functions.
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Affiliation(s)
- C. H. Hubscher
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky; and
| | - D. S. Gupta
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky; and
| | - T. S. Brink
- Neuromodulation Research, Medtronic Incorporated, Minneapolis, Minnesota
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Abstract
Ejaculatory dysfunction may occur after many different disorders ranging from traumatic spinal cord injury to diabetes mellitus. With an understanding of the many facets and nuances of the ejaculatory apparatus, both anatomic and neurologic, the well-versed clinician can proceed along a safe, efficient, and appropriate treatment algorithm to help affected men and their partners achieve parenthood.
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Affiliation(s)
- Elizabeth Phillips
- Division of Urology, Boston University School of Medicine, Shapiro Center, Suite 3B, 715 Albany Street, Boston, MA 02118, USA
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Kobayashi T, Kiyokawa Y, Arata S, Takeuchi Y, Mori Y. c-Fos expression during the modulation of sexual behavior by an alarm pheromone. Behav Brain Res 2013; 237:230-7. [DOI: 10.1016/j.bbr.2012.09.042] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 09/20/2012] [Accepted: 09/23/2012] [Indexed: 10/27/2022]
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KOBAYASHI T, KIYOKAWA Y, ARATA S, TAKEUCHI Y, MORI Y. Naloxone Blocks the Deterioration of Male Sexual Behavior Induced by Alarm Pheromone in Rats. J Vet Med Sci 2013; 75:761-5. [DOI: 10.1292/jvms.12-0454] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Tatsuya KOBAYASHI
- Laboratory of Veterinary Ethology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1–1–1 Yayoi, Bunkyo-ku, Tokyo 113–8657, Japan
| | - Yasushi KIYOKAWA
- Laboratory of Veterinary Ethology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1–1–1 Yayoi, Bunkyo-ku, Tokyo 113–8657, Japan
| | - Sayaka ARATA
- Laboratory of Veterinary Ethology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1–1–1 Yayoi, Bunkyo-ku, Tokyo 113–8657, Japan
| | - Yukari TAKEUCHI
- Laboratory of Veterinary Ethology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1–1–1 Yayoi, Bunkyo-ku, Tokyo 113–8657, Japan
| | - Yuji MORI
- Laboratory of Veterinary Ethology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1–1–1 Yayoi, Bunkyo-ku, Tokyo 113–8657, Japan
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Clément P, Laurin M, Compagnie S, Facchinetti P, Bernabé J, Alexandre L, Giuliano F. Effect of Dapoxetine on Ejaculatory Performance and Related Brain Neuronal Activity in Rapid Ejaculator Rats. J Sex Med 2012; 9:2562-73. [DOI: 10.1111/j.1743-6109.2012.02884.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kozyrev N, Lehman MN, Coolen LM. Activation of Gastrin‐releasing Peptide Receptors in the Lumbosacral Spinal Cord is Required for Ejaculation in Male Rats. J Sex Med 2012; 9:1303-18. [DOI: 10.1111/j.1743-6109.2012.02688.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Kozyrev N, Figley CR, Alexander MS, Richards JS, Bosma RL, Stroman PW. Neural correlates of sexual arousal in the spinal cords of able-bodied men: a spinal fMRI investigation. JOURNAL OF SEX & MARITAL THERAPY 2012; 38:418-435. [PMID: 22900624 DOI: 10.1080/0092623x.2011.606887] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The purpose of this study was to determine whether spinal cord functional magnetic resonance imaging could be used to map neural activity throughout the lower thoracic, lumbar, and sacral spinal cord regions during sexual arousal in healthy men. The authors found that viewing erotic films and genital self-stimulation elicited predominantly increased signal, indicative of amplified neuronal input to the dorsal and ventral horns and in the autonomic preganglionic nuclei of the lower thoracic, lumbar, and sacral spinal cord. In addition, linear regression analyses revealed a number of robust correlations (|R| ≥ 0.7) between signal intensity changes in these spinal cord regions and self-reported ratings of mental and physical sexual arousal. Taken together, these results demonstrate that spinal cord functional magnetic resonance imaging is an effective and sensitive technique for mapping the neural correlates of sexual arousal in the spinal cords of able-bodied men. Most important, the results from this study indicate that spinal cord functional magnetic resonance imaging may have important applications as a clinical tool for assessing and mapping the changes that occur in the spinal cords of men suffering from sexual dysfunction as a result of spinal cord trauma.
