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Melis MR, Argiolas A. Erectile Function and Sexual Behavior: A Review of the Role of Nitric Oxide in the Central Nervous System. Biomolecules 2021; 11:biom11121866. [PMID: 34944510 PMCID: PMC8699072 DOI: 10.3390/biom11121866] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 12/06/2021] [Accepted: 12/08/2021] [Indexed: 12/21/2022] Open
Abstract
Nitric oxide (NO), the neuromodulator/neurotransmitter formed from l-arginine by neuronal, endothelial and inducible NO synthases, is involved in numerous functions across the body, from the control of arterial blood pressure to penile erection, and at central level from energy homeostasis regulation to memory, learning and sexual behavior. The aim of this work is to review earlier studies showing that NO plays a role in erectile function and sexual behavior in the hypothalamus and its paraventricular nucleus and the medial preoptic area, and integrate these findings with those of recent studies on this matter. This revisitation shows that NO influences erectile function and sexual behavior in males and females by acting not only in the paraventricular nucleus and medial preoptic area but also in extrahypothalamic brain areas, often with different mechanisms. Most importantly, since these areas are strictly interconnected with the paraventricular nucleus and medial preoptic area, send to and receive neural projections from the spinal cord, in which sexual communication between brain and genital apparatus takes place, this review reveals that central NO participates in concert with neurotransmitters/neuropeptides to a neural circuit controlling both the consummatory (penile erection, copulation, lordosis) and appetitive components (sexual motivation, arousal, reward) of sexual behavior.
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Oxytocin, Erectile Function and Sexual Behavior: Last Discoveries and Possible Advances. Int J Mol Sci 2021; 22:ijms221910376. [PMID: 34638719 PMCID: PMC8509000 DOI: 10.3390/ijms221910376] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 09/20/2021] [Accepted: 09/23/2021] [Indexed: 12/30/2022] Open
Abstract
A continuously increasing amount of research shows that oxytocin is involved in numerous central functions. Among the functions in which oxytocin is thought to be involved are those that play a role in social and sexual behaviors, and the involvement of central oxytocin in erectile function and sexual behavior was indeed one of the first to be discovered in laboratory animals in the 1980s. The first part of this review summarizes the results of studies done in laboratory animals that support a facilitatory role of oxytocin in male and female sexual behavior and reveal mechanisms through which this ancient neuropeptide participates in concert with other neurotransmitters and neuropeptides in this complex function, which is fundamental for the species reproduction. The second part summarizes the results of studies done mainly with intranasal oxytocin in men and women with the aim to translate the results found in laboratory animals to humans. Unexpectedly, the results of these studies do not appear to confirm the facilitatory role of oxytocin found in male and female sexual behavior in animals, both in men and women. Possible explanations for the failure of oxytocin to improve sexual behavior in men and women and strategies to attempt to overcome this impasse are considered.
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Rats selectively bred for showing divergent behavioral traits in response to stress or novelty or spontaneous yawning with a divergent frequency show similar changes in sexual behavior: the role of dopamine. Rev Neurosci 2018; 30:427-454. [DOI: 10.1515/revneuro-2018-0058] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 07/26/2018] [Indexed: 02/07/2023]
Abstract
Abstract
Sexual behavior plays a fundamental role for reproduction in mammals and other animal species. It is characterized by an anticipatory and a consummatory phase, and several copulatory parameters have been identified in each phase, mainly in rats. Sexual behavior varies significantly across rats even when they are of the same strain and reared under identical conditions. This review shows that rats of the same strain selectively bred for showing a divergent behavioral trait when exposed to stress or novelty (i.e. Roman high and low avoidance rats, bred for their different avoidance response to the shuttle box, and high and low novelty exploration responders rats, bred for their different exploratory response to a novel environment) or a spontaneous behavior with divergent frequency (i.e. low and high yawning frequency rats, bred for their divergent yawning frequency) show similar differences in sexual behavior, mainly in copulatory pattern, but also in sexual motivation. As shown by behavioral pharmacology and intracerebral microdialysis experiments carried out mainly in Roman rats, these sexual differences may be due to a more robust dopaminergic tone present in the mesocorticolimbic dopaminergic system of one of the two sub-lines (e.g. high avoidance, high novelty exploration, and low yawning rat sub-lines). Thus, differences in genotype and/or in prenatal/postnatal environment lead not only to individual differences in temperament and environmental/emotional reactivity but also in sexual behavior. Because of the highly conserved mechanisms controlling reproduction in mammals, this may occur not only in rats but also in humans.
