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Argiolas A, Argiolas FM, Argiolas G, Melis MR. Erectile Dysfunction: Treatments, Advances and New Therapeutic Strategies. Brain Sci 2023; 13:802. [PMID: 37239274 PMCID: PMC10216368 DOI: 10.3390/brainsci13050802] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 05/08/2023] [Accepted: 05/11/2023] [Indexed: 05/28/2023] Open
Abstract
Erectile dysfunction (ED) is the inability to get and maintain an adequate penile erection for satisfactory sexual intercourse. Due to its negative impacts on men's life quality and increase during aging (40% of men between 40 and 70 years), ED has always attracted researchers of different disciplines, from urology, andrology and neuropharmacology to regenerative medicine, and vascular and prosthesis implant surgery. Locally and/or centrally acting drugs are used to treat ED, e.g., phosphodiesterase 5 inhibitors (first in the list) given orally, and phentolamine, prostaglandin E1 and papaverine injected intracavernously. Preclinical data also show that dopamine D4 receptor agonists, oxytocin and α-MSH analogues may have a role in ED treatment. However, since pro-erectile drugs are given on demand and are not always efficacious, new strategies are being tested for long lasting cures of ED. These include regenerative therapies, e.g., stem cells, plasma-enriched platelets and extracorporeal shock wave treatments to cure damaged erectile tissues. Although fascinating, these therapies are laborious, expensive and not easily reproducible. This leaves old vacuum erection devices and penile prostheses as the only way to get an artificial erection and sexual intercourse with intractable ED, with penile prosthesis used only by accurately selected patients.
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Affiliation(s)
- Antonio Argiolas
- Department of Biomedical Sciences, Section of Neuroscience and Clinical Pharmacology, University of Cagliari, 09042 Monserrato, Italy; (F.M.A.); (M.R.M.)
| | - Francesco Mario Argiolas
- Department of Biomedical Sciences, Section of Neuroscience and Clinical Pharmacology, University of Cagliari, 09042 Monserrato, Italy; (F.M.A.); (M.R.M.)
| | - Giacomo Argiolas
- General Medicine Unit, Hospital San Michele, ARNAS“G. Brotzu”, Piazzale Ricchi 1, 09100 Cagliari, Italy;
| | - Maria Rosaria Melis
- Department of Biomedical Sciences, Section of Neuroscience and Clinical Pharmacology, University of Cagliari, 09042 Monserrato, Italy; (F.M.A.); (M.R.M.)
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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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Hasenmajer V, Bonaventura I, Minnetti M, Sada V, Sbardella E, Isidori AM. Non-Canonical Effects of ACTH: Insights Into Adrenal Insufficiency. Front Endocrinol (Lausanne) 2021; 12:701263. [PMID: 34489864 PMCID: PMC8416901 DOI: 10.3389/fendo.2021.701263] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 08/04/2021] [Indexed: 01/13/2023] Open
Abstract
Introduction Adrenocorticotropic hormone (ACTH) is produced from proopiomelanocortin, which is predominantly synthetized in the corticotroph and melanotroph cells of the anterior and intermediate lobes of the pituitary gland and the arcuate nucleus of the hypothalamus. Although ACTH clearly has an effect on adrenal homeostasis and maintenance of steroid hormone production, it also has extra-adrenal effects that require further elucidation. Methods We comprehensively reviewed English language articles, regardless of whether they reported the presence or absence of adrenal and extra-adrenal ACTH effects. Results In the present review, we provide an overview on the current knowledge on adrenal and extra-adrenal effects of ACTH. In the section on adrenal ACTH effects, we focused on corticosteroid rhythmicity and effects on steroidogenesis, mineralocorticoids and adrenal growth. In the section on extra-adrenal effects, we have analyzed the effects of ACTH on the osteoarticular and reproductive systems, adipocytes, immune system, brain and skin. Finally, we focused on adrenal insufficiency. Conclusions The role of ACTH in maintaining the function of the hypothalamic-pituitary-adrenal axis is well known. Conversely, if we broaden our vision and analyze its role as a potential treatment strategy in other conditions, it will be evident in the literature that researchers seem to have abandoned this aspect in studies conducted several years ago. We believe it is worth re-evaluating the role of ACTH considering its noncanonical effects on the adrenal gland itself and on extra-adrenal organs and tissues; however, this would not have been possible without the recent advances in the pertinent technologies.
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Affiliation(s)
| | | | | | | | | | - Andrea M. Isidori
- Department of Experimental Medicine, Sapienza University of Rome - Policlinico Umberto I Hospital, Rome, Italy
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Hull EM, Dominguez JM. Neuroendocrine Regulation of Male Sexual Behavior. Compr Physiol 2019; 9:1383-1410. [DOI: 10.1002/cphy.c180018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Semple E, Shalabi F, Hill JW. Oxytocin Neurons Enable Melanocortin Regulation of Male Sexual Function in Mice. Mol Neurobiol 2019; 56:6310-6323. [PMID: 30756300 PMCID: PMC6684847 DOI: 10.1007/s12035-019-1514-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 01/28/2019] [Indexed: 12/13/2022]
Abstract
The melanocortin pathway has been implicated in both metabolism and sexual function. When the melanocortin 4 receptor (MC4R) is knocked out globally, male mice display obesity, low sexual desire, and copulatory difficulties; however, it is unclear whether these phenotypes are interdependent. To elucidate the neuronal circuitry involved in sexual dysfunction in MC4R knockouts, we re-expressed the MC4R in these mice exclusively on Sim1 neurons (tbMC4RSim1 mice) or on a subset of Sim1 neurons, namely oxytocin neurons (tbMC4Roxt mice). The groups were matched at young ages to control for the effects of obesity. Interestingly, young MC4R null mice had no deficits in sexual motivation or erectile function. However, MC4R null mice were found to have an increased latency to reach ejaculation compared to control mice, which was restored in both tbMC4RSim1 and tbMC4Roxt mice. These results indicate that melanocortin signaling via the MC4R on oxytocin neurons is important for normal ejaculation independent of the male's metabolic health.
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Affiliation(s)
- Erin Semple
- Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, 3000 Arlington Ave., Toledo, OH, 43614, USA
| | - Firas Shalabi
- Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, 3000 Arlington Ave., Toledo, OH, 43614, USA
| | - Jennifer W Hill
- Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, 3000 Arlington Ave., Toledo, OH, 43614, USA.
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Duque-Díaz E, Alvarez-Ojeda O, Coveñas R. Enkephalins and ACTH in the mammalian nervous system. VITAMINS AND HORMONES 2019; 111:147-193. [PMID: 31421699 DOI: 10.1016/bs.vh.2019.05.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The pentapeptides methionine-enkephalin and leucine-enkephalin belong to the opioid family of peptides, and the non-opiate peptide adrenocorticotropin hormone (ACTH) to the melanocortin peptide family. Enkephalins/ACTH are derived from pro-enkephalin, pro-dynorphin or pro-opiomelanocortin precursors and, via opioid and melanocortin receptors, are responsible for many biological activities. Enkephalins exhibit the highest affinity for the δ receptor, followed by the μ and κ receptors, whereas ACTH binds to the five subtypes of melanocortin receptor, and is the only member of the melanocortin family of peptides that binds to the melanocortin-receptor 2 (ACTH receptor). Enkephalins/ACTH and their receptors exhibit a widespread anatomical distribution. Enkephalins are involved in analgesia, angiogenesis, blood pressure, embryonic development, emotional behavior, feeding, hypoxia, limbic system modulation, neuroprotection, peristalsis, and wound repair; as well as in hepatoprotective, motor, neuroendocrine and respiratory mechanisms. ACTH plays a role in acetylcholine release, aggressive behavior, blood pressure, bone maintenance, hyperalgesia, feeding, fever, grooming, learning, lipolysis, memory, nerve injury repair, neuroprotection, sexual behavior, sleep, social behavior, tissue growth and stimulates the synthesis and secretion of glucocorticoids. Enkephalins/ACTH are also involved in many pathologies. Enkephalins are implicated in alcoholism, cancer, colitis, depression, heart failure, Huntington's disease, influenza A virus infection, ischemia, multiple sclerosis, and stress. ACTH plays a role in Addison's disease, alcoholism, cancer, Cushing's disease, dermatitis, encephalitis, epilepsy, Graves' disease, Guillain-Barré syndrome, multiple sclerosis, podocytopathies, and stress. In this review, we provide an updated description of the enkephalinergic and ACTH systems.
