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Quintana GR. Can Orgasms Be Disentangled Into Their Parts? A Response to McKenna (2021). ARCHIVES OF SEXUAL BEHAVIOR 2022; 51:699-702. [PMID: 34799833 DOI: 10.1007/s10508-021-02219-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/01/2021] [Accepted: 11/03/2021] [Indexed: 06/13/2023]
Affiliation(s)
- Gonzalo R Quintana
- Escuela de Psicología y Filosofía, Facultad de Ciencias Sociales y Jurídicas, Universidad de Tarapacá, 7-D, Arica, Chile.
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McKenna KE. What Is the Trigger for Sexual Climax? ARCHIVES OF SEXUAL BEHAVIOR 2022; 51:383-390. [PMID: 34664153 DOI: 10.1007/s10508-021-02164-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 08/27/2021] [Accepted: 09/20/2021] [Indexed: 06/13/2023]
Abstract
A model is proposed to consider sexual climax in men, women, and animals as a unitary phenomenon. Sexual climax is a stereotyped rhythmic pattern of spinally generated neural activity in the autonomic and somatic nerves innervating pelvic organs. A column of neurons in the spinal cord of the male rat is strongly activated by ejaculation (sexual climax in the male). These neurons project to the thalamus and are therefore called lumbar spinothalamic cells (LSt cells). Comprehensive studies have demonstrated that the LSt cells constitute a central pattern generator of ejaculation. These findings have been extended to female animals. Further studies identified LSt cells in the lumbar spinal cord of men and women. Strong evidence indicates that the LSt cells mediate ejaculation in men. The climax model generalizes and extends these studies. It postulates that LSt cells in the lumbar spinal cord of humans and animals of both sexes generate climax. The LSt cells generate the neural activity driving the pelvic contractions and other responses of climax. The activity is transmitted to supraspinal sites to activate orgasm. The LSt cells receive excitatory and inhibitory projections from supraspinal sites. The descending projections reflect subjective arousal and inhibitions. Spinal sensory neurons from the genitals provide excitatory and inhibitory innervation to the LSt cells. These represent pleasurable and noxious sensations. The supraspinal and spinal excitatory and inhibitory inputs are integrated by the LSt. When the sum of the excitatory inputs, minus the sum of the inhibitory inputs reaches a threshold, the LSt cells generate sexual climax.
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Affiliation(s)
- Kevin E McKenna
- Departments of Neuroscience and Urology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave., Chicago, IL, 60611, USA.
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Persistent genital arousal disorder: a special sense neuropathy. Pain Rep 2020; 5:e801. [PMID: 32072096 PMCID: PMC7004503 DOI: 10.1097/pr9.0000000000000801] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 09/13/2019] [Accepted: 11/06/2019] [Indexed: 12/18/2022] Open
Abstract
Introduction Persistent genital arousal (PGAD) is a syndrome of unprovoked sexual arousal/orgasm of uncertain cause primarily reported in female patients. Most patients are referred for mental-health treatment, but as research suggests associations with neurological symptoms and conditions, there is need to analyze cases comprehensively evaluated by neurologists. Methods The IRB waived consent requirements for this retrospective university-hospital study. We extracted and analyzed neurological symptoms, test, and treatment results from all qualifying participants' records and recontacted some for details. Results All 10 participants were female; their PGAD symptoms began between ages 11 to 70 years. Two patterns emerged: 80% reported daily out-of-context sexual arousal episodes (≤30/day) that usually included orgasm and 40% reported lesser, often longer-lasting, nonorgasmic arousals. Most also had symptoms consistent with sacral neuropathy-70% had urologic complaints and 60% had neuropathic perineal or buttock pain. In 90% of patients, diagnostic testing identified anatomically appropriate and plausibly causal neurological lesions. Sacral dorsal-root Tarlov cysts were most common (in 4), then sensory polyneuropathy (2). One had spina bifida occulta and another drug-withdrawal effect as apparently causal; lumbosacral disc herniation was suspected in another. Neurological treatments cured or significantly improved PGAD symptoms in 4/5 patients, including 2 cures. Conclusions Although limited by small size and referral bias to neurologists, this series strengthens associations with Tarlov cysts and sensory polyneuropathy and suggests new ones. We hypothesize that many cases of PGAD are caused by unprovoked firing of C-fibers in the regional special sensory neurons that subserve sexual arousal. Some PGAD symptoms may share pathophysiologic mechanisms with neuropathic pain and itch.