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Affiliation(s)
- Natalie Kozyrev
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
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Brown A, Weaver LC. The dark side of neuroplasticity. Exp Neurol 2011; 235:133-41. [PMID: 22116043 DOI: 10.1016/j.expneurol.2011.11.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 10/04/2011] [Accepted: 11/07/2011] [Indexed: 12/19/2022]
Abstract
Whether dramatic or modest, recovery of neurological function after spinal cord injury (SCI) is greatly due to neuroplasticity--the process by which the nervous system responds to injury by establishing new synaptic connections or by altering the strength of existing synapses. However, the same neuroplasticity that allows locomotor function to recover also produces negative consequences such as pain and dysfunction of organs controlled by the autonomic nervous system. In this review we focus specifically on structural neuroplasticity (the growth of new synaptic connections) after SCI and on the consequent development of pain and autonomic dysreflexia, a condition of episodic hypertension. Neuroplasticity after SCI is stimulated by the deafferentation of spinal neurons below the lesion and by the expression of growth-promoting neurotrophins such as nerve growth factor (NGF). A broad range of therapeutic strategies that affect neuroplasticity is being developed for the treatment of SCI. At one end of the spectrum are therapeutic strategies that directly or indirectly increase NGF in the injured spinal cord, and have the most robust effects on neuroplasticity. At the other end of the spectrum are neuroprotective strategies focused on supporting and rescuing uninjured, or partially injured, axons; these might limit the deafferentation stimulus for neuroplasticity. In the middle of this spectrum are strategies that block axon growth inhibitors without necessarily providing a growth stimulus. The literature supports the view that the negative consequences of neuroplasticity develop more commonly with therapies that directly stimulate nerve growth than they develop in the untreated injured cord. Compared to these conditions, neuroplasticity with negative outcomes is less prevalent after treatments that that neutralize axon growth inhibitors, and least apparent after strategies that promote neuroprotection.
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Affiliation(s)
- Arthur Brown
- Spinal Cord Injury Laboratory, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada.
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Perrin FE, Gerber YN, Teigell M, Lonjon N, Boniface G, Bauchet L, Rodriguez JJ, Hugnot JP, Privat AM. Anatomical study of serotonergic innervation and 5-HT(1A) receptor in the human spinal cord. Cell Death Dis 2011; 2:e218. [PMID: 21993394 PMCID: PMC3219094 DOI: 10.1038/cddis.2011.98] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Serotonergic innervation of the spinal cord in mammals has multiple roles in the control of motor, sensory and visceral functions. In rats, functional consequences of spinal cord injury at thoracic level can be improved by a substitutive transplantation of serotonin (5-HT) neurons or regeneration under the trophic influence of grafted stem cells. Translation to either pharmacological and/or cellular therapies in humans requires the mapping of the spinal cord 5-HT innervation and its receptors to determine their involvement in specific functions. Here, we have performed a preliminary mapping of serotonergic processes and serotonin-lA (5-HT1A) receptors in thoracic and lumbar segments of the human spinal cord. As in rodents and non-human primates, 5-HT profiles in human spinal cord are present in the ventral horn, surrounding motoneurons, and also contact their presumptive dendrites at lumbar level. 5-HT1A receptors are present in the same area, but are more densely expressed at lumbar level. 5-HT profiles are also present in the intermediolateral region, where 5-HT1A receptors are absent. Finally, we observed numerous serotonergic profiles in the superficial part (equivalent of Rexed lamina II) of the dorsal horn, which also displayed high levels of 5-HT1A receptors. These findings pave the way for local specific therapies involving cellular and/or pharmacological tools targeting the serotonergic system.