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Affiliation(s)
- Ewing Duque-Díaz
- Universidad de Santander UDES, Laboratory of Neurosciences, School of Medicine, Bucaramanga, Colombia.
| | - Olga Alvarez-Ojeda
- Universidad Industrial de Santander, Department of Pathology, School of Medicine, Bucaramanga, Colombia
| | - Rafael Coveñas
- Laboratory of Neuroanatomy of the Peptidergic Systems, Institute of Neurosciences of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain
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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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Semple E, Hill JW. Sim1 Neurons Are Sufficient for MC4R-Mediated Sexual Function in Male Mice. Endocrinology 2018; 159:439-449. [PMID: 29059347 PMCID: PMC5761591 DOI: 10.1210/en.2017-00488] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 10/12/2017] [Indexed: 12/24/2022]
Abstract
Sexual dysfunction is a poorly understood condition that affects up to one-third of men around the world. Existing treatments that target the periphery do not work for all men. Previous studies have shown that central melanocortins, which are released by pro-opiomelanocortin neurons in the arcuate nucleus of the hypothalamus, can lead to male erection and increased libido. Several studies specifically implicate the melanocortin 4 receptor (MC4R) in the central control of sexual function, but the specific neural circuitry involved is unknown. We hypothesized that single-minded homolog 1 (Sim1) neurons play an important role in the melanocortin-mediated regulation of male sexual behavior. To test this hypothesis, we examined the sexual behavior of mice expressing MC4R only on Sim1-positive neurons (tbMC4Rsim1 mice) in comparison with tbMC4R null mice and wild-type controls. In tbMC4Rsim1 mice, MC4R reexpression was found in the medial amygdala and paraventricular nucleus of the hypothalamus. These mice were paired with sexually experienced females, and their sexual function and behavior was scored based on mounting, intromission, and ejaculation. tbMC4R null mice showed a longer latency to mount, a reduced intromission efficiency, and an inability to reach ejaculation. Expression of MC4R only on Sim1 neurons reversed the sexual deficits seen in tbMC4R null mice. This study implicates melanocortin signaling via the MC4R on Sim1 neurons in the central control of male sexual behavior.
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MESH Headings
- Amygdala/drug effects
- Amygdala/metabolism
- Amygdala/pathology
- Animals
- Arcuate Nucleus of Hypothalamus/drug effects
- Arcuate Nucleus of Hypothalamus/metabolism
- Arcuate Nucleus of Hypothalamus/pathology
- Basic Helix-Loop-Helix Transcription Factors/metabolism
- Copulation/drug effects
- Crosses, Genetic
- Fertility Agents, Male/administration & dosage
- Fertility Agents, Male/therapeutic use
- Heterozygote
- Infertility, Male/drug therapy
- Infertility, Male/metabolism
- Infertility, Male/pathology
- Injections, Intraventricular
- Male
- Mice, Knockout
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Neurons/drug effects
- Neurons/metabolism
- Neurons/pathology
- Organ Specificity
- Paraventricular Hypothalamic Nucleus/drug effects
- Paraventricular Hypothalamic Nucleus/metabolism
- Paraventricular Hypothalamic Nucleus/pathology
- Random Allocation
- Receptor, Melanocortin, Type 4/genetics
- Receptor, Melanocortin, Type 4/metabolism
- Repressor Proteins/metabolism
- Sexual Behavior, Animal/drug effects
- alpha-MSH/administration & dosage
- alpha-MSH/therapeutic use
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Affiliation(s)
- Erin Semple
- Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio 43606
| | - Jennifer W. Hill
- Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio 43606
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10
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Yawning-Its anatomy, chemistry, role, and pathological considerations. Prog Neurobiol 2017; 161:61-78. [PMID: 29197651 DOI: 10.1016/j.pneurobio.2017.11.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 10/29/2017] [Accepted: 11/28/2017] [Indexed: 12/11/2022]
Abstract
Yawning is a clinical sign of the activity of various supra- and infratentorial brain regions including the putative brainstem motor pattern, hypothalamic paraventricular nucleus, probably the insula and limbic structures that are interconnected via a fiber network. This interaction can be seen in analogy to other cerebral functions arising from a network or zone such as language. Within this network, yawning fulfills its function in a stereotype, reflex-like manner; a phylogenetically old function, preserved across species barriers, with the purpose of arousal, communication, and maybe other functions including respiration. Abnormal yawning with ≥3 yawns/15min without obvious cause arises from lesions of brain areas involved in the yawning zone, its trajectories causing a disconnection syndrome, or from alteration of network activity by physical or metabolic etiologies including medication.
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Navarro M. The Role of the Melanocortin System in Drug and Alcohol Abuse. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2017; 136:121-150. [DOI: 10.1016/bs.irn.2017.06.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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12
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Boulle F, Velthuis H, Koedam K, Steinbusch HW, van den Hove DLA, Kenis G, Gabriel C, Mocaer E, Franc B, Rognan D, Mongeau R, Lanfumey L. Behavioral and neurochemical characterization of TrkB-dependent mechanisms of agomelatine in glucocorticoid receptor-impaired mice. Eur Neuropsychopharmacol 2016; 26:65-77. [PMID: 26653128 DOI: 10.1016/j.euroneuro.2015.11.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 09/30/2015] [Accepted: 11/08/2015] [Indexed: 12/13/2022]
Abstract
Growing evidence indicates that impairment of the stress response, in particular the negative feedback regulation mechanism exerted by the hypothalamo-pituitary-adrenal (HPA) axis, might be responsible for the hippocampal atrophy observed in depressed patients. Antidepressants, possibly through the activation of BDNF signaling, may enhance neuroplasticity and restore normal hippocampal functions. In this context, glucocorticoid receptor-impaired (GR-i) mice-a transgenic mouse model of reduced GR-induced negative feedback regulation of the HPA axis-were used to investigate the role of BDNF/TrkB signaling in the behavioral and neurochemical effects of the new generation antidepressant drug, agomelatine. GR-i mice exhibited marked alterations in depressive-like and anxiety-like behaviors, together with a decreased cell proliferation and altered levels of neuroplastic and epigenetic markers in the hippocampus. GR-i mice and their wild-type littermates were treated for 21 days with vehicle, agomelatine (50mg/kg/day; i.p) or the TrkB inhibitor Ana-12 (0.5mg/kg/day, i.p) alone, or in combination with agomelatine. Chronic treatment with agomelatine resulted in antidepressant-like effects in GR-i mice and reversed the deficit in hippocampal cell proliferation and some of the alterations of mRNA plasticity markers in GR-i mice. Ana-12 blocked the effect of agomelatine on motor activity as well as its ability to restore a normal hippocampal cell proliferation and expression of neurotrophic factors. Altogether, our findings indicate that agomelatine requires TrkB signaling to reverse some of the molecular and behavioral alterations caused by HPA axis impairment.
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Affiliation(s)
- F Boulle
- Centre de Psychiatrie et Neurosciences, Inserm UMR 894, Paris, France; Université Paris Descartes, UMR S894, Paris, France; Department of Psychiatry and Neuropsychology, European Graduate School for Neuroscience (EURON), Maastricht University, Maastricht, The Netherlands
| | - H Velthuis
- Centre de Psychiatrie et Neurosciences, Inserm UMR 894, Paris, France; Université Paris Descartes, UMR S894, Paris, France
| | - K Koedam
- Department of Psychiatry and Neuropsychology, European Graduate School for Neuroscience (EURON), Maastricht University, Maastricht, The Netherlands
| | - H W Steinbusch
- Department of Psychiatry and Neuropsychology, European Graduate School for Neuroscience (EURON), Maastricht University, Maastricht, The Netherlands
| | - D L A van den Hove
- Department of Psychiatry and Neuropsychology, European Graduate School for Neuroscience (EURON), Maastricht University, Maastricht, The Netherlands; Department of Psychiatry, Psychosomatics and Psychotherapy, University of Wuerzburg, Wuerzburg, Germany
| | - G Kenis
- Department of Psychiatry and Neuropsychology, European Graduate School for Neuroscience (EURON), Maastricht University, Maastricht, The Netherlands
| | - C Gabriel
- Institut de Recherche International Servier, Suresnes, France
| | - E Mocaer
- Institut de Recherche International Servier, Suresnes, France
| | - B Franc
- Centre de Psychiatrie et Neurosciences, Inserm UMR 894, Paris, France; Université Paris Descartes, UMR S894, Paris, France
| | - D Rognan
- Laboratoire d'Innovation Thérepeutique, UMR 7200 CNRS, Université de Strasbourg, Illkirch, France
| | - R Mongeau
- Centre de Psychiatrie et Neurosciences, Inserm UMR 894, Paris, France; Université Paris Descartes, UMR S894, Paris, France; EA4475, Pharmacology department, University Paris Descartes, Paris, France
| | - L Lanfumey
- Centre de Psychiatrie et Neurosciences, Inserm UMR 894, Paris, France; Université Paris Descartes, UMR S894, Paris, France.
