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A Double-Blind, Placebo-Controlled Parallel Group Study to Evaluate the Effect of a Single Oral Dose of 5-HT1A Antagonist GSK958108 on Ejaculation Latency Time in Male Patients Suffering From Premature Ejaculation. J Sex Med 2020; 18:63-71. [PMID: 33223426 DOI: 10.1016/j.jsxm.2020.09.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 09/20/2020] [Accepted: 09/26/2020] [Indexed: 01/23/2023]
Abstract
BACKGROUND Premature ejaculation (PE) is a common male neurobiological sexual disorder, related to a disturbance in central serotonin (5-hydroxytryptamine or 5-HT) neurotransmission. AIM To assess the efficacy of a single oral dose of 5HT1A receptor antagonist GSK958108 on ejaculation latency time (ELT) in male subjects suffering from PE. METHODS A total of 35 male subjects were enrolled in a Phase 1 double-blind, placebo-controlled, parallel group masturbation-model study. All subjects completed the study. No subject was withdrawn from the study. There were no major protocol deviations reported during the study. OUTCOMES The primary outcome of the study was to evaluate the effect of a single oral dose of 5HT1A receptor antagonist GSK958108 on ELT as measured in the masturbation model; additionally, we investigated drug's safety and tolerability. RESULTS In the 3 mg GSK958108 treatment group, the ELT was estimated to be 16% longer (1.542 vs 1.328, 95% CI: -16% to +61%) than if the subjects had taken placebo. In the 7 mg GSK958108 treatment group, the ELT was estimated to be 77% longer (2.346 vs 1.328, 95% CI: +28% to +144%) than in the placebo group. The systemic exposure to GSK958108 increased with dosage between 3 mg and 7 mg. A significant trend toward an increase of ELT was observed with increasing plasma concentrations of GSK958108. A total of 4 patients all treated with 7 mg dose experienced minor drug related adverse events (5 adverse events in 4 patients): somnolence (n = 3), headache (n = 1), tinnitus (n = 1). CLINICAL IMPLICATIONS In the current double-blind, placebo-controlled parallel group study the 5HT1A receptor antagonist GSK958108 was tested in 3 mg and 7 mg doses for PE treatment in humans. It was shown that GSK958108 significantly delayed ejaculation showing a new and safe alternative in PE treatment. STRENGTHS & LIMITATIONS The present study showed innovative results suggesting an important role of 5HT1A receptor antagonist in the PE treatment. However, the use of masturbation model and the small population are the main limitations of this investigation. CONCLUSION 5HT1A receptor antagonist GSK958108 3 mg per day and 7 mg per day was found to be well-tolerated, safe and effective for the treatment of PE subjects and demonstrated a strong association between 5HT1A receptors and ejaculation control in humans (NCT00861484). Migliorini F, Tafuri A, Bettica P, et al. A Double-Blind, Placebo-Controlled Parallel Group Study to Evaluate the Effect of a Single Oral Dose of 5-HT1A Antagonist GSK958108 on Ejaculation Latency Time in Male Patients Suffering From Premature Ejaculation. J Sex Med 2021;18:63-71.