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van den Brink WJ, Palic S, Köhler I, de Lange ECM. Access to the CNS: Biomarker Strategies for Dopaminergic Treatments. Pharm Res 2018; 35:64. [PMID: 29450650 PMCID: PMC5814527 DOI: 10.1007/s11095-017-2333-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 12/18/2017] [Indexed: 12/26/2022]
Abstract
Despite substantial research carried out over the last decades, it remains difficult to understand the wide range of pharmacological effects of dopaminergic agents. The dopaminergic system is involved in several neurological disorders, such as Parkinson's disease and schizophrenia. This complex system features multiple pathways implicated in emotion and cognition, psychomotor functions and endocrine control through activation of G protein-coupled dopamine receptors. This review focuses on the system-wide effects of dopaminergic agents on the multiple biochemical and endocrine pathways, in particular the biomarkers (i.e., indicators of a pharmacological process) that reflect these effects. Dopaminergic treatments developed over the last decades were found to be associated with numerous biochemical pathways in the brain, including the norepinephrine and the kynurenine pathway. Additionally, they have shown to affect peripheral systems, for example the hypothalamus-pituitary-adrenal (HPA) axis. Dopaminergic agents thus have a complex and broad pharmacological profile, rendering drug development challenging. Considering the complex system-wide pharmacological profile of dopaminergic agents, this review underlines the needs for systems pharmacology studies that include: i) proteomics and metabolomics analysis; ii) longitudinal data evaluation and mathematical modeling; iii) pharmacokinetics-based interpretation of drug effects; iv) simultaneous biomarker evaluation in the brain, the cerebrospinal fluid (CSF) and plasma; and v) specific attention to condition-dependent (e.g., disease) pharmacology. Such approach is considered essential to increase our understanding of central nervous system (CNS) drug effects and substantially improve CNS drug development.
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Affiliation(s)
- Willem Johan van den Brink
- Division of Systems Biomedicine and Pharmacology, Leiden Academic Centre for Drug Research, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Semra Palic
- Division of Systems Biomedicine and Pharmacology, Leiden Academic Centre for Drug Research, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Isabelle Köhler
- Division of Systems Biomedicine and Pharmacology, Leiden Academic Centre for Drug Research, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Elizabeth Cunera Maria de Lange
- Division of Systems Biomedicine and Pharmacology, Leiden Academic Centre for Drug Research, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands.
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Wang M, Yu Y, Shao J, Heng BC, Ye H. Engineering synthetic optogenetic networks for biomedical applications. QUANTITATIVE BIOLOGY 2017. [DOI: 10.1007/s40484-017-0105-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Argiolas A, Melis MR. Neuropeptides and central control of sexual behaviour from the past to the present: a review. Prog Neurobiol 2013; 108:80-107. [PMID: 23851261 DOI: 10.1016/j.pneurobio.2013.06.006] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2013] [Revised: 06/28/2013] [Accepted: 06/29/2013] [Indexed: 12/23/2022]
Abstract
Of the numerous neuropeptides identified in the central nervous system, only a few are involved in the control of sexual behaviour. Among these, the most studied are oxytocin, adrenocorticotropin, α-melanocyte stimulating hormone and opioid peptides. While opioid peptides inhibit sexual performance, the others facilitate sexual behaviour in most of the species studied so far (rats, mice, monkeys and humans). However, evidence for a sexual role of gonadotropin-releasing hormone, corticotropin releasing factor, neuropeptide Y, galanin and galanin-like peptide, cholecystokinin, substance P, vasoactive intestinal peptide, vasopressin, angiotensin II, hypocretins/orexins and VGF-derived peptides are also available. Corticotropin releasing factor, neuropeptide Y, cholecystokinin, vasopressin and angiotensin II inhibit, while substance P, vasoactive intestinal peptide, hypocretins/orexins and some VGF-derived peptide facilitate sexual behaviour. Neuropeptides influence sexual behaviour by acting mainly in the hypothalamic nuclei (i.e., lateral hypothalamus, paraventricular nucleus, ventromedial nucleus, arcuate nucleus), in the medial preoptic area and in the spinal cord. However, it is often unclear whether neuropeptides influence the anticipatory phase (sexual arousal and/or motivation) or the consummatory phase (performance) of sexual behaviour, except in a few cases (e.g., opioid peptides and oxytocin). Unfortunately, scarce information has been added in the last 15 years on the neural mechanisms by which neuropeptides influence sexual behaviour, most studied neuropeptides apart. This may be due to a decreased interest of researchers on neuropeptides and sexual behaviour or on sexual behaviour in general. Such a decrease may be related to the discovery of orally effective, locally acting type V phosphodiesterase inhibitors for the therapy of erectile dysfunction.
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Affiliation(s)
- Antonio Argiolas
- Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy.