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13
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Modi ME, Inoue K, Barrett CE, Kittelberger KA, Smith DG, Landgraf R, Young LJ. Melanocortin Receptor Agonists Facilitate Oxytocin-Dependent Partner Preference Formation in the Prairie Vole. Neuropsychopharmacology 2015; 40:1856-65. [PMID: 25652247 PMCID: PMC4839509 DOI: 10.1038/npp.2015.35] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 01/22/2015] [Accepted: 01/26/2015] [Indexed: 12/21/2022]
Abstract
The central melanocortin (MC) system has been widely studied for its effects on food intake and sexual behavior. However, the MC system, and more specifically the MC4 receptor (MC4R), also interacts with neurochemical systems that regulate socioemotional behaviors, including oxytocin (OT) and dopamine. In monogamous prairie voles, OT and dopamine interact to promote partner preference formation, a laboratory measure of an enduring social bond between mates. Here we investigated the effects of MC receptor activation on partner preference formation in prairie voles, as well as the interaction between the MC and OT systems during this process. Peripheral administration of the brain penetrant MC3/4R receptor peptide agonist, Melanotan II (MTII), and the highly selective, small-molecule MC4R agonist, Pf-446687, enhanced partner preference formation in the prairie vole, but not in the non-monogamous meadow vole. MTII-induced partner preferences were enduring, as they were present 1 week after drug manipulation. The prosocial effects of MCR agonists may be mediated, in part, through modulation of OT, as coadministration of an OT receptor antagonist prevented MTII-induced partner preferences. MTII also selectively activated hypothalamic OT neurons and potentiated central OT release. As OT has been shown to enhance some aspects of social cognition in humans, our data suggest that the MC4R may be a viable therapeutic target for enhancing social function in psychiatric disorders, including autism spectrum disorders and schizophrenia, potentially through activation of the OT system.
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Affiliation(s)
- Meera E Modi
- Center Translational Social Neuroscience, Silvio O Conte Center for Oxytocin and Social Cognition, Department of Psychiatry and Behavioral Sciences, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
- Neuroscience Research Unit, Pfizer Worldwide Research and Development, Cambridge, MA, USA
| | - Kiyoshi Inoue
- Center Translational Social Neuroscience, Silvio O Conte Center for Oxytocin and Social Cognition, Department of Psychiatry and Behavioral Sciences, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
| | - Catherine E Barrett
- Center Translational Social Neuroscience, Silvio O Conte Center for Oxytocin and Social Cognition, Department of Psychiatry and Behavioral Sciences, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
| | - Kara A Kittelberger
- Center Translational Social Neuroscience, Silvio O Conte Center for Oxytocin and Social Cognition, Department of Psychiatry and Behavioral Sciences, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
| | - Daniel G Smith
- Neuroscience Research Unit, Pfizer Worldwide Research and Development, Cambridge, MA, USA
- Autism Speaks, Boston, MA, USA
| | | | - Larry J Young
- Center Translational Social Neuroscience, Silvio O Conte Center for Oxytocin and Social Cognition, Department of Psychiatry and Behavioral Sciences, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
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14
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Faulkner LD, Dowling AR, Stuart RC, Nillni EA, Hill JW. Reduced melanocortin production causes sexual dysfunction in male mice with POMC neuronal insulin and leptin insensitivity. Endocrinology 2015; 156:1372-85. [PMID: 25590244 PMCID: PMC4399313 DOI: 10.1210/en.2014-1788] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Proopiomelanocortin (POMC)-derived peptides like α-melanocyte-stimulating hormone (MSH) substantially improve hepatic insulin sensitivity and regulate energy expenditure. Melanocortinergic agents are also powerful inducers of sexual arousal that are being investigated for a possible therapeutic role in erectile dysfunction. It is currently unclear whether reduced melanocortin (MC) activity may contribute to the sexual dysfunction accompanying obesity and type 2 diabetes. Male rodents with leptin and insulin resistance targeted to POMC neurons (leptin receptor [LepR]/insulin receptor [IR]POMC mice) exhibit obesity, hyperinsulinemia, hyperglycemia, and systemic insulin resistance. In this study, we demonstrate that LepR/IRPOMC males are also subfertile due to dramatic alterations in sexual behavior. Remarkably, these reproductive changes are accompanied by decreased α-MSH production not present when a single receptor type is deleted. Unexpectedly, behavioral sensitivity to α-MSH and MC receptor expression are also reduced in LepR/IRPOMC males, a potential adaptation of the MC system to altered α-MSH production. Together, these results suggest that concurrent insulin and leptin resistance in POMC neurons in individuals with obesity or type 2 diabetes can reduce endogenous α-MSH levels and impair sexual function.
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Affiliation(s)
- Latrice D Faulkner
- Department of Physiology and Pharmacology (L.D.F., A.R.D., J.W.H.), College of Medicine, The University of Toledo, Toledo, Ohio 43614-2598; and Division of Endocrinology (R.C.S., E.A.N.), Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, Rhode Island 02912-9107
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15
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Shelkar GP, Kale AD, Singh U, Singru PS, Subhedar NK, Kokare DM. Alpha-melanocyte stimulating hormone modulates ethanol self-administration in posterior ventral tegmental area through melanocortin-4 receptors. Addict Biol 2015; 20:302-15. [PMID: 24635847 DOI: 10.1111/adb.12126] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Although the role of alpha-melanocyte stimulating hormone (α-MSH) in alcohol seeking behaviour in rats has been demonstrated, the underlying mechanisms are not understood. Herein, we test the hypothesis that α-MSH might have a permissive effect in promoting the reward action of ethanol. Rats were implanted with cannulae targeted at the posterior ventral tegmental area (pVTA), because the site is sensitive to reinforcing effects of ethanol. These rats were trained to self-administer ethanol in standard two-lever (active/inactive) operant chamber test. Each active lever press resulted in self-administration of 100 nl of ethanol (100-300 mg%) containing solution. Over a period of 7 days, ethanol significantly increased the number of lever presses, which was considered as a measure of reward. Because ethanol at 200 mg% resulted in maximum number of lever presses (∼18-20 lever presses/30-minute session), the dose was employed in further studies. While prior administration of melanocortin (MC) agonists, α-MSH or [Nle4,D-Phe7]-alpha-MSH into pVTA, resulted in an 89% increase in lever presses, the response was attenuated following pre-treatment with MC4 receptors (MC4R) antagonist, HS014. In an immunohistochemical study, the brains of rats that were trained to self-infuse ethanol showed significantly increased α-MSH immunoreactivity in the nucleus accumbens shell, bed nucleus of stria terminalis and arcuate nucleus of the hypothalamus. In the pVTA, α-MSH fibres were found to run close to the dopamine cells, labelled with tyrosine hydroxylase antibodies. We suggest that α-MSH-MC4R system in the pVTA might be a part of the neuroadaptive mechanism underlying ethanol addiction.