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Medial Preoptic Regulation of the Ventral Tegmental Area Related to the Control of Sociosexual Behaviors. eNeuro 2017; 3:eN-NWR-0283-16. [PMID: 28083561 PMCID: PMC5220225 DOI: 10.1523/eneuro.0283-16.2016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 12/03/2016] [Accepted: 12/08/2016] [Indexed: 11/21/2022] Open
Abstract
During sociosexual encounters, different brain mechanisms interact to orchestrate information about the salience of external stimuli along with the current physiological and environmental conditions in order to process these in an optimal manner. One candidate neural system involves the potential interplay between the medial preoptic nucleus (POM) and mesolimbic reward circuitry. We present here evidence indicating that projections originating from the POM play a modulatory role on the mesolimbic reward circuitry related to male sexual behavior in Japanese quail (Coturnix japonica). First, we used an asymmetrical inactivation strategy where POM and ventral tegmental area (VTA) were unilaterally inactivated via the GABAA agonist muscimol, either in an ipsilateral or contralateral fashion. Ipsilateral injections of muscimol had negligible effects on both appetitive and consummatory sexual behaviors. In contrast, contralateral injections significantly impaired appetitive sexual behaviors but had no clear effect on consummatory sexual behaviors. Next, we labeled cells projecting from the POM to the VTA by stereotaxic injection into VTA of the retrograde tracer biotinylated dextran amine (BDA). Two weeks later, brains from males who had been allowed to interact freely with a female (15 min) or kept as controls were collected and fixed for double immunohistochemical labeling of BDA and the immediate early gene Fos. More retrogradely labeled BDA cells in POM expressed Fos after sociosexual interactions than in control conditions. Overall, these findings provide novel evidence for the interplay between POM and VTA in the modulation of appetitive but not consummatory sexual behaviors. Schematic representation of the putative role of the projection from the medial POM to the VTA in the regulation of appetitive and consummatory sexual behaviors. Unilateral inactivation of POM and VTA on (1) ipsilateral sides has negligible effects on both aspects of sexual behaviors, whereas (2) contralateral inactivation disrupts appetitive sexual behaviors.
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Normal male sexual function: emphasis on orgasm and ejaculation. Fertil Steril 2015; 104:1051-60. [PMID: 26385403 DOI: 10.1016/j.fertnstert.2015.08.033] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 08/17/2015] [Accepted: 08/26/2015] [Indexed: 12/31/2022]
Abstract
Orgasm and ejaculation are two separate physiological processes that are sometimes difficult to distinguish. Orgasm is an intense transient peak sensation of intense pleasure creating an altered state of consciousness associated with reported physical changes. Antegrade ejaculation is a complex physiological process that is composed of two phases (emission and expulsion), and is influenced by intricate neurological and hormonal pathways. Despite the many published research projects dealing with the physiology of orgasm and ejaculation, much about this topic is still unknown. Ejaculatory dysfunction is a common disorder, and currently has no definitive cure. Understanding the complex physiology of orgasm and ejaculation allows the development of therapeutic targets for ejaculatory dysfunction. In this article, we summarize the current literature on the physiology of orgasm and ejaculation, starting with a brief description of the anatomy of sex organs and the physiology of erection. Then, we describe the physiology of orgasm and ejaculation detailing the neuronal, neurochemical, and hormonal control of the ejaculation process.
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Clement P, Giuliano F. Anatomy and physiology of genital organs - men. HANDBOOK OF CLINICAL NEUROLOGY 2015; 130:19-37. [PMID: 26003237 DOI: 10.1016/b978-0-444-63247-0.00003-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Male sexual functions involve a number of organs and structures in genitalia whose role is to produce fertilizing gametes and to allow female-partner insemination. The testes belong to the reproductive and endocrine systems as they synthesize spermatozoa and androgens, and are under finely regulated hormonal control by the hypothalamopituitary axis. Sexual responses are controlled by a complex and coordinated interplay of both the somatic and the autonomic nervous system in multiple components of the brain, spinal cord, and relevant peripheral organs. Erectile bodies are an essential element of the penis and engorgement of the penis with blood leads to penile tumescence. Blood engorgement is due to relaxation of smooth-muscle cells of erectile tissue and endothelium of the penile arteries. The penis gains additional rigidity when the ischiocavernosus muscles contract. Stimuli from peripheral and/or central origins activate particular spinal nuclei, causing penile erection. Ejaculation consists of two phases, emission and expulsion, which correspond, respectively, to secretion of the different components of the semen by sex glands and forceful expulsion of semen due to rhythmic contractions of the bulbospongiosus muscle. A spinal generator of ejaculation integrates genital stimuli and sexual cues and, when the excitatory threshold is reached, triggers ejaculation by orchestrating the activation of autonomic and somatic pathways commanding the peripheral events of ejaculation.
