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Oti T, Sakamoto H. Neuropeptidergic control circuits in the spinal cord for male sexual behaviour: Oxytocin-gastrin-releasing peptide systems. J Neuroendocrinol 2023; 35:e13324. [PMID: 37515539 DOI: 10.1111/jne.13324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 06/30/2023] [Accepted: 07/08/2023] [Indexed: 07/31/2023]
Abstract
The neuropeptidergic mechanisms controlling socio-sexual behaviours consist of complex neuronal circuitry systems in widely distributed areas of the brain and spinal cord. At the organismal level, it is now becoming clear that "hormonal regulations" play an important role, in addition to the activation of neuronal circuits. The gastrin-releasing peptide (GRP) system in the lumbosacral spinal cord is an important component of the neural circuits that control penile reflexes in rats, circuits that are commonly referred to as the "spinal ejaculation generator (SEG)." Oxytocin, long known as a neurohypophyseal hormone, is now known to be involved in the regulation of socio-sexual behaviors in mammals, ranging from social bonding to empathy. However, the functional interaction between the SEG neurons and the hypothalamo-spinal oxytocin system remains unclear. Oxytocin is known to be synthesised mainly in hypothalamic neurons and released from the posterior pituitary into the circulation. Oxytocin is also released from the dendrites of the neurons into the hypothalamus where they have important roles in social behaviours via non-synaptic volume transmission. Because the most familiar functions of oxytocin are to regulate female reproductive functions including parturition, milk ejection, and maternal behaviour, oxytocin is often thought of as a "feminine" hormone. However, there is evidence that a group of parvocellular oxytocin neurons project to the lower spinal cord and control male sexual function in rats. In this report, we review the functional interaction between the SEG neurons and the hypothalamo-spinal oxytocin system and effects of these neuropeptides on male sexual behaviour. Furthermore, we discuss the finding of a recently identified, localised "volume transmission" role of oxytocin in the spinal cord. Findings from our studies suggest that the newly discovered "oxytocin-mediated spinal control of male sexual function" may be useful in the treatment of erectile and ejaculatory dysfunction.
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Affiliation(s)
- Takumi Oti
- Department of Biological Sciences, Faculty of Science, Kanagawa University, Hiratsuka, Japan
- Ushimado Marine Institute (UMI), Faculty of Environmental, Life, Natural Science and Technology, Okayama University, Okayama, Japan
| | - Hirotaka Sakamoto
- Ushimado Marine Institute (UMI), Faculty of Environmental, Life, Natural Science and Technology, Okayama University, Okayama, Japan
- Department of Biology, Faculty of Environmental, Life, Natural Science and Technology, Okayama University, Okayama, Japan
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Knöchel C, Frickmann H, Nürnberger F. Effects of Sleep Deprivation by Olfactorily Induced Sexual Arousal Compared to Immobilization Stress and Manual Sleep Deprivation on Neuromessengers and Time Keeping Genes in the Suprachiasmatic Nuclei and Other Cerebral Entities of Syrian Hamsters-An Immunohistochemical Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18179169. [PMID: 34501759 PMCID: PMC8430648 DOI: 10.3390/ijerph18179169] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/13/2021] [Accepted: 08/27/2021] [Indexed: 11/16/2022]
Abstract
We investigated the effects of sexual arousal induced by olfactory stimuli on the expression of neuromodulators, neurotransmitters and sexual steroid receptors in the suprachiasmatic nucleus (SCN, the circadian pacemaker of mammals) and other cerebral entities of Syrian hamsters (Mesocricetus auratus) compared to manual sleep deprivation and immobilization stress. The hamsters kept under a 12:12 hours (h) light:dark cycle were deprived of sleep by sexual stimulation, gentle manual handling or immobilization stress for 1 h at the beginning of the light phase and subsequently sacrificed at zeitgeber time 01:00, respectively; for comparison, hamsters were manually sleep deprived for 6 or 20 h or sacrificed after completing a full sleep phase. As demonstrated by immunohistochemistry, apart from various alterations after manual sleep deprivation, sexual stimulation caused down-regulation of arginine-vasopressin (AVP), vasointestinal peptide (VIP), serotonin (5-HT), substance P (SP), and met-enkephalin (ME) in the SCN. Somatostatin (SOM) was diminished in the medial periventricular nucleus (MPVN). In contrast, an increase in AVP was observed in the PVN, that of oxytocin (OXY) in the supraoptic nucleus (SON), of tyrosine-hydroxylase (TH) in the infundibular nucleus (IN), and dopamine beta-hydroxylase (DBH) in the A7 neuron population of the brain stem (A7), respectively. Testosterone in plasma was increased. The results indicate that sexual arousal extensively influences the neuropeptide systems of the SCN, suggesting an involvement of the SCN in reproductive behavior.