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Affiliation(s)
- Gajanan P. Shelkar
- Department of Pharmaceutical Sciences; Rashtrasant Tukadoji Maharaj Nagpur University; Nagpur Maharashtra India
| | - Atmaram D. Kale
- Department of Pharmaceutical Sciences; Rashtrasant Tukadoji Maharaj Nagpur University; Nagpur Maharashtra India
| | - Uday Singh
- School of Biological Sciences; National Institute of Science Education & Research (NISER); Institute of Physics Campus; Bhubaneswar Orrisa India
| | - Praful S. Singru
- School of Biological Sciences; National Institute of Science Education & Research (NISER); Institute of Physics Campus; Bhubaneswar Orrisa India
| | | | - Dadasaheb M. Kokare
- Department of Pharmaceutical Sciences; Rashtrasant Tukadoji Maharaj Nagpur University; Nagpur Maharashtra India
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16
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Toque HA, Caldwell RW. New approaches to the design and discovery of therapies to prevent erectile dysfunction. Expert Opin Drug Discov 2014; 9:1447-69. [DOI: 10.1517/17460441.2014.949234] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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17
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Neonatal melanocortin receptor agonist treatment reduces play fighting and promotes adult attachment in prairie voles in a sex-dependent manner. Neuropharmacology 2014; 85:357-66. [PMID: 24923239 DOI: 10.1016/j.neuropharm.2014.05.041] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 05/15/2014] [Accepted: 05/23/2014] [Indexed: 02/03/2023]
Abstract
The melanocortin receptor (MCR) system has been studied extensively for its role in feeding and sexual behavior, but effects on social behavior have received little attention. α-MSH interacts with neural systems involved in sociality, including oxytocin, dopamine, and opioid systems. Acute melanotan-II (MTII), an MC3/4R agonist, potentiates brain oxytocin (OT) release and facilitates OT-dependent partner preference formation in socially monogamous prairie voles. Here we examined the long-term impact of early-life MCR stimulation on hypothalamic neuronal activity and social development in prairie voles. Male and female voles were given daily subcutaneous injections of 10 mg/kg MTII or saline between postnatal days (PND) 1-7. Neonatally-treated males displayed a reduction in initiated play fighting bouts as juveniles compared to control males. Neonatal exposure to MTII facilitated partner preference formation in adult females, but not males, after a brief cohabitation with an opposite-sex partner. Acute MTII injection elicited a significant burst of the immediate early gene EGR-1 immunoreactivity in hypothalamic OT, vasopressin, and corticotrophin releasing factor neurons, when tested in PND 6-7 animals. Daily neonatal treatment with 1 mg/kg of a more selective, brain penetrant MC4R agonist, PF44687, promoted adult partner preferences in both females and males compared with vehicle controls. Thus, developmental exposure to MCR agonists lead to a persistent change in social behavior, suggestive of structural or functional changes in the neural circuits involved in the formation of social relationships.
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18
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Olney JJ, Sprow GM, Navarro M, Thiele TE. The protective effects of the melanocortin receptor (MCR) agonist, melanotan-II (MTII), against binge-like ethanol drinking are facilitated by deletion of the MC3 receptor in mice. Neuropeptides 2014; 48:47-51. [PMID: 24290566 PMCID: PMC3946855 DOI: 10.1016/j.npep.2013.11.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 10/24/2013] [Accepted: 11/07/2013] [Indexed: 01/22/2023]
Abstract
Recent data have implicated the melanocortin (MC) system in modulating voluntary ethanol consumption. Administration of melanotan-II (MTII), a nonselective melanocortin receptor (MCR) agonist, reduces voluntary ethanol consumption in C57BL/6J mice. Previous studies have demonstrated that central infusion of MTII effectively reduced voluntary ethanol drinking in mutant mice lacking normal expression of MC3R (MC3R-/- mice) but failed to alter ethanol drinking in mice lacking expression of MC4R, demonstrating that central MTII administration reduces voluntary ethanol drinking by signaling through the MC4R. However, evidence shows that the neurocircuitry recruited during excessive binge-like ethanol drinking versus moderate ethanol drinking are not identical. Thus the present study sought to investigate the potential role of the MC3R in binge-like ethanol intake. To this end, the "drinking in the dark" (DID) procedure, a commonly used animal model of binge-like ethanol drinking, was employed. Wild-type MC3R+/+ and MC3R-/- mice were given intracerebroventricular (i.c.v.) infusion of MTII (0.0, 0.25, 0.50, or 1.0 μg) prior to the onset of a 4-h testing period in which mice were given access to 20% (v/v) ethanol. Immediately after the 4-h testing period, tail blood samples were collected from each animal in order to assess blood ethanol concentrations (BECs). Consistent with previous findings, central administration of MTII blunted binge-like ethanol drinking in both MC3R+/+ and MC3R-/- mice. Interestingly, all doses of MTII blunted binge-like ethanol drinking in MC3R-/- mice during the first hour of testing, while only the 1.0 μg dose reduced binge-like drinking in MC3R+/+ mice. Thus, MC3R-/- mice were more sensitive to the protective effects of MTII. These data suggest that MC3Rs oppose the protective effects of MTII against binge-like ethanol drinking, and thus selective MC3R antagonists may have potential therapeutic roles in treating excessive ethanol drinking.
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Affiliation(s)
- J J Olney
- Department of Psychology, University of North Carolina, Chapel Hill, NC, USA
| | - G M Sprow
- Department of Psychology, University of North Carolina, Chapel Hill, NC, USA
| | - M Navarro
- Department of Psychology, University of North Carolina, Chapel Hill, NC, USA
| | - T E Thiele
- Department of Psychology, University of North Carolina, Chapel Hill, NC, USA; Bowles Center for Alcohol Studies, University of North Carolina, Chapel Hill, NC, USA.
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Azadzoi KM, Yang J, Siroky MB. Neural regulation of sexual function in men. World J Clin Urol 2013; 2:32-41. [PMID: 34707982 PMCID: PMC8547275 DOI: 10.5410/wjcu.v2.i3.32] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 07/30/2013] [Accepted: 08/20/2013] [Indexed: 02/06/2023] Open
Abstract
Male sexual response is controlled by a series of neurally mediated phenomena regulating libido, motivation, arousal and genital responses such as penile erection and ejaculation. These neural events that occur in a hormonally defined milieu involve different neurophysiological, neurochemical, and neuropsychological parameters controlled by central mechanisms, spinal reflexes and peripheral nervous system. Epidemiologic studies have suggested the high prevalence of male sexual dysfunction worldwide with significant impact on the quality of life of patients suffering from this problem. The incidence of sexual dysfunction is particularly high among men with neurologic disorders. Sexual dysfunction in men, such as loss of sexual desire, erectile dysfunction (ED), changes in arousal, and disturbances in orgasm and ejaculation may involve organic causes, psychological problems, or both. Organic male sexual disorders include a wide variety of neurologic, vasculogenic, neurovascular or hormonal factors that interfere with libido, erection, ejaculation and orgasm. Neurogenic sexual dysfunction may result from a specific neurologic problem or it could be the presenting symptom of a developing neurologic disease. Neurologic ED could result from complications of chronic neurologic disorders, trauma, surgical injury or iatrogenic causes. These etiologic factors and the underlying pathophysiologic conditions could overlap, which should be considered when making a diagnosis and selecting a treatment. A detailed history of physical examination, neurologic disorders, as well as any past history of psychological and psychiatric disturbances, and a thorough neurological examination will provide better understanding of the underlying causes of neurogenic sexual dysfunction. In patients with spinal cord injury, the location of the lesion and the time of onset of injury should be determined. Therapeutic strategies against erectile dysfunction are initiated with the least invasive options using the phosphodiesterase inhibitors. When oral medication options are exhausted, intraurethral and intracavernosal therapies and ultimately vacuum constriction devices and penile implants are considered. Recent basic research has suggested the potential role of stem cell-based therapeutic strategies to protect penile neural integrity and reverse cavernosal neurodegeneration in experimental models. Further insight into the central, spinal and peripheral neural mechanisms of male sexual response may help precise diagnosis and better management of neurogenic sexual dysfunction in men.
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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: 102] [Impact Index Per Article: 9.3] [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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21
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Giuliano F. Control of Penile Erection by the Melanocortinergic System: Experimental Evidences and Therapeutic Perspectives. ACTA ACUST UNITED AC 2013; 25:683-91. [PMID: 15292097 DOI: 10.1002/j.1939-4640.2004.tb02842.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- François Giuliano
- Department of Urology, CHU de Bicêtre, 78 rue du Général Leclerc, 94270 Le Kremlin Bicêtre Cedex, France.
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22
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Caquineau C, Leng G, Douglas AJ. Sexual behaviour and neuronal activation in the vomeronasal pathway and hypothalamus of food-deprived male rats. J Neuroendocrinol 2012; 24:712-23. [PMID: 22309296 DOI: 10.1111/j.1365-2826.2012.02290.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
As feeding and mating are mutually-exclusive goal-orientated behaviours, we investigated whether brief food deprivation would impair the display of sexual behaviour of male rats. Analysis of performance in a sexual incentive motivation test revealed that, similar to fed males, food-deprived males preferred spending time in the vicinity of receptive females rather than nonreceptive females. Despite this, food-deprived males were more likely to be slow to mate than normally-fed males, and a low dose of the satiety peptide α-melanocyte-stimulating-hormone attenuated the effect of hunger. Using Fos immunocytochemistry, we compared neuronal activity in the vomeronasal projection pathway in response to oestrous cues from receptive females between food-deprived and fed males. As in fed males, more Fos expression was seen in the rostral part of the bed nucleus of the stria terminalis and in the medial preoptic area in food-deprived males, confirming that food-deprived males can recognise and respond to female oestrous cues. However, although there was also an increase in Fos expression in the bed nucleus of the accessory tract and in the posteromedial amygdala in fed males, no increases were seen in these areas in food-deprived rats. We also found selective attenuation in the activation of lateral posterior paraventricular nucleus (lpPVN) oxytocin neurones in food-deprived males. Taken together, the data show that, although food-deprived males can still become sexually motivated, copulation is delayed, and this is accompanied by variations in neuronal activity in the vomeronasal projection pathway. We propose that, in hungry rats, the lpPVN oxytocin neurones (which project to the spinal cord and are involved in maintaining penile erection) facilitate the transition from motivation to intromission, and their lack of activation impairs intromission, and thus delays mating.