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Affiliation(s)
- Pierre Clement
- School of Health Sciences, University of Versailles-St. Quentin en Yvelines, Montigny le Bretonneux, France; Pelvipharm Laboratories, Montigny le Bretonneux, France
| | - François Giuliano
- School of Health Sciences, University of Versailles-St. Quentin en Yvelines, Montigny le Bretonneux, France; Pelvipharm Laboratories, Montigny le Bretonneux, France; Neuro-Uro-Andrology, Department of Physical Medicine and Rehabilitation, Raymond Poincaré Hospital, Garches, France.
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Clément P, Bernabé J, Compagnie S, Alexandre L, McCallum S, Giuliano F. Inhibition of ejaculation by the non-peptide oxytocin receptor antagonist GSK557296: a multi-level site of action. Br J Pharmacol 2014; 169:1477-85. [PMID: 23530818 DOI: 10.1111/bph.12198] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 02/01/2013] [Accepted: 02/14/2013] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Oxytocin (OT) plays a major role in the control of male sexual responses. Notably, blockade of OT receptors has been reported to inhibit ejaculation in animals. The study aimed to investigate the action of a highly selective, non-peptide OT antagonist GSK557296 in a model of pharmacologically induced ejaculation in anaesthetized rats. The site of action was assessed by investigating different delivery routes for this compound. EXPERIMENTAL APPROACH Urethane-anaesthetized Wistar rats were implanted with a cerebral ventricle cannula for i.c.v. injections or with a subdural catheter for intrathecal (i.t.) GSK557296 injections. Occurrence of ejaculation was assessed following i.v. 7-hydroxy-2-(di-N-propylamino)tetralin (7-OH-DPAT), a dopamine D3 receptor agonist. In addition, seminal vesicle pressures (SVP) and bulbospongiosus muscle (BS) EMG were recorded as physiological markers of emission and expulsion phases of ejaculation respectively. KEY RESULTS Highest i.v. GSK557296 dose reduced occurrence of ejaculation and increases in SVP but had no effect on BS-EMG. I.c.v. GSK557296 dose dependently inhibited ejaculation, increases in SVP and BS contractions. At spinal thoracic level, GSK557296 dose dependently inhibited ejaculation and increases in SVP but BS-EMG was impaired only with the highest dose. When delivered at lumbar level, GSK557296 dose dependently inhibited ejaculation, increases in SVP and BS contractions. CONCLUSIONS AND IMPLICATIONS In the 7-OH-DPAT-induced ejaculation model, GSK557296 acts peripherally and centrally to inhibit ejaculation with different modalities. Blockade of brain OT receptors seems to be the most effective mechanism of action. Targeting central OT receptors with highly selective antagonist seems a promising approach for the treatment of premature ejaculation.
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Erbs E, Faget L, Veinante P, Kieffer BL, Massotte D. In vivo neuronal co-expression of mu and delta opioid receptors uncovers new therapeutic perspectives. ACTA ACUST UNITED AC 2014; 1. [PMID: 25938125 DOI: 10.14800/rci.210] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Opioid receptors belong to the G protein coupled receptor family. They modulate brain function at all levels of neural integration and therefore impact on autonomous, sensory, emotional and cognitive processing. In vivo functional interaction between mu and delta opioid receptors are known to take place though it is still debated whether interactions occur at circuitry, cellular or molecular level. Also, the notion of receptor crosstalk via mu-delta heteromers is well documented in vitro but in vivo evidence remains scarce. To identify neurons in which receptor interactions could take place, we designed a unique double mutant knock-in mouse line that expresses functional red-fluorescent mu receptors and green-fluorescent delta receptors. We mapped mu and delta receptor distribution and co-localization throughout the nervous system and created the first interactive brain atlas with concomitant mu-delta visualization at subcellular resolution (http://mordor.ics-mci.fr/). Mu and delta receptors co-localize in neurons from subcortical networks but are mainly detected in separate neurons in the forebrain. Also, co-immunoprecipitation experiments indicated physical proximity in the hippocampus, a prerequisite to mu-delta heteromerization. Altogether, data suggest that mu-delta functional interactions take place at systems level for high-order emotional and cognitive processing whereas mu-delta may interact at cellular level in brain networks essential for survival, which has potential implications for innovative drug design in pain control, drug addiction and eating disorders.