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Shi Y, Li L, Zhou J, Sun J, Chen L, Zhao J, Wu L, Cui Y, Wu L, Wu H. Efficacy of electroacupuncture in regulating the imbalance of AMH and FSH to improve follicle development and hyperandrogenism in PCOS rats. Biomed Pharmacother 2019; 113:108687. [PMID: 30851546 DOI: 10.1016/j.biopha.2019.108687] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 02/11/2019] [Accepted: 02/12/2019] [Indexed: 01/24/2023] Open
Abstract
Polycystic ovary syndrome (PCOS) is characterized by hyperandrogenism and follicular arrest. These two characteristics may result from an imbalance between anti-Müllerian hormone and follicle stimulating hormone. Electroacupuncture is effective in improving hyperandrogenism and follicular arrest in PCOS; however, the mechanism is not sufficiently clear. This study aimed to elucidate whether electroacupuncture in PCOS is exerted by regulating an imbalance of anti-Müllerian hormone and follicle stimulating hormone. In this study, a rat model of polycystic ovary syndrome was treated with low-frequency electroacupuncture at acupoints (CV-3 and CV-4). To observe the mechanism of electroacupuncture in PCOS, we first observed the estrous cycle. We then observed ovarian morphology by hematoxylin-eosin staining and evaluated levels of testosterone, estradiol, P450arom, follicle stimulating hormone and its receptor, and anti-Müllerian hormone and its receptor by enzyme-linked immunosorbent assay, western blotting, double immunofluorescence assay and real-time PCR. Our results showed that in 80% of rats in the electroacupuncture acupoints group, their estrous cycle recovered, ovarian morphology significantly improved, testosterone level significantly decreased, and levels of estradiol and P450arom significantly increased in peripheral serum after 14 consecutive days of treatment (P < 0.01). The expression of anti-Müllerian hormone and anti-Müllerian hormone type II receptor decreased (P < 0.05), whereas the expression of follicle stimulating hormone receptor increased (P < 0.05). These results indicated that electroacupuncture improved hyperandrogenism and follicular arrest by decreasing the excessive expression of AMH to regulate FSH and AMH imbalance in granulosa cells in PCOS.
