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Melis MR, Sanna F, Argiolas A. Dopamine, Erectile Function and Male Sexual Behavior from the Past to the Present: A Review. Brain Sci 2022; 12:brainsci12070826. [PMID: 35884633 PMCID: PMC9312911 DOI: 10.3390/brainsci12070826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 06/08/2022] [Accepted: 06/21/2022] [Indexed: 11/16/2022] Open
Abstract
Early and recent studies show that dopamine through its neuronal systems and receptor subtypes plays different roles in the control of male sexual behavior. These studies show that (i) the mesolimbic/mesocortical dopaminergic system plays a key role in the preparatory phase of sexual behavior, e.g., in sexual arousal, motivation and reward, whereas the nigrostriatal system controls the sensory-motor coordination necessary for copulation, (ii) the incertohypothalamic system is involved in the consummatory aspects of sexual behavior (penile erection and copulation), but evidence for its role in sexual motivation is also available, (iii) the pro-sexual effects of dopamine occur in concert with neural systems interconnecting the hypothalamus and preoptic area with the spinal cord, ventral tegmental area and other limbic brain areas and (iv) D2 and D4 receptors play a major role in the pro-sexual effects of dopamine. Despite some controversy, increases or decreases, respectively, of brain dopamine activity induced by drugs or that occur physiologically, usually improves or worsens, respectively, sexual activity. These findings suggest that an altered central dopaminergic tone plays a role in mental pathologies characterized by aberrant sexual behavior, and that pro-erectile D4 receptor agonists may be considered a new strategy for the treatment of erectile dysfunction in men.
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Kohtz AS, Walf AA, Frye CA. Effects of non-contingent cocaine on 3alpha-androstanediol. I. Disruption of male sexual behavior. Physiol Behav 2019; 203:120-127. [PMID: 29248633 DOI: 10.1016/j.physbeh.2017.12.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 12/03/2017] [Accepted: 12/14/2017] [Indexed: 01/21/2023]
Abstract
One of the hallmarks of drug abuse is a reduction in the salience of, and motivation for, natural rewards, such as mating. The effects of psychostimulants on male sexual interest and performance are conflicting; use of psychostimulants can produce increases in risky sexual behaviors but have detrimental effects on sexual ability. We hypothesize that these conflicting effects on sexual behavior are due to interactions between cocaine and androgens, such as testosterone and its neuroactive metabolite, 3α-androstanediol (3α-diol). Male rats were administered saline or cocaine (5, 10, or 20mg/kg, i.p.). Motor behavior was observed in the first 30min following drug-administration, and then sexual responding was assessed for 15min. Levels of androgens (testosterone, 3ɑ-diol, and testosterone's aromatized metabolite, estradiol) were measured in circulation and brain regions (frontal cortex, hippocampus, hypothalamus/striatum (hypo/str), and midbrain). Cocaine had no effect on measures of sexual interest (i.e. anogenital investigation). However, cocaine had substantial effects on consummatory sexual behaviors, such as the latency to mount/intromit and the number of sexual contacts. Frontal cortex and hypo/str 3α-diol levels were strongly correlated with consummatory behaviors in saline administered rats; however, this relationship was disrupted by cocaine at all dosages, concomitant with impaired sexual behaviors. Additionally, there was a shift in metabolism at low dosages of cocaine to push testosterone metabolism in the midbrain towards 3α-diol. On the contrary, moderate and high dosages of cocaine shifted testosterone metabolism towards estradiol. These data demonstrate that the association between cortical and hypo/str 3α-diol levels and sexual behavior of male rats is disrupted by non-contingent cocaine and that there may be dose-dependent effects of acute cocaine on androgen metabolism.