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Affiliation(s)
- Eric Erbs
- Dept of Neurogenetics and Translational Medicine, IGBMC, F-67404 Illkirch, France
| | - Lauren Faget
- Dept of Neurogenetics and Translational Medicine, IGBMC, F-67404 Illkirch, France
| | - Pierre Veinante
- Institut des Neurosciences Cellulaires et Intégratives, UPR 3212, F-67000 Strasbourg, France
| | - Brigitte L Kieffer
- Dept of Neurogenetics and Translational Medicine, IGBMC, F-67404 Illkirch, France ; Douglas Research Centre, Dept Psychiatry, Faculty of Medicine, McGill University, H4H 1R3 Montréal, Canada
| | - Dominique Massotte
- Dept of Neurogenetics and Translational Medicine, IGBMC, F-67404 Illkirch, France ; Institut des Neurosciences Cellulaires et Intégratives, UPR 3212, F-67000 Strasbourg, France
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Erbs E, Faget L, Scherrer G, Matifas A, Filliol D, Vonesch JL, Koch M, Kessler P, Hentsch D, Birling MC, Koutsourakis M, Vasseur L, Veinante P, Kieffer BL, Massotte D. A mu-delta opioid receptor brain atlas reveals neuronal co-occurrence in subcortical networks. Brain Struct Funct 2014; 220:677-702. [PMID: 24623156 PMCID: PMC4341027 DOI: 10.1007/s00429-014-0717-9] [Citation(s) in RCA: 203] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2013] [Accepted: 01/27/2014] [Indexed: 12/19/2022]
Abstract
Opioid receptors are G protein-coupled receptors (GPCRs) that modulate brain function at all levels of neural integration, including autonomic, sensory, emotional and cognitive processing. Mu (MOR) and delta (DOR) opioid receptors functionally interact in vivo, but whether interactions occur at circuitry, cellular or molecular levels remains unsolved. To challenge the hypothesis of MOR/DOR heteromerization in the brain, we generated redMOR/greenDOR double knock-in mice and report dual receptor mapping throughout the nervous system. Data are organized as an interactive database offering an opioid receptor atlas with concomitant MOR/DOR visualization at subcellular resolution, accessible online. We also provide co-immunoprecipitation-based evidence for receptor heteromerization in these mice. In the forebrain, MOR and DOR are mainly detected in separate neurons, suggesting system-level interactions in high-order processing. In contrast, neuronal co-localization is detected in subcortical networks essential for survival involved in eating and sexual behaviors or perception and response to aversive stimuli. In addition, potential MOR/DOR intracellular interactions within the nociceptive pathway offer novel therapeutic perspectives.