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Affiliation(s)
- Christian Knöchel
- Vitos Clincis of Forensic Psychiatry Eltville, 65346 Eltville, Germany;
| | - Hagen Frickmann
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Hamburg, 20359 Hamburg, Germany; or
- Institute for Medical Microbiology, Virology and Hygiene, University Medicine Rostock, 18057 Rostock, Germany
| | - Frank Nürnberger
- Institute for Anatomy II, Goethe-Universität Frankfurt am Main, 60590 Frankfurt am Main, Germany
- Correspondence:
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Oti T, Sakamoto T, Sakamoto H. Systemic effects of oxytocin on male sexual activity via the spinal ejaculation generator in rats. Commun Integr Biol 2021; 14:55-60. [PMID: 33828638 PMCID: PMC8009111 DOI: 10.1080/19420889.2021.1902056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Oxytocin is produced in the hypothalamus and stimulates uterine contraction and milk ejection. While many people consider oxytocin to be a female hormone, it is reported that, in men, the plasma oxytocin level increases markedly after ejaculation. However, this aspect of oxytocin physiology is poorly understood. The spinal ejaculation generator (SEG), which expresses the neuropeptide, gastrin-releasing peptide (GRP), can trigger ejaculation in rats. Therefore, we focused on systemic effects of oxytocin on the GRP/SEG neuron system in the lumbar spinal cord controlling sexual activity in male rats. We found that systemic administration of oxytocin significantly shortened the latency to the first mount, intromission and ejaculation during male copulatory behavior. In addition, the local oxytocin level in the lumbar cord was significantly higher in males than in females. Histological analysis showed that oxytocin-binding is apparent in spinal GRP/SEG neurons. We therefore conclude that oxytocin influences male sexual activity via the SEG.
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Affiliation(s)
- Takumi Oti
- Department of Biological Sciences, Faculty of Science, Kanagawa University, Hiratsuka, Japan.,Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, Setouchi, Japan
| | - Tatsuya Sakamoto
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, Setouchi, Japan
| | - Hirotaka Sakamoto
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, Setouchi, Japan
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Chiang VSC, Park JH. Glutamate in Male and Female Sexual Behavior: Receptors, Transporters, and Steroid Independence. Front Behav Neurosci 2020; 14:589882. [PMID: 33328921 PMCID: PMC7732465 DOI: 10.3389/fnbeh.2020.589882] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 10/20/2020] [Indexed: 01/12/2023] Open
Abstract
The survival of animal species predicates on the success of sexual reproduction. Neurotransmitters play an integral role in the expression of these sexual behaviors in the brain. Here, we review the role of glutamate in sexual behavior in rodents and non-rodent species for both males and females. These encompass the release of glutamate and correlations with glutamate receptor expression during sexual behavior. We then present the effects of glutamate on sexual behavior, as well as the effects of antagonists and agonists on different glutamate transporters and receptors. Following that, we discuss the potential role of glutamate on steroid-independent sexual behavior. Finally, we demonstrate the interaction of glutamate with other neurotransmitters to impact sexual behavior. These sexual behavior studies are crucial in the development of novel treatments of sexual dysfunction and in furthering our understanding of the complexity of sexual diversity. In the past decade, we have witnessed the burgeoning of novel techniques to study and manipulate neuron activity, to decode molecular events at the single-cell level, and to analyze behavioral data. They pose exciting avenues to gain further insight into future sexual behavior research. Taken together, this work conveys the essential role of glutamate in sexual behavior.
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Affiliation(s)
- Vic Shao-Chih Chiang
- Developmental and Brain Sciences, Department of Psychology, University of Massachusetts Boston, Boston, MA, United States
| | - Jin Ho Park
- Developmental and Brain Sciences, Department of Psychology, University of Massachusetts Boston, Boston, MA, United States
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Oti T, Satoh K, Uta D, Nagafuchi J, Tateishi S, Ueda R, Takanami K, Young LJ, Galione A, Morris JF, Sakamoto T, Sakamoto H. Oxytocin Influences Male Sexual Activity via Non-synaptic Axonal Release in the Spinal Cord. Curr Biol 2020; 31:103-114.e5. [PMID: 33125871 DOI: 10.1016/j.cub.2020.09.089] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/21/2020] [Accepted: 09/29/2020] [Indexed: 01/15/2023]
Abstract
Oxytocinergic neurons in the paraventricular nucleus of the hypothalamus that project to extrahypothalamic brain areas and the lumbar spinal cord play an important role in the control of erectile function and male sexual behavior in mammals. The gastrin-releasing peptide (GRP) system in the lumbosacral spinal cord is an important component of the neural circuits that control penile reflexes in rats, circuits that are commonly referred to as the "spinal ejaculation generator (SEG)." We have examined the functional interaction between the SEG neurons and the hypothalamo-spinal oxytocin system in rats. Here, we show that SEG/GRP neurons express oxytocin receptors and are activated by oxytocin during male sexual behavior. Intrathecal injection of oxytocin receptor antagonist not only attenuates ejaculation but also affects pre-ejaculatory behavior during normal sexual activity. Electron microscopy of potassium-stimulated acute slices of the lumbar cord showed that oxytocin-neurophysin-immunoreactivity was detected in large numbers of neurosecretory dense-cored vesicles, many of which are located close to the plasmalemma of axonal varicosities in which no electron-lucent microvesicles or synaptic membrane thickenings were visible. These results suggested that, in rats, release of oxytocin in the lumbar spinal cord is not limited to conventional synapses but occurs by exocytosis of the dense-cored vesicles from axonal varicosities and acts by diffusion-a localized volume transmission-to reach oxytocin receptors on GRP neurons and facilitate male sexual function.