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Affiliation(s)
- Yin Shi
- Key Laboratory of Acupuncture and Immunological Effects, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China; Outpatient Department, Shanghai Institute of Acupuncture-Moxibustion and Meridian, Shanghai 200030, China
| | - Liang Li
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Jing Zhou
- Graduate School, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Jie Sun
- Department of Acupuncture and Moxibustion, Shanghai Songjiang District Central Hospital, Shanghai 201600, China
| | - Liu Chen
- Graduate School, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Jimeng Zhao
- Key Laboratory of Acupuncture and Immunological Effects, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Luyi Wu
- Qigong Institute, Shanghai University of Traditional Chinese Medicine, Shanghai 200030, China
| | - Yunhua Cui
- Key Laboratory of Acupuncture and Immunological Effects, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Lingxiang Wu
- Editorial Department, Shanghai Institute of Acupuncture-Moxibustion and Meridian, Shanghai 200030, China
| | - Huangan Wu
- Key Laboratory of Acupuncture and Immunological Effects, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
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Zhang FX, Ge SN, Dong YL, Shi J, Feng YP, Li Y, Li YQ, Li JL. Vesicular glutamate transporter isoforms: The essential players in the somatosensory systems. Prog Neurobiol 2018; 171:72-89. [PMID: 30273635 DOI: 10.1016/j.pneurobio.2018.09.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 08/28/2018] [Accepted: 09/23/2018] [Indexed: 02/08/2023]
Abstract
In nervous system, glutamate transmission is crucial for centripetal conveyance and cortical perception of sensory signals of different modalities, which necessitates vesicular glutamate transporters 1-3 (VGLUT 1-3), the three homologous membrane-bound protein isoforms, to load glutamate into the presysnaptic vesicles. These VGLUTs, especially VGLUT1 and VGLUT2, selectively label and define functionally distinct neuronal subpopulations at each relay level of the neural hierarchies comprising spinal and trigeminal sensory systems. In this review, by scrutinizing each structure of the organism's fundamental hierarchies including dorsal root/trigeminal ganglia, spinal dorsal horn/trigeminal sensory nuclear complex, somatosensory thalamic nuclei and primary somatosensory cortex, we summarize and characterize in detail within each relay the neuronal clusters expressing distinct VGLUT protein/transcript isoforms, with respect to their regional distribution features (complementary distribution in some structures), axonal terminations/peripheral innervations and physiological functions. Equally important, the distribution pattern and characteristics of VGLUT1/VGLUT2 axon terminals within these structures are also epitomized. Finally, the correlation of a particular VGLUT isoform and its physiological role, disclosed thus far largely via studying the peripheral receptors, is generalized by referring to reports on global and conditioned VGLUT-knockout mice. Also, researches on VGLUTs relating to future direction are tentatively proposed, such as unveiling the elusive differences between distinct VGLUTs in mechanism and/or pharmacokinetics at ionic/molecular level, and developing VGLUT-based pain killers.
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Affiliation(s)
- Fu-Xing Zhang
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China
| | - Shun-Nan Ge
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China; Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, PR China
| | - Yu-Lin Dong
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China
| | - Juan Shi
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China
| | - Yu-Peng Feng
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China
| | - Yang Li
- Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, PR China
| | - Yun-Qing Li
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China; Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, PR China.
| | - Jin-Lian Li
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China.
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Alexander MS, Marson L. The neurologic control of arousal and orgasm with specific attention to spinal cord lesions: Integrating preclinical and clinical sciences. Auton Neurosci 2018; 209:90-99. [DOI: 10.1016/j.autneu.2017.01.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 12/09/2016] [Accepted: 01/23/2017] [Indexed: 12/14/2022]
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Altered spinal cord activity during sexual stimulation in women with SCI: a pilot fMRI study. Spinal Cord Ser Cases 2017; 3:16041. [PMID: 28382212 DOI: 10.1038/scsandc.2016.41] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 12/11/2016] [Indexed: 11/08/2022] Open
Abstract
INTRODUCTION The objective of this study was to assess the feasibility of the use of functional magnetic resonance imaging (fMRI) to evaluate the spinal activation during sexual response of the thoracic, lumbar and sacral spinal cord. MATERIALS AND METHODS This is a laboratory-based pilot study in human females at a University-based medical center in the United States. In three healthy spinal cord injury (SCI) females, spinal cord activations during sexual audiovisual stimulation (alone), genital self-stimulation (alone) and simultaneous audiovisual and genital self-stimulation (combined) were assessed and then compared with each subjects' remaining sensory and motor function. RESULTS Spinal fMRI responses of the intermediolateral columns were found during audiovisual stimulation in both subjects with incomplete injuries, but they were not observed in the subject with a complete injury. Moreover, sacral responses to combined stimulation differed greatly between the subjects with complete and incomplete injuries. CONCLUSION These results not only provide the first in vivo documentation of spinal fMRI responses associated with sexual arousal in women with SCIs, but also suggest that spinal cord fMRI is capable of distinguishing between injury subtypes. Therefore, although there are certain limitations associated with fMRI during sexual stimulation (for example, movement artifacts, an artificially controlled environment and so), these findings demonstrate the potential utility of incorporating spinal cord fMRI in future research to evaluate the impact of specific patterns of SCI on sexual responses and/or the effects of treatment.