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Affiliation(s)
- F E Perrin
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
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Normandin JJ, Murphy AZ. Somatic genital reflexes in rats with a nod to humans: anatomy, physiology, and the role of the social neuropeptides. Horm Behav 2011; 59:656-65. [PMID: 21338605 PMCID: PMC3105176 DOI: 10.1016/j.yhbeh.2011.02.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 02/03/2011] [Accepted: 02/03/2011] [Indexed: 12/31/2022]
Abstract
Somatic genital reflexes such as ejaculation and vaginocervical contractions are produced through the striated muscles associated with the genitalia. The coordination of these reflexes is surprisingly complex and involves a number of lumbosacral spinal and supraspinal systems. The rat model has been proven to be an excellent source of information regarding these mechanisms, and many parallels to research in humans can be drawn. An understanding of the spinal systems involving the lumbosacral spinal cord, both efferent and afferent, has been generated through decades of research. Spinal and supraspinal mechanisms of descending excitation, through a spinal ejaculation generator in the lumbar spinal cord and thalamus, and descending inhibition, through the ventrolateral medulla, have been identified and characterized both anatomically and physiologically. In addition, delineation of the neural circuits whereby ascending genitosensory information regarding the regulation of somatic genital reflexes is relayed supraspinally has also been the topic of recent investigation. Lastly, the importance of the "social neuropeptides" oxytocin and vasopressin in the regulation of somatic genital reflexes, and associated sociosexual behaviors, is emerging. This work not only has implications for understanding how nervous systems generate sexual behavior but also provides treatment targets for sexual dysfunction in people.
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Affiliation(s)
- Joseph J. Normandin
- Department of Biology, Georgia State University, Atlanta, Georgia 30302-5010
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, Georgia 30302-5010
| | - Anne Z. Murphy
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, Georgia 30302-5010
- Neuroscience Institute, Georgia State University, Atlanta, Georgia 30302-5010
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Johnson RD, Chadha HK, Dugan VP, Gupta DS, Ferrero SL, Hubscher CH. Bilateral bulbospinal projections to pudendal motoneuron circuitry after chronic spinal cord hemisection injury as revealed by transsynaptic tracing with pseudorabies virus. J Neurotrauma 2011; 28:595-605. [PMID: 21265606 DOI: 10.1089/neu.2009.1180] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Complications of spinal cord injury in males include losing brainstem control of pudendal nerve-innervated perineal muscles involved in erection and ejaculation. We previously described, in adult male rats, a bulbospinal pathway originating in a discrete area within the medullary gigantocellularis (GiA/Gi), and lateral paragigantocellularis (LPGi) nuclei, which when electrically microstimulated unilaterally, produces a bilateral inhibition of pudendal motoneuron reflex circuitry after crossing to the contralateral spinal cord below T8. Microstimulation following a long-term lateral hemisection, however, revealed reflex inhibition from both sides of the medulla, suggesting the development or unmasking of an injury-induced bulbospinal pathway crossing the midline cranial to the spinal lesion. In the present study, we investigated this pathway anatomically using the transsynaptic neuronal tracer pseudorabies virus (PRV) injected unilaterally into the bulbospongiosus muscle in uninjured controls, and ipsilateral to a chronic (1-2 months) unilateral lesion of the lateral funiculus. At 4.75 days post-injection, PRV-labeled cells were found bilaterally in the GiA/Gi/LPGi with equal side-to-side labeling in uninjured controls, and with significantly greater labeling contralateral to the lesion/injection in lesioned animals. The finding of PRV-labeled neurons on both sides of the medulla after removing the mid-thoracic spinal pathway on one side provides anatomical evidence for the bilaterality in both the brainstem origin and the lumbosacral pudendal circuit termination of the spared lateral funicular bulbospinal pathway. This also suggests that this bilaterality may contribute to the quick functional recovery of bladder and sexual functions observed in animals and humans with lateral hemisection injury.
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Affiliation(s)
- Richard D Johnson
- Department of Physiological Sciences, University of Florida College of Veterinary Medicine, Gainesville, Florida 32610-0144, USA.