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Affiliation(s)
- Amy S Kohtz
- Dept. of Psychology, The University at Albany, SUNY, Albany, NY, USA
| | - Alicia A Walf
- Dept. of Psychology, The University at Albany, SUNY, Albany, NY, USA; Cognitive Science Dept., Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Cheryl A Frye
- Dept. of Psychology, The University at Albany, SUNY, Albany, NY, USA; Biological Sciences, The University at Albany, SUNY, Albany, NY, USA; Center for Neuroscience, The University at Albany, SUNY, Albany, NY, USA; Center for Life Sciences Research, The University at Albany, SUNY, Albany, NY, 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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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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Portillo W, Antonio-Cabrera E, Camacho FJ, Díaz NF, Paredes RG. Behavioral characterization of non-copulating male mice. Horm Behav 2013; 64:70-80. [PMID: 23673371 DOI: 10.1016/j.yhbeh.2013.05.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 04/30/2013] [Accepted: 05/02/2013] [Indexed: 11/26/2022]
Abstract
Non-copulating (NC) males are those animals that do not mate in spite of repeated testing with sexually receptive females. They have been observed in several species including rats and mice. The present experiment was designed to perform a detailed behavioral characterization of NC male mice. Thus, we evaluated their sexual incentive motivation for a sexually receptive female or a sexually active male, olfactory preference for volatile and non-volatile odors from females or males, and olfactory discrimination between female and male volatile odors and food related odors (milk versus vinegar). We compared the activity of the accessory olfactory system (AOS) in copulating (C) and NC males in response to estrous bedding using the induction of Fos-immunoreactivity (Fos-IR) as a measure of neuronal activation. We also determined if estradiol or dopamine treatment could induce sexual behavior in NC males. Finally, we compared the testis weight and the number of penile spines in C, NC, and gonadectomized males. In the sexual incentive motivation test C males spend significantly more time in the female incentive zone than in the male incentive zone. On the other hand, NC males spend the same amount of time in both incentive zones. In tests of olfactory preference, NC males spent less time investigating estrous odors than C males. As well, NC males discriminate urine from conspecifics but they spend less time smelling these odors than C males. In addition, no increase in Fos expression is observed in NC males when they are exposed to odors from estrous females. Our data also suggest that the deficits observed in NC males are not due to lower circulating levels of gonadal hormones, because estradiol supplementation does not induce sexual behavior in these animals, and their testis weight and the number of penile spines are normal. The results suggest that NC males are not sexually motivated by the receptive females and their odors.
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Affiliation(s)
- W Portillo
- Instituto de Neurobiología Universidad Nacional Autónoma de México, México.
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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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Abstract
INTRODUCTION Penile erection and ejaculation are closely associated during sexual intercourse. Erection is a central psychoneuroendocrine and peripheral neuro-vasculo-tissular event, resulting in blood filling the sinusoidal spaces of the corpora cavernosa and corpus spongiosum. Ejaculation represents the climax of the sexual cycle and comprises emission (secretion of semen) and expulsion (propulsion of semen) phases. AIM This article provides an overview of the proposed neurophysiology of erection and ejaculation. METHODS Review of the literature. MAIN OUTCOME MEASURES Current data on the neurophysiology of erection and ejaculation. RESULTS In terms of peripheral innervation, the pelvic plexus represents a junction for efferent nerves to the structures involved in erection and ejaculation. At the spinal level, the spinal cord contains three sets of neurons (thoracolumbar sympathetic, sacral parasympathetic, and somatic) innervating the sexual organs involved in erection and ejaculation. The presence of cerebral descending pathways to spinal erection and ejaculation centers indicates that the brain has an excitatory or inhibitory effect on these processes. Brain structures that modulate spinal command of erection and ejaculation are part of a larger network that is dedicated to regulating sexual responses. Neurophysiological and pharmacological research has elucidated that dopamine and serotonin have central roles in modulating erection and ejaculation. Interestingly, erection is not a prerequisite for ejaculation, and each of these sexual responses can exist without the other. CONCLUSION Despite the association between erection and ejaculation during intercourse, these two processes can be considered distinct events from an anatomical, physiological, and pharmacological perspective.
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Affiliation(s)
- François Giuliano
- Department of Physical Medicine and Rehabilitation, Raymond Poincaré Academic Hospital, Garches, Versailles Saint Quentin en Yvelines University, Garches, France.