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Courtois F, Alexander M, McLain AB(J. Women's Sexual Health and Reproductive Function After SCI. Top Spinal Cord Inj Rehabil 2017; 23:20-30. [PMID: 29339874 PMCID: PMC5340506 DOI: 10.1310/sci2301-20] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Sexual function and to a lesser extent reproduction are often disrupted in women with spinal cord injuries (SCI), who must be educated to better understand their sexual and reproductive health. Women with SCI are sexually active; they can use psychogenic or reflexogenic stimulation to obtain sexual pleasure and orgasm. Treatment should consider a holistic approach using autonomic standards to describe remaining sexual function and to assess both genital function and psychosocial factors. Assessment of genital function should include thoracolumbar dermatomes, vulvar sensitivity (touch, pressure, vibration), and sacral reflexes. Self-exploration should include not only clitoral stimulation, but also stimulation of the vagina (G spot), cervix, and nipples conveyed by different innervation sources. Treatments may consider PDE5 inhibitors and flibanserin on an individual basis, and secondary consequences of SCI should address concerns with spasticity, pain, incontinence, and side effects of medications. Psychosocial issues must be addressed as possible contributors to sexual dysfunctions (eg, lower self-esteem, past sexual history, depression, dating habits). Pregnancy is possible for women with SCI; younger age at the time of injury and at the time of pregnancy being significant predictors of successful pregnancy, along with marital status, motor score, mobility, and occupational scores. Pregnancy may decrease the level of functioning (eg, self-care, ambulation, upper-extremity tasks), may involve complications (eg, decubitus ulcers, weight gain, urological complications), and must be monitored for postural hypotension and autonomic dysreflexia. Taking into consideration the physical and psychosocial determinants of sexuality and childbearing allows women with SCI to achieve positive sexual and reproductive health.
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Affiliation(s)
- Frédérique Courtois
- Departement of Sexology, Université du Québec à Montréal, Montreal, Canada
- Institut de réadaptation Gingras Lindsay de Montréal, Montreal, Canada
| | - Marcalee Alexander
- Department of Rehabilitative Medicine, Birmingham VA Medical Center, Birmingham, Alabama
- Department of Physical Medicine and Rehabilitation, University of Alabama at Birmingham
- Department of Physical Medicine and Rehabilitation, Harvard School of Medicine, Boston, Massachusetts
| | - Amie B. (Jackson) McLain
- Department of Physical Medicine and Rehabilitation, University of Alabama School of Medicine, Birmingham, Alabama
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Marson L, Giamberardino MA, Costantini R, Czakanski P, Wesselmann U. Animal Models for the Study of Female Sexual Dysfunction. Sex Med Rev 2015; 1:108-122. [PMID: 27784584 DOI: 10.1002/smrj.14] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
INTRODUCTION Significant progress has been made in elucidating the physiological and pharmacological mechanisms of female sexual function through preclinical animal research. The continued development of animal models is vital for the understanding and treatment of the many diverse disorders that occur in women. AIM To provide an updated review of the experimental models evaluating female sexual function that may be useful for clinical translation. METHODS Review of English written, peer-reviewed literature, primarily from 2000 to 2012, that described studies on female sexual behavior related to motivation, arousal, physiological monitoring of genital function and urogenital pain. MAIN OUTCOMES MEASURES Analysis of supporting evidence for the suitability of the animal model to provide measurable indices related to desire, arousal, reward, orgasm, and pelvic pain. RESULTS The development of female animal models has provided important insights in the peripheral and central processes regulating sexual function. Behavioral models of sexual desire, motivation, and reward are well developed. Central arousal and orgasmic responses are less well understood, compared with the physiological changes associated with genital arousal. Models of nociception are useful for replicating symptoms and identifying the neurobiological pathways involved. While in some cases translation to women correlates with the findings in animals, the requirement of circulating hormones for sexual receptivity in rodents and the multifactorial nature of women's sexual function requires better designed studies and careful analysis. The current models have studied sexual dysfunction or pelvic pain in isolation; combining these aspects would help to elucidate interactions of the pathophysiology of pain and sexual dysfunction. CONCLUSIONS Basic research in animals has been vital for understanding the anatomy, neurobiology, and physiological mechanisms underlying sexual function and urogenital pain. These models are important for understanding the etiology of female sexual function and for future development of pharmacological treatments for sexual dysfunctions with or without pain. Marson L, Giamberardino MA, Costantini R, Czakanski P, and Wesselmann U. Animal models for the study of female sexual dysfunction. Sex Med Rev 2013;1:108-122.
