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Corchuelo S, Martinez ERM, Butzge AJ, Doretto LB, Ricci JMB, Valentin FN, Nakaghi LSO, Somoza GM, Nóbrega RH. Characterization of Gnrh/Gnih elements in the olfacto-retinal system and ovary during zebrafish ovarian maturation. Mol Cell Endocrinol 2017; 450:1-13. [PMID: 28400274 DOI: 10.1016/j.mce.2017.04.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 03/15/2017] [Accepted: 04/04/2017] [Indexed: 01/13/2023]
Abstract
Gonadotropin releasing hormone (GnRH) is one of the key players of brain-pituitary-gonad axis, exerting overall control over vertebrate reproduction. In zebrafish, two variants were characterized and named as Gnrh2 and Gnrh3. In this species, Gnrh3, the hypohysiotropic form, is expressed by neurons of the olfactory-retinal system, where it is related with food detection, intra/interspecific recognition, visual acuity and retinal processing modulation. Previous studies have reported the presence of Gnrh receptors in the zebrafish retina, but not yet in the zebrafish olfactory epithelium. The current study analyzed the presence of gnrh2 and gnrh3, their receptors (gnrhr 1,2,3 and 4) and gnih (gonadotropin inhibitory hormone) transcripts, as well as the Gnrh3 protein in the olfactory epithelium (OE), olfactory bulb (OB), retina and ovary during zebrafish ovarian maturation. We found an increase of gnrh receptors transcripts in the OE at the final stages of ovarian maturation. In the OE, Gnrh3 protein was detected in the olfactory receptor neurons cilia and in the olfactory nerve fibers. Interestingly, in the OB, we found an inverse expression pattern between gnih and gnrh3. In the retina, gnrhr4 mRNA was found in the nuclei of amacrine, bipolar, and ganglion cells next to Gnrh3 positive fibers. In the ovary, gnrh3, gnrhr2 and gnrhr4 transcripts were found in perinucleolar oocytes, while gnih in oocytes at the cortical alveolus stage. Our results suggested that Gnrh/Gnih elements are involved in the neuromodulation of the sensorial system particularly at the final stages of maturation, playing also a paracrine role in the ovary.
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Affiliation(s)
- Sheryll Corchuelo
- Aquaculture Center of São Paulo State University (CAUNESP), Jaboticabal, São Paulo, Brazil
| | - Emanuel R M Martinez
- Reproductive and Molecular Biology Group, Department of Morphology, Institute of Bioscience of Botucatu, São Paulo State University, Botucatu, São Paulo, Brazil
| | - Arno J Butzge
- Aquaculture Center of São Paulo State University (CAUNESP), Jaboticabal, São Paulo, Brazil; Reproductive and Molecular Biology Group, Department of Morphology, Institute of Bioscience of Botucatu, São Paulo State University, Botucatu, São Paulo, Brazil
| | - Lucas B Doretto
- Reproductive and Molecular Biology Group, Department of Morphology, Institute of Bioscience of Botucatu, São Paulo State University, Botucatu, São Paulo, Brazil
| | - Juliana M B Ricci
- Reproductive and Molecular Biology Group, Department of Morphology, Institute of Bioscience of Botucatu, São Paulo State University, Botucatu, São Paulo, Brazil
| | - Fernanda N Valentin
- Aquaculture Center of São Paulo State University (CAUNESP), Jaboticabal, São Paulo, Brazil
| | - Laura S O Nakaghi
- Department of Animal Morphology and Physiology, São Paulo State University (UNESP), Jaboticabal, São Paulo, Brazil.
| | - Gustavo M Somoza
- Laboratorio de Ictiofisiología y Acuicultura, Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (CONICET-UNSAM), Chascomús, Argentina
| | - Rafael H Nóbrega
- Reproductive and Molecular Biology Group, Department of Morphology, Institute of Bioscience of Botucatu, São Paulo State University, Botucatu, São Paulo, Brazil.