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Affiliation(s)
- Eric Erbs
- Department of Neurogenetics and Translational Medicine, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, 1 rue Laurent Fries, BP10142, 67404 Illkirch cedex, France
| | - Lauren Faget
- Department of Neurogenetics and Translational Medicine, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, 1 rue Laurent Fries, BP10142, 67404 Illkirch cedex, France
- Present Address: University of California, La Jolla, CA 92093 USA
| | - Gregory Scherrer
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford Institute for Neuro-Innovation and Translational Neurosciences, Stanford University, Stanford, 94305 CA USA
| | - Audrey Matifas
- Department of Neurogenetics and Translational Medicine, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, 1 rue Laurent Fries, BP10142, 67404 Illkirch cedex, France
| | - Dominique Filliol
- Department of Neurogenetics and Translational Medicine, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, 1 rue Laurent Fries, BP10142, 67404 Illkirch cedex, France
| | - Jean-Luc Vonesch
- Imaging Centre, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, BP 10142, 1 rue Laurent Fries, 67404 Illkirch cedex, France
| | - Marc Koch
- Imaging Centre, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, BP 10142, 1 rue Laurent Fries, 67404 Illkirch cedex, France
| | - Pascal Kessler
- Imaging Centre, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, BP 10142, 1 rue Laurent Fries, 67404 Illkirch cedex, France
| | - Didier Hentsch
- Imaging Centre, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, BP 10142, 1 rue Laurent Fries, 67404 Illkirch cedex, France
| | | | - Manoussos Koutsourakis
- Institut Clinique de la Souris, 1 rue Laurent Fries, 67404 Illkirch cedex, France
- Present Address: Sanger Institute, Hinxton, Cambridge CB 10 1SA UK
| | - Laurent Vasseur
- Institut Clinique de la Souris, 1 rue Laurent Fries, 67404 Illkirch cedex, France
| | - Pierre Veinante
- Institut des Neurosciences Cellulaires et Intégratives CNRS UPR 3212, 5 rue Blaise Pascal, 67084 Strasbourg cedex 03, France
| | - Brigitte L. Kieffer
- Department of Neurogenetics and Translational Medicine, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, 1 rue Laurent Fries, BP10142, 67404 Illkirch cedex, France
| | - Dominique Massotte
- Department of Neurogenetics and Translational Medicine, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, 1 rue Laurent Fries, BP10142, 67404 Illkirch cedex, France
- Institut des Neurosciences Cellulaires et Intégratives CNRS UPR 3212, 5 rue Blaise Pascal, 67084 Strasbourg cedex 03, France
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Chéhensse C, Bahrami S, Denys P, Clément P, Bernabé J, Giuliano F. The spinal control of ejaculation revisited: a systematic review and meta-analysis of anejaculation in spinal cord injured patients. Hum Reprod Update 2013; 19:507-26. [DOI: 10.1093/humupd/dmt029] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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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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Giuliano F, Clèment P. Pharmacology for the Treatment of Premature Ejaculation. Pharmacol Rev 2012; 64:621-44. [DOI: 10.1124/pr.111.004952] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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Marson L, Yu G, Farber NM. The Effects of Oral Administration of D-Modafinil on Male Rat Ejaculatory Behavior. J Sex Med 2010; 7:70-8. [DOI: 10.1111/j.1743-6109.2009.01509.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Spritzer MD, Weinberg A, Viau V, Galea LAM. Prior sexual experience increases hippocampal cell proliferation and decreases risk assessment behavior in response to acute predator odor stress in the male rat. Behav Brain Res 2009; 200:106-12. [PMID: 19166878 DOI: 10.1016/j.bbr.2009.01.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Revised: 12/27/2008] [Accepted: 01/03/2009] [Indexed: 02/05/2023]
Abstract
Acute exposure to the predator odor trimethylthiazoline (TMT) induces defensive behavior in the male rat, and this response is associated with a decrease in cell proliferation within the dentate gyrus of the hippocampus. Sexual experience appears to be protective, as it exerts anxiolytic-like effects and sustains gonadal function in the face of stress. To examine the influence of sexual experience on subsequent stress-induced defensive behavior and cell proliferation in the hippocampus we exposed adult male rats to TMT odor with or without prior exposure to sexually receptive female rats. A subset of rats was injected with the DNA-synthesis marker bromodeoxyuridine (BrdU; 200 mg/kg) during TMT exposure and perfused 24 h later to provide an index of cell proliferation within the dentate gyrus. In response to TMT, sexual experience reduced the duration of stretched attend postures, but had no significant effect on defensive burying. Furthermore, TMT induced a significant increase in cell proliferation in the dentate gyrus, but only in males with sexual experience. The results demonstrate an influence of socio-sexual experience on the magnitude of the behavioral and neural responses to predator odor stress.