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Affiliation(s)
- Lesley Marson
- University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | | | | | - Peter Czakanski
- University of Alabama at Birmingham-Departments of Anesthesiology and Obstetrics & Gynecology, Birmingham, AL, USA
| | - Ursula Wesselmann
- University of Alabama at Birmingham-Departments of Anesthesiology and Neurology, Birmingham, AL, USA
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Yang CQ, Duan LP, Qiao PT, Zhao L, Guo LL. Increased VGLUT3 involved in visceral hyperalgesia in a rat model of irritable bowel syndrome. World J Gastroenterol 2015; 21:2959-2966. [PMID: 25780293 PMCID: PMC4356915 DOI: 10.3748/wjg.v21.i10.2959] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 10/10/2014] [Accepted: 12/08/2014] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the activity of vesicular glutamate transporter-3 (VGLUT3) in a visceral hyperalgesia rat model of irritable bowel syndrome, and the role of mast cells (MCs).
METHODS: Transient intestinal infection was induced by oral administration of Trichinella spiralis larvae in rats. On the 100th day post-infection (PI), the rats were divided into an acute cold restraint stress (ACRS) group and a non-stressed group. Age-matched untreated rats served as controls. The abdominal withdrawal reflex was used to measure the visceromotor response to colorectal distension (CRD). The expression levels of VGLUT3 in peripheral and central neurons were analyzed by immunofluorescence and western blotting.
RESULTS: VGLUT3 expression in the L6S1 dorsal root ganglion cells was significantly higher in the PI group than in the control group (0.32 ± 0.009 vs 0.22 ± 0.008, P < 0.01), and there was no significant difference in the expression of VGLUT3 between MC-deficient rats and their normal wild-type littermates. Immunofluorescence showed that the expression levels of VGLUT3 in PI + ACRS rats were enhanced in the prefrontal cortex of the brain compared with the control group.
CONCLUSION: VGLUT3 is involved in the pathogenesis of visceral hyperalgesia. Coexpression of c-fos, 5-hydroxytryptamine and VGLUT3 after CRD was observed in associated neuronal pathways. Increased VGLUT3 induced by transient intestinal infection was found in peripheral nerves, and was independent of MCs. Moreover, the expression of VGLUT3 was enhanced in the prefrontal cortex in rats with induced infection and stress.
