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Uehara SK, Nishiike Y, Maeda K, Karigo T, Kuraku S, Okubo K, Kanda S. Identification of the FSH-RH as the other gonadotropin-releasing hormone. Nat Commun 2024; 15:5342. [PMID: 38937445 PMCID: PMC11211334 DOI: 10.1038/s41467-024-49564-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 06/10/2024] [Indexed: 06/29/2024] Open
Abstract
In vertebrates, folliculogenesis and ovulation are regulated by two distinct pituitary gonadotropins: follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Currently, there is an intriguing consensus that a single hypothalamic neurohormone, gonadotropin-releasing hormone (GnRH), regulates the secretion of both FSH and LH, although the required timing and functions of FSH and LH are different. However, recent studies in many non-mammalian vertebrates indicated that GnRH is dispensable for FSH function. Here, by using medaka as a model teleost, we successfully identify cholecystokinin as the other gonadotropin regulator, FSH-releasing hormone (FSH-RH). Our histological and in vitro analyses demonstrate that hypothalamic cholecystokinin-expressing neurons directly affect FSH cells through the cholecystokinin receptor, Cck2rb, thereby increasing the expression and release of FSH. Remarkably, the knockout of this pathway minimizes FSH expression and results in a failure of folliculogenesis. Here, we propose the existence of the "dual GnRH model" in vertebrates that utilize both FSH-RH and LH-RH.
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Affiliation(s)
- Shun Kenny Uehara
- Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, Japan
| | - Yuji Nishiike
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Kazuki Maeda
- Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, Japan
| | - Tomomi Karigo
- Kennedy Krieger Institute, Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Shigehiro Kuraku
- Laboratory for Phyloinformatics, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
- Molecular Life History Laboratory, Department of Genomics and Evolutionary Biology, National Institute of Genetics, Mishima, Japan
| | - Kataaki Okubo
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Shinji Kanda
- Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, Japan.
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Ruqa WA, Pennacchia F, Rusi E, Zoccali F, Bruno G, Talarico G, Barbato C, Minni A. Smelling TNT: Trends of the Terminal Nerve. Int J Mol Sci 2024; 25:3920. [PMID: 38612730 PMCID: PMC11011448 DOI: 10.3390/ijms25073920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 03/29/2024] [Accepted: 03/30/2024] [Indexed: 04/14/2024] Open
Abstract
There is very little knowledge regarding the terminal nerve, from its implications in the involvement and pathogenesis of certain conditions, to its embryological origin. With this review, we try to summarize the most important evidence on the terminal nerve, aiming to clarify its anatomy and the various functions attributed to it, to better interpret its potential involvement in pathological processes. Recent studies have also suggested its potential role in the control of human reproductive functions and behaviors. It has been hypothesized that it plays a role in the unconscious perception of specific odors that influence autonomic and reproductive hormonal systems through the hypothalamic-pituitary-gonadal axis. We used the PubMed database and found different articles which were then selected independently by three authors. We found 166 articles, of which, after careful selection, only 21 were analyzed. The terminal nerve was always thought to be unimportant in our body. It was well studied in different types of animals, but few studies have been completed in humans. For this reason, its function remains unknown. Studies suggest a possible implication in olfaction due to the anatomical proximity with the olfactive nerve. Others suggest a more important role in reproduction and sexual behaviors. New emerging information suggests a possible role in Kallmann syndrome and COVID-19.
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Affiliation(s)
- Wael Abu Ruqa
- Department of Sense Organs, Sapienza University of Rome, Policlinico Umberto I, 00161 Roma, Italy; (W.A.R.); (F.P.); (F.Z.)
| | - Fiorenza Pennacchia
- Department of Sense Organs, Sapienza University of Rome, Policlinico Umberto I, 00161 Roma, Italy; (W.A.R.); (F.P.); (F.Z.)
| | - Eqrem Rusi
- Department of Human Neuroscience, Sapienza University of Rome, 00185 Rome, Italy; (E.R.); (G.B.); (G.T.)
| | - Federica Zoccali
- Department of Sense Organs, Sapienza University of Rome, Policlinico Umberto I, 00161 Roma, Italy; (W.A.R.); (F.P.); (F.Z.)
| | - Giuseppe Bruno
- Department of Human Neuroscience, Sapienza University of Rome, 00185 Rome, Italy; (E.R.); (G.B.); (G.T.)
| | - Giuseppina Talarico
- Department of Human Neuroscience, Sapienza University of Rome, 00185 Rome, Italy; (E.R.); (G.B.); (G.T.)
| | - Christian Barbato
- Institute of Biochemistry and Cell Biology (IBBC-CNR), Sapienza University Rome, Policlinico Umberto I, 00161 Roma, Italy
| | - Antonio Minni
- Department of Sense Organs, Sapienza University of Rome, Policlinico Umberto I, 00161 Roma, Italy; (W.A.R.); (F.P.); (F.Z.)