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Staudt MD, Truitt WA, McKenna KE, de Oliveira CVR, Lehman MN, Coolen LM. A pivotal role of lumbar spinothalamic cells in the regulation of ejaculation via intraspinal connections. J Sex Med 2011; 9:2256-65. [PMID: 22189051 DOI: 10.1111/j.1743-6109.2011.02574.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
INTRODUCTION A population of lumbar spinothalamic cells (LSt cells) has been demonstrated to play a pivotal role in ejaculatory behavior and comprise a critical component of the spinal ejaculation generator. LSt cells are hypothesized to regulate ejaculation via their projections to autonomic and motor neurons in the lumbosacral spinal cord. AIM The current study tested the hypothesis that ejaculatory reflexes are dependent on LSt cells via projections within the lumbosacral spinal cord. METHODS Male rats received intraspinal injections of neurotoxin saporin conjugated to substance P analog, previously shown to selectively lesion LSt cells. Two weeks later, males were anesthetized and spinal cords were transected. Subsequently, males were subjected to ejaculatory reflex paradigms, including stimulation of the dorsal penile nerve (DPN), urethrogenital stimulation or administration of D3 agonist 7-OH-DPAT. Electromyographic recordings of the bulbocavernosus muscle (BCM) were analyzed for rhythmic bursting characteristic of the expulsion phase of ejaculation. In addition, a fourth commonly used paradigm for ejaculation and erections in unanesthetized, spinal-intact male rats was utilized: the ex copula reflex paradigm. MAIN OUTCOME MEASURES LSt cell lesions were predicted to prevent rhythmic bursting of BCM following DPN, urethral, or pharmacological stimulation, and emissions in the ex copula paradigm. In contrast, LSt cell lesions were not expected to abolish erectile function as measured in the ex copula paradigm. RESULTS LSt cell lesions prevented rhythmic contractions of the BCM induced by any of the ejaculatory reflex paradigms in spinalized rats. However, LSt cell lesions did not affect erectile function nor emissions determined in the ex copula reflex paradigm. CONCLUSIONS These data demonstrate that LSt cells are essential for ejaculatory, but not erectile reflexes, as previously reported for mating animals. Moreover, LSt cells mediate ejaculation via projections within the spinal cord, presumably to autonomic and motor neurons.
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Affiliation(s)
- Michael D Staudt
- Department of Anatomy & Cell Biology, The University of Western Ontario, London, Ontario, Canada
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Clément P, Pozzato C, Heidbreder C, Alexandre L, Giuliano F, Melotto S. Delay of Ejaculation Induced by SB-277011, a Selective Dopamine D3 Receptor Antagonist, in the Rat. J Sex Med 2009; 6:980-988. [DOI: 10.1111/j.1743-6109.2008.01173.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Clément P, Peeters M, Bernabé J, Denys P, Alexandre L, Giuliano F. Brain oxytocin receptors mediate ejaculation elicited by 7-hydroxy-2-(di-N-propylamino) tetralin (7-OH-DPAT) in anaesthetized rats. Br J Pharmacol 2008; 154:1150-9. [PMID: 18469843 DOI: 10.1038/bjp.2008.176] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE The involvement of the neuropeptide oxytocin in the control of male sexual responses is documented although its exact mechanisms of action, and especially the site(s) of action, are not fully delineated. In order to clarify this issue, we tested the effects of a peptide oxytocin antagonist delivered through different routes on sexual responses elicited, in anaesthetized male rats, by i.c.v. 7-hydroxy-2-(di-N-propylamino) tetralin (7-OH-DPAT), a dopamine agonist, preferentially active on D3 receptors. EXPERIMENTAL APPROACH Seminal vesicle pressure (SVP) and bulbospongiosus muscle (BS) electromyograms were recorded as physiological markers of emission and expulsion phases of ejaculation respectively and intracavernosal pressure (ICP) was monitored as a physiological marker of erection. KEY RESULTS When injected i.v., the oxytocin antagonist did not impair 7-OH-DPAT-induced SVP and ICP responses while BS burst frequency was diminished. When delivered i.c.v., the oxytocin antagonist dose-dependently inhibited occurrence of 7-OH-DPAT-induced sexual responses. When delivered intrathecally (i.t.) at the level of the 6th lumbar (L6) segment, but not the 13th thoracic (T13) segment, the oxytocin antagonist reduced the duration of BS responses and the occurrence of ejaculation without impairing ICP responses. CONCLUSIONS AND IMPLICATIONS Brain oxytocin receptors mediate male sexual responses elicited by i.c.v. 7-OH-DPAT in anaesthetized rats whereas L6 spinal oxytocin receptors only impair the occurrence of ejaculation. Peripheral oxytocin receptors are marginally involved in 7-OH-DPAT-induced sexual responses. These findings should be considered for the development of potential pharmacological treatment of premature ejaculation in man.