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Normandin JJ, Murphy AZ. Serotonergic lesions of the periaqueductal gray, a primary source of serotonin to the nucleus paragigantocellularis, facilitate sexual behavior in male rats. Pharmacol Biochem Behav 2011; 98:369-75. [PMID: 21296106 DOI: 10.1016/j.pbb.2011.01.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 01/21/2011] [Accepted: 01/28/2011] [Indexed: 10/18/2022]
Abstract
While selective serotonin reuptake inhibitors (SSRIs) are widely used to treat anxiety and depression, they also produce profound disruptions of sexual function including delayed orgasm/ejaculation. The nucleus paragigantocellularis (nPGi), a primary source of inhibition of ejaculation in male rats, contains receptors for serotonin (5-HT). The ventrolateral periaqueductal gray (vlPAG) provides serotonin to this region, thus providing an anatomical and neurochemical basis for serotonergic regulation of the nPGi. We hypothesize that 5-HT acting at the nPGi could underlie the SSRI-induced inhibition of ejaculation in rodents. To this end, we produced 5-HT lesions of the source of 5-HT to the nPGi (the vlPAG) and examined sexual behavior. Removing the source of 5-HT to the nPGi facilitated genital reflexes, but not other aspects of sexual behavior, consistent with our hypothesis. Namely, 5-HT lesions produced a significant increase in the mean number of ejaculations and a significant decrease in ejaculation latency as compared to sham lesioned animals, while latency to mating and the post-ejaculatory interval did not differ. These data suggest that the serotonergic vlPAG-nPGi pathway is an important regulatory mechanism for the inhibition of ejaculation in rats and supports the hypothesis that this circuit contributes to SSRI-induced inhibition of ejaculation.
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Affiliation(s)
- Joseph J Normandin
- Department of Biology, Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA 30302-4010, USA
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Normandin JJ, Murphy AZ. Excitotoxic lesions of the nucleus paragigantocellularis facilitate male sexual behavior but attenuate female sexual behavior in rats. Neuroscience 2010; 175:212-23. [PMID: 21144886 DOI: 10.1016/j.neuroscience.2010.11.030] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Revised: 11/11/2010] [Accepted: 11/13/2010] [Indexed: 01/23/2023]
Abstract
Little is known regarding the descending inhibitory control of genital reflexes such as ejaculation and vaginal contractions. The brainstem nucleus paragigantocellularis (nPGi) projects bilaterally to the lumbosacral motoneuron pools that innervate the genital musculature of both male and female rats. Electrolytic nPGi lesions facilitate ejaculation in males, leading to the hypothesis that the nPGi is the source of descending inhibition to genital reflexes. However, the function of the nPGi in female sexual behavior remains to be elucidated. To this end, male and female rats received bilateral excitotoxic fiber-sparing lesions of the nPGi, and sexual behavior and sexual behavior-induced Fos expression were examined. In males, nPGi lesions facilitated copulation, supporting the hypothesis that the nPGi, and not fibers-of-passage, is the source of descending inhibition of genital reflexes in male rats. nPGi lesions in males did not alter sexual behavior-induced Fos expression in any brain region examined. nPGi-lesioned females spent significantly less time mating with stimulus males and had significantly longer ejaculation-return latencies compared to baseline. These results did not significantly differ from control females, but this trend warranted further analysis of the reinforcing value of sexual behavior. Both lesioned and non-lesioned females formed a conditioned place preference (CPP) for artificial vaginocervical stimulation (aVCS). However, post-reinforcement, nPGi-lesioned females did not differ in the percentage of time spent in the non-reinforced chamber versus the reinforced chamber, suggesting a weakened CPP for aVCS. nPGi lesions in females reduced sexual behavior-induced Fos expression throughout the hypothalamus and amygdala. Taken together, these results suggest that while nPGi lesions in males facilitate copulation, such lesions in females attenuate several aspects of sexual behavior resulting in a reduction in the rewarding value of copulation that may be mediated by nPGi control of genital reflexes. This work has important implications for the understanding and treatment of sexual dysfunction in people including delayed/premature ejaculation, involuntary vaginal spasms, and pain during intercourse.