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Affiliation(s)
- C Caquineau
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK.
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23
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Williams SK, melman A. Novel therapeutic targets for erectile dysfunction. Maturitas 2012; 71:20-7. [DOI: 10.1016/j.maturitas.2011.11.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Accepted: 11/07/2011] [Indexed: 11/15/2022]
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24
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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: 234] [Impact Index Per Article: 18.0] [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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25
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Endothelins & erectile dysfunction. Pharmacol Res 2011; 63:496-501. [DOI: 10.1016/j.phrs.2010.12.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 12/16/2010] [Accepted: 12/17/2010] [Indexed: 11/23/2022]
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26
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Bertolucci LF. Pandiculation: nature's way of maintaining the functional integrity of the myofascial system? J Bodyw Mov Ther 2011; 15:268-80. [PMID: 21665102 DOI: 10.1016/j.jbmt.2010.12.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2009] [Revised: 09/14/2010] [Accepted: 12/11/2010] [Indexed: 10/18/2022]
Abstract
Pandiculation is the involuntary stretching of the soft tissues, which occurs in most animal species and is associated with transitions between cyclic biological behaviors, especially the sleep-wake rhythm (Walusinski, 2006). Yawning is considered a special case of pandiculation that affects the musculature of the mouth, respiratory system and upper spine (Baenninger, 1997). When, as often happens, yawning occurs simultaneously with pandiculation in other body regions (Bertolini and Gessa, 1981; Lehmann, 1979; Urba-Holmgren et al., 1977) the combined behavior is referred to as the stretch-yawning syndrome (SYS). SYS has been associated with the arousal function, as it seems to reset the central nervous system to the waking state after a period of sleep and prepare the animal to respond to environmental stimuli (Walusinski, 2006). This paper explores the hypothesis that the SYS might also have an auto-regulatory role regarding the locomotor system: to maintain the animal's ability to express coordinated and integrated movement by regularly restoring and resetting the structural and functional equilibrium of the myofascial system. It is now recognized that the myofascial system is integrative, linking body parts, as the force of a muscle is transmitted via the fascial structures well beyond the tendonous attachments of the muscle itself (Huijing and Jaspers, 2005). It is argued here that pandiculation might preserve the integrative role of the myofascial system by (a) developing and maintaining appropriate physiological fascial interconnections and (b) modulating the pre-stress state of the myofascial system by regularly activating the tonic musculature. The ideas presented here initially arose from clinical observations during the practice of a manual therapy called Muscular Repositioning (MR) (Bertolucci, 2008; Bertolucci and Kozasa, 2010a; Bertolucci, 2010b). These observations were supplemented by a review of the literature on the subject. A possible link between MR and SYS is presented: The neural reflexes characteristically evoked through MR are reminiscent of SYS, which both suggests that MR might stimulate parts of the SYS reaction, and also points to one of MR's possible mechanisms of action.
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Siljee-Wong JE. Melanocortin MC₄ receptor expression sites and local function. Eur J Pharmacol 2011; 660:234-40. [PMID: 21199645 DOI: 10.1016/j.ejphar.2010.10.104] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Revised: 09/30/2010] [Accepted: 10/12/2010] [Indexed: 01/09/2023]
Abstract
The melanocortin MC(4) receptor plays an important role in energy metabolism, but also affects blood pressure, heart rate and erectile function. Localization of the receptors that fulfill these distinct roles is only partially known. Mapping of the melanocortin MC(4) receptor has been stymied by the absence of a functional antibody. Several groups have examined mRNA expression of the melanocortin MC(4) receptor in the rodent brain and transgenic approaches have also been utilized to visualize melanocortin MC(4) receptor expression sites within the brain. Ligand expression and binding studies have provided additional information on the areas of the brain where this elusive receptor is functionally expressed. Finally, microinjection of melanocortin MC(4) receptor ligands in specific nuclei has further served to elucidate the function of melanocortin MC(4) receptors in these nuclei. These combined approaches have helped link the anatomy and function of this receptor, such as the role of paraventricular hypothalamic nucleus melanocortin MC(4) receptor in the regulation of food intake. Intriguingly, however, numerous expression-sites have been identified that have not been linked to a specific receptor function such as those along the optic tract and olfactory tubercle. Further research is needed to clarify the function of the melanocortin MC(4) receptor at these sites.
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Affiliation(s)
- Jacqueline E Siljee-Wong
- Department of Endocrinology and Metabolism, Amsterdam Medical Center, Meibergdreef 47 1105 BA Amsterdam, the Netherlands.
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28
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Gelez H, Poirier S, Facchinetti P, Allers KA, Wayman C, Bernabé J, Alexandre L, Giuliano F. Neuroanatomical distribution of the melanocortin-4 receptors in male and female rodent brain. J Chem Neuroanat 2010; 40:310-24. [DOI: 10.1016/j.jchemneu.2010.09.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Revised: 09/16/2010] [Accepted: 09/20/2010] [Indexed: 11/29/2022]
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29
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Fridmanis D, Petrovska R, Kalnina I, Slaidina M, Peculis R, Schiöth HB, Klovins J. Identification of domains responsible for specific membrane transport and ligand specificity of the ACTH receptor (MC2R). Mol Cell Endocrinol 2010; 321:175-83. [PMID: 20206229 DOI: 10.1016/j.mce.2010.02.032] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Revised: 02/23/2010] [Accepted: 02/23/2010] [Indexed: 12/26/2022]
Abstract
The adrenocorticotropic hormone (ACTH) receptor has highly specific membrane expression that is limited to adrenal cells; in other cell types the polypeptide fails to be transported to the cell surface. Unlike other evolutionarily related members of the melanocortin receptor family (MC1R-MC5R) that recognize different melanocortin peptides, ACTHR (MC2R) binds only ACTH. We used a mutagenesis approach involving systematic construction of chimeric ACTHR/MC4R receptors to identify the domains determining the selectivity of ACTHR membrane transport and ACTH binding. In total 15 chimeric receptors were created by replacement of selected domains of human ACTHR with the corresponding regions of human MC4R. We developed an analytical method to accurately quantify cell-membrane localization of recombinant receptors fused with enhanced green fluorescent protein by confocal fluorescence microscopy. The chimeric receptors were also tested for their ability to bind ACTH (1-24) and the melanocyte-stimulating hormone (MSH) analog, Nle4, DPhe7-alpha-MSH, and to induce a cAMP response. Our results indicate that substitution of the MC4R N-terminal segment with the homologous segment of ACTHR significantly decreased membrane transport. We also identified another signal localized in the third and fourth transmembrane regions as the main determinant of ACTHR intracellular retention. In addition, we found that the fourth and fifth transmembrane domains of the ACTHR are involved in ACTH binding selectivity. We discuss the mechanisms involved in bypassing these arrest signals via an interaction with melanocortin 2 receptor accessory protein (MRAP) and the possible mechanisms that determine the high ligand-binding specificity of ACTHR.