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Yeh KY, Wu CH, Tsai YF. Noncontact erection is enhanced by Ginkgo biloba treatment in rats: role of neuronal NOS in the paraventricular nucleus and sacral spinal cord. Psychopharmacology (Berl) 2012; 222:439-46. [PMID: 22389046 DOI: 10.1007/s00213-012-2660-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 02/03/2012] [Indexed: 12/21/2022]
Abstract
RATIONALE Nitric oxide (NO) is an important messenger mediating erection in the central nervous system (CNS). Paraventricular nucleus (PVN) neurons can be activated by NO and project the signals to the sacral spinal cord, which is involved in regulation of erection. Ginkgo biloba extract (EGb 761) facilitates noncontact erection (NCE) in rats; however, it is not clear whether EGb 761 increased NCE is associated with NO. OBJECTIVE The present study was designed to investigate the effects of neuronal nitric oxide synthase (nNOS) on NCE in rats following EGb 761 treatment. METHODS Adult Long-Evans male rats were treated with 50 mg/kg of EGb 761 or distilled water for 14 days. The NCE test was performed after 14 days of EGb 761 treatment and the NCE frequency was recorded. Approximately 14 h following the NCE behavioral tests, animals were sacrificed, and nNOS activity in the PVN and S6-L1 spinal cord was measured by immunohistochemistry and western blotting, respectively. RESULTS Treatment with 50 mg/kg of EGb 761 for 14 days increased the NCE numbers compared to either the controls treated with distilled water on the same day or the same group on day 0. Also, EGb 761 treatment enhanced nNOS-immunoreactive cell numbers in the PVN. Furthermore, western blot analysis showed that EGb 761-treated animals displayed higher levels of nNOS expression in the S1 spinal cord than controls. CONCLUSION Our results suggest that enhanced NCE in male rats administrated with EGb 761 may be related to the central nNOS activity in the PVN and the spinal cord.
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Affiliation(s)
- Kuei-Ying Yeh
- Department of Physical Therapy, HungKuang University, No. 34 Chung-Chie Road, Sha Lu, Taichung, 443, Taiwan, Republic of China.
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Andersson KE. Mechanisms of penile erection and basis for pharmacological treatment of erectile dysfunction. Pharmacol Rev 2011; 63:811-59. [PMID: 21880989 DOI: 10.1124/pr.111.004515] [Citation(s) in RCA: 228] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Erection is basically a spinal reflex that can be initiated by recruitment of penile afferents, both autonomic and somatic, and supraspinal influences from visual, olfactory, and imaginary stimuli. Several central transmitters are involved in the erectile control. Dopamine, acetylcholine, nitric oxide (NO), and peptides, such as oxytocin and adrenocorticotropin/α-melanocyte-stimulating hormone, have a facilitatory role, whereas serotonin may be either facilitatory or inhibitory, and enkephalins are inhibitory. The balance between contractant and relaxant factors controls the degree of contraction of the smooth muscle of the corpora cavernosa (CC) and determines the functional state of the penis. Noradrenaline contracts both CC and penile vessels via stimulation of α₁-adrenoceptors. Neurogenic NO is considered the most important factor for relaxation of penile vessels and CC. The role of other mediators, released from nerves or endothelium, has not been definitely established. Erectile dysfunction (ED), defined as the "inability to achieve or maintain an erection adequate for sexual satisfaction," may have multiple causes and can be classified as psychogenic, vasculogenic or organic, neurologic, and endocrinologic. Many patients with ED respond well to the pharmacological treatments that are currently available, but there are still groups of patients in whom the response is unsatisfactory. The drugs used are able to substitute, partially or completely, the malfunctioning endogenous mechanisms that control penile erection. Most drugs have a direct action on penile tissue facilitating penile smooth muscle relaxation, including oral phosphodiesterase inhibitors and intracavernosal injections of prostaglandin E₁. Irrespective of the underlying cause, these drugs are effective in the majority of cases. Drugs with a central site of action have so far not been very successful. There is a need for therapeutic alternatives. This requires identification of new therapeutic targets and design of new approaches. Research in the field is expanding, and several promising new targets for future drugs have been identified.
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Affiliation(s)
- K-E Andersson
- Wake Forest Institute for Regenerative Medicine, Wake Forest University School of Medicine, Medical Center Boulevard, Winston Salem, NC 27157, USA.
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Behavioral characterization of non-copulating male rats with high spontaneous yawning frequency rate. Behav Brain Res 2010; 214:225-30. [DOI: 10.1016/j.bbr.2010.05.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 05/13/2010] [Accepted: 05/18/2010] [Indexed: 11/24/2022]
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Gratzke C, Angulo J, Chitaley K, Dai YT, Kim NN, Paick JS, Simonsen U, Uckert S, Wespes E, Andersson KE, Lue TF, Stief CG. Anatomy, physiology, and pathophysiology of erectile dysfunction. J Sex Med 2010; 7:445-75. [PMID: 20092448 DOI: 10.1111/j.1743-6109.2009.01624.x] [Citation(s) in RCA: 231] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Significant scientific advances during the past 3 decades have deepened our understanding of the physiology and pathophysiology of penile erection. A critical evaluation of the current state of knowledge is essential to provide perspective for future research and development of new therapies. AIM To develop an evidence-based, state-of-the-art consensus report on the anatomy, physiology, and pathophysiology of erectile dysfunction (ED). METHODS Consensus process over a period of 16 months, representing the opinions of 12 experts from seven countries. MAIN OUTCOME MEASURE Expert opinion was based on the grading of scientific and evidence-based medical literature, internal committee discussion, public presentation, and debate. RESULTS ED occurs from multifaceted, complex mechanisms that can involve disruptions in neural, vascular, and hormonal signaling. Research on central neural regulation of penile erection is progressing rapidly with the identification of key neurotransmitters and the association of neural structures with both spinal and supraspinal pathways that regulate sexual function. In parallel to advances in cardiovascular physiology, the most extensive efforts in the physiology of penile erection have focused on elucidating mechanisms that regulate the functions of the endothelium and vascular smooth muscle of the corpus cavernosum. Major health concerns such as atherosclerosis, hyperlipidemia, hypertension, diabetes, and metabolic syndrome (MetS) have become well integrated into the investigation of ED. CONCLUSIONS Despite the efficacy of current therapies, they remain insufficient to address growing patient populations, such as those with diabetes and MetS. In addition, increasing awareness of the adverse side effects of commonly prescribed medications on sexual function provides a rationale for developing new treatment strategies that minimize the likelihood of causing sexual dysfunction. Many basic questions with regard to erectile function remain unanswered and further laboratory and clinical studies are necessary.