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D’Aniello B, Polese G, Luongo L, Scandurra A, Magliozzi L, Aria M, Pinelli C. Neuroanatomical relationships between FMRFamide-immunoreactive components of the nervus terminalis and the topology of olfactory bulbs in teleost fish. Cell Tissue Res 2015; 364:43-57. [DOI: 10.1007/s00441-015-2295-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 09/07/2015] [Indexed: 10/22/2022]
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Saha S, Kumar S, Singh U, Singh O, Singru PS. Interaction between dopamine and neuropeptide Y in the telencephalon of the Indian major carp, Cirrhinus cirrhosus. Gen Comp Endocrinol 2015; 220:78-87. [PMID: 24967949 DOI: 10.1016/j.ygcen.2014.06.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 06/06/2014] [Accepted: 06/14/2014] [Indexed: 12/28/2022]
Abstract
In teleosts, while neuropeptide Y (NPY) has emerged as one of the potent regulators of GnRH-LH axis, entopeduncular nucleus (EN) in the ventral telencephalon serves as major site for NPY synthesis/storage. Neurons of the EN innervate preoptic area and pituitary, respond to gonadal steroids, undergo reproduction phase-related changes, and are believed to convey sex steroid-borne information to GnRH neurons. In spite of the importance of EN, the neural circuitry associated with the nucleus has not been defined. Aim of the present study is to examine the possibility of the dopaminergic regulation of EN. NPY-immunoreactive cells and fibers were extensively distributed in the forebrain and pituitary of Cirrhinus cirrhosus. NPY immunoreactivity was observed in the olfactory receptor neurons, ganglion cells of terminal nerve, and in neurons of area ventralis telencephali/pars lateralis, EN, nucleus preopticus periventricularis (NPP), and nucleus lateralis tuberis. NPY-fibers were observed in the dorsal telencephalon, tuberal area and pituitary. While the area ventralis telencephali/pars intermedialis (Vi) located just above the EN contained a distinct population of tyrosine hydroxylase neurons, their axons seem to innervate NPY neurons in EN. Superfused brain slices containing EN were treated with DA D1- and D2-like receptor agonists. NPY-immunoreactivity in the EN showed significant increase (P<0.001) following DA D1-like receptor agonist, SKF-38393 treatment, but DA D2-like receptor agonist, quinpirole was ineffective. DA may regulate NPY neurons in EN via D1-like receptors. DA-NPY interaction in the EN might be important in the central regulation of reproduction in teleosts.
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Affiliation(s)
- Soham Saha
- School of Biological Sciences, National Institute of Science Education and Research (NISER), Institute of Physics Campus, Sachivalaya Marg, Bhubaneswar 751005, Odisha, India
| | - Santosh Kumar
- School of Biological Sciences, National Institute of Science Education and Research (NISER), Institute of Physics Campus, Sachivalaya Marg, Bhubaneswar 751005, Odisha, India
| | - Uday Singh
- School of Biological Sciences, National Institute of Science Education and Research (NISER), Institute of Physics Campus, Sachivalaya Marg, Bhubaneswar 751005, Odisha, India
| | - Omprakash Singh
- School of Biological Sciences, National Institute of Science Education and Research (NISER), Institute of Physics Campus, Sachivalaya Marg, Bhubaneswar 751005, Odisha, India
| | - Praful S Singru
- School of Biological Sciences, National Institute of Science Education and Research (NISER), Institute of Physics Campus, Sachivalaya Marg, Bhubaneswar 751005, Odisha, India.
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Lai XJ, Hong WS, Liu F, Zhang YT, Chen SX. Cloning and expression of prostaglandin E2 receptor subtype 1 (ep 1 ) in Bostrichthys sinensis. FISH PHYSIOLOGY AND BIOCHEMISTRY 2014; 40:1281-1288. [PMID: 24566823 DOI: 10.1007/s10695-014-9923-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 02/17/2014] [Indexed: 06/03/2023]
Abstract
Our previous studies suggested that prostaglandin E2 (PGE2) is a putative sex pheromone in Chinese black sleeper Bostrichthys sinensis, a fish species that inhabits intertidal zones and mates and spawns inside a muddy burrow. We found immunoreactivities of PGE2 receptor subtypes (Ep1-3) expressed in the olfactory sac, but only Ep1 presented higher density of immunoreactivity in mature fish than that in immature fish in both sexes. To gain a better understanding of the underlying molecular mechanism for the detection of PGE2 in the olfactory system, we cloned an ep 1 cDNA from the adult olfactory sac. The open-reading frame of the ep 1 consisted of 1,134-bp nucleotides that encoded a 378-amino acid-long protein with a seven-transmembrane domain, typical for the G protein-coupled receptors superfamily. Expression of ep 1 mRNA was observed in all tissues examined, with higher levels obtained in the olfactory sacs and testes. The expression of ep 1 mRNA in the olfactory sacs and gonads was significantly higher in both sexes of mature fish than in those of immature ones. Taken together, our results suggested that Ep1, which is highly expressed in the olfactory sacs and gonads of mature fish, is important for the control of reproduction and may be involved in PGE2-initiated spawning behavior in B. sinensis.