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30
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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: 233] [Impact Index Per Article: 16.6] [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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31
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Lansdell MI, Hepworth D, Calabrese A, Brown AD, Blagg J, Burring DJ, Wilson P, Fradet D, Brown TB, Quinton F, Mistry N, Tang K, Mount N, Stacey P, Edmunds N, Adams C, Gaboardi S, Neal-Morgan S, Wayman C, Cole S, Phipps J, Lewis M, Verrier H, Gillon V, Feeder N, Heatherington A, Sultana S, Haughie S, Martin SW, Sudworth M, Tweedy S. Discovery of a Selective Small-Molecule Melanocortin-4 Receptor Agonist with Efficacy in a Pilot Study of Sexual Dysfunction in Humans. J Med Chem 2010; 53:3183-97. [DOI: 10.1021/jm9017866] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Mark I. Lansdell
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - David Hepworth
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Andrew Calabrese
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Alan D. Brown
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Julian Blagg
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Denise J. Burring
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Peter Wilson
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - David Fradet
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - T. Bruce Brown
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Faye Quinton
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Neela Mistry
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Kim Tang
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Natalie Mount
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Peter Stacey
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Nick Edmunds
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Cathryn Adams
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Samantha Gaboardi
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Stevie Neal-Morgan
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Chris Wayman
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Susan Cole
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Joanne Phipps
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Mark Lewis
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Hugh Verrier
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Val Gillon
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Neil Feeder
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Anne Heatherington
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Stefan Sultana
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Scott Haughie
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Steven W. Martin
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Maria Sudworth
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Sarah Tweedy
- Pfizer Global Research and Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
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Bertolucci LF. Muscle repositioning: combining subjective and objective feedbacks in the teaching and practice of a reflex-based myofascial release technique. Int J Ther Massage Bodywork 2010; 3:26-35. [PMID: 21589699 PMCID: PMC3091424 DOI: 10.3822/ijtmb.v3i1.72] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Muscle Repositioning (MR) is a new style of myofascial release that elicits involuntary motor reactions detectable by electromyography. This article* describes the principal theoretical and practical concepts of MR, and summarizes a workshop presented October 31, 2009, after the Second International Fascia Research Congress, held at Vrije Universitiet, Amsterdam. The manual mechanical input of MR integrates the client’s body segments into a block, which is evident as a result of the diagnostic manual oscillations the practitioner imparts to the client’s body. Segmental integration is achieved when the client’s body responds as a unit to the oscillatory assessment. It appears that manually sustaining the condition of segmental integration evokes involuntary muscle reactions, which reactions might correspond to mechanisms that maintain homeostasis, such as pandiculation. It might be that these reactions are part of the MR mechanism of action and underlie its clinically observed efficacy in the treatment of musculoskeletal disorders. For the practitioner and the client alike, segmental integration provides unique sensations. In teaching MR, these paired sensations can be used as kinesthetic feedback resources, because quality of touch can be guided by the client’s reported sensations, which should match the practitioner’s sensations. Another form of feedback with respect to quality of touch is the visually discernable degree of segmental integration. Finally, because the involuntary motor activity elicited by the MR touch can be objectively monitored through electromyography and possibly other instrumented measurements, the MR approach might yield objectivity, precision, and reproducibility—features seldom found in manual therapies.
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Kimura Y, Naitou Y, Wanibuchi F, Yamaguchi T. 5-HT2C receptor activation is a common mechanism on proerectile effects of apomorphine, oxytocin and melanotan-II in rats. Eur J Pharmacol 2008; 589:157-62. [DOI: 10.1016/j.ejphar.2008.05.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Revised: 04/25/2008] [Accepted: 05/19/2008] [Indexed: 11/15/2022]
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Targeting melanocortin receptors: an approach to treat weight disorders and sexual dysfunction. Nat Rev Drug Discov 2008; 7:307-23. [PMID: 18323849 DOI: 10.1038/nrd2331] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The melanocortin system has multifaceted roles in the control of body weight homeostasis, sexual behaviour and autonomic functions, and so targeting this pathway has immense promise for drug discovery across multiple therapeutic areas. In this Review, we first outline the physiological roles of the melanocortin system, then discuss the potential of targeting melanocortin receptors by using MC3 and MC4 agonists for treating weight disorders and sexual dysfunction, and MC4 antagonists to treat anorectic and cachectic conditions. Given the complexity of the melanocortin system, we also highlight the challenges and opportunities for future drug discovery in this area.
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Kokare DM, Singru PS, Dandekar MP, Chopde CT, Subhedar NK. Involvement of alpha-melanocyte stimulating hormone (alpha-MSH) in differential ethanol exposure and withdrawal related depression in rat: neuroanatomical-behavioral correlates. Brain Res 2008; 1216:53-67. [PMID: 18499089 DOI: 10.1016/j.brainres.2008.03.064] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Revised: 03/22/2008] [Accepted: 03/24/2008] [Indexed: 10/22/2022]
Abstract
We investigated the involvement of alpha-melanocyte stimulating hormone (alpha-MSH) following acute, chronic and withdrawal treatments of ethanol with reference to depression. The degree of depression was evaluated using Porsolt's forced swim test. While intracerebroventricular (i.c.v.) alpha-MSH (100-400 ng/rat) dose-dependently increased the immobility, opposite response was observed following administration of selective MC4 receptor antagonist HS014 (0.01-0.07 ng/rat, i.c.v.). The anti-immobility effect of acute ethanol (1-2 g/kg), injected via intra-peritoneal route (i.p.), was suppressed by central administration of alpha-MSH (100 ng/rat, i.c.v.), but was enhanced following pretreatment with HS014 (0.01 ng/rat, i.c.v.). Chronic ethanol resulted in increased immobility time, while further augmentation in immobility was noticed following ethanol withdrawal. However, concomitant HS014 (0.01 ng/rat, i.c.v.) treatment prevented tolerance as well as attenuated enhanced immobility in ethanol-withdrawn rats. Acute administration of HS014 (0.01-0.03 ng/rat, i.c.v.), at 24h post-withdrawal time point, also antagonized the ethanol withdrawal immobility in rats. The profile of alpha-MSH-immunoreactivity in the paraventricular (PVN), arcuate (ARC), paraventricular thalamic (PVT), dorsomedial hypothalamic-dorsal (DMNd) and -ventral (DMNv) nuclei, lateral hypothalamus (LH) and central nucleus of amygdala (CeA) was investigated with immunocytochemistry. Acute ethanol significantly reduced the alpha-MSH-immunoreactivity in the cells and fibers of ARC, and fibers in the PVN, DMNd, DMNv and CeA. While chronic ethanol treatment significantly increased the alpha-MSH-immunoreactivity as compared to the pair-fed control group, further augmentation was noticed following 24 h ethanol withdrawal. However, the alpha-MSH-immunoreactive profile in the PVT and LH did not respond. alpha-MSH in discrete areas may play a role in ethanol-induced antidepressant-like response and withdrawal-induced depression.
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Affiliation(s)
- Dadasaheb M Kokare
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University Campus, Nagpur, 440 033, India
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Pohorecky LA, Blakley GG, Ma EW, Soini HA, Wiesler D, Bruce KE, Novotny MV. Social housing influences the composition of volatile compounds in the preputial glands of male rats. Horm Behav 2008; 53:536-45. [PMID: 18255066 DOI: 10.1016/j.yhbeh.2007.12.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Revised: 12/14/2007] [Accepted: 12/18/2007] [Indexed: 10/22/2022]
Abstract
In rodents the preputial glands are one of the major sources of pheromones. These volatile chemosignaling compounds are known to elicit specific behavioral and physiological effects in their conspecifics. While social stress can alter both the behavior and hormonal status of rodents, little is known about its influence on the volatile constituents of the preputial glands. We have examined the composition of volatile compounds in the preputial glands of gonadally intact male rats housed for 70 days in either unisex triads (three/cage) or singly. The rank status of triad-housed rats was based on quantitative behavioral assessments taken during the initial 30 min of triad housing. Dominant rats had heavier preputial glands compared to subdominant and subordinate rats. Capillary gas chromatography-mass spectrometry identified 56 volatile preputial compounds, of these 17 did not differ between groups while 26 compounds were significantly higher in the single-housed compared to the triad-housed rats. Six additional volatile compounds were higher in the dominant compared to the other 3 groups, while another six compounds were higher in both the dominant and single-housed rats compared to the subdominant and subordinate rats. It can be concluded that both housing condition and social rank status have significant but different effects on the composition of volatile compounds found in preputial glands of male rats. The physiological and behavioral significance of these changes in preputial gland volatile compound composition in rats remain to be investigated.
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Affiliation(s)
- L A Pohorecky
- Center of Alcohol Studies, Rutgers University, 607 Allison Road, Piscataway, NJ 08854-1100, USA.