- Division of Otolaryngology-Head and Neck Surgery, ASL Rieti-Sapienza University, Ospedale San Camillo de Lellis, 02100 Rieti, Italy
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Fujimori C, Sugimoto K, Ishida M, Yang C, Kayo D, Tomihara S, Sano K, Akazome Y, Oka Y, Kanda S. Long-lasting redundant gnrh1/3 expression in GnRH neurons enabled apparent switching of paralog usage during evolution. iScience 2024; 27:109304. [PMID: 38464591 PMCID: PMC10924128 DOI: 10.1016/j.isci.2024.109304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 12/08/2023] [Accepted: 02/16/2024] [Indexed: 03/12/2024] Open
Abstract
Expressed subtype of paralogous genes in functionally homologous cells sometimes show differences across species, the reasons for which have not been explained. The present study examined hypophysiotropic gonadotropin-releasing hormone (GnRH) neurons in vertebrates to investigate this mechanism. These neurons express either gnrh1 or gnrh3 paralogs, depending on the species, and apparent switching of the expressed paralogs in them occurred at least four times in vertebrate evolution. First, we found redundant expression of gnrh1 and gnrh3 in a single neuron in piranha and hypothesized that it may represent an ancestral GnRH system. Moreover, the gnrh1/gnrh3 enhancer of piranha induced reporter RFP/GFP co-expression in a single hypophysiotropic GnRH neuron in both zebrafish and medaka, whose GnRH neurons only express either gnrh3 or gnrh1. Thus, we propose that redundant expression of gnrh1/3 of relatively recent common ancestors may be the key to apparent switching of the paralog usage among present-day species.
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Affiliation(s)
- Chika Fujimori
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba, Japan
- Optics and Imaging Facility, National Institute for Basic Biology, Okazaki, Aichi, Japan
| | - Kohei Sugimoto
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba, Japan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Mio Ishida
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Christopher Yang
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
| | - Daichi Kayo
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Soma Tomihara
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba, Japan
- Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, Japan
| | - Kaori Sano
- Department of Chemistry, Faculty of Science, Josai University, Sakado, Saitama, Japan
| | - Yasuhisa Akazome
- Department of Anatomy, St. Marianna University School of Medicine, Kawasaki, Kanagawa, Japan
| | - Yoshitaka Oka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Shinji Kanda
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba, Japan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
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Dussenne M, Alward BA. Expression of novel androgen receptors in three GnRH neuron subtypes in the cichlid brain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.02.578641. [PMID: 38352335 PMCID: PMC10862814 DOI: 10.1101/2024.02.02.578641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Within a social hierarchy, an individuals' social status determines its physiology and behavior. In A. burtoni, subordinate males can rise in rank to become dominant, which is accompanied by the upregulation of the entire HPG axis, including activation of GnRH1 neurons, a rise in circulating androgen levels and the display of specific aggressive and reproductive behaviors. Cichlids possess two other GnRH subtypes, GnRH2 and GnRH3, the latter being implicated in the display of male specific behaviors. Interestingly, some studies showed that these GnRH neurons are responsive to fluctuations in circulating androgen levels, suggesting a link between GnRH neurons and androgen receptors (ARs). Due to a teleost-specific whole genome duplication, A. burtoni possess two AR paralogs (ARα and ARβ) that are encoded by two different genes, ar1 and ar2, respectively. Even though social status has been strongly linked to androgens, whether ARα and/or ARβ are present in GnRH neurons remains unclear. Here, we used immunohistochemistry and in situ hybridization chain reaction (HCR) to investigate ar1 and ar2 expression specifically in GnRH neurons. We find that all GnRH1 neurons intensely express ar1 but only a few of them express ar2, suggesting the presence of genetically-distinct GnRH1 subtypes. Very few ar1 and ar2 transcripts were found in GnRH2 neurons. GnRH3 neurons were found to express both ar genes. The presence of distinct ar genes within GnRH neuron subtypes, most clearly observed for GnRH1 neurons, suggests differential control of these neurons by androgenic signaling. These findings provide valuable insight for future studies aimed at disentangling the androgenic control of GnRH neuron plasticity and reproductive plasticity across teleosts.
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Affiliation(s)
- Mélanie Dussenne
- University of Houston, Department of Psychology, United States of America
| | - Beau A. Alward
- University of Houston, Department of Psychology, United States of America
- University of Houston, Department of Biology and Biochemistry, United States of America
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Kim MA, Kim TH, Kannan P, Kho KH, Park K, Sohn YC. Functional Characterization of Gonadotropin-Releasing Hormone and Corazonin Signaling Systems in Pacific Abalone: Toward Reclassification of Invertebrate Neuropeptides. Neuroendocrinology 2023; 114:64-89. [PMID: 37703838 DOI: 10.1159/000533662] [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: 05/09/2023] [Accepted: 08/14/2023] [Indexed: 09/15/2023]
Abstract
INTRODUCTION The proposed evolutionary origins and corresponding nomenclature of bilaterian gonadotropin-releasing hormone (GnRH)-related neuropeptides have changed tremendously with the aid of receptor deorphanization. However, the reclassification of the GnRH and corazonin (CRZ) signaling systems in Lophotrochozoa remains unclear. METHODS We characterized GnRH and CRZ receptors in the mollusk Pacific abalone, Haliotis discus hannai (Hdh), by phylogenetic and gene expression analyses, bioluminescence-based reporter, Western blotting, substitution of peptide amino acids, in vivo neuropeptide injection, and RNA interference assays. RESULTS Two Hdh CRZ-like receptors (Hdh-CRZR-A and Hdh-CRZR-B) and three Hdh GnRH-like receptors (Hdh-GnRHR1-A, Hdh-GnRHR1-B, and Hdh-GnRHR2) were identified. In phylogenetic analysis, Hdh-CRZR-A and -B grouped within the CRZ-type receptors, whereas Hdh-GnRHR1-A/-B and Hdh-GnRHR2 clustered within the GnRH/adipokinetic hormone (AKH)/CRZ-related peptide-type receptors. Hdh-CRZR-A/-B and Hdh-GnRHR1-A were activated by Hdh-CRZ (pQNYHFSNGWHA-NH2) and Hdh-GnRH (pQISFSPNWGT-NH2), respectively. Hdh-CRZR-A/-B dually coupled with the Gαq and Gαs signaling pathways, whereas Hdh-GnRHR1-A was linked only with Gαq signaling. Analysis of substituted peptides, [I2S3]Hdh-CRZ and [N2Y3H4]Hdh-GnRH, and in silico docking models revealed that the N-terminal amino acids of the peptides are critical for the selectivity of Hdh-CRZR and Hdh-GnRHR. Two precursor transcripts for Hdh-CRZ and Hdh-GnRH peptides and their receptors were mainly expressed in the neural ganglia, and their levels increased in starved abalones. Injection of Hdh-CRZ peptide into abalones decreased food consumption, whereas Hdh-CRZR knockdown increased food consumption. Moreover, Hdh-CRZ induced germinal vesicle breakdown in mature oocytes. CONCLUSION Characterization of Hdh-CRZRs and Hdh-GnRHRs and their cognate peptides provides new insight into the evolutionary route of GnRH-related signaling systems in bilaterians.