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Affiliation(s)
- J J Normandin
- Department of Biology, Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA 30302-4010, USA
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Kirby MA, Groves MM, Yellon SM. Retrograde tracing of spinal cord connections to the cervix with pregnancy in mice. Reproduction 2010; 139:645-53. [PMID: 19965985 PMCID: PMC4242584 DOI: 10.1530/rep-09-0361] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
In contrast to the uterus, the cervix is well innervated during pregnancy and the density of nerve fibers increases before birth. To assess neural connections between the cervix and the spinal cord, the cervix of pregnant mice was injected with the trans-synaptic retrograde neural tract tracer pseudorabies virus (PRV). After 5 days, the virus was present in nerve cells and fibers in specific areas of the sensory, autonomic, and motor subdivisions of the thoracolumbar spinal cord. In nonpregnant controls, the virus was predominantly distributed in laminae I-III in the dorsal gray sensory areas with the heaviest label in the substantia gelatinosa compared with the autonomic or motor areas. Labeled cells and processes were sparse in other regions, except for a prominent cluster in the intermediolateral column (lamina VII). Photomicrographs of spinal cord sections were digitized, and the total area with the virus was estimated. Compared with nonpregnant controls, the area with PRV was significantly decreased in all the spinal cord subdivisions in pregnant mice except in the intermediolateral column. However, areas with the virus were equivalent in mice injected with PRV at 4 days or 1 day before birth. These findings suggest that the predominant innervation of the murine cervix is from the sensory regions of the thoracolumbar spinal cord, and that these connections diminish with pregnancy. The results raise the possibility that the remaining connections from sensory and autonomic subdivisions, particularly the intermediolateral column, of the thoracolumbar spinal cord may be important for increased density of nerve fibers in the cervix as pregnancy nears term.
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Affiliation(s)
- Michael A Kirby
- Department of Physiology, Loma Linda University School of Medicine, Loma Linda, California 92350, USA
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Hubscher CH, Reed WR, Kaddumi EG, Armstrong JE, Johnson RD. Select spinal lesions reveal multiple ascending pathways in the rat conveying input from the male genitalia. J Physiol 2010; 588:1073-83. [PMID: 20142271 DOI: 10.1113/jphysiol.2009.186544] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The specific white matter location of all the spinal pathways conveying penile input to the rostral medulla is not known. Our previous studies using rats demonstrated the loss of low but not high threshold penile inputs to medullary reticular formation (MRF) neurons after acute and chronic dorsal column (DC) lesions of the T8 spinal cord and loss of all penile inputs after lesioning the dorsal three-fifths of the cord. In the present study, select T8 lesions were made and terminal electrophysiological recordings were performed 45-60 days later in a limited portion of the nucleus reticularis gigantocellularis (Gi) and Gi pars alpha. Lesions included subtotal dorsal hemisections that spared only the lateral half of the dorsal portion of the lateral funiculus on one side, dorsal and over-dorsal hemisections, and subtotal transections that spared predominantly just the ventromedial white matter. Electrophysiological data for 448 single unit recordings obtained from 32 urethane-anaesthetized rats, when analysed in groups based upon histological lesion reconstructions, revealed (1) ascending bilateral projections in the dorsal, dorsolateral and ventrolateral white matter of the spinal cord conveying information from the male external genitalia to MRF, and (2) ascending bilateral projections in the ventrolateral white matter conveying information from the pelvic visceral organs (bladder, descending colon, urethra) to MRF. Multiple spinal pathways from the penis to the MRF may correspond to different functions, including those processing affective/pleasure/motivational, nociception, and mating-specific (such as for erection and ejaculation) inputs.
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Affiliation(s)
- C H Hubscher
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY 40292, USA.