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Affiliation(s)
- Christian Gratzke
- Department of Urology, Ludwig-Maximilians-Universität, München, Germany
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Interactions between morphine and nitric oxide in various organs. J Anesth 2009; 23:554-68. [DOI: 10.1007/s00540-009-0793-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Accepted: 05/11/2009] [Indexed: 02/02/2023]
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12
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Naltrexone effects on male sexual behavior, corticosterone, and testosterone in stressed male rats. Physiol Behav 2009; 96:333-42. [DOI: 10.1016/j.physbeh.2008.10.022] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2008] [Revised: 10/03/2008] [Accepted: 10/23/2008] [Indexed: 11/23/2022]
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Sun X, Xu L, Zhang J, Guo F, Tang M. The Effects of Alprostadil on Hypothalamic and Amygdalar Function and the Central Expression of Oxytocin: A Potential Central Role of Alprostadil Cream. J Sex Med 2009; 6:81-90. [DOI: 10.1111/j.1743-6109.2008.01060.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Succu S, Mascia MS, Melis T, Sanna F, Boi A, Melis MR, Argiolas A. Morphine reduces penile erection induced by the cannabinoid receptor antagonist SR 141617A in male rats: Role of paraventricular glutamic acid and nitric oxide. Neurosci Lett 2006; 404:1-5. [PMID: 16725257 DOI: 10.1016/j.neulet.2006.05.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2006] [Revised: 04/14/2006] [Accepted: 05/04/2006] [Indexed: 11/25/2022]
Abstract
The effect of the opiate morphine, on penile erection induced by the cannabinoid CB1 receptor antagonist SR 141716A injected into the paraventricular nucleus of the hypothalamus and on the increase in the concentration of glutamic acid and of NO(2)(-) and NO(3)(-), which occurs concomitantly in the paraventricular dialysate obtained by intracerebral microdialysis, was studied in male rats. Morphine (0.5, 1 and 5 microg), given into the paraventricular nucleus, reduced dose-dependently penile erection induced by SR 141716A (2 microg) injected into the paraventricular nucleus. The reduction of penile erection was parallel to a decrease of the concomitant glutamic acid and NO(2)(-) and NO(3)(-) increase that occurs in the paraventricular dialysate in these experimental conditions. Morphine effects on SR 141716A-induced penile erection, glutamic acid and NO(2)(-) increase were prevented by the prior administration of naloxone, an opioid receptor antagonist (5 microg) given into the paraventricular nucleus. The present results show that the activation of opioid receptors in the paraventricular nucleus impairs penile erection induced by SR 141716A, by reducing the increase in glutamic acid and in NO activity that occurs in this hypothalamic nucleus in these experimental conditions.
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Affiliation(s)
- Salvatora Succu
- Bernard B. Brodie Department of Neuroscience and Centre of Excellence for the Neurobiology of Addictions, University of Cagliari, SP Monserrato-Sestu, Italy
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Kendirci M, Walls MM, Hellstrom WJG. Central Nervous System Agents in the Treatment of Erectile Dysfunction. Urol Clin North Am 2005; 32:487-501, vii. [PMID: 16291040 DOI: 10.1016/j.ucl.2005.08.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In the last two decades, a better understanding of the mechanisms governing erectile function and the pathophysiologies underlying erectile dysfunction (ED) have led re-searchers to investigate novel treatment concepts. Selective type-5 phosphodiesterase inhibitors are recommended as first-line therapy because of their high efficacy, but 30% to 40% of patients who have ED do not respond adequately to these agents and require alternative methods. The central nervous system plays a fundamental role in sexual behavior. Animal models have advanced our understanding of the neuroanatomic and neuropharmacologic basis of centrally induced penile erections. Clinical research with apomorphine has demonstrated efficacy in men who have a range of ED. Recent interest has focused on other centrally acting agents for ED treatment, including the melanocortin receptor agonists.