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Affiliation(s)
- Mi Ae Kim
- Department of Marine Bioscience, Gangneung-Wonju National University, Gangneung, Republic of Korea
- East Coast Life Sciences Institute, Gangneung-Wonju National University, Gangneung, Republic of Korea
| | - Tae Ha Kim
- Department of Marine Bioscience, Gangneung-Wonju National University, Gangneung, Republic of Korea
| | - Priyadharshini Kannan
- Natural Product Informatics Research Center, KIST Gangneung Institute of Natural Products, Gangneung, Republic of Korea
- Department of Biochemical Engineering, Gangneung-Wonju National University, Gangneung, Republic of Korea
| | - Kang Hee Kho
- Department of Fisheries Science, Chonnam National University, Yeosu, Republic of Korea
| | - Keunwan Park
- Natural Product Informatics Research Center, KIST Gangneung Institute of Natural Products, Gangneung, Republic of Korea
| | - Young Chang Sohn
- Department of Marine Bioscience, Gangneung-Wonju National University, Gangneung, Republic of Korea
- East Coast Life Sciences Institute, Gangneung-Wonju National University, Gangneung, Republic of Korea
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Oka Y. Neural Control of Sexual Behavior in Fish. Zoolog Sci 2023; 40:128-140. [PMID: 37042692 DOI: 10.2108/zs220108] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 01/09/2023] [Indexed: 03/17/2023]
Abstract
Many vertebrate species show breeding periods and exhibit series of characteristic species-specific sexual behaviors only during the breeding period. Here, secretion of gonadal sex hormones from the mature gonads has been considered to facilitate sexual behaviors. Thus, the sexual behavior has long been considered to be regulated by neural and hormonal mechanisms. In this review, we discuss recent progress in the study of neural control mechanisms of sexual behavior with a focus on studies using fish, which have often been the favorite animals used by many researchers who study instinctive animal behaviors. We first discuss control mechanisms of sexual behaviors by sex steroids in relation to the anatomical studies of sex steroid-concentrating neurons in various vertebrate brains, which are abundantly distributed in evolutionarily conserved areas such as preoptic area (POA) and anterior hypothalamus. We then focus on another brain area called the ventral telencephalic area, which has also been suggested to contain sex steroid-concentrating neurons and has been implicated in the control of sexual behaviors, especially in teleosts. We also discuss control of sex-specific behaviors and sexual preference influenced by estrogenic signals or by olfactory/pheromonal signals. Finally, we briefly summarize research on the modulatory control of motivation for sexual behaviors by a group of peptidergic neurons called terminal nerve gonadotropin-releasing hormone (TN-GnRH) neurons, which are known to be especially developed in fishes among various vertebrate species.
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Affiliation(s)
- Yoshitaka Oka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Tanaka A, Umatani C, Oka Y. Acetylcholine Inhibits Spontaneous Firing Activity of Terminal Nerve GnRH Neurons in Medaka. Zoolog Sci 2023; 40:151-159. [PMID: 37042694 DOI: 10.2108/zs220070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 01/04/2023] [Indexed: 03/17/2023]
Abstract
Vertebrates generally possess hypophysiotropic and non-hypophysiotropic gonadotropin releasing hormone (GnRH) neurons. The terminal nerve (TN) GnRH neurons are known to belong to the non-hypophysiotropic neurons and have been suggested to modulate sexual behaviors. These neurons show spontaneous pacemaker firing activity and release neuropeptides GnRH and neuropeptide FF. Since the spontaneous firing activities of peptidergic neurons, including GnRH neurons, are believed to play important roles in the release of neuropeptides, understanding the regulatory mechanisms of these spontaneous firing activities is important. Here, we analyzed firing activities of the TN-GnRH neurons in medaka during application of acetylcholine (ACh), which is one of the essential neuromodulators in the brain. Whole cell patch clamp recording of TN-GnRH neurons demonstrated that ACh induces hyperpolarization and inhibits their pacemaker firing. Electrophysiological analysis using an antagonist for acetylcholine receptors and in situ hybridization analysis showed that firing of TN-GnRH neurons is inhibited via M2-type muscarinic acetylcholine receptor. These findings, taken together with literature from several other fish species (including teleosts and elasmobranchs), indicate that ACh may generally play an inhibitory role in modulating spontaneous activities of TN-GnRH neurons and thereby sexual behaviors in fish.