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Everaert K, de Waard WIQ, Van Hoof T, Kiekens C, Mulliez T, D'herde C. Neuroanatomy and neurophysiology related to sexual dysfunction in male neurogenic patients with lesions to the spinal cord or peripheral nerves. Spinal Cord 2010; 48:182-91. [PMID: 20048757 DOI: 10.1038/sc.2009.172] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
STUDY DESIGN Review article. OBJECTIVES The neuroanatomy and physiology of psychogenic erection, cholinergic versus adrenergic innervation of emission and the predictability of outcome of vibration and electroejaculation require a review and synthesis. SETTING University Hospital Belgium. METHODS We reviewed the literature with PubMed 1973-2008. RESULTS Erection, emission and ejaculation are separate phenomena and have different innervations. It is important to realize, which are the afferents and efferents and where the motor neuron of the end organ is located. When interpreting a specific lesion it is important to understand if postsynaptic fibres are intact or not. Afferents of erection, emission and ejaculation are the pudendal nerve and descending pathways from the brain. Erection is cholinergic and NO-mediated. Emission starts cholinergically (as a secretion) and ends sympathetically (as a contraction). Ejaculation is mainly adrenergic and somatic. For vibratory-evoked ejaculation, the reflex arch must be complete; for electroejaculation, the postsynaptic neurons (paravertebral ganglia) must be intact. CONCLUSION Afferents of erection, emission and ejaculation are the pudendal nerve and descending pathways from the brain. Erection is cholinergic and NO-mediated. Emission starts cholinergically (as a secretion) and ends sympathetically (as a contraction). Ejaculation is mainly adrenergic and somatic. In neurogenic disease, a good knowledge of neuroanatomy and physiology makes understanding of sexual dysfunction possible and predictable. The minimal requirement for the success of penile vibration is a preserved reflex arch and the minimal requirement for the success of electroejaculation is the existence of intact post-ganglionic fibres.
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Affiliation(s)
- K Everaert
- Department of Urology, Ghent University Hospital, Ghent, Belgium.
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Broad KD, Curley JP, Keverne EB. Increased apoptosis during neonatal brain development underlies the adult behavioral deficits seen in mice lacking a functional paternally expressed gene 3 (Peg3). Dev Neurobiol 2009; 69:314-25. [PMID: 19224563 DOI: 10.1002/dneu.20702] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Inactivation of the maternally imprinted, paternally expressed gene 3 (Peg3) induces deficits in olfactory function, sexual and maternal behaviors, oxytocin neuron number, metabolic homeostasis and growth. Peg3 is expressed in a number of developing hypothalamic and basal forebrain structures and is a component of the P53 apoptosis pathway. Peg3 inactivation in neuronal cell culture lines inhibits P53 mediated apoptosis, which is important in the early postnatal development and sexual differentiation of the brain. In this study, we investigated the effect of inactivating the Peg3 gene on the incidence of caspase 3 positive cells (a marker of apoptosis) in 4- and 6-day postpartum mouse brain. Inactivating the Peg3 gene resulted in an increase in the incidence of total forebrain caspase 3 positive cells at 4 and 6 days postpartum. Increases in specific neuroanatomical regions including the bed nucleus of the stria terminalis, nucleus accumbens, caudate putamen, medial pre-optic area, arcuate nucleus, medial amygdala, anterior cortical and posteriodorsal amygdaloid nuclei, were also observed. In wild-type mice, sex differences in the incidence of caspase 3 positive cells in the medial amygdala, bed nucleus of the stria terminalis, nucleus accumbens, arcuate nucleus and the M2 motor cortex, were also observed. This neural sex difference was ameliorated in the Peg-3 mutant. These findings suggest that the neuronal and behavioral deficits seen in mice lacking a functional Peg3 gene are mediated by increases in the incidence of early neonatal apoptosis in neuroanatomical regions important for reproductive behavior, olfactory and pheromonal processing, thermoregulation and reward.
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Affiliation(s)
- Kevin D Broad
- Sub-Department of Animal Behaviour, University of Cambridge, Madingley, Cambridge, CB3 8AA, United Kingdom.
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Arvanian VL, Schnell L, Lou L, Golshani R, Hunanyan A, Ghosh A, Pearse DD, Robinson JK, Schwab ME, Fawcett JW, Mendell LM. Chronic spinal hemisection in rats induces a progressive decline in transmission in uninjured fibers to motoneurons. Exp Neurol 2009; 216:471-80. [PMID: 19320005 DOI: 10.1016/j.expneurol.2009.01.004] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Although most spinal cord injuries are anatomically incomplete, only limited functional recovery has been observed in people and rats with partial lesions. To address why surviving fibers cannot mediate more complete recovery, we evaluated the physiological and anatomical status of spared fibers after unilateral hemisection (HX) of thoracic spinal cord in adult rats. We made intracellular and extracellular recordings at L5 (below HX) in response to electrical stimulation of contralateral white matter above (T6) and below (L1) HX. Responses from T6 displayed reduced amplitude, increased latency and elevated stimulus threshold in the fibers across from HX, beginning 1-2 weeks after HX. Ultrastructural analysis revealed demyelination of intact axons contralateral to the HX, with a time course similar to the conduction changes. Behavioral studies indicated partial recovery which arrested when conduction deficits began. In conclusion, this study is the first demonstration of the delayed decline of transmission through surviving axons to individual lumbar motoneurons during chronic stage of incomplete spinal cord injury in adult rats. These findings suggest a chronic pathological state in intact fibers and necessity for prompt treatment to minimize it.