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Kalange AS, Kokare DM, Singru PS, Upadhya MA, Chopde CT, Subhedar NK. Central administration of selective melanocortin 4 receptor antagonist HS014 prevents morphine tolerance and withdrawal hyperalgesia. Brain Res 2007; 1181:10-20. [PMID: 17915196 DOI: 10.1016/j.brainres.2007.08.054] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2006] [Revised: 08/20/2007] [Accepted: 08/24/2007] [Indexed: 11/17/2022]
Abstract
Major problem involved in treatment of chronic pain with morphine is the development of tolerance and dependence. Previous studies have demonstrated the participation of melanocortin (MC) system in the development of tolerance to antinociceptive effect of morphine. However, the impact of supraspinal MC4 receptors (MC4 R) modulation on this phenomenon and morphine withdrawal hyperalgesia remained unexplored. We investigated the role of central MC4 R in acute, chronic effects and withdrawal reactions of morphine using tail flick test. Acute intracerebroventricular (icv) administration of morphine (2-20 microg/rat) exhibited antinociceptive activity, which was antagonized by subeffective dose of nonselective MC R agonist NDP-MSH (0.04 ng/rat, icv), and potentiated by subeffective dose of MC4 R antagonist HS014 (0.008 ng/rat, icv). Isobolographic analysis revealed antagonistic interaction between NDP-MSH and morphine, and additive interaction between HS014 and morphine combinations. While chronic icv infusion of morphine (20 ng/microl/h) via osmotic pump for 7 days developed tolerance to its antinociceptive effect, its discontinuation produced hyperalgesia. Co-administration of HS014 (0.008 ng/rat, icv) with chronic morphine not only delayed the development of tolerance but also prevented withdrawal hyperalgesia. Furthermore, acute treatment with HS014 (0.008 and 0.04 ng/rat, icv) dose dependently attenuated the withdrawal hyperalgesia. This suggests the involvement of central MC4 R in the mechanism of development of tolerance and dependence following chronic morphine administration. We speculate that targeting this receptor may be a novel strategy to improve the effectiveness of morphine in the treatment of chronic pain.
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Affiliation(s)
- Annasaheb S Kalange
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University Campus, Nagpur-440 033, India
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Glavas MM, Joachim SE, Draper SJ, Smith MS, Grove KL. Melanocortinergic activation by melanotan II inhibits feeding and increases uncoupling protein 1 messenger ribonucleic acid in the developing rat. Endocrinology 2007; 148:3279-87. [PMID: 17412803 DOI: 10.1210/en.2007-0184] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The hypothalamic neurocircuitry that regulates energy homeostasis in adult rats is not fully developed until the third postnatal week. In particular, fibers from the hypothalamic arcuate nucleus, including both neuropeptide Y (NPY) and alpha-MSH fibers, do not begin to innervate downstream hypothalamic targets until the second postnatal week. However, alpha-MSH fibers from the brainstem and melanocortin receptors are present in the hypothalamus at birth. The present study investigated the melanocortin system in the early postnatal period by examining effects of the melanocortin receptor agonist melanotan II (MTII) on body weight, energy expenditure, and hypothalamic NPY expression. Rat pups were injected ip with MTII (3 mg/kg body weight) or saline on postnatal day (P) 5 to P6, P10-P11, or P15-P16 at 1700 and 0900 h and then killed at 1300 h. Stomach weight and brown adipose tissue uncoupling protein 1 mRNA were determined. In addition, we assessed central c-Fos activation 90 min after MTII administration and hypothalamic NPY mRNA after twice daily MTII administration from P5-P10 or P10-P15. MTII induced hypothalamic c-Fos activation as well as attenuating body weight gain in rat pups. Stomach weight was significantly decreased and uncoupling protein 1 mRNA was increased at all ages, indicating decreased food intake and increased energy expenditure, respectively. However, MTII had no effect on NPY mRNA levels in any hypothalamic region. These findings demonstrate that MTII can inhibit food intake and stimulate energy expenditure before the full development of hypothalamic feeding neurocircuitry. These effects do not appear to be mediated by changes in NPY expression.
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Affiliation(s)
- Maria M Glavas
- Oregon National Primate Research Center, Department of Physiology and Pharmacology, Oregon Health and Science University, 505 NW 185th Avenue, Beaverton, Oregon 97006, USA
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Temel Y, Hafizi S, Beuls E, Visser-Vandewalle V. The supraspinal network in the control of erection. Expert Opin Ther Targets 2007; 9:941-54. [PMID: 16185150 DOI: 10.1517/14728222.9.5.941] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Penile erection is a complex event controlled by vascular, hormonal and neuronal systems. The neuronal system involved in erection is often divided into spinal and supraspinal networks. It is generally accepted that the spinal system directly controls erection and that the supraspinal network modulates this control mechanism through different ascending and descending pathways. In contrast to the spinal control of erection, relatively little is known about the supraspinal network. In the present review, the authors outline the supraspinal network involved in the control of penile erection. Firstly, the brain regions reported to be involved in erection are described and the brain circuit of erection is outlined. Subsequently, the neuromediators involved in erection are summarised. Finally, these data are discussed in the light of therapeutic possibilities in the management of erectile dysfunction by targeting the supraspinal system.
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Affiliation(s)
- Yasin Temel
- University Hospital Maastricht, Department of Neurosurgery, PO Box 5800, 6202 AZ Maastricht, The Netherlands.
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Diamond LE, Earle DC, Heiman JR, Rosen RC, Perelman MA, Harning R. An effect on the subjective sexual response in premenopausal women with sexual arousal disorder by bremelanotide (PT-141), a melanocortin receptor agonist. J Sex Med 2006; 3:628-638. [PMID: 16839319 DOI: 10.1111/j.1743-6109.2006.00268.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
INTRODUCTION Melanocortins affect multiple physiological responses, including sexual behaviors. Bremelanotide is a synthetic peptide melanocortin analog of alpha-melanocyte-stimulating hormone that is an agonist at melanocortin receptors MC3R and MC4R. AIM To evaluate a single intranasal dose of bremelanotide for potential effects on physiological and subjective measurements of sexual arousal and desire in premenopausal women with sexual arousal disorder. MAIN OUTCOME MEASURES Change in vaginal pulse amplitude during neutral and erotic videos after treatment with bremelanotide or placebo and subjects' perceptions of physiological and sexual response within 24 hours of treatment with bremelanotide or placebo. METHODS Eighteen premenopausal women with a primary diagnosis of female sexual arousal disorder were randomly assigned to receive a single intranasal dose of 20 mg bremelanotide or matching placebo in a double-blind manner during the first in-clinic treatment session, and the alternate medication during the second in-clinic treatment session. During each session, subjects viewed a 20-minute neutral video followed by a 20-minute sexually explicit video. Vaginal photoplethysmography was used to monitor vaginal vasocongestion and questionnaires were used to evaluate perceptions of sexual response within the following 24-hour period. RESULTS More women reported moderate or high sexual desire following bremelanotide treatment vs. placebo (P = 0.0114), and a trend toward more positive responses regarding feelings of genital arousal occurred after bremelanotide compared with placebo (P = 0.0833). Among women who attempted sexual intercourse within 24 hours after treatment, significantly more were satisfied with their level of sexual arousal following bremelanotide, compared with placebo (P = 0.0256). Vaginal vasocongestion did not change significantly while viewing erotic videos following bremelanotide administration compared with placebo. CONCLUSION This preliminary evaluation suggests the potential for bremelanotide to positively affect desire and arousal in women with female sexual arousal disorder and indicates that bremelanotide is a promising candidate for further evaluation in an at-home study.
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Affiliation(s)
| | | | - Julia R Heiman
- Kinsey Institute, Indiana University, Bloomington, IN, USA
| | - Raymond C Rosen
- Department of Psychiatry, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, NJ, USA
| | - Michael A Perelman
- Weill Medical College of Cornell University, Psychiatry, Reproductive Medicine, and Urology, NY, USA
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Caquineau C, Leng G, Guan XMM, Jiang M, Van der Ploeg L, Douglas AJ. Effects of alpha-melanocyte-stimulating hormone on magnocellular oxytocin neurones and their activation at intromission in male rats. J Neuroendocrinol 2006; 18:685-91. [PMID: 16879167 DOI: 10.1111/j.1365-2826.2006.01465.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The peptides alpha-melanocyte-stimulating hormone (alpha-MSH) and oxytocin have very similar effects on several behaviours, including male sexual behaviour. Both induce penile erection and enhance copulatory behaviour when given centrally, suggesting that their central actions are not independent. Here, we used intromission as a physiological stimulus to investigate whether some central effects of alpha-MSH during male sexual behaviour are mediated by oxytocin neurones. We used the expression of the immediate-early gene product Fos to investigate oxytocin neurone activation at intromission and after intracerebroventricular (i.c.v.) administration of alpha-MSH (1 microg/5 microl) and studied the effects of i.c.v. administration of a MC4 receptor antagonist on Fos expression and on the latency of male rats to exhibit sexual behaviour in the presence of a receptive female. In rats that showed intromission, Fos was expressed in magnocellular oxytocin neurones in both the paraventricular nucleus (PVN) and the supraoptic nucleus (SON), but there was no significant activation of parvocellular oxytocin neurones of the PVN. Similarly, alpha-MSH increased Fos expression in magnocellular oxytocin neurones but had little or no effect in parvocellular oxytocin neurones. In male rats that achieved intromission, central injection of a MC4 receptor antagonist significantly attenuated the increase in Fos expression in magnocellular oxytocin neurones in both the PVN and the SON and increased mount and intromission latencies compared to vehicle-injected controls. Together, the results indicate that magnocellular oxytocin neurones are involved in the central regulation of male sexual behaviour, and that some of the central effects of alpha-MSH are likely to be mediated by magnocellular oxytocin neurones.