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Affiliation(s)
- Muammer Kendirci
- Department of Urology, Tulane University, Health Sciences Center, SL-42, New Orleans, LA 70112, USA
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Argiolas A, Melis MR. Central control of penile erection: Role of the paraventricular nucleus of the hypothalamus. Prog Neurobiol 2005; 76:1-21. [PMID: 16043278 DOI: 10.1016/j.pneurobio.2005.06.002] [Citation(s) in RCA: 157] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2004] [Revised: 05/02/2005] [Accepted: 06/14/2005] [Indexed: 11/29/2022]
Abstract
The paraventricular nucleus of the hypothalamus is an integration centre between the central and peripheral autonomic nervous systems. It is involved in numerous functions from feeding, metabolic balance, blood pressure and heart rate, to erectile function and sexual behaviour. In particular, a group of oxytocinergic neurons originating in this nucleus and projecting to extra-hypothalamic brain areas (e.g., hippocampus, medulla oblongata and spinal cord) control penile erection in male rats. Activation of these neurons by dopamine and its agonists, excitatory amino acids (N-methyl-D-aspartic acid) or oxytocin itself, or by electrical stimulation leads to penile erection, while their inhibition by gamma-amino-butyric acid (GABA) and its agonists or by opioid peptides and opiate-like drugs inhibits this sexual response. The activation of these neurons is secondary to the activation of nitric oxide synthase, which produces nitric oxide. Nitric oxide in turn causes, by a mechanism that is as yet unidentified, the release of oxytocin in extra-hypothalamic brain areas. Other compounds recently identified that facilitate penile erection by activating central oxytocinergic neurons are peptide analogues of hexarelin, a growth hormone releasing peptide, pro-VGF-derived peptides, endogenous peptides that may be released by neuronal nerve endings impinging on oxytocinergic cell bodies, SR 141716A, a cannabinoid CB1 receptor antagonist, and, less convincingly, adrenocorticotropin-melanocyte-stimulating hormone (ACTH-MSH)-related peptides. Paraventricular oxytocinergic neurons and similar mechanisms are also involved in penile erection occurring in physiological contexts, namely noncontact erections that occur in male rats in the presence of an inaccessible receptive female, and during copulation. These findings show that the paraventricular nucleus of the hypothalamus plays an important role in the control of erectile function and sexual activity. As the male rat is a model of sexual behaviour and penile physiology, which has largely increased in the last years our knowledge of peripheral and central mechanisms controlling erectile function (drugs that induce penile erection in male rats usually do so also in man), the above results may have great significance in terms of a human perspective for the treatment of erectile dysfunction.
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Affiliation(s)
- Antonio Argiolas
- Bernard B. Brodie Department of Neuroscience, Centre of Excellence for the Neurobiology of Addictions, University of Cagliari, S.P. Sestu-Monserrato Km 0.700, 09042 Monserrato, Cagliari, Italy.
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Chen KK, Chang LS. Effect of excitatory amino acid receptor agonists on penile erection after administration into paraventricular nucleus of hypothalamus in the rat. Urology 2003; 62:575-80. [PMID: 12946780 DOI: 10.1016/s0090-4295(03)00411-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVES To investigate whether the excitatory amino acid receptor agonists can activate the paraventricular nucleus of the hypothalamus (PVN) and induce penile erections in the rat. METHODS Male adult Sprague-Dawley rats were used. A 26-gauge needle was inserted into the corpus cavernosum to monitor the intracavernous pressure (ICP) simultaneously with the systemic arterial pressure and heart rate. The study was divided into seven parts: stereotaxic delivery of N-methyl-d-aspartic acid (NMDA) (50 ng/500 nL) into the PVN; administration of the NMDA noncompetitive antagonist MK-801 (100 ng/250 nL) and NMDA (50 ng/250 nL) into the PVN; administration of the NMDA competitive antagonist (+/-)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP; 100 ng/250 nL) and NMDA (50 ng/250 nL) into the PVN; microinjection of (+/-)-alpha-(amino)-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA; 100 ng/500 nL) into the PVN; microinjection of trans-(+/-)-1-amino-1,3-cyclopentanedicarboxylic acid (ACPD; 100 ng/500 nL) into the PVN; saline 500 nL into the PVN; and intracavernous administration of NMDA (50 ng/100 microL). RESULTS On administration of NMDA into the PVN, a significant increase occurred in the ICP from a resting 8.3 +/- 1.8 mm Hg to a peak at 59.0 +/- 8.4 mm Hg. No change occurred in the resting ICP after administration of either the mixture of MK-801 and NMDA or CPP and NMDA into the PVN. Microinjection of AMPA, ACPD, or saline into the PVN and intracavernous administration of NMDA were all ineffective to induce an increase in ICP. CONCLUSIONS The results of this study suggest that ionotropic excitatory amino acid (NMDA) may have an effect on inducing penile erection through activation of the PVN in the rat.