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Affiliation(s)
- P Clément
- Pelvipharm Laboratories, Parc d'Orsay, Orsay, France
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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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Kitrey N, Clément P, Bernabé J, Alexandre L, Giuliano F. Microinjection of the preferential dopamine receptor D3 agonist 7-hydroxy-N,N-di-n-propylaminotetralin hydrobromide into the hypothalamic medial preoptic area induced ejaculation in anesthetized rats. Neuroscience 2007; 149:636-41. [DOI: 10.1016/j.neuroscience.2007.06.051] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2007] [Revised: 06/18/2007] [Accepted: 06/27/2007] [Indexed: 11/25/2022]
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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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Andersen ML, Papale LA, Hipólide DC, Nobrega JN, Tufik S. Involvement of dopamine receptors in cocaine-induced genital reflexes after paradoxical sleep deprivation. Behav Brain Res 2005; 160:44-50. [PMID: 15836899 DOI: 10.1016/j.bbr.2004.11.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2004] [Revised: 09/17/2004] [Accepted: 11/14/2004] [Indexed: 11/18/2022]
Abstract
Previous work has demonstrated that paradoxical sleep deprivation (PSD) potentiates cocaine-induced genital reflexes in male rats. To examine the possibility that this effect might involve alterations in binding to the DA transporter (DAT), we examined [3H] WIN 35,248 binding in brain after 96 h of PSD. No changes were found in any of the 11 brain regions examined. Since we had previously identified changes in D2 receptor binding after PSD, we next examined the effects of DA receptor subtype antagonists on cocaine-induced reflexes in sleep-deprived rats. Separate groups of PSD rats received saline, haloperidol (0.4, 0.8 or 1.6 mg/kg), SCH 23390 (0.25, 0.5, 1 mg/kg) or sulpiride (50, 100, 200 mg/kg) 60 min prior to acute cocaine (7 mg/kg). In saline pretreated rats, cocaine-induced penile erection (PE) in 100% of SD rats. This percentage was not significantly reduced by haloperidol at any dose, but was significantly reduced in rats pretreated with SCH 23390 (1 mg/kg) or sulpiride (100 or 200 mg/kg). In addition, acute cocaine-induced ejaculation in 80% of SD rats. This effect was not affected by haloperidol at any dose, but was significantly reduced by all doses of SCH 23390 and by the 200 mg/kg dose of sulpiride. These results suggest that the potentiating effects of cocaine on penile erection and ejaculation are likely due to PSD-induced changes in DA postsynaptic receptor sensitivity rather than alterations in DA transporter. They further suggest that both D1 and D2 receptors may play a role in these effects.
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Affiliation(s)
- Monica Levy Andersen
- Department of Psychobiology, Universidade Federal de São Paulo, Escola Paulista de Medicina (UNIFESP/EPM), R. Napoleão de Barros, 925, V. Clementino 04024-002, São Paulo, SP, Brazil.