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Novel spinal pathways identified by neuronal c-Fos expression after urethrogenital reflex activation in female guinea pigs. Neuroscience 2015; 288:37-50. [DOI: 10.1016/j.neuroscience.2014.12.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 11/26/2014] [Accepted: 12/13/2014] [Indexed: 12/18/2022]
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Abud EM, Ichiyama RM, Havton LA, Chang HH. Spinal stimulation of the upper lumbar spinal cord modulates urethral sphincter activity in rats after spinal cord injury. Am J Physiol Renal Physiol 2015; 308:F1032-40. [PMID: 25694482 DOI: 10.1152/ajprenal.00573.2014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 02/11/2015] [Indexed: 01/01/2023] Open
Abstract
After spinal cord injury (SCI), the neurogenic bladder is observed to develop asynchronous bladder and external urethral sphincter (EUS) contractions in a condition known as detrusor-sphincter dyssnergia (DSD). Activation of the EUS spinal controlling center located at the upper lumbar spinal cord may contribute to reduce EUS dyssynergic contractions and decrease urethral resistance during voiding. However, this mechanism has not been well studied. This study aimed at evaluating the effects of epidural stimulation (EpS) over the spinal EUS controlling center (L3) in combination with a serotonergic receptor agonist on EUS relaxation in naive rats and chronic (6-8 wk) T8 SCI rats. Cystometrogram and EUS electromyography (EMG) were obtained before and after the intravenous administration of 5HT-1A receptor agonist and antagonist. The latency, duration, frequency, amplitude, and area under curve of EpS-evoked EUS EMG responses were analyzed. EpS on L3 evoked an inhibition of EUS tonic contraction and an excitation of EUS intermittent bursting/relaxation correlating with urine expulsion in intact rats. Combined with a 5HT-1A receptor agonist, EpS on L3 evoked a similar effect in chronic T8 SCI rats to reduce urethral contraction (resistance). This study examined the effect of facilitating the EUS spinal controlling center to switch between urine storage and voiding phases by using EpS and a serotonergic receptor agonist. This novel approach of applying EpS on the EUS controlling center modulates EUS contraction and relaxation as well as reduces urethral resistance during voiding in chronic SCI rats with DSD.
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Affiliation(s)
- Edsel M Abud
- Department of Neurobiology and Behavior, University of California, Irvine, California
| | - Ronaldo M Ichiyama
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Leif A Havton
- Department of Anesthesiology and Perioperative Care, University of California, Irvine, California; Department of Anatomy and Neurobiology, University of California, Irvine, California; Department of Neurology, University of California, Irvine, California; Reeve-Irvine Research Center, University of California, Irvine, California; Department of Neurology, University of California, Los Angeles, California; and
| | - Huiyi H Chang
- Department of Anesthesiology and Perioperative Care, University of California, Irvine, California; Department of Neurology, University of California, Los Angeles, California; and
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Tanahashi M, Karicheti V, Thor KB, Marson L. Characterization of bulbospongiosus muscle reflexes activated by urethral distension in male rats. Am J Physiol Regul Integr Comp Physiol 2012; 303:R737-47. [DOI: 10.1152/ajpregu.00004.2012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The urethrogenital reflex (UGR) is used as a surrogate model of the autonomic and somatic nerve and muscle activity that accompanies ejaculation. The UGR is evoked by distension of the urethra and activation of penile afferents. The current study compares two methods of elevating urethral intraluminal pressure in spinalized, anesthetized male Sprague-Dawley rats ( n = 60). The first method, penile extension UGR, involves extracting the penis from the foreskin, so that urethral pressure rises due to a natural anatomical flexure in the penis. The second method, penile clamping UGR, involves penile extension UGR with the addition of clamping of the glans penis. Groups of animals were prepared that either received no additional treatment, surgical shams, or received bilateral nerve cuts (4 nerve cut groups): either the pudendal sensory nerve branch (SbPN), the pelvic nerves, the hypogastric nerves, or all three nerves. Penile clamping UGR was characterized by multiple bursts, monitored by electromyography (EMG) of the bulbospongiosus muscle (BSM) accompanied by elevations in urethral pressure. The penile clamping UGR activity declined across multiple trials and eventually resulted in only a single BSM burst, indicating desensitization. In contrast, the penile extension UGR, without penile clamping, evoked only a single BSM EMG burst that showed no desensitization. Thus, the UGR is composed of two BSM patterns: an initial single burst, termed urethrobulbospongiosus (UBS) reflex and a subsequent multiple bursting pattern (termed ejaculation-like response, ELR) that was only induced with penile clamping urethral occlusion. Transection of the SbPN eliminated the ELR in the penile clamping model, but the single UBS reflex remained in both the clamping and extension models. Pelvic nerve (PelN) transection increased the threshold for inducing BSM activation with both methods of occlusion but actually unmasked an ELR in the penile extension method. Hypogastric nerve (HgN) cuts did not significantly alter any parameter. Transection of all three nerves eliminated BSM activation completely. In conclusion, penile clamping occlusion recruits penile and urethral primary afferent fibers that are necessary for an ELR. Urethral distension without significant penile afferent activation recruits urethral primary afferent fibers carried in either the pelvic or pudendal nerve that are necessary for the single-burst UBS reflex.