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Affiliation(s)
- Kuang-Kuo Chen
- Division of Urology, Department of Surgery, Taipei Veterans General Hospital, Taiwan, People's Republic of China
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Melis MR, Succu S, Mascia MS, Cortis L, Argiolas A. Extra-cellular dopamine increases in the paraventricular nucleus of male rats during sexual activity. Eur J Neurosci 2003; 17:1266-72. [PMID: 12670314 DOI: 10.1046/j.1460-9568.2003.02558.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) concentrations were measured in the dialysate obtained with vertical microdialysis probes implanted into the paraventricular nucleus of the hypothalamus of sexually potent male rats. Animals showed noncontact erections when put in the presence of, and copulated with a receptive (ovarietomized oestrogen and progesterone primed) female rat. Dopamine and DOPAC concentrations in the paraventricular dialysate increased 140% and 19%, respectively, above baseline values during exposure to the receptive female and 280% and 31%, respectively, during copulation. No changes in dopamine and DOPAC concentrations were detected in the paraventricular dialysate when sexually potent male rats were exposed to nonreceptive (ovariectomized not oestrogen plus progesterone primed) female rats. These results confirm the involvement of the paraventricular nucleus in control of erectile function and copulatory behaviour and show for the first time that dopamine neurotransmission is increased in this hypothalamic nucleus when erection occurs in physiological contexts.
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Affiliation(s)
- Maria Rosaria Melis
- Bernard B. Brodie Department of Neuroscience, University of Cagliari, S.P. Monserrato-Sestu, Km 0.700, 09042 Monserrato (CA), Italy.
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Jang CG, Lee SY, Loh HH, Ho IK. Lack of mu-opioid receptor leads to an increase in the NMDA receptor subunit mRNA expression and NMDA-induced convulsion. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 2001; 94:105-11. [PMID: 11597770 DOI: 10.1016/s0169-328x(01)00222-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The present study investigated in situ hybridization of N-methyl-D-aspartate (NMDA) receptor (NR) subunit mRNA and convulsion induced by intracerebroventricular injection of NMDA, in order to examine changes in NMDA receptor function in mu-opioid receptor gene knockout mice. Levels of NR1 and NR2A subunit mRNA were significantly increased in the parietal cortex (8.4 and 10.6%, respectively) and hypothalamus (8.7 and 15.2%, respectively) in mu-opioid receptor knockout mice. Levels of NR2B subunit mRNA were noted to be increased in the parietal cortex (9.1%), thalamus (7.7%), and hypothalamus (10.4%) in mu-opioid receptor knockout mice. The ED(50) for NMDA-induced convulsion in wild-type mice was 0.20 microg/10 microl/mouse. The ED(50) in mu-opioid receptor knockout mice was 0.14 microg/10 microl/mouse. There is a significant difference in the potency ratio of wild-type mice versus knockout mice (potency ratio: 1.44, P < 0.05). These results indicate that mu-opioid receptor knockout mice are more sensitive to NMDA-induced convulsion. Therefore, these results suggest that absence of mu-opioid receptor gene is accompanied by changes in the NMDA receptor system which can modulate the synaptic excitability in the process such as convulsion or epilepsy.
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Affiliation(s)
- C G Jang
- Department of Pharmacology, College of Pharmacy, Sungkyunkwan University, 440-746, Suwon, South Korea
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20
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Abstract
YAWNING IS A COMMON PHYSIOLOGICAL EVENT THAT CAN BE DIVIDED INTO THREE DISTINCT PHASES: a long inspiratory phase, a brief acme and a rapid expiration. The aim of yawning is not yet well defined. However this semi-voluntary event increases vigilance and aims to alert when drowsiness occurs. Yawning probably has an important role for social communication as well. Yawning can be responsible for pain, luxation or even transient ischaemic attack. Abnormal yawning is present in various pathologies: migraine, Parkinson's disease, tumours, psychiatric diseases, infections or iatrogenic pathologies. The neuro-pharmacology of yawning is complex and knowledge of its mechanisms is incomplete. While under the control of several neurotransmitters, yawning is largely affected by dopamine. Dopamine may activate oxytocin production in the paraventricular nucleus of the hypothalamus. Oxytocin may then activate cholinergic transmission in the hippocampus and, finally, acetylcholine might induce yawning via the muscarinic receptors of the effectors. This is an over-simplification; many other molecules can modulate yawning, such as nitric oxide, glutamate, GABA, serotonin, ACTH, MSH, sexual hormones and opium derivate peptides. Dopamine involvement in yawning could have practical applications in the study of new drugs or the exploration of neurological diseases such as migraine or psychosis. 2001 Harcourt Publishers Ltd
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Affiliation(s)
- G Daquin
- Clinical Pharmacology and CPCET, UMR CNRS FRE DPM, Timone Hospital, Marseille, France
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21
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Abstract
Central regulation of the erectile process involves several transmitters, including dopamine, serotonin, noradrenaline, and nitric oxide, and peptides, such as oxytocin and ACTH/alpha-MSH. These systems may be targets for future drugs designed to treat erectile dysfunction. Peripherally, the different steps involved in neurotransmission, impulse propagation, and intracellular transduction of neural signals in penile smooth muscles need further investigation. Continued studies of the interactions between different transmitters/modulators may reveal new combination therapies. Increased knowledge of the changes in penile tissues associated with erectile dysfunction may explain the pathogenetic mechanisms and help to prevent the disorder.
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Affiliation(s)
- K E Andersson
- Department of Clinical Pharmacology, University of Lund, Lund, Sweden.