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Ottani A, Giuliani D, Ferrari F. Modulatory activity of sildenafil on copulatory behaviour of both intact and castrated male rats. Pharmacol Biochem Behav 2002; 72:717-22. [PMID: 12175469 DOI: 10.1016/s0091-3057(02)00744-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The first experiment of the present study investigates the effects induced by sildenafil (1 or 10 mg/kg po) on the copulatory behaviour of intact male rats, categorized, on the basis of seven consecutive mating pretests, as sluggish or normal ejaculators (SE or NE, respectively). The data obtained show that sildenafil modifies both sexual arousal and the ejaculatory mechanisms of copulation, diminishing ejaculation latency in both categories and increasing copulatory efficacy in SE rats; in addition, it reduced the inter-intromission interval in both SE and NE animals and the post-ejaculatory interval only in SE animals. The second experiment, conducted on rats 3 weeks after their castration, shows that sildenafil alone (1 or 10 mg/kg) did not modify copulatory failure. However, 3 months after castration, and 24 h after the last injection of testosterone (25 microg/kg sc) given twice weekly for 4 weeks, sildenafil (1 or 10 mg/kg) ameliorated rat copulatory performance.
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Affiliation(s)
- A Ottani
- Department of Biomedical Sciences, Division of Pharmacology, University of Modena and Reggio Emilia, Via G. Campi 287, Italy
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Giuliani D, Ottani A, Ferrari F. Influence of sildenafil on copulatory behaviour in sluggish or normal ejaculator male rats: a central dopamine mediated effect? Neuropharmacology 2002; 42:562-7. [PMID: 11955526 DOI: 10.1016/s0028-3908(01)00195-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The present study investigates the effects induced by sildenafil (1 mg/kg, p.o.) and the dopamine agonist, SND 919 (0.1 mg/kg, i.p.) on copulatory behaviour of male rats, categorized, on the basis of seven consecutive mating pre-tests, as sluggish and normal ejaculators (SE and NE, respectively). The data obtained show that sildenafil modifies both sexual arousal and ejaculatory mechanisms of copulation. It appears that, although it induced a facilitatory effect on ejaculation of all rats, similarly to SND 919, the lowering of ejaculatory threshold was achieved by means of a reduction of mount frequency and intromission frequency in SE and NE groups, respectively. Differently from SND 919, sildenafil increased sexual arousal, diminishing post ejaculatory interval in SE animals and inter-intromission interval in both SE and NE rats. As the dopamine antagonist, (-)eticlopride (0.02 mg/kg, s.c.), significantly inhibited sildenafil-induced enhancement of sexual arousal in SE rats, it is suggested that the drug acts both peripherally and centrally.
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Affiliation(s)
- D Giuliani
- Department of Biomedical Sciences, Division of Pharmacology, University of Modena and Reggio Emilia, via G. Campi 287, 41100, Modena, Italy
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Ottani A, Ferrari F, Giuliani D. Neuroleptic-like profile of the cannabinoid agonist, HU 210, on rodent behavioural models. Prog Neuropsychopharmacol Biol Psychiatry 2002; 26:91-6. [PMID: 11853125 DOI: 10.1016/s0278-5846(01)00224-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
(1) The present study was performed to assess the effects exerted by the cannabinoid (CB) agonist, (-)11-hydroxy-delta8-tetrahydrocannabinol-dymethylheptyl (HU 210; 12.5-50 microg/kg ip), on rodent behavioural tests involving dopamine (DA) transmission; in comparison, the DA D2 antagonist, S(-)-3-chloro-5-ethyl-N-[(1-ethyl-2-pyrrolidinyl)methyl]-6-hydroxy-2-methoxy-benzamide hydrochloride ((-)eticlopride; 50 microg/kg sc), was used. (2) In rats, HU 210, at all doses, potently antagonized penile erection (PE) and stretching-yawning (SY) typically elicited by the DA D2/D3 agonists, 6-allyl-2-amino-5,6,7,8-tetrahydro-4H-thiazolo-[4,5-d]-azepine (B-HT 920) and +/-7-hydroxy-N,N-di-n-propylaminotetralin hydrobromide (7-OH-DPAT) both at 100 pg/kg ip. (3) In nonreserpinized mice, HU 210 impaired motor ability assessed by means of a motor test battery, and B-HT 920 (1 mg/kg ip) worsened the phenomenon. (4) In reserpinized mice, HU 210 at 50 microg/kg counteracted the amelioration exerted by B-HT 920 (1 mg/kg ip) on reserpine-induced akinesia. (5) As all these effects were similarly displayed by (-)eticlopride (50 microg/kg sc), our data suggest a neuroleptic-like profile of acute HU 210 in animal behavioural tests.