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Affiliation(s)
- Takumi Oti
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, Ushimado, Setouchi, Okayama 701-4303, Japan; Department of Biological Sciences, Faculty of Science, Kanagawa University, Hiratsuka, Kanagawa 259-1293, Japan
| | - Keita Satoh
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, Ushimado, Setouchi, Okayama 701-4303, Japan; Department of Anatomy, Kawasaki Medical School, Kurashiki, Okayama 701-0192, Japan
| | - Daisuke Uta
- Department of Applied Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194, Japan
| | - Junta Nagafuchi
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, Ushimado, Setouchi, Okayama 701-4303, Japan
| | - Sayaka Tateishi
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, Ushimado, Setouchi, Okayama 701-4303, Japan; Department of Biology, Faculty of Science, Okayama University, 3-1-1 Kita-ku, Tsushimanaka, Okayama 700-8530, Japan
| | - Ryota Ueda
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, Ushimado, Setouchi, Okayama 701-4303, Japan; Department of Biology, Faculty of Science, Okayama University, 3-1-1 Kita-ku, Tsushimanaka, Okayama 700-8530, Japan
| | - Keiko Takanami
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, Ushimado, Setouchi, Okayama 701-4303, Japan; Mouse Genomics Resources Laboratory, National Institute of Genetics, Yata, Mishima, Shizuoka 411-8540, Japan
| | - Larry J Young
- Center for 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; Center for Social Neural Networks, University of Tsukuba, Tsukuba 305-8577, Japan
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - John F Morris
- Department of Physiology, Anatomy & Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Tatsuya Sakamoto
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, Ushimado, Setouchi, Okayama 701-4303, Japan
| | - Hirotaka Sakamoto
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, Ushimado, Setouchi, Okayama 701-4303, Japan; Department of Physiology, Anatomy & Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK.
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Trejo-Sánchez I, Pérez-Monter C, Huerta-Pacheco S, Gutiérrez-Ospina G. Male Ejaculatory Endophenotypes: Revealing Internal Inconsistencies of the Concept in Heterosexual Copulating Rats. Front Behav Neurosci 2020; 14:90. [PMID: 32670030 PMCID: PMC7332778 DOI: 10.3389/fnbeh.2020.00090] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 05/14/2020] [Indexed: 12/17/2022] Open
Abstract
Distinct manifestations of sexual behavior are conceived as separate phenotypes. Each sexual phenotype is assumed to be associated with a characteristic brain. These notions have justified the phenotyping of heterosexual copulator males based upon their ejaculation's latencies (EL) or frequencies (i.e., cumulative ejaculation number; EN). For instance, men and male rats showing premature, normal or retarded ejaculation are assumed to be distinctive endophenotypes. This concept, nonetheless, contradicts past and recent evidence that supports that sexual behavior is highly variable within each sex, and that the brain sexual functional morphology represents an intricate sexual phenotypic mosaic. Hence, for ejaculatory male endophenotypes to be considered as a valid biological concept, it must show internal consistency at various levels of organization (including genetic architectures), after being challenged by intrinsic and/or extrinsic factors. We then judged the internal consistency of the presumed ejaculatory endophenotypes by assessing whether copulatory behavior and the expression of copulation relevant genes and brain limbic structures are specific to each of the presumed EL- or EN-ejaculatory endophenotypes. To do this, copulating male rats were first phenotyped in groups consistently displaying short, average or long ejaculation latencies or very high, high, average, low or very low EN, based in their copulatory performance. Then, the internal consistency of the presumed EL- or EN-endophenotypes was tested by introducing as covariates of phenotyping other copulatory parameters (e.g., number of intromissions) in addition to EL or EN, or by analyzing the expression levels of genes encoding for estrogen receptor alpha, progesterone receptor, androgen receptor, aromatase, DNA methyl-transferase 3a and DNA methyl-transferase 1 in the amygdala, medial preoptic area, ventromedial hypothalamus and olfactory bulb. We found that even though there were group-level differences in all the variables that were studied, these differences did not add-up to create the presumed EL- or EN-ejaculatory endophenotypes. In fact, the extensive overlapping of copulatory parameters and expression levels of copulation relevant genes in limbic structures across EL- or EN-phenotyped copulating male rats, is not consistent with the hypothesis that distinct ejaculatory endophenotypes exist and that they are associated with specific brain characteristics.