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Affiliation(s)
- Aiki Tanaka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Chie Umatani
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yoshitaka Oka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Ogawa S, Yamamoto N, Hagio H, Oka Y, Parhar IS. Multiple gonadotropin-releasing hormone systems in non-mammalian vertebrates: Ontogeny, anatomy, and physiology. J Neuroendocrinol 2022; 34:e13068. [PMID: 34931380 DOI: 10.1111/jne.13068] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/17/2021] [Accepted: 11/19/2021] [Indexed: 01/08/2023]
Abstract
Three paralogous genes for gonadotropin-releasing hormone (GnRH; gnrh1, gnrh2, and gnrh3) and GnRH receptors exist in non-mammalian vertebrates. However, there are some vertebrate species in which one or two of these paralogous genes have become non-functional during evolution. The developmental migration of GnRH neurons in the brain is evolutionarily conserved in mammals, reptiles, birds, amphibians, and jawed teleost fish. The three GnRH paralogs have specific expression patterns in the brain and originate from multiple sites. In acanthopterygian teleosts (medaka, cichlid, etc.), the preoptic area (POA)-GnRH1 and terminal nerve (TN)-GnRH3 neuronal types originate from the olfactory regions. In other fish species (zebrafish, goldfish and salmon) with only two GnRH paralogs (GnRH2 and GnRH3), the TN- and POA-GnRH3 neuronal types share the same olfactory origin. However, the developmental origin of midbrain (MB)-GnRH2 neurons is debatable between mesencephalic or neural crest site. Each GnRH system has distinctive anatomical and physiological characteristics, and functions differently. The POA-GnRH1 neurons are hypophysiotropic in nature and function in the neuroendocrine control of reproduction. The non-hypophysiotropic GnRH2/GnRH3 neurons probably play neuromodulatory roles in metabolism (MB-GnRH2) and the control of motivational state for sexual behavior (TN-GnRH3).
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Affiliation(s)
- Satoshi Ogawa
- Jeffrey Cheah School of Medicine & Health Sciences, Monash University Malaysia, Selangor, Malaysia
| | - Naoyuki Yamamoto
- Laboratory of Fish Biology, Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Hanako Hagio
- Laboratory of Fish Biology, Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
- Institute for Advanced Research, Nagoya University, Nagoya, Japan
| | - Yoshitaka Oka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Ishwar S Parhar
- Jeffrey Cheah School of Medicine & Health Sciences, Monash University Malaysia, Selangor, Malaysia
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Whitlock KE, Palominos MF. The Olfactory Tract: Basis for Future Evolution in Response to Rapidly Changing Ecological Niches. Front Neuroanat 2022; 16:831602. [PMID: 35309251 PMCID: PMC8927807 DOI: 10.3389/fnana.2022.831602] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 02/01/2022] [Indexed: 01/10/2023] Open
Abstract
Within the forebrain the olfactory sensory system is unique from other sensory systems both in the projections of the olfactory tract and the ongoing neurogenic potential, characteristics conserved across vertebrates. Olfaction plays a crucial role in behaviors such as mate choice, food selection, homing, escape from predators, among others. The olfactory forebrain is intimately associated with the limbic system, the region of the brain involved in learning, memory, and emotions through interactions with the endocrine system and the autonomic nervous system. Previously thought to lack a limbic system, we now know that teleost fishes process emotions, have exceptional memories, and readily learn, behaviors that are often associated with olfactory cues. The association of neuromodulatory hormones, and more recently, the immune system, with odor cues underlies behaviors essential for maintenance and adaptation within natural ecological niches. Increasingly anthropogenic perturbations affecting ecosystems are impacting teleost fishes worldwide. Here we examine the role of the olfactory tract as the neural basis for the integration of environmental cues and resulting behaviors necessary for the regulation of biotic interactions that allow for future adaptation as the climate spins out of control.