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Affiliation(s)
- C Caquineau
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK.
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Leng G, Ludwig M. Jacques Benoit Lecture. Information processing in the hypothalamus: peptides and analogue computation. J Neuroendocrinol 2006; 18:379-92. [PMID: 16684129 DOI: 10.1111/j.1365-2826.2006.01428.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Peptides in the hypothalamus are not like conventional neurotransmitters; their release is not particularly associated with synapses, and their long half-lives mean that they can diffuse to distant targets. Peptides can act on their cells of origin to facilitate the development of patterned electrical activity, they can act on their neighbours to bind the collective activity of a neural population into a coherent signalling entity, and the co-ordinated population output can transmit waves of peptide secretion that act as a patterned hormonal analogue signal within the brain. At their distant targets, peptides can re-programme neural networks, by effects on gene expression, synaptogenesis, and by functionally rewiring connections by priming activity-dependent release.
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Affiliation(s)
- G Leng
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK.
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Abstract
INTRODUCTION Hypoactive sexual desire disorder (HSDD) is a common problem that is often treatment refractory. This refractoriness to treatment is reflective of our lack of knowledge concerning the determinants of sexual libido in women. AIM To review the development and current status of information concerning the diagnosis and treatment of HSDD. METHODOLOGY Literature on HSDD published between 1950 and 2005 was reviewed. RESULTS Historically, HSDD was considered to be a psychiatric disorder. Thus, the diagnostic criteria utilized in studies of interventions for this disorder are based on the Diagnostic and Statistical Manual of the American Psychiatric Association. This system was never designed to encompass organic causes of sexual dysfunction and has evolved by expert opinion. If the syndrome is poorly defined by these diagnostic criteria, this could limit progress in this field. Epidemiological studies have found that approximately 24-43% of women complain of low sexual desire in the preceding year. The percentage of the population meeting diagnostic criteria for HSDD is probably much lower. There has been considerable progress in the development of psychometrically sound instruments for the assessment of libido. The development of approaches to treatment was reviewed. Approaches to treatment have evolved in three major areas: psychological, hormonal, and use of psychopharmacological agents. There is some evidence of efficacy utilizing all three approaches. The major evidence of efficacy concerns the use of testosterone therapy. Long-term safety data concerning this treatment are absent. CONCLUSION There is a rapidly expanding knowledge base concerning the diagnosis and treatment of HSDD. However, the contemporary clinician is faced with the absence of an approved treatment for this disorder and the lack of clear guidelines concerning the indications and safety of the use of non-approved agents.
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Affiliation(s)
- Robert Segraves
- Department of Psychiatry, MetroHealth, Cleveland, OH 44122, USA.
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Kita I, Yoshida Y, Nishino S. An activation of parvocellular oxytocinergic neurons in the paraventricular nucleus in oxytocin-induced yawning and penile erection. Neurosci Res 2006; 54:269-75. [PMID: 16427151 DOI: 10.1016/j.neures.2005.12.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2005] [Revised: 12/08/2005] [Accepted: 12/14/2005] [Indexed: 11/26/2022]
Abstract
Intracerebroventricular (ICV) or PVN local injections of oxytocin induce yawning and penile erection, for which a positive feedback mechanism for the PVN oxytocinergic activation is suggested, but this had not been directly substantiated in vivo. We have assessed the behavioral effects and activity of oxytocinergic neurons with double-staining for c-Fos and oxytocin in the PVN after ICV administration of oxytocin in adult male rats. ICV oxytocin injections (50 and 200 ng) dose-dependently induced yawning and penile erection and significantly increased the percentage of c-Fos positive oxytocin neurons in the medial, dorsal and lateral parvocellular subdivision of the PVN. However, increases in the magnocellular portion were not significant. We also found that lithium chloride (LiCl, 0.5 and l.0 mEq), a compound known to activate oxytocinergic neurons, also significantly increased the percentage of c-Fos positive oxytocin neurons in all PVN portions. However, LiCl did not induce yawning and penile erection, but counteracted the oxytocin-induced yawning and penile erection. These results suggest that if the activation of oxytocinergic neurons in the PVN is important for mediating oxytocin-induced yawning and penile erection, a selective activation of parvocellular oxytocinergic neurons in the PVN is likely to be involved.
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Affiliation(s)
- Ichiro Kita
- Sleep and Circadian Neurobiology Laboratory, Center for Narcolepsy, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, CA 94304-5489, USA
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Getting SJ. Targeting melanocortin receptors as potential novel therapeutics. Pharmacol Ther 2006; 111:1-15. [PMID: 16488018 DOI: 10.1016/j.pharmthera.2005.06.022] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2005] [Accepted: 06/21/2005] [Indexed: 10/25/2022]
Abstract
Adrenocorticotrophic hormone (ACTH(1-39)) and the melanocortins (alpha, beta and gamma-melanocyte-stimulating hormone [MSH]) are derived from a larger precursor molecule known as the pro-opiomelanocortin (POMC) protein. They exert their numerous biological effects by activating 7 transmembrane G-protein coupled receptors (GPCR), leading to adenylyl cyclase activation and subsequent cAMP accumulation within the target cell. To date, 5 melanocortin receptors (MCR) have been identified and termed MC1R to MC5R, they have been shown to have a wide and varied distribution throughout the body, being found in the central nervous system (CNS), periphery and immune cells. Melanocortins have a multitude of actions including: (i) modulating disease pathologies including arthritis, asthma, obesity; (ii) affecting functions, for example erectile dysfunction, skin tanning; and (iii) organ systems, for example cardiovascular system. Recently a mechanistic approach has been identified with alpha-MSH preventing NF-kappaB activation via the preservation and expression of IkappaBalphaprotein. This leads to a reduction of pro-inflammatory mediators including cytokines and inhibition of adhesion molecule expression, with subsequent reduction in leukocyte emigration. Development of selective ligands with an appropriate pharmacokinetic profile will enable a pharmacological evaluation of the potential beneficial effects of the melanocortins. In this review I have discussed the potential mechanistic action for the melanocortins and some of the disease pathologies shown to be modulated. This review proposes targeting the MCR with the ultimate aim of controlling many of the diseases that we face today.
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Affiliation(s)
- Stephen J Getting
- The William Harvey Research Institute, Charterhouse Square, London, EC1M 6BQ, United Kingdom.
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Giuliano F, Clément P, Droupy S, Alexandre L, Bernabé J. Melanotan-II: Investigation of the inducer and facilitator effects on penile erection in anaesthetized rat. Neuroscience 2006; 138:293-301. [PMID: 16360286 DOI: 10.1016/j.neuroscience.2005.11.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2005] [Revised: 10/20/2005] [Accepted: 11/07/2005] [Indexed: 11/15/2022]
Abstract
The effects of melanotan-II, a non-specific agonist of melanocortin receptors, on erection and its possible sites of action were investigated in anesthetized rats. Delivered i.v. (0.1, 0.3 and 1 mg/kg) or within the paraventricular nucleus of the hypothalamus (0.1 and 1 microg), melanotan-II exerted a dose-dependent inducer activity on erection by eliciting erectile events and shortening latency of the first erectile event to occur. Erectile events were of higher amplitude in rats treated with melanotan-II i.t. (0.2 microg) delivered at the L6-S1 level than in animals treated with the vehicle i.t. delivered. Erectile responses elicited by cavernous nerve stimulation were increased after i.v. melanotan-II (1 mg/kg), thereby exerting facilitator effect on erection. In contrast, melanotan-II injected within the corpus cavernosum (1 microg) did not display any facilitator activity. To investigate the neural pathways involved in the facilitator effect of melanotan-II, we performed acute spinalization (T8 level) and differential selective nerve transections. Neither spinalization nor bilateral transection of pelvic nerves or dorsal penile nerves impaired facilitator activity of i.v. melanotan-II (1 mg/kg). Conversely, the facilitator effect of melanotan-II was abolished after acute removal of the lumbar paravertebral sympathetic chain. These results lead to the conclusion that central and peripheral melanocortin pathways are recruited by melanotan-II, depending on its route of delivery, to exert both inducer and facilitator activities on erection.
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Affiliation(s)
- F Giuliano
- Pelvipharm Laboratories, CNRS, Bat 5, avenue de la Terrasse, 91190 Gif-sur-Yvette, France.
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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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