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Affiliation(s)
- Itztli Trejo-Sánchez
- Laboratorio de Biología de Sistemas, Instituto de Investigaciones Biomédicas, Departamento de Biología Celular y Fisiología, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Programa de Doctorado en Ciencias Biomédicas, Unidad de Posgrado, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Carlos Pérez-Monter
- Departamento de Gastroenterología, Instituto Nacional de Ciencias Médicas y Nutrición “Salvador Zubirán”, Mexico City, Mexico
| | - Sofía Huerta-Pacheco
- Consejo Nacional de Ciencia y Tecnología, Ciencia Forense, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Gabriel Gutiérrez-Ospina
- Laboratorio de Biología de Sistemas, Instituto de Investigaciones Biomédicas, Departamento de Biología Celular y Fisiología, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Coordinación de Psicobiología y Neurociencias, Facultad de Psicología, Universidad Nacional Autónoma de México, Mexico City, Mexico
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Oti T, Takanami K, Ito S, Ueda T, Matsuda KI, Kawata M, Soh J, Ukimura O, Sakamoto T, Sakamoto H. Effects of Sex Steroids on the Spinal Gastrin-Releasing Peptide System Controlling Male Sexual Function in Rats. Endocrinology 2018. [PMID: 29534195 DOI: 10.1210/en.2018-00043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The gastrin-releasing peptide (GRP) system in the lumbosacral spinal cord controls male sexual function in rats. In contrast, in female rats, GRP neurons could scarcely be detected around puberty when circulating ovarian steroid hormones such as estradiol and progesterone levels are increasing. However, little information is available on feminizing or demasculinizing effects of ovarian steroids on the central nervous system in female puberty and adulthood. In this study, to visualize the spinal GRP neurons in vivo, we generated a GRP-promoter-Venus transgenic (Tg) rat line and studied the effects of the sex steroid hormones on GRP expression in the rat lumbar cord by examining the Venus fluorescence. In these Tg rats, the sexually dimorphic spinal GRP neurons controlling male sexual function were clearly labeled with Venus fluorescence. As expected, Venus fluorescence in the male lumbar cord was markedly decreased after castration and restored by chronic androgen replacement. Furthermore, androgen-induced Venus expression in the spinal cord of adult Tg males was significantly attenuated by chronic treatment with progesterone but not with estradiol. A luciferase assay using a human GRP-promoter construct showed that androgens enhance the spinal GRP system, and more strikingly, that progesterone acts to inhibit the GRP system via an androgen receptor-mediated mechanism. These results demonstrate that circulating androgens may play an important role in the spinal GRP system controlling male sexual function not only in rats but also in humans and that progesterone could be an important feminizing factor in the spinal GRP system in females during pubertal development.
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Affiliation(s)
- Takumi Oti
- Ushimado Marine Institute, Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Keiko Takanami
- Ushimado Marine Institute, Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
- Department of Anatomy and Neurobiology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Saya Ito
- Department of Urology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Takashi Ueda
- Department of Urology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Ken Ichi Matsuda
- Department of Anatomy and Neurobiology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Mitsuhiro Kawata
- Department of Anatomy and Neurobiology, Kyoto Prefectural University of Medicine, Kyoto, Japan
- Department of Physical Therapy, School of Health Sciences, Bukkyo University, Kyoto, Japan
| | - Jintetsu Soh
- Department of Urology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Osamu Ukimura
- Department of Urology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Tatsuya Sakamoto
- Ushimado Marine Institute, Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Hirotaka Sakamoto
- Ushimado Marine Institute, Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
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Formaldehyde Inhibits Sexual Behavior and Expression of Steroidogenic Enzymes in the Testes of Mice. J Sex Med 2017; 14:1297-1306. [DOI: 10.1016/j.jsxm.2017.09.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 08/29/2017] [Accepted: 09/01/2017] [Indexed: 02/02/2023]
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A sexually dimorphic peptidergic system in the lower spinal cord controlling penile function in non-human primates. Spinal Cord 2017; 56:57-62. [PMID: 28895579 DOI: 10.1038/sc.2017.105] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 07/18/2017] [Accepted: 07/19/2017] [Indexed: 12/13/2022]
Abstract