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Affiliation(s)
- Kathleen E. Whitlock
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Universidad de ValparaísoValparaíso, Chile
- Instituto de Neurociencia, Universidad de ValparaísoValparaíso, Chile
- *Correspondence: Kathleen E. Whitlock
| | - M. Fernanda Palominos
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Universidad de ValparaísoValparaíso, Chile
- Instituto de Neurociencia, Universidad de ValparaísoValparaíso, Chile
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Umatani C, Yoshida N, Yamamoto E, Akazome Y, Mori Y, Kanda S, Okubo K, Oka Y. Co-existing Neuropeptide FF and Gonadotropin-Releasing Hormone 3 Coordinately Modulate Male Sexual Behavior. Endocrinology 2022; 163:6486464. [PMID: 34962983 DOI: 10.1210/endocr/bqab261] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Indexed: 11/19/2022]
Abstract
Animals properly perform sexual behaviors by using multiple sensory cues. However, neural mechanisms integrating multiple sensory cues and regulating motivation for sexual behaviors remain unclear. Here, we focused on peptidergic neurons, terminal nerve gonadotropin-releasing hormone (TN-GnRH) neurons, which receive inputs from various sensory systems and co-express neuropeptide FF (NPFF) in addition to GnRH. Our behavioral analyses using knockout medaka of GnRH (gnrh3) and/or NPFF (npff) demonstrated that some sexual behavioral repertoires were delayed, not disrupted, in gnrh3 and npff single knockout males, while the double knockout appeared to alleviate the significant defects that were observed in single knockouts. We also found anatomical evidence to show that both neuropeptides modulate the sexual behavior-controlling brain areas. Furthermore, we demonstrated that NPFF activates neurons in the preoptic area via indirect pathway, which is considered to induce the increase in motivation for male sexual behaviors. Considering these results, we propose a novel mechanism by which co-existing peptides of the TN-GnRH neurons, NPFF, and GnRH3 coordinately modulate certain neuronal circuit for the control of behavioral motivation. Our results may go a long way toward understanding the functional significance of peptidergic neuromodulation in response to sensory information from the external environments.
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Affiliation(s)
- Chie Umatani
- Department of Biological Sciences, Graduate School of Science, the University of Tokyo, Tokyo, Japan
| | - Nagisa Yoshida
- Department of Biological Sciences, Graduate School of Science, the University of Tokyo, Tokyo, Japan
| | - Eri Yamamoto
- Department of Biological Sciences, Graduate School of Science, the University of Tokyo, Tokyo, Japan
| | - Yasuhisa Akazome
- Department of Anatomy, St. Marianna University School of Medicine, Kanagawa, Japan
| | - Yasutaka Mori
- Department of Biological Sciences, Graduate School of Science, the University of Tokyo, Tokyo, Japan
| | - Shinji Kanda
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, the University of Tokyo, Chiba, Japan
| | - Kataaki Okubo
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, the University of Tokyo, Tokyo, Japan
| | - Yoshitaka Oka
- Department of Biological Sciences, Graduate School of Science, the University of Tokyo, Tokyo, Japan
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Ogawa S, Parhar IS. Heterogeneity in GnRH and kisspeptin neurons and their significance in vertebrate reproductive biology. Front Neuroendocrinol 2022; 64:100963. [PMID: 34798082 DOI: 10.1016/j.yfrne.2021.100963] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 10/11/2021] [Accepted: 10/31/2021] [Indexed: 02/07/2023]
Abstract
Vertebrate reproduction is essentially controlled by the hypothalamus-pituitary-gonadal (HPG) axis, which is a central dogma of reproductive biology. Two major hypothalamic neuroendocrine cell groups containing gonadotropin-releasing hormone (GnRH) and kisspeptin are crucial for control of the HPG axis in vertebrates. GnRH and kisspeptin neurons exhibit high levels of heterogeneity including their cellular morphology, biochemistry, neurophysiology and functions. However, the molecular foundation underlying heterogeneities in GnRH and kisspeptin neurons remains unknown. More importantly, the biological and physiological significance of their heterogeneity in reproductive biology is poorly understood. In this review, we first describe the recent advances in the neuroendocrine functions of kisspeptin-GnRH pathways. We then view the recent emerging progress in the heterogeneity of GnRH and kisspeptin neurons using morphological and single-cell transcriptomic analyses. Finally, we discuss our views on the significance of functional heterogeneity of reproductive endocrine cells and their potential relevance to reproductive health.
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Affiliation(s)
- Satoshi Ogawa
- Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, 47500 Bandar Sunway, Selangor, Malaysia
| | - Ishwar S Parhar
- Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, 47500 Bandar Sunway, Selangor, Malaysia.
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Jiang P, Pan X, Zhang W, Dai Z, Lu W. Neuromodulatory effects of GnRH on the caudal neurosecretory Dahlgren cells in female olive flounder. Gen Comp Endocrinol 2021; 307:113754. [PMID: 33711313 DOI: 10.1016/j.ygcen.2021.113754] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 02/19/2021] [Accepted: 02/28/2021] [Indexed: 01/28/2023]
Abstract
Gonadotropin-releasing hormone (GnRH) is considered a key player in reproduction. The caudal neurosecretory system (CNSS) is a unique neurosecretory structure of fish that may be involved in osmoregulation, nutrition, reproduction, and stress-related responses. However, a direct effect of GnRH on Dahlgren cells remains underexplored. Here, we examined the electrophysiological response of Dahlgren cell population of the CNSS to GnRH analog LHRH-A2 and the transcription of related key genes of CNSS. We found that GnRH increased overall firing frequency and may be changed the firing pattern from silent to burst or phasic firing in a subpopulation of Dahlgren cells. The effect of GnRH on a subpopulation of Dahlgren cells firing activity was blocked by the GnRH receptor (GnRH-R) antagonist cetrorelix. A positive correlation was observed between the UII and GnRH-R mRNA levels in CNSS or gonadosomatic index (GSI) during the breeding season. These findings are the first demonstration of the ability of GnRH acts as a modulator within the CNSS and add to our understanding of the physiological role of the CNSS in reproduction and seasonal adaptation.