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Vesicular glutamate transporter-3 contributes to visceral hyperalgesia induced by Trichinella spiralis infection in rats. Dig Dis Sci 2012; 57:865-72. [PMID: 22160634 DOI: 10.1007/s10620-011-1970-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Accepted: 11/02/2011] [Indexed: 12/14/2022]
Abstract
BACKGROUND According to a recent study, vesicular glutamate transporter-3 (VGLUT3) contributes to injury-induced mechanical hyperalgesia in mice. AIMS The aims of the study were to investigate whether VGLUT3 is involved in visceral pain, and whether transient intestinal infection or acute cold restraint stress (ACRS) affects VGLUT3 expression levels in rats. METHODS Changes in VGLUT3 and c-Fos proteins were evaluated in rats which received noxious colorectal distension (CRD) stimulation. Transient intestinal infection was effected by oral administration of Trichinella spiralis (T. spiralis) larvae in Brown Norway rats. On the 100th day post-infection (PI), half of the PI-rats and non infected controls were subjected to an ACRS procedure. The visceromotor response to CRD was measured using the abdominal withdrawal reflex (AWR) score. Immunofluorescence and western blot analysis were used to estimate the expression of VGLUT3 in both peripheral and central neurons. RESULTS Noxious stimulation induced a significant increase in the expression of VGLUT3 in the L6S1 spinal dorsal horn. Compared with the control group, the pain threshold was significantly decreased in the ACRS, PI, and PI + ACRS groups. VGLUT3 expression in the L6S1 dorsal root ganglion (DRG) and spinal neurons were significantly increased in PI and PI + ACRS groups as compared with the control group. CONCLUSIONS VGLUT3 is involved in conduction of visceral pain sensation and in visceral hyperalgesia induced by Trichinella spiralis infection in rats.
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Yuan SY, Gibbins IL, Zagorodnyuk VP, Morris JL. Sacro-lumbar Intersegmental Spinal Reflex in Autonomic Pathways Mediating Female Sexual Function. J Sex Med 2011; 8:1931-42. [DOI: 10.1111/j.1743-6109.2010.02160.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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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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Staudt MD, de Oliveira CVR, Lehman MN, McKenna KE, Coolen LM. Activation of NMDA receptors in lumbar spinothalamic cells is required for ejaculation. J Sex Med 2011; 8:1015-26. [PMID: 21235717 PMCID: PMC3253366 DOI: 10.1111/j.1743-6109.2010.02168.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
INTRODUCTION The sexual reflex ejaculation is controlled by a spinal ejaculation generator located in the lumbosacral spinal cord. A population of spinothalamic (LSt) neurons forms a key component of this generator, as manipulations of LSt cells either block or trigger ejaculation. However, it is currently unknown which afferent signals contribute to the activation of LSt cells and ejaculation. AIM The current study tested the hypothesis that glutamate, via activation of N-Methyl-D-aspartic acid (NMDA) receptors in LSt cells, is a key regulator of ejaculation. METHODS Expression of phosphorylated NMDA receptor subunit 1 (NR1) was investigated following mating, or following ejaculation induced by electrical stimulation of the dorsal penile nerve (DPN) in anesthetized, spinalized male rats. Next, the effects of intraspinal delivery of NMDA receptor antagonist AP-5 on DPN stimulation-induced ejaculation were examined. Moreover, the ability of intraspinal delivery of NMDA to trigger ejaculation was