STUDY DESIGN Experimental animal study. OBJECTIVES Although a population of gastrin-releasing peptide (GRP) neurons in the lumbar spinal cord has an important role in erection and ejaculation in rats, little information exists on this GRP system in primates. To identify the male-specific GRP system in the primate spinal cord, we studied the lumbosacral cord in macaque monkeys as a non-human primate model. SETTING University laboratory in Japan. METHODS To determine the gene sequence of GRP precursors, the rhesus macaque monkey genomic sequence data were searched, followed by phylogenetic analysis. Subsequently, immunocytochemical analysis for GRP was performed in the monkey spinal cord. RESULTS We have used bioinformatics to identify the ortholog gene for GRP precursor in macaque monkeys. Phylogenetic analysis suggested that primate prepro-GRP is separated from that of other mammalian species and clustered to an independent branch as primates. Immunocytochemistry for GRP further demonstrated that male-dominant sexual dimorphism was found in the spinal GRP system in monkeys as in rodents. CONCLUSION We have demonstrated in macaque monkeys that the GRP system in the lower spinal cord shows male-specific dimorphism and may have an important role in penile functions not only in rodents but also in primates. SPONSORSHIP Tissues of Nihonzaru (Japanese macaque monkeys) were provided in part by National Institutes of Natural Sciences (NINS) through the National Bio-Resource Project (NBRP) of the MEXT, Japan. This work was supported in part by KAKENHI from the Japan Society for the Promotion of Science (JSPS) (to KT; 15KK0343, 15J40220 and HS; 15K15202, 15KK0257, 15H05724).
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Tamura K, Kobayashi Y, Hirooka A, Takanami K, Oti T, Jogahara T, Oda SI, Sakamoto T, Sakamoto H. Identification of the sexually dimorphic gastrin-releasing peptide system in the lumbosacral spinal cord that controls male reproductive function in the mouse and Asian house musk shrew (Suncus murinus). J Comp Neurol 2017; 525:1586-1598. [DOI: 10.1002/cne.24138] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 10/18/2016] [Accepted: 10/19/2016] [Indexed: 01/29/2023]
Affiliation(s)
- Kei Tamura
- Ushimado Marine Institute (UMI); Graduate School of Natural Science and Technology, Okayama University; Ushimado, Setouchi Okayama 701-4303 Japan
| | - Yasuhisa Kobayashi
- Ushimado Marine Institute (UMI); Graduate School of Natural Science and Technology, Okayama University; Ushimado, Setouchi Okayama 701-4303 Japan
- Laboratory for Aquatic Biology; Department of Fisheries, Graduate School of Agriculture, Kindai University; Nara 631-0052 Japan
| | - Asuka Hirooka
- Ushimado Marine Institute (UMI); Graduate School of Natural Science and Technology, Okayama University; Ushimado, Setouchi Okayama 701-4303 Japan
| | - Keiko Takanami
- Ushimado Marine Institute (UMI); Graduate School of Natural Science and Technology, Okayama University; Ushimado, Setouchi Okayama 701-4303 Japan
| | - Takumi Oti
- Ushimado Marine Institute (UMI); Graduate School of Natural Science and Technology, Okayama University; Ushimado, Setouchi Okayama 701-4303 Japan
| | - Takamichi Jogahara
- Laboratory of Animal Management and Resources; Department of Zoology, Okayama University of Science; Okayama 700-0005 Japan
- Division of Bio-Resources; Department of Biotechnology, Frontier Science Research Center, University of Miyazaki; Miyazaki 889-1692 Japan
| | - Sen-ichi Oda
- Laboratory of Animal Management and Resources; Department of Zoology, Okayama University of Science; Okayama 700-0005 Japan
| | - Tatsuya Sakamoto
- Ushimado Marine Institute (UMI); Graduate School of Natural Science and Technology, Okayama University; Ushimado, Setouchi Okayama 701-4303 Japan
| | - Hirotaka Sakamoto
- Ushimado Marine Institute (UMI); Graduate School of Natural Science and Technology, Okayama University; Ushimado, Setouchi Okayama 701-4303 Japan
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Xia JD, Chen J, Sun HJ, Zhou LH, Zhu GQ, Chen Y, Dai YT. Centrally mediated ejaculatory response via sympathetic outflow in rats: role of N-methyl-D-aspartic acid receptors in paraventricular nucleus. Andrology 2016; 5:153-159. [PMID: 27860425 DOI: 10.1111/andr.12274] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 07/03/2016] [Accepted: 07/19/2016] [Indexed: 11/29/2022]
Affiliation(s)
- J.-D. Xia
- Department of Urology; The First Affiliated Hospital of Nanjing Medical University; Nanjing China
| | - J. Chen
- Department of Obstetrics and Gynecology; Nanjing Drum Tower Hospital; Nanjing Medical University; Nanjing China
| | - H.-J. Sun
- Key Laboratory of Cardiovascular Disease and Molecular Intervention; Department of Physiology; Nanjing Medical University; Nanjing China
| | - L.-H. Zhou
- Department of Urology; The First Affiliated Hospital of Nanjing Medical University; Nanjing China
| | - G.-Q. Zhu
- Key Laboratory of Cardiovascular Disease and Molecular Intervention; Department of Physiology; Nanjing Medical University; Nanjing China
| | - Y. Chen
- Department of Andrology; Nanjing Drum Tower Hospital; Nanjing Medical University; Nanjing China
| | - Y.-T. Dai
- Department of Andrology; Nanjing Drum Tower Hospital; Nanjing Medical University; Nanjing China
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12