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Affiliation(s)
- Mark D Spritzer
- Department of Psychology, The University of British Columbia, 2136 West Mall, Vancouver, BC V6T1Z4, Canada
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Neurologic and neuroendocrinologic responses during orgasm: What do we know? CURRENT SEXUAL HEALTH REPORTS 2008. [DOI: 10.1007/s11930-008-0025-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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15
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Central neurophysiology and dopaminergic control of ejaculation. Neurosci Biobehav Rev 2008; 32:438-53. [DOI: 10.1016/j.neubiorev.2007.07.013] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2007] [Revised: 07/31/2007] [Accepted: 07/31/2007] [Indexed: 01/09/2023]
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16
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Clément P, Bernabé J, Denys P, Alexandre L, Giuliano F. Ejaculation induced by i.c.v. injection of the preferential dopamine D3 receptor agonist 7-hydroxy-2-(di-N-propylamino)tetralin in anesthetized rats. Neuroscience 2007; 145:605-10. [PMID: 17258866 DOI: 10.1016/j.neuroscience.2006.12.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2006] [Revised: 11/30/2006] [Accepted: 12/01/2006] [Indexed: 10/23/2022]
Abstract
In addition to serotonin, dopamine within the CNS is known to play a primary role in the control of ejaculation. However, whether D(2) and/or D(3) dopamine receptor subtypes mediate this effect is still unclear. In order to clarify this issue, a pharmacological competitive study using the preferential D(3) agonist 7-hydroxy-2-(di-N-propylamino)tetralin (7-OH-DPAT) alone or in combination with competitive nonpreferential or preferential D(2) and D(3) antagonists delivered intracerebroventricularly (i.c.v.) was undertaken in anesthetized rats. Urethane-anesthetized male rats were implanted into the cerebral ventricle with a cannula for i.c.v. injections, and recording electrodes were placed within the bulbospongiosus (BS) muscle to monitor BS muscle contractions, which were used as a marker for the expulsion phase of ejaculation. Following i.c.v. injection, 7-OH-DPAT induced ejaculation and rhythmic BS muscle contractions. Co-injected i.c.v. with 7-OH-DPAT, the nonselective D(2)/D(3) antagonist (raclopride), and the preferential D(3) antagonist (S(-)-N[n-butyl-2-pyrrolidinyl)methyl]-1-methoxy-4-cyanonaphtalene-2-carboxamide; nafadotride) but not the preferential D(2) antagonist ((+/-)-3-[4-(4-chlorophenyl)-4-hydroxypiperidinyl]methylindole; L 741,626) inhibited the occurrence of ejaculation and BS muscle contractions. These results suggest that i.c.v. delivery of 7-OH-DPAT does represent a pertinent model to investigate the physio-pharmacology of ejaculation. It is inferred that targeting brain D(3) receptors may provide a therapeutic approach for treating ejaculatory disorders in humans.
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MESH Headings
- Anesthetics, General/pharmacology
- Animals
- Dopamine/metabolism
- Dopamine Agonists/pharmacology
- Dopamine Antagonists/pharmacology
- Dopamine D2 Receptor Antagonists
- Drug Interactions/physiology
- Ejaculation/drug effects
- Ejaculation/physiology
- Erectile Dysfunction/drug therapy
- Erectile Dysfunction/metabolism
- Erectile Dysfunction/physiopathology
- Genitalia, Male/innervation
- Genitalia, Male/physiology
- Injections, Intraventricular
- Male
- Models, Biological
- Muscle Contraction/drug effects
- Muscle Contraction/physiology
- Muscle, Skeletal/innervation
- Muscle, Skeletal/physiology
- Rats
- Rats, Wistar
- Receptors, Dopamine D2/agonists
- Receptors, Dopamine D2/metabolism
- Receptors, Dopamine D3/agonists
- Receptors, Dopamine D3/antagonists & inhibitors
- Receptors, Dopamine D3/metabolism
- Tetrahydronaphthalenes/pharmacology
- Urethane/pharmacology
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Affiliation(s)
- P Clément
- Pelvipharm Laboratories, Centre National de la Recherche Scientifique, Batiment 5, avenue de la Terrasse, 91190 Gif-sur-Yvette, France