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Affiliation(s)
- Xiao Jian Lai
- College of Fisheries, Jimei University, Xiamen, 361021, People's Republic of China
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Kumar S, Singh U, Saha S, Singru PS. Tyrosine hydroxylase in the olfactory system, forebrain and pituitary of the Indian major carp, Cirrhinus cirrhosus: organisation and interaction with neuropeptide Y in the preoptic area. J Neuroendocrinol 2014; 26:400-11. [PMID: 24750502 DOI: 10.1111/jne.12160] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Revised: 04/06/2014] [Accepted: 04/12/2014] [Indexed: 12/13/2022]
Abstract
Dopamine (DA) inhibits, whereas gonadotrophin-releasing hormone (GnRH) stimulates, luteinisiing (LH) cells in the pituitary of some but not all teleosts. A reduction in the hypophysiotropic dopaminergic tone is necessary for the stimulatory effect of GnRH on LH cells. Neuropeptide Y (NPY) has emerged as one of the potent, endogenous agent that modulates LH secretion directly or indirectly via GnRH. Involvement of NPY in the regulation of hypophysiotropic DA neurones, however, is not known, but there is good evidence suggesting an interaction in the mammalian hypothalamus. DA neurones, identified by tyrosine hydroxylase (TH)-immunoreactivity, were observed widely throughout the brain of the Indian major carp, Cirrhinus cirrhosus. The granule cells and ganglion cells of terminal nerve in the olfactory bulb, and cells in ventral telencephalon and preoptic area (POA) showed conspicuous TH immunoreactivity. In the POA, the nucleus preopticus periventricularis (NPP), divisible into anterior (NPPa) and posterior (NPPp) components, showed prominent TH-immunoreactivity. The majority of TH neurones in NPPa showed axonal extensions to the pituitary and were closely associated with LH cells. The NPPa also appeared to be the site for intense interaction between NPY and DA because it contains a rich network of NPY fibres and few immunoreactive cells. Approximately 89.7 ± 1.5% TH neurones in NPPa were contacted by NPY fibres. Superfused POA slices treated with a NPY Y2 -receptor agonist, NPY 13-36 resulted in a significant (P < 0.001) reduction in TH-immunoreactivity in NPPa. TH neurones in NPPa did not respond to NPY Y1 -receptor agonist, [Leu(31) , Pro(34) ] Neuropeptide Y treatment. We suggest that, by inhibiting DAergic neurones in NPPa via Y2 -receptors, NPY may contribute to the up-regulation of the GnRH-LH cells axis. The microcircuitry of DA and NPY and their interaction in NPPa might be a crucial component in the central regulation of LH secretion in the teleosts.
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Affiliation(s)
- S Kumar
- School of Biological Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, Odisha, India
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Patle PJ, Baile VV. Olfactory Sensory Neuron Morphotypes in the Featherback Fish, Notopterus notopterus (Osteoglossiformes: Notopteridae). Ann Neurosci 2014; 21:51-6. [PMID: 25206061 PMCID: PMC4117162 DOI: 10.5214/ans.0972.7531.210205] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 04/09/2014] [Accepted: 04/29/2014] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND As in other vertebrates, olfactory sensory neurons (OSNs) in fishes are the main components of sensory part of olfactory epithelium that relay olfactory information (smell and taste) to the brain. PURPOSE Objective of the present study was to analyze if any polymorphism occurs in the OSNs in a featherback fish, Notopterus notopterus as far as the teleost lineage is concerned. METHODS With the help of neuronal staining technique, polymorphism of OSNs in N. notopterus was studied. RESULTS Three polymorphic forms of OSNs were identified which are ciliated OSNs, microvillus OSNs and crypt OSNs. These morphotypes were identified on the basis of location of their somata within the depth of olfactory epithelium and resulting length of their dendrites. The ciliated OSNs have basally situated somata and long, thin dendrites with a few apically arranged cilia while microvillous OSNs have somata located midway in the epithelium and thick moderate-length dendrites with microvilli. Third cell type is crypt OSNs which are spherical or pear-shaped, located apically just close to the epithelial surface having cilia and microvilli in an invagination and devoid of any dendrite. CONCLUSION N. notopterus belongs to order Osteoglossiformes which is a representative of an early evolutionary lineage of teleost fishes. OSN polymorphism reported in the present work indicates that it is a fairly conserved trait throughout the evolution of teleosts. To our knowledge, we are the first ones to report OSN polymorphism in a member of the order Osteoglossiformes.