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Affiliation(s)
- Pengxin Jiang
- National Demonstration Center for Experimental Fisheries Science Education (Shanghai Ocean University), Shanghai 201306, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources (Shanghai Ocean University), Ministry of Education, Shanghai 201306, China
| | - Xinbei Pan
- National Demonstration Center for Experimental Fisheries Science Education (Shanghai Ocean University), Shanghai 201306, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources (Shanghai Ocean University), Ministry of Education, Shanghai 201306, China
| | - Wei Zhang
- National Demonstration Center for Experimental Fisheries Science Education (Shanghai Ocean University), Shanghai 201306, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources (Shanghai Ocean University), Ministry of Education, Shanghai 201306, China
| | - Zhiqi Dai
- National Demonstration Center for Experimental Fisheries Science Education (Shanghai Ocean University), Shanghai 201306, China
| | - Weiqun Lu
- National Demonstration Center for Experimental Fisheries Science Education (Shanghai Ocean University), Shanghai 201306, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources (Shanghai Ocean University), Ministry of Education, Shanghai 201306, China; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, Shanghai 201306, China.
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13
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Kuburas A, Mason BN, Hing B, Wattiez AS, Reis AS, Sowers LP, Moldovan Loomis C, Garcia-Martinez LF, Russo AF. PACAP Induces Light Aversion in Mice by an Inheritable Mechanism Independent of CGRP. J Neurosci 2021; 41:4697-4715. [PMID: 33846231 PMCID: PMC8260237 DOI: 10.1523/jneurosci.2200-20.2021] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 02/26/2021] [Accepted: 03/27/2021] [Indexed: 01/18/2023] Open
Abstract
The neuropeptides CGRP (calcitonin gene-related peptide) and PACAP (pituitary adenylate cyclase-activating polypeptide) have emerged as mediators of migraine, yet the potential overlap of their mechanisms remains unknown. Infusion of PACAP, like CGRP, can cause migraine in people, and both peptides share similar vasodilatory and nociceptive functions. In this study, we have used light aversion in mice as a surrogate for migraine-like photophobia to compare CGRP and PACAP and ask whether CGRP or PACAP actions were dependent on each other. Similar to CGRP, PACAP induced light aversion in outbred CD-1 mice. The light aversion was accompanied by increased resting in the dark, but not anxiety in a light-independent open field assay. Unexpectedly, about one-third of the CD-1 mice did not respond to PACAP, which was not seen with CGRP. The responder and nonresponder phenotypes were stable, inheritable, and not sex linked, although there was a trend for greater responses among male mice. RNA-sequencing analysis of trigeminal ganglia yielded hierarchical clustering of responder and nonresponder mice and revealed a number of candidate genes, including greater expression of the Trpc5 and Kcnk12 ion channels and glycoprotein hormones and receptors in a subset of male responder mice. Importantly, an anti-PACAP monoclonal antibody could block PACAP-induced light aversion but not CGRP-induced light aversion. Conversely, an anti-CGRP antibody could not block PACAP-induced light aversion. Thus, we propose that CGRP and PACAP act by independent convergent pathways that cause a migraine-like symptom in mice.SIGNIFICANCE STATEMENT The relationship between the neuropeptides CGRP (calcitonin gene-related peptide) and PACAP (pituitary adenylate cyclase-activating polypeptide) in migraine is relevant given that both peptides can induce migraine in people, yet to date only drugs that target CGRP are available. Using an outbred strain of mice, we were able to show that most, but not all, mice respond to PACAP in a preclinical photophobia assay. Our finding that CGRP and PACAP monoclonal antibodies do not cross-inhibit the other peptide indicates that CGRP and PACAP actions are independent and suggests that PACAP-targeted drugs may be effective in patients who do not respond to CGRP-based therapeutics.
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Affiliation(s)
- Adisa Kuburas
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa 52242
| | - Bianca N Mason
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa 52242
- Molecular and Cellular Biology Program, University of Iowa, Iowa City, Iowa 52242
| | - Benjamin Hing
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa 52242
| | - Anne-Sophie Wattiez
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa 52242
| | - Alyssa S Reis
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa 52242
| | - Levi P Sowers
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa 52242
- Center for the Prevention and Treatment of Visual Loss, Veterans Affairs Health Care System, Iowa City, Iowa 52246
| | | | | | - Andrew F Russo
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa 52242
- Department of Neurology, University of Iowa, Iowa City, Iowa 52242
- Center for the Prevention and Treatment of Visual Loss, Veterans Affairs Health Care System, Iowa City, Iowa 52246
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14
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Ogawa S, Pfaff DW, Parhar IS. Fish as a model in social neuroscience: conservation and diversity in the social brain network. Biol Rev Camb Philos Soc 2021; 96:999-1020. [PMID: 33559323 DOI: 10.1111/brv.12689] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 01/19/2021] [Accepted: 01/20/2021] [Indexed: 12/21/2022]
Abstract
Mechanisms for fish social behaviours involve a social brain network (SBN) which is evolutionarily conserved among vertebrates. However, considerable diversity is observed in the actual behaviour patterns amongst nearly 30000 fish species. The huge variation found in socio-sexual behaviours and strategies is likely generated by a morphologically and genetically well-conserved small forebrain system. Hence, teleost fish provide a useful model to study the fundamental mechanisms underlying social brain functions. Herein we review the foundations underlying fish social behaviours including sensory, hormonal, molecular and neuroanatomical features. Gonadotropin-releasing hormone neurons clearly play important roles, but the participation of vasotocin and isotocin is also highlighted. Genetic investigations of developing fish brain have revealed the molecular complexity of neural development of the SBN. In addition to straightforward social behaviours such as sex and aggression, new experiments have revealed higher order and unique phenomena such as social eavesdropping and social buffering in fish. Finally, observations interpreted as 'collective cognition' in fish can likely be explained by careful observation of sensory determinants and analyses using the dynamics of quantitative scaling. Understanding of the functions of the SBN in fish provide clues for understanding the origin and evolution of higher social functions in vertebrates.