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Oti T, Takanami K, Katayama N, Edey T, Satoh K, Sakamoto T, Sakamoto H. Perinatal testosterone exposure is critical for the development of the male-specific sexually dimorphic gastrin-releasing peptide system in the lumbosacral spinal cord that mediates erection and ejaculation. Biol Sex Differ 2016; 7:4. [PMID: 26759714 PMCID: PMC4710030 DOI: 10.1186/s13293-016-0058-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 01/04/2016] [Indexed: 02/02/2023] Open
Abstract
Background In rats, a sexually dimorphic spinal gastrin-releasing peptide (GRP) system in the lumbosacral spinal cord projects to spinal centers that control erection and ejaculation. This system controls the sexual function of adult males in an androgen-dependent manner. In the present study, we assessed the influence of androgen exposure on the spinal GRP system during a critical period of the development of sexual dimorphism. Methods Immunohistochemistry was used to determine if the development of the spinal GRP system is regulated by the perinatal androgen surge. We first analyzed the responses of neonates administered with anti-androgen flutamide. To remove endogenous androgens, rats were castrated at birth. Further, neonatal females were administered androgens during a critical period to evaluate the development of the male-specific spinal GRP system. Results Treatment of neonates with flutamide on postnatal days 0 and 1 attenuated the spinal GRP system during adulthood. Castrating male rats at birth resulted in a decrease in the number of GRP neurons and the intensity of neuronal GRP in the spinal cord during adulthood despite testosterone supplementation during puberty. This effect was prevented if the rats were treated with testosterone propionate immediately after castration. Moreover, treating female rats with androgens on the day of birth and the next day, masculinized the spinal GRP system during adulthood, which resembled the masculinized phenotype of adult males and induced a hypermasculine appearance. Conclusions The perinatal androgen surge plays a key role in masculinization of the spinal GRP system that controls male sexual behavior. Further, the present study provides potentially new approaches to treat sexual disorders of males.
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Affiliation(s)
- Takumi Oti
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, 130-17 Kashino, Ushimado, Setouchi, Okayama 701-4303 Japan
| | - Keiko Takanami
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, 130-17 Kashino, Ushimado, Setouchi, Okayama 701-4303 Japan
| | - Nao Katayama
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, 130-17 Kashino, Ushimado, Setouchi, Okayama 701-4303 Japan
| | - Tomoca Edey
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, 130-17 Kashino, Ushimado, Setouchi, Okayama 701-4303 Japan
| | - Keita Satoh
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, 130-17 Kashino, Ushimado, Setouchi, Okayama 701-4303 Japan
| | - Tatsuya Sakamoto
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, 130-17 Kashino, Ushimado, Setouchi, Okayama 701-4303 Japan
| | - Hirotaka Sakamoto
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, 130-17 Kashino, Ushimado, Setouchi, Okayama 701-4303 Japan
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Abstract
Spinal cord injury (SCI) results not only in motor and sensory deficits but also in autonomic dysfunctions. The disruption of connections between higher brain centers and the spinal cord, or the impaired autonomic nervous system itself, manifests a broad range of autonomic abnormalities. This includes compromised cardiovascular, respiratory, urinary, gastrointestinal, thermoregulatory, and sexual activities. These disabilities evoke potentially life-threatening symptoms that severely interfere with the daily living of those with SCI. In particular, high thoracic or cervical SCI often causes disordered hemodynamics due to deregulated sympathetic outflow. Episodic hypertension associated with autonomic dysreflexia develops as a result of massive sympathetic discharge often triggered by unpleasant visceral or sensory stimuli below the injury level. In the pelvic floor, bladder and urethral dysfunctions are classified according to upper motor neuron versus lower motor neuron injuries; this is dependent on the level of lesion. Most impairments of the lower urinary tract manifest in two interrelated complications: bladder storage and emptying. Inadequate or excessive detrusor and sphincter functions as well as detrusor-sphincter dyssynergia are examples of micturition abnormalities stemming from SCI. Gastrointestinal motility disorders in spinal cord injured-individuals are comprised of gastric dilation, delayed gastric emptying, and diminished propulsive transit along the entire gastrointestinal tract. As a critical consequence of SCI, neurogenic bowel dysfunction exhibits constipation and/or incontinence. Thus, it is essential to recognize neural mechanisms and pathophysiology underlying various complications of autonomic dysfunctions after SCI. This overview provides both vital information for better understanding these disorders and guides to pursue novel therapeutic approaches to alleviate secondary complications.