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Affiliation(s)
- Pratap J. Patle
- Division of Fish Neurobiology, PG Department of Zoology, RTM Nagpur University Campus, Nagpur - 440 033, India
| | - Vidya V. Baile
- Division of Fish Neurobiology, PG Department of Zoology, RTM Nagpur University Campus, Nagpur - 440 033, India
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ABE H, OKA Y. Mechanisms of Neuromodulation by a Nonhypophysiotropic GnRH System Controlling Motivation of Reproductive Behavior in the Teleost Brain. J Reprod Dev 2011; 57:665-74. [DOI: 10.1262/jrd.11-055e] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Hideki ABE
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
| | - Yoshitaka OKA
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
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Kawai T, Abe H, Akazome Y, Oka Y. Neuromodulatory Effect of GnRH on the Synaptic Transmission of the Olfactory Bulbar Neural Circuit in Goldfish, Carassius auratus. J Neurophysiol 2010; 104:3540-50. [DOI: 10.1152/jn.00639.2010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Gonadotropin-releasing hormone (GnRH) is well known as a hypophysiotropic hormone that is produced in the hypothalamus and facilitates the release of gonadotropins from the pituitary gonadotropes. On the other hand, the functions of extrahypothalamic GnRH systems still remain elusive. Here we examined whether the activity of the olfactory bulbar neural circuits is modulated by GnRH that originates mainly from the terminal nerve (TN) GnRH system in goldfish ( Carassius auratus). As the morphological basis, we first observed that goldfish TNs mainly express salmon GnRH (sGnRH) mRNA and that sGnRH-immunoreactive fibers are distributed in both the mitral and the granule cell layers. We then examined by extracellular recordings the effect of GnRH on the electrically evoked in vitro field potentials that arise from synaptic activities from mitral to granule cells. We found that GnRH enhances the amplitude of the field potentials. Furthermore, these effects were observed in both cases when the field potentials were evoked by stimulating either the lateral or the medial olfactory tract, conveying functionally different sensory information, separately, and suggesting that GnRH may modulate the responsiveness to wide categories of odorants in the olfactory bulb. Because GnRH also changed the paired-pulse ratio, it is suggested that the increased amplitude of the field potential results from changes in the presynaptic glutamate release of mitral cells rather than the increase in the glutamate receptor sensitivity of granule cells. These results suggest that TN regulates the olfactory responsiveness of animals appropriately by releasing sGnRH peptides in the olfactory bulbar neural circuits.
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Affiliation(s)
- Takafumi Kawai
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Hideki Abe
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Yasuhisa Akazome
- Department of Biological Sciences, Graduate School of Science, 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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Lai XJ, Hong WS. Variation with reproductive status of PGE₂receptor immunoreactivities in the Bostrichthys sinensis olfactory system. JOURNAL OF FISH BIOLOGY 2010; 77:1542-1551. [PMID: 21078017 DOI: 10.1111/j.1095-8649.2010.02791.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The role of PGE(2) as a putative sex pheromone in Chinese black sleeper Bostrichthys sinensis was investigated, using immunocytochemistry and how the immunoreactivities of the prostaglandin E(2) (PGE(2) ) receptor subtypes EP(1) , EP(2) , EP(3) and EP(4) varied with reproductive status in the olfactory system was determined. The results showed that PGE(2) receptors were present in the whole of the olfactory system of B. sinensis, and that the number of receptors was linked to the reproductive status of the fish. The densities of EP(1) immunoreactivity in the olfactory epithelium of mature fish were significantly (P < 0·01) higher than those in immature fish of both sexes, and the densities of EP(2) and EP(3) immunoreactivities in mature fish were higher (but not significantly) than those in immature fish of both sexes. In the olfactory nerve, the density of EP(2) immunoreactivity in mature fish was higher (but not significantly) than that in immature fish in both sexes. In the olfactory bulb, the densities of EP(1-4) immunoreactivities in mature females were significantly (P < 0·05 or <0·01) higher than those in immature females, and the density of EP(4) immunoreactivity in mature males was significantly (P < 0·01) higher than that in immature males. As far as is known, the present study is the first report of the immunoreactivities of PGE(2) receptor subtypes in the olfactory system of a teleost, and offers new findings regarding the role of PGE(2) as sex pheromone and hormone in the reproductive behaviour and pheromonal communication of B. sinensis.
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Affiliation(s)
- X-J Lai
- State Key Laboratory of Marine Environmental Science and Department of Oceanography, Xiamen University, Xiamen, China
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Maruska KP, Fernald RD. Reproductive status regulates expression of sex steroid and GnRH receptors in the olfactory bulb. Behav Brain Res 2010; 213:208-17. [PMID: 20466023 DOI: 10.1016/j.bbr.2010.04.058] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Revised: 04/29/2010] [Accepted: 04/30/2010] [Indexed: 10/19/2022]
Abstract
Neuromodulators including gonadotropin-releasing hormone (GnRH) and sex steroids help integrate an animal's internal physiological state with incoming external cues, and can have profound effects on the processing of behaviorally relevant information, particularly from the olfactory system. While GnRH and steroid receptors are present in olfactory processing regions across vertebrates, little is known about whether their expression levels change with internal physiological state or external social cues. We used qRT-PCR to measure mRNA levels of two GnRH receptors (GnRH-R1, GnRH-R2), five sex steroid receptors (estrogen receptors: ERalpha, ERbetaa, ERbetab; androgen receptors: ARalpha, ARbeta), and