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Affiliation(s)
- Victor L Arvanian
- Department of Neurobiology and Behavior, SUNY at Stony Brook, Life Sciences Building Room 550, Stony Brook, NY 11794-5230, USA.
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Pastelín CF, Zempoalteca R, Pacheco P, Downie JW, Cruz Y. Sensory and somatomotor components of the “sensory branch” of the pudendal nerve in the male rat. Brain Res 2008; 1222:149-55. [DOI: 10.1016/j.brainres.2008.05.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Revised: 05/06/2008] [Accepted: 05/06/2008] [Indexed: 10/22/2022]
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Inskip JA, Ramer LM, Ramer MS, Krassioukov AV. Autonomic assessment of animals with spinal cord injury: tools, techniques and translation. Spinal Cord 2008; 47:2-35. [DOI: 10.1038/sc.2008.61] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Carro-Juárez M, Rodríguez-Manzo G. The spinal pattern generator for ejaculation. ACTA ACUST UNITED AC 2008; 58:106-20. [PMID: 18241924 DOI: 10.1016/j.brainresrev.2007.12.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Revised: 11/14/2007] [Accepted: 12/05/2007] [Indexed: 01/08/2023]
Affiliation(s)
- Miguel Carro-Juárez
- Laboratorio de Comportamiento Reproductivo, Escuela de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Tlaxcala, C.P.90000, Tlaxcala, México.
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Ejaculation elicited by microstimulation of lumbar spinothalamic neurons. Eur Urol 2008; 54:449-56. [PMID: 18394782 DOI: 10.1016/j.eururo.2008.03.043] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Accepted: 03/18/2008] [Indexed: 11/20/2022]
Abstract
BACKGROUND Neuroanatomical and lesion studies have identified lumbar spinothalamic (LSt) neurons to be essential for ejaculation, but their precise role remains elusive. OBJECTIVE To assess the role of LSt neurons as a spinal pattern generator for ejaculation (SGE) and their action on anatomical structures involved in the two ejaculation phases, the emission and expulsion of semen. DESIGN The bulbospongiosus muscle (BSM) was implanted with electrodes and the seminal vesicle (SV) or vas deferens (VD) lumen catheterized in adult anaesthetized rats. Spinal exposure at the fourth lumbar segment (L4) allowed lowering an electrode stereotaxically into area VII/X for brief (300-500ms) electrical stimulation of LSt neurons, while recording BSM-EMG and intraluminal SV or VD pressure. RESULTS Brief electrical microstimulation in the LSt neuron area evoked the expulsion of semen in 17 of 17 rats, with motile spermatozoa in 10 of 17 rats. After stimulation, SV/VD luminal pressure directly rose and fell, followed by rhythmic BSM contractions lasting approximately 25s. Acute T8-T9 spinalization (n=4) did not alter the activation pattern of the BSM-EMG response. Injection of the GABA(A)-receptor agonist muscimol, inhibiting neuronal activity into the LSt neuron area after LSt neuron microstimulation (n=5), stopped BSM contractions in midstream. CONCLUSIONS Electrical microstimulation of LSt neurons activates the entire sequence of ejaculation in rats in a coordinated fashion, ie the emission (SV/VD contraction) followed by expulsion (rhythmic BSM contractions) of living spermatozoa. Midcourse interruption of ejaculation following intraspinal muscimol injection establishes that LSt neurons are the SGE. This could help to identify spinal pharmacological targets for the treatment of ejaculatory disorders and provide the rationale for intraspinal stimulation to treat anejaculation in infertile spinal cord injured (SCI) patients.