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Affiliation(s)
- Shaoping Hou
- Spinal Cord Research Center, Department of Neurobiology & Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania
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14
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Takanami K, Sakamoto H. The Gastrin-Releasing Peptide Receptor (GRPR) in the Spinal Cord as a Novel Pharmacological Target. Curr Neuropharmacol 2014; 12:434-43. [PMID: 25426011 PMCID: PMC4243033 DOI: 10.2174/1570159x12666140923201432] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 07/28/2014] [Accepted: 09/10/2014] [Indexed: 12/02/2022] Open
Abstract
Gastrin-releasing peptide (GRP) is a mammalian neuropeptide that acts through the G protein-coupled receptor, GRP receptor (GRPR). Increasing evidence indicates that GRPR-mediated signaling in the central nervous system plays an important role in many physiological processes in mammals. Additionally, we have recently reported that the GRP system within the lumbosacral spinal cord not only controls erection but also triggers ejaculation in male rats. This system of GRP neurons is sexually dimorphic, being prominent in male rats but vestigial or absent in females. It is suggested that the sexually dimorphic GRP/GRPR system in the lumbosacral spinal cord plays a critical role in the regulation of male sexual function. In parallel, it has been reported that the somatosensory GRP/GRPR system in the spinal cord contributes to the regulation of itch specific transmission independently of the pain transmission. Interestingly, these two distinct functions in the same spinal region are both regulated by the neuropeptide, GRP. In this report, we review findings on recently identified GRP/GRPR systems in the spinal cord. These GRP/GRPR systems in the spinal cord provide new insights into pharmacological treatments for psychogenic erectile dysfunction as well as for chronic pruritus.
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Affiliation(s)
- Keiko Takanami
- Department of Anatomy and Neurobiology, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566, Japan
| | - Hirotaka Sakamoto
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, Ushimado, Setouchi, Okayama 701-4303, Japan
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15
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Sakamoto H. Sexually dimorphic nuclei in the spinal cord control male sexual functions. Front Neurosci 2014; 8:184. [PMID: 25071429 PMCID: PMC4092374 DOI: 10.3389/fnins.2014.00184] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 06/10/2014] [Indexed: 01/06/2023] Open
Abstract
Lower spinal cord injuries frequently cause sexual dysfunction in men, including erectile dysfunction and an ejaculation disorder. This indicates that the important neural centers for male sexual function are located within the lower spinal cord. It is interesting that the lumbar spinal segments contain several neural circuits, showing a clear sexually dimorphism that, in association with neural circuits of the thoracic and sacral spinal cord, are critical in expressing penile reflexes during sexual behavior. To date, many sex differences in the spinal cord have been discovered. Interestingly, most of these are male dominant. Substantial evidence of sexually dimorphic neural circuits in the spinal cord have been reported in many animal models, but major issues remain unknown. For example, it is not known how the different circuits cooperatively function during male sexual behavior. In this review, therefore, the anatomical and functional significance of the sexually dimorphic nuclei in the spinal cord corresponding to the expression of male sexual behavior is discussed.
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Affiliation(s)
- Hirotaka Sakamoto
- Laboratory of Neuroendocrinology, Ushimado Marine Institute, Graduate School of Natural Science and Technology, Okayama University Okayama, Japan
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16
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Androgen regulates development of the sexually dimorphic gastrin-releasing peptide neuron system in the lumbar spinal cord: evidence from a mouse line lacking androgen receptor in the nervous system. Neurosci Lett 2013; 558:109-14. [PMID: 24211692 DOI: 10.1016/j.neulet.2013.10.068] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 10/27/2013] [Accepted: 10/30/2013] [Indexed: 12/21/2022]
Abstract
Androgens including testosterone, organize the nervous system as well as masculine external and internal genitalia during the perinatal period. Androgen organization involves promotion of masculine body features, usually by acting through androgen receptors (ARs). We have recently demonstrated that the gastrin-releasing peptide (GRP) system in the lumbar spinal cord also mediates spinal centers promoting penile reflexes during male sexual behavior in rats. Testosterone may induce sexual differentiation of this spinal GRP system during development and maintain its activation in adulthood. In the present study, we examined the role of ARs in the nervous system regulating the development of the sexually dimorphic GRP system. For this purpose, we used a conditional mouse line selectively lacking the AR gene in the nervous system. AR floxed males carrying (mutants) or not (controls) the nestin-Cre transgene were castrated in adulthood and supplemented with physiological amounts of testosterone. Loss of AR expression in the nervous system resulted in a significant decrease in the number of GRP neurons compared to control littermates. Consequently, the intensity of GRP axonal projections onto the lower lumbar and upper sacral spinal cord was greater in control males than in mutant males. These results suggest that ARs expressed in the nervous system play a significant role in the development of the GRP system in the male lumbar spinal cord. The AR-deletion mutation may attenuate sexual behavior and activity of mutant males via spinal GRP system-mediated neural mechanisms.