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Giuliano F. 5-hydroxytryptamine in premature ejaculation: opportunities for therapeutic intervention. Trends Neurosci 2007; 30:79-84. [PMID: 17169440 DOI: 10.1016/j.tins.2006.12.002] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2006] [Revised: 10/24/2006] [Accepted: 12/05/2006] [Indexed: 10/23/2022]
Abstract
Ejaculation, although mediated by a spinal ejaculation generator, is subject to descending supraspinal modulation from several brain regions. 5-Hydroxytryptamine (5-HT or serotonin) is involved in ejaculatory control, with its ejaculation-retarding effects likely to be attributable to activation of 5-HT1B and 5-HT2C receptors, both spinally and supraspinally. By contrast, stimulation of 5-HT1A receptors precipitates ejaculation. Selective serotonin reuptake inhibitors (SSRIs), which are used for treatment of psychiatric disorders, can delay ejaculation in humans and are widely used 'off-label' for treatment of premature ejaculation. SSRIs require 1-2 weeks' chronic dosing to be effective, similar to their use for treatment of depression. However, a new short-acting SSRI is effective 'on demand' and might represent the first of a new generation of therapies targeted to premature ejaculation.
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Affiliation(s)
- François Giuliano
- AP-HP, Neuro-Uro-Andrology Unit, Department of Physical Medicine and Rehabilitation, Raymond Poincaré Hospital, 104 Bd Raymond Poincaré, 92380 Garches, France.
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Giuliano F, Clément P. Serotonin and Premature Ejaculation: From Physiology to Patient Management. Eur Urol 2006; 50:454-66. [PMID: 16844284 DOI: 10.1016/j.eururo.2006.05.055] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2006] [Accepted: 05/31/2006] [Indexed: 01/23/2023]
Abstract
INTRODUCTION Premature ejaculation (PE), whose pathophysiology is still not clearly identified, is the most common male sexual dysfunction, yet it remains underdiagnosed and undertreated. The aims of this paper are to provide a scientific and pharmacologic rationale, and to discuss to what extent selective serotonin reuptake inhibitors (SSRIs) can help patients with PE. MATERIALS AND METHODS A comprehensive evaluation of available published data included analysis of published full-length papers that were identified with Medline and Cancerlit from January 1981 to January 2006. Official proceedings of internationally known scientific societies held in the same time period were also assessed. RESULTS The central ejaculatory neural circuit comprises spinal and cerebral areas that form a highly interconnected network. The sympathetic, parasympathetic, and somatic spinal centers, under the influence of sensory genital and cerebral stimuli integrated and processed at the spinal cord level, act in synergy to command physiologic events occurring during ejaculation. Experimental evidence indicates that serotonin (5-HT), throughout brain descending pathways, exerts an inhibitory role on ejaculation. To date, three 5-HT receptor subtypes (5-HT1A, 5-HT1B, and 5-HT2C) have been postulated to mediate 5-HT's modulating activity on ejaculation. Pharmacologic manipulation of the serotonergic system has been performed in rats, with the antidepressant selective serotonin reuptake inhibitors (SSRIs) exhibiting the greatest efficacy in delaying ejaculation. The mechanism of action by which SSRIs modulate central 5-HT tone has been studied in depth, but gaps in this knowledge prevent an explanation of the efficacy of acute treatment in delaying ejaculation. Emerging clinical evidence indicates chronic and on-demand dosing of SSRIs has a beneficial effect for the treatment of men with PE, at least for paroxetine. On-demand dapoxetine, and SSRI with a short half-life, recently has been shown to significantly increase intravaginal latency time and PE patient-related outcomes in phase 3 clinical trials. CONCLUSIONS Nowadays there is no doubt that PE can be treated effectively by SSRIs. Nevertheless their mechanism of action is not yet well understood and deserves more research. In particular it is not understood why all the SSRIs are not equal in terms of their ability to delay ejaculation. Therefore, there is a need for more research to better characterize the mechanism of action of SSRIs as well their clinical benefit in patients affected by PE.