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Affiliation(s)
- Satoshi Ogawa
- Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Selangor, 47500, Malaysia
| | - Donald W Pfaff
- Laboratory of Neurobiology and Behavior, Rockefeller University, New York, NY, 10065, U.S.A
| | - Ishwar S Parhar
- Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Selangor, 47500, Malaysia
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15
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Wu HM, Chang HM, Leung PCK. Gonadotropin-releasing hormone analogs: Mechanisms of action and clinical applications in female reproduction. Front Neuroendocrinol 2021; 60:100876. [PMID: 33045257 DOI: 10.1016/j.yfrne.2020.100876] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 09/23/2020] [Accepted: 10/04/2020] [Indexed: 12/15/2022]
Abstract
Extra-hypothalamic GnRH and extra-pituitary GnRH receptors exist in multiple human reproductive tissues, including the ovary, endometrium and myometrium. Recently, new analogs (agonists and antagonists) and modes of GnRH have been developed for clinical application during controlled ovarian hyperstimulation for assisted reproductive technology (ART). Additionally, the analogs and upstream regulators of GnRH suppress gonadotropin secretion and regulate the functions of the reproductive axis. GnRH signaling is primarily involved in the direct control of female reproduction. The cellular mechanisms and action of the GnRH/GnRH receptor system have been clinically applied for the treatment of reproductive disorders and have widely been introduced in ART. New GnRH analogs, such as long-acting GnRH analogs and oral nonpeptide GnRH antagonists, are being continuously developed for clinical application. The identification of the upstream regulators of GnRH, such as kisspeptin and neurokinin B, provides promising potential to develop these upstream regulator-related analogs to control the hypothalamus-pituitary-ovarian axis.
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Affiliation(s)
- Hsien-Ming Wu
- Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Linkou Medical Center, Chang Gung University School of Medicine, Taoyuan 333, Taiwan, ROC
| | - Hsun-Ming Chang
- Department of Obstetrics and Gynaecology, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, British Columbia V6H 3V5, Canada
| | - Peter C K Leung
- Department of Obstetrics and Gynaecology, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, British Columbia V6H 3V5, Canada.
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Zohar Y. Fish reproductive biology - Reflecting on five decades of fundamental and translational research. Gen Comp Endocrinol 2021; 300:113544. [PMID: 32615136 PMCID: PMC7324349 DOI: 10.1016/j.ygcen.2020.113544] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 06/26/2020] [Indexed: 12/20/2022]
Abstract
Driven by the broad diversity of species and physiologies and by reproduction-related bottlenecks in aquaculture, the field of fish reproductive biology has rapidly grown over the last five decades. This review provides my perspective on the field during this period, integrating fundamental and applied developments and milestones. Our basic understanding of the brain-pituitary-gonadal axis led to overcoming the failure of farmed fish to ovulate and spawn in captivity, allowing us to close the fish life cycle and establish a predictable, year-round production of eggs. Dissecting the molecular and hormonal mechanisms associated with sex determination and differentiation drove technologies for producing better performing mono-sex and reproductively-sterile fish. The growing contingent of passionate fish biologists, together with the availability of innovative platforms such as transgenesis and gene editing, as well as new models such as the zebrafish and medaka, have generated many discoveries, also leading to new insights of reproductive biology in higher vertebrates including humans. Consequently, fish have now been widely accepted as vertebrate reproductive models. Perhaps the best testament of the progress in our discipline is demonstrated at the International Symposia on Reproductive Physiology of Fish (ISRPF), at which our scientific family has convened every four years since the grandfather of the field, the late Ronald Billard, organized the inaugural 1977 meeting in Paimpont, France. As the one person who has been fortunate enough to attend all of these meetings since their inception, I have witnessed first-hand the astounding evolution of our field as we capitalized on the molecular and biotechnological revolutions in the life sciences, which enabled us to provide a higher resolution of fish reproductive and endocrine processes, answer more questions, and dive into deeper comprehension. Undoubtedly, the next (five) decades will be similarly exciting as we continue to integrate physiology with genomics, basic and translational research, and the small fish models with the aquacultured species.
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Affiliation(s)
- Yonathan Zohar
- Department of Marine Biotechnology, Institute of Marine and Environmental Technology, University of Maryland, Baltimore County, Baltimore, MD 21202, United States
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17
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Abstract
Vertebrates develop an olfactory system that detects odorants and pheromones through their interaction with specialized cell surface receptors on olfactory sensory neurons. During development, the olfactory system forms from the olfactory placodes, specialized areas of the anterior ectoderm that share cellular and molecular properties with placodes involved in the development of other cranial senses. The early-diverging chordate lineages amphioxus, tunicates, lampreys and hagfishes give insight into how this system evolved. Here, we review olfactory system development and cell types in these lineages alongside chemosensory receptor gene evolution, integrating these data into a description of how the vertebrate olfactory system evolved. Some olfactory system cell types predate the vertebrates, as do some of the mechanisms specifying placodes, and it is likely these two were already connected in the common ancestor of vertebrates and tunicates. In stem vertebrates, this evolved into an organ system integrating additional tissues and morphogenetic processes defining distinct olfactory and adenohypophyseal components, followed by splitting of the ancestral placode to produce the characteristic paired olfactory organs of most modern vertebrates.