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Vardenafil improves ejaculation success rates and self-confidence in men with erectile dysfunction due to spinal cord injury. Spine (Phila Pa 1976) 2008; 33:709-15. [PMID: 18379396 DOI: 10.1097/brs.0b013e3181695040] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Multicenter, double-blind, placebo-controlled, parallel-group study. OBJECTIVE To assess the effect of the oral phosphodiesterase type-5 inhibitor, vardenafil, on ejaculation rates and self-confidence in men with spinal cord injury (SCI). SUMMARY OF BACKGROUND DATA Spinal command of male sexual functions is often seriously impaired by traumatic spinal cord injury (SCI). A high proportion of men with SCI cannot ejaculate during sexual intercourse. SCI-related ejaculatory disorders are often responsible for male infertility. Sexual dysfunction associated with SCI can also affect men's self-confidence. METHODS In this 12-week study, 418 men aged >or=18 years with erectile dysfunction >6 months resulting from a traumatic SCI were randomized to vardenafil (n = 207) or placebo (n = 211) 10 mg for 4 weeks, then maintained or titrated to 5 or 20 mg at weeks 4 and 8. Assessments included questions of the International Index of Erectile Function (IIEF) about ejaculation success and orgasmic perception; the Global Confidence Question; and quality-of-life scales to measure psychological well-being, self-esteem, depression, and mental health status. RESULTS Overall per patient ejaculation success rates were significantly greater with vardenafil than placebo over 12 weeks of treatment (19% vs. 10%; P < 0.001). At last observation carried forward, the IIEF "orgasmic function" score increased from 2.9 at baseline to 4.0 for vardenafil and from 3.0 at baseline to 3.4 for placebo. Sixteen percent of men receiving vardenafil and 8% receiving placebo felt orgasm "almost always" or "always" at weeks 8-12, compared with 4% and 6%, respectively, at baseline. Significant improvements in confidence scores were observed with vardenafil compared with placebo (P < 0.0001). There were no clinically significant differences between vardenafil and placebo in the quality-of-life measures at the study endpoint, but these had been in the normal range at baseline. CONCLUSION Vardenafil significantly improved ejaculation and self-confidence in men with erectile dysfunction due to SCI.
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Ricciardi R, Szabo CM, Poullos AY. Sexuality and Spinal Cord Injury. Nurs Clin North Am 2007; 42:675-84; viii-ix. [DOI: 10.1016/j.cnur.2007.08.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Anderson KD, Borisoff JF, Johnson RD, Stiens SA, Elliott SL. Long-term effects of spinal cord injury on sexual function in men: implications for neuroplasticity. Spinal Cord 2006; 45:338-48. [PMID: 17016492 DOI: 10.1038/sj.sc.3101978] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
STUDY DESIGN Secure, web-based survey. OBJECTIVES Elicit specific information about sexual function from men with spinal cord injuries (SCI). SETTING World-wide web. METHODS Individuals 18 years or older living with SCI obtained a pass-code to enter a secure website and then answered survey questions. RESULTS The presence of genital sensation was positively correlated with the ability to feel a build up of sexual tension in the body during sexual stimulation and in the feeling that mental arousal translates to the genitals as physical sensation. There was an inverse relationship between developing new areas of arousal above the level of lesion and not having sensation or movement below the lesion. A positive relationship existed between the occurrence of spasticity during sexual activity and erectile ability. Roughly 60% of the subjects had tried some type of erection enhancing method. Only 48% had successfully achieved ejaculation postinjury and the most commonly used methods were hand stimulation, sexual intercourse, and vibrostimulation. The most commonly cited reasons for trying to ejaculate were for pleasure and for sexual intimacy. Less than half reported having experienced orgasm postinjury and this was influenced by the length of time postinjury and sacral sparing. CONCLUSION SCI not only impairs male erectile function and ejaculatory ability, but also alters sexual arousal in a manner suggestive of neuroplasticity. More research needs to be pursued in a manner encompassing all aspects of sexual function.
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Affiliation(s)
- K D Anderson
- Department of Neurological Surgery, Reeve-Irvine Research Center, University of California, Irvine, CA 92697, USA
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