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Abstract
There is now abundant functional and anatomical evidence that autonomic motor pathways represent a highly organized output of the central nervous system. Simplistic notions of antagonistic all-or-none activation of sympathetic or parasympathetic pathways are clearly wrong. Sympathetic or parasympathetic pathways to specific target tissues generally can be activated tonically or phasically, depending on current physiological requirements. For example, at rest, many sympathetic pathways are tonically active, such as those limiting blood flow to the skin, inhibiting gastrointestinal tract motility and secretion, or allowing continence in the urinary bladder. Phasic parasympathetic activity can be seen in lacrimation, salivation or urination. Activity in autonomic motor pathways can be modulated by diverse sensory inputs, including the visual, auditory and vestibular systems, in addition to various functional populations of visceral afferents. Identifying the central pathways responsible for coordinated autonomic activity has made considerable progress, but much more needs to be done.
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Affiliation(s)
- Ian Gibbins
- Anatomy & Histology; Flinders University; SA Austraila
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18
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Abstract
It has been known for over a century that these cranial nerves exist, and that they are not typographical errors nor a sensational event reported in the medical literature. A number of scientific articles on anatomy highlight how textbooks on descriptive anatomy do not always consider variables such as differences related to the geographical areas where people live, and these differences do exist. This is an important concept not only for surgeons, but also for all medical professionals who use manual techniques when treating their patients, ie, osteopaths, chiropractors, physiotherapists, and other manual therapists. This paper highlights the latest developments regarding these cranial nerves, offering at the same time some ideas for further reflection when looking at clinical scenarios that appear to bear little relationship to each other. Inclusion of these concepts in everyday anamnesis is encouraged.
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Affiliation(s)
- Bruno Bordoni
- Don Carlo Gnocchi IRCCS, Department of Cardiology, Milan
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19
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McCormick CM, Green MR, Cameron NM, Nixon F, Levy MJ, Clark RA. Deficits in male sexual behavior in adulthood after social instability stress in adolescence in rats. Horm Behav 2013; 63:5-12. [PMID: 23174754 DOI: 10.1016/j.yhbeh.2012.11.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 11/04/2012] [Accepted: 11/09/2012] [Indexed: 01/18/2023]
Abstract
There is increasing evidence that exposure to stressors in adolescence has long-lasting effects on emotional and cognitive behavior, but little is known as to whether reproductive functions are affected. We investigated appetitive and consummatory aspects of sexual behavior in male rats that were exposed to chronic social instability stress (SS, n=24) for 16 days in mid-adolescence compared to control rats (CTL, n=24). Over five sexual behavior test sessions with a receptive female, SS rats made fewer ejaculations (p=0.02) and had longer latencies to ejaculation (p=0.03). When only data from rats that ejaculated in the fifth session were analyzed, SS rats (n=18) had reduced copulatory efficiency (more mounts and intromissions before ejaculation) compared to CTL rats (n=19) (p=0.004), and CTL rats were twice as likely as SS rats to make more than one ejaculation in the fifth session (p=0.05). Further, more CTL (14/24) than SS (5/25) rats ejaculated in four or more sessions (p=0.05). SS rats had lower plasma testosterone concentrations than CTL rats (p=0.05), but did not differ in androgen receptor, estrogen receptor alpha, or Fos immunoreactive cell counts in the medial preoptic area. The groups did not differ in a partner preference test administered between the fourth and fifth sexual behavior session. The results suggest that developmental history contributes to individual differences in reproductive behavior, and that stress exposures in adolescence may be a factor in sexual sluggishness.
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Affiliation(s)
- Cheryl M McCormick
- Department of Psychology, 500 Glenridge Ave., St. Catharines, Ontario, Canada L2S 3A1.
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Oti T, Satoh K, Saito K, Murata K, Kawata M, Sakamoto T, Sakamoto H. Three-dimensional evaluation of the spinal local neural network revealed by the high-voltage electron microscopy: a double immunohistochemical study. Histochem Cell Biol 2012; 138:693-7. [DOI: 10.1007/s00418-012-0976-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2012] [Indexed: 12/19/2022]
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