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22
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Melis MR, Succu S, Spano MS, Locatelli V, Torsello A, Muller EE, Deghenghi R, Argiolas A. EP 60761 and EP 50885, two hexarelin analogues, induce penile erection in rats. Eur J Pharmacol 2000; 404:137-43. [PMID: 10980272 DOI: 10.1016/s0014-2999(00)00481-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The effect of hexarelin and four related peptide analogues, EP 40904, EP 40737, EP 50885 and EP 60761, injected into the paraventricular nucleus of the hypothalamus of male rats in doses between 2 and 2000 ng on spontaneous penile erection was studied. Of these peptides, EP 60761 and EP 50885, but not hexarelin, EP 40904 or EP 40737, increased dose-dependently the number of spontaneous penile erections. EP 60761 was active already at the dose of 20 ng, which induced the sexual response in 70% of the treated rats. The maximal response was induced by 200 ng of the peptide. EP 50885 was less potent than EP 60761, with 1000 ng being the minimal effective dose and 2000 ng as the dose required to induce the maximal response. At the doses used, both peptides also increased slightly the number of spontaneous yawning episodes. EP 60761- and EP 50885-induced penile erection was prevented by the oxytocin receptor antagonist [d(CH(2))(5)Tyr(Me)(2)-Orn(8)]vasotocin (0.1-1 microg) given intracerebroventricularly (i.c.v.), but not into the paraventricular nucleus (0.1-1 microg), by the competitive nitric oxide (NO) inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) given either into the paraventricular nucleus (10-20 microg) or i.c.v. (75-150 microg), by the N-type Ca(2+) channel blocker omega-conotoxin-GVIA (2-5 ng) or by the opiate morphine (1-10 microg), but not by the dopamine receptor antagonist (Z)-4-[3-[2-(trifluoromethyl)-9H-thioxanthen-9-ylidene]propyl]-1-p ipe razine-ethanol (cis-flupenthixol) (10 microg) or by the N-methyl-D-aspartic acid (NMDA) receptor antagonist (5R, 10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5, 10-imine ((+)-MK-801) (1 microg), all given into the paraventricular nucleus before either peptide. The present results show that EP 60761 and EP 50885 induced penile erection by increasing central oxytocin transmission, possibly by activating NO synthase in the cell bodies of oxytocinergic neurons located in the paraventricular nucleus that control penile erection.
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Affiliation(s)
- M R Melis
- Bernard B. Brodie Department of Neuroscience, University of Cagliari, Via Porcell 4, 09124, Cagliari, Italy
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23
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Abstract
Many neuropeptides are involved in the control of sexual behaviour at the central level. Among these, the most studied are adrenocorticotropin, alpha-melanocyte stimulating hormone, oxytocin and opioid peptides. This attempt to review old and new neuropharmacological, biochemical and psychobiological studies in this field, shows that all these neuropeptides apparently facilitate sexual behaviour, except for opioid peptides, which inhibit sexual performance, in most of the species studied so far (rats, mice, monkeys and humans). However, gonadotropin-releasing hormone, corticotropin releasing factor, neuropeptide Y, galanin, cholecystokinin, substance P and vasoactive intestinal peptide may be also involved in the control of sexual behaviour. Apparently, corticotropin releasing factor, neuropeptide Y and cholecystokinin inhibit, while substance P and vasoactive intestinal peptide facilitate, sexual behaviour. In contrast, gonadotropin-releasing hormone has been reported to exert a facilitative, inhibitory or no effect at all on sexual behaviour. Galanin was also shown either to facilitate or inhibit sexual behaviour. The above-mentioned putative role of the neuropeptides in sexual behaviour derives mainly from studies done in rats. In these studies, neuropeptides, their antisera or drugs that act as agonists or antagonists of neuropeptide receptors, were tested for their effect on sexual behaviour after systemic, intracerebroventricular, or intracerebral administration. The latter were infused into brain areas relevant for sexual behaviour, such as the medial preoptic area, and the ventromedial and paraventricular nuclei of the hypothalamus. The above studies show that little information is available on the mechanisms by which neuropeptides influence sexual behaviour. Also unclear is whether the above neuropeptides influence the anticipatory phase (sexual arousal and/or motivation) or the consummatory phase (performance) of sexual behaviour, except for opioid peptides. New information about the role of neuropeptides may come from the application of molecular biology and genetic manipulation techniques to the study of sexual behaviour. Of these, FOS protein determination, antisense oligonucleotides aimed at the neutralisation of neuropeptide and/or neuropeptide receptor mRNAs in specific brain areas, and gene ablation seem the most promising. Although still in the early stages, it is likely that these methodologies will provide new insights into the role of neuropeptides in the control of sexual behaviour.
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Affiliation(s)
- A Argiolas
- Bernard B. Brodie Department of Neuroscience and Centre for Neuropharmacology, National Research Council, Cagliari, Italy.