examined. Finally, the site of action of NMDA was determined by studying effects of NMDA in male rats with LSt cell-specific lesions. MAIN OUTCOME MEASURES Expression of NR1 and phosphorylated NR1 in LSt cells was analyzed. Electromyographic recordings of the bulbocavernosus muscle (BCM) were recorded in anesthetized, spinalized rats following stimulation of the DPN and delivery of AP-5 or NMDA. RESULTS Results indicate that the NR1 receptors are activated in LSt cells following ejaculation in mating animals or induced by DPN stimulation in anesthetized, spinalized animals. Moreover, NR1 activation in LSt cells is an essential trigger for rhythmic BCM bursting, as DPN stimulation-induced reflexes were absent following administration of NMDA receptor antagonist in the L3-L4 spinal area, and were triggered by NMDA. NMDA effects were dependent on intact LSt cells and were absent in LSt-lesioned males. CONCLUSION These results demonstrate that glutamate, via activation of NMDA receptors in LSt cells, is a key afferent signal for ejaculation.
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Affiliation(s)
- Michael D Staudt
- The University of Western Ontario-Department of Anatomy and Cell Biology, London, Canada
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Staudt MD, De Oliveira CV, Lehman MN, McKenna KE, Coolen LM. Activation of MAP Kinase in Lumbar Spinothalamic Cells Is Required for Ejaculation. J Sex Med 2010; 7:2445-57. [DOI: 10.1111/j.1743-6109.2010.01741.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Karicheti V, Langdale CL, Ukai M, Thor KB. Characterization of a spinal, urine storage reflex, inhibitory center and its regulation by 5-HT1A receptors in female cats. Am J Physiol Regul Integr Comp Physiol 2010; 298:R1198-208. [PMID: 20164207 DOI: 10.1152/ajpregu.00599.2009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Urine storage is facilitated by somatic (pudendal nerve) and sympathetic [hypogastric nerve (HgN)] reflexes to the urethral rhabdosphincter (URS) and urethral smooth muscle, respectively, initiated by primary afferent fibers in the pelvic nerve (PelN). Inhibition of storage reflexes is required for normal voiding. This study characterizes a urine storage reflex inhibitory network that can be activated by PelN afferent fibers concurrently with the reflexes themselves. Electrical stimulation of PelN produced evoked potentials recorded by URS EMG electrodes (10-ms latency) or HgN electrodes (60-ms latency) in chloralose-anesthetized cats. When a second (i.e., paired) pulse of the same stimulus intensity was applied to the PelN 50-500 ms after the first, the reflexes evoked by the second stimulus were inhibited. The inhibition was maximal at paired-pulse intervals of 50-100 ms and remained after acute spinal transection at T10, confirming that the inhibitory center is located in the spinal cord. The 5-HT(1A) receptor agonist 8-hydroxy-2-(di-n-propylamino)tertralin (8-OH-DPAT; 3-300 mug/kg iv) consistently reduced the paired-pulse inhibition from 20% to 60% of control in spinal-intact animals but had no effect in acute spinal animals (i.e., supraspinal site of action). N-{2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl}-N-2-pyridinylcyclohexanecarboxamide maleate (300 mug/kg iv) completely reversed 8-OH-DPAT's effects. The PelN-HgN reflex paired-pulse inhibition was not affected by 8-OH-DPAT. These results indicate the presence of a spinal, urine storage reflex, inhibitory center (SUSRIC) that is activated within 50 ms after activation of the reflexes themselves. SUSRIC is inhibited (disfacilitated) by supraspinal 5-HT(1A) receptors.
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