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Affiliation(s)
- Guillaume Poncelet
- Department of Zoology, University of Oxford, 11a Mansfield Road, Oxford OX1 3SZ, UK
| | - Sebastian M Shimeld
- Department of Zoology, University of Oxford, 11a Mansfield Road, Oxford OX1 3SZ, UK
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18
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Duan C, Allard J. Gonadotropin-releasing hormone neuron development in vertebrates. Gen Comp Endocrinol 2020; 292:113465. [PMID: 32184073 DOI: 10.1016/j.ygcen.2020.113465] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 02/26/2020] [Accepted: 03/12/2020] [Indexed: 11/21/2022]
Abstract
Gonadotropin-releasing hormone (GnRH) neurons are master regulators of the reproductive axis in vertebrates. During early mammalian embryogenesis, GnRH1 neurons emerge in the nasal/olfactory placode. These neurons undertake a long-distance migration, moving from the nose to the preoptic area and hypothalamus. While significant advances have been made in understanding the functional importance of the GnRH1 neurons in reproduction, where GnRH1 neurons come from and how are they specified during early development is still under debate. In addition to the GnRH1 gene, most vertebrate species including humans have one or two additional GnRH genes. Compared to the GnRH1 neurons, much less is known about the development and regulation of GnRH2 neuron and GnRH3 neurons. The objective of this article is to review what is currently known about GnRH neuron development. We will survey various cell autonomous and non-autonomous factors implicated in the regulation of GnRH neuron development. Finally, we will discuss emerging tools and new approaches to resolve open questions pertaining to GnRH neuron development.
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Affiliation(s)
- Cunming Duan
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, United States.
| | - John Allard
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, United States
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Muñoz-Cueto JA, Zmora N, Paullada-Salmerón JA, Marvel M, Mañanos E, Zohar Y. The gonadotropin-releasing hormones: Lessons from fish. Gen Comp Endocrinol 2020; 291:113422. [PMID: 32032603 DOI: 10.1016/j.ygcen.2020.113422] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 02/02/2020] [Accepted: 02/03/2020] [Indexed: 12/26/2022]
Abstract
Fish have been of paramount importance to our understanding of vertebrate comparative neuroendocrinology and the mechanisms underlying the physiology and evolution of gonadotropin-releasing hormones (GnRH) and their genes. This review integrates past and recent knowledge on the Gnrh system in the fish model. Multiple Gnrh isoforms (two or three forms) are present in all teleosts, as well as multiple Gnrh receptors (up to five types), which differ in neuroanatomical localization, pattern of projections, ontogeny and functions. The role of the different Gnrh forms in reproduction seems to also differ in teleost models possessing two versus three Gnrh forms, Gnrh3 being the main hypophysiotropic hormone in the former and Gnrh1 in the latter. Functions of the non-hypothalamic Gnrh isoforms are still unclear, although under suboptimal physiological conditions (e.g. fasting), Gnrh2 may increase in the pituitary to ensure the integrity of reproduction under these conditions. Recent developments in transgenesis and mutagenesis in fish models have permitted the generation of fish lines expressing fluorophores in Gnrh neurons and to elucidate the dynamics of the elaborate innervations of the different neuronal populations, thus enabling a more accurate delineation of their reproductive roles and regulations. Moreover, in combination with neuronal electrophysiology, these lines have clarified the Gnrh mode of actions in modulating Lh and Fsh activities. While loss of function and genome editing studies had the premise to elucidate the exact roles of the multiple Gnrhs in reproduction and other processes, they have instead evoked an ongoing debate about these roles and opened new avenues of research that will no doubt lead to new discoveries regarding the not-yet-fully-understood Gnrh system.
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Affiliation(s)
- José A Muñoz-Cueto
- Department of Biology, Faculty of Marine and Environmental Sciences and INMAR, University of Cádiz, CEIMAR, The European University of the Seas (SEA-EU), Puerto Real (Cádiz), Spain.
| | - Nilli Zmora
- Department of Marine Biotechnology, Institute of Marine and Environmental Technology, University of Maryland Baltimore County, Baltimore, MD, USA
| | - José A Paullada-Salmerón
- Department of Biology, Faculty of Marine and Environmental Sciences and INMAR, University of Cádiz, CEIMAR, The European University of the Seas (SEA-EU), Puerto Real (Cádiz), Spain
| | - Miranda Marvel
- Department of Marine Biotechnology, Institute of Marine and Environmental Technology, University of Maryland Baltimore County, Baltimore, MD, USA
| | - Evaristo Mañanos
- Institute of Aquaculture of Torre de la Sal, CSIC, Castellón, Spain
| | - Yonathan Zohar
- Department of Marine Biotechnology, Institute of Marine and Environmental Technology, University of Maryland Baltimore County, Baltimore, MD, USA.
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