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24
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Melis MR, Succu S, Spano MS, Argiolas A. Morphine injected into the paraventricular nucleus of the hypothalamus prevents noncontact penile erections and impairs copulation: involvement of nitric oxide. Eur J Neurosci 1999; 11:1857-64. [PMID: 10336653 DOI: 10.1046/j.1460-9568.1999.00603.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Male rats show four to six penile erection episodes when put in the presence of an inaccessible receptive female for 80 min. These noncontact erections occur concomitantly with an increase in nitric oxide production in the paraventricular nucleus of the hypothalamus. This is shown by the increases in the NO2- and NO3- concentrations in the paraventricular dialysate obtained from these males by in vivo microdialysis. The NO2- concentration increased from 0.75 +/- 0. 10 microm to 2.89 +/- 0.39 microm and that of NO3- from 4.13 +/- 0. 58 microm to 9.5 +/- 1.2 microm. Morphine (0.5, 1 and 5 microg), given unilaterally into the paraventricular nucleus 15 min before the introduction of the receptive female, prevented the NO2- and NO3- increases, and noncontact erections, dose-dependently. In contrast, the kappa opioid receptor agonist U-69 593 (5 microg) was ineffective. The effects of morphine on NO2- and NO3-, and on noncontact erections, were prevented by the opiate receptor antagonist naloxone (10 microg) injected into the paraventricular nucleus 15 min before morphine. The NO2- and NO3- concentrations were also increased in the paraventricular dialysate of male rats during copulation, i.e. when in copula penile erections occurred. As found with noncontact erections, morphine, but not U-69 593, injected into the paraventricular nucleus prevented the NO2- and NO3- increases and impaired copulatory behaviour, and naloxone prevented these responses when given before morphine. Although some diffusion of the opiate to surrounding brain areas cannot be completely ruled out, the present results suggest that morphine acts through mu receptors in the paraventricular nucleus to impair noncontact erections and copulation. These effects of morphine are apparently mediated by a prevention of the increased nitric oxide production that occurs in the paraventricular nucleus of the hypothalamus of male rats during sexual activity.
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Affiliation(s)
- M R Melis
- Bernard B. Brodie Department of Neuroscience, University of Cagliari, Italy
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25
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Abstract
Yawning is a phylogenetically old, stereotyped event that occurs alone or associated with stretching and/or penile erection in humans and in animals from reptiles to birds and mammals under different conditions. Although its physiological function is still unknown, yawning is under the control of several neurotransmitters and neuropeptides at the central level as this short overview of the literature on the neurochemistry of yawning shows. Among these substances, the best known are dopamine, excitatory amino acids, acetylcholine, serotonin, nitric oxide, adrenocorticotropic hormone-related peptides and oxytocin, that facilitate yawning and opioid peptides that inhibit this behavioral response. Some of the above compounds interact in the paraventricular nucleus of the hypothalamus to control yawning. This hypothalamic nucleus contains the cell bodies of oxytocinergic neurons projecting to extra-hypothalamic brain areas that play a key role in the expression of this behavioral event. When activated by dopamine, excitatory amino acids and oxytocin itself, these neurons facilitate yawning by releasing oxytocin at sites distant form the paraventricular nucleus, i.e. the hippocampus, the pons and/or the medulla oblongata. Conversely, activation of these neurons by dopamine, oxytocin or excitatory amino acids, is antagonized by opioid peptides, that, in turn, prevent the yawning response. The activation and inhibition, respectively of these oxytocinergic neurons is related to a concomitant increase and decrease, respectively, of paraventricular nitric oxide synthase activity. However, other neuronal systems in addition to the central paraventricular oxytocinergic neurons are involved in the control of yawning, since they do not seem to be involved in the expression of yawning induced by the stimulation of acetylcholine or serotoninergic receptors, nor by adrenocorticotropic hormone (ACTH) and related peptides. Nitric oxide is also involved in the induction of yawning by the latter compounds and neuronal links, for instance between dopamine and acetylcholine and dopamine and serotonin, seem to be involved in the yawning response. Finally, other neurotransmitters, i.e. gamma-aminobutyric acid (GABA) and noradrenaline, and neuropeptides, i.e. neurotensin and luteinizing hormone-releasing hormone (LH-RH), influence this behavioral response. In conclusion, in spite of some recent progress, little is known of, and more has to be done to identify, the neurochemical mechanisms underlying yawning at the central level.
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Affiliation(s)
- A Argiolas
- Bernard B. Brodie Department of Neuroscience, University of Cagliari and Center for Neuropharmacology, National Research Council, Italy.
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26
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Abstract
This paper is the twentieth installment of our annual review of research concerning the opiate system. It summarizes papers published during 1997 that studied the behavioral effects of the opiate peptides and antagonists, excluding the purely analgesic effects, although stress-induced analgesia is included. The specific topics covered this year include stress; tolerance and dependence; eating and drinking; alcohol; gastrointestinal, renal, and hepatic function; mental illness and mood; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurologic disorders; electrical-related activity; general activity and locomotion; sex, pregnancy, and development; immunologic responses; and other behaviors.
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Affiliation(s)
- G A Olson
- Department of Psychology, University of New Orleans, LA 70148, USA
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