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Giuliano F, Clément P. Physiology of Ejaculation: Emphasis on Serotonergic Control. Eur Urol 2005; 48:408-17. [PMID: 15996810 DOI: 10.1016/j.eururo.2005.05.017] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2005] [Accepted: 05/20/2005] [Indexed: 01/23/2023]
Abstract
Ejaculation is constituted by two distinct phases, emission and expulsion. Orgasm, a feature perhaps unique in humans, is a cerebral process that occurs, in normal conditions, concomitantly to expulsion of semen. Normal antegrade ejaculation is a highly coordinated physiological process with emission and expulsion phases being under the control of autonomic and somatic nervous systems respectively. The central command of ejaculation is located at the thoracolumbar and lumbosacral levels of the spinal cord and is activated by stimuli from genital, mainly penile, origin although cerebral descending pathways exert both inhibitory and excitatory regulatory roles. Cerebral structures specifically activated during ejaculation form a tightly interconnected network comprising hypothalamic, diencephalic and pontine areas. A rational neurobiological approach has led to identify several neurotransmitters contributing to the ejaculatory process. Amongst them, serotonin (5-HT) has received strong experimental evidences indicating its inhibitory role in the central control of ejaculation. In particular, 5-HT1A cerebral autoreceptors but also spinal 5-HT1B and, in a lesser extent, 5-HT2C receptors have been shown to mediate the effects of 5-HT on ejaculation. Pharmacological strategies, especially those targeting serotonergic system, for the treatment of ejaculatory disorders in human will undoubtedly benefit from the application of basic and clinical research findings. In this perspective, the use of selective serotonin reuptake inhibitors (SSRIs) which basically increase the amount of central 5-HT and delay ejaculation in humans seems promising.
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Hamson DK, Jones BA, Watson NV. Distribution of androgen receptor immunoreactivity in the brainstem of male rats. Neuroscience 2004; 127:797-803. [PMID: 15312892 DOI: 10.1016/j.neuroscience.2004.06.006] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/05/2004] [Indexed: 11/17/2022]
Abstract
Gonadal steroids such as testosterone and estrogen are necessary for the normal activation of male rat sexual behavior. The medial preoptic area (MPOA), an important neural substrate regulating mating, accumulates steroids and also expresses functional androgen receptors (AR). The MPOA is intimately connected with other regions implicated in copulation, such as the bed nucleus of the stria terminalis and medial amygdala. Inputs to the MPOA arise from several areas within the brainstem, synapsing preferentially onto steroid sensitive MPOA cells which are activated during sexual activity. Given that little is known about the distribution of AR protein in the brainstem of male rats, we mapped the distribution of AR expressing cells in the pons and medulla using immunocytochemistry. In agreement with previous reports, AR immunoreactivity (AR-ir) was detected in ventral spinal motoneurons and interneurons. In addition, AR-ir was detected in areas corresponding to the solitary tract, lateral paragigantocellular and alpha and ventral divisions of the gigantocellular reticular nuclei, area postrema, raphe pallidus, ambiguus nucleus, and intermediate reticular nucleus. Several regions within the pons contained AR-ir, such as the tegmental and central gray, parabrachial nucleus, locus coeruleus, Barrington's nucleus, periaqueductal gray, and dorsal raphe. In contrast with in situ hybridization studies, auditory and somatosensory areas were AR-ir negative, and, except for very light staining in the prepositus nucleus, areas carrying vestibular information did not display AR-ir. Additionally, cranial nerve motoneurons of the hypoglossal, facial, dorsal vagus, and spinal trigeminal did not display AR-ir in contrast to previous reports. The data presented here indicate that androgens may influence numerous cell groups within the brainstem. Some of these probably constitute a steroid sensitive circuit linking the MPOA to motoneurons in the spinal cord via androgen responsive cells in the caudal ventral medulla.
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Affiliation(s)
- D K Hamson
- Hormones and Behaviour Laboratory, Department of Psychology, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
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