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Affiliation(s)
- Alessandra Ottani
- Department of Biomedical Sciences, University of Modena and Reggio Emilia, Italy
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Ferrari F, Ottani A, Giuliani D. Inhibitory effects of the cannabinoid agonist HU 210 on rat sexual behaviour. Physiol Behav 2000; 69:547-54. [PMID: 10913795 DOI: 10.1016/s0031-9384(00)00214-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The present study investigates the effects induced by the cannabinoid agonist HU 210 (25-100 microg/kg, administered intraperitoneally [i.p.]) on the following parameters: (a) sexual behaviour of male rats, categorised on the basis of seven consecutive mating pretests as sexually active (SA) and sexually inactive (SI) and (b) sexual receptivity of ovariectomised female rats displaying hormonally induced heat. The data obtained show that HU 210, administered in acute or subchronic mode (once daily for 7 and 14 days), impaired the copulatory pattern of SA rats in a dose- and mode-dependent manner, decreasing their sexual drive, mainly as represented by an increase in mount and intromission latencies, and affecting ejaculation mechanisms (represented as a decrease in intromission frequency and increase in ejaculation latency). After subchronic treatment with the highest dose had been suspended for 2 weeks, SA males' performance was still impaired. In SI rats, acute injections of the drug (25 and 50 microg/kg, i.p.) at the higher dose increased contact latency and decreased genital exploration time towards the female. Acute HU 210 (25-100 microg/kg, i.p.) also inhibited female sexual behaviour, potently reducing lordosis quotient and lordosis intensity.
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Affiliation(s)
- F Ferrari
- Department of Biomedical Sciences, Division of Pharmacology, University of Modena and Reggio Emilia, Via G. Campi 287, I-41100, Modena, Italy.
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Ferrari F, Giuliani D. Involvement of dopamine D2 receptors in the effect of cocaine on sexual behaviour and stretching-yawning of male rats. Neuropharmacology 1997; 36:769-77. [PMID: 9225304 DOI: 10.1016/s0028-3908(97)00041-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The effect of cocaine (7.5, 15 and 30 mg/kg) administered in acute or subchronic mode, on the mating behaviour of sexually active male rats varied in a dose- and mode-dependent manner. Regardless of mode of treatment, 30 mg/kg markedly impaired the rats copulatory ability and impairment continued for a week after suspension of subchronic treatment. An acute dose of 15 mg/kg reduced intromission frequency, while in subchronic mode it also reduced ejaculation latency. Mount frequency was increased by 7.5 and 15 mg/kg, but only on first injection. In the case of sexually-naive male rats, acute administration of cocaine (3-30 mg/kg) stimulated penile erections at 7.5 mg/kg and motor hyperactivity at all doses. (-) Eticlopride (0.025 and 0.05 mg/kg), a DA D2 antagonist, counteracted cocaine-induced motor hyperactivity but not penile erection, which it enhanced. (-) Eticlopride at the same doses also antagonized cocaine potentiation of lisuride (0.2 mg/kg)-induced behavioural effects. When male rats treated with subchronic cocaine (15 mg/kg) were injected with the DA D2 agonist SND 919 (0.1 mg/kg), they displayed a more marked stretching-yawning behaviour than control animals receiving SND 919 at the same dose. The involvement of DA D2 receptors in cocaine-induced effects is suggested.
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Affiliation(s)
- F Ferrari
- Department of Biomedical Sciences, University of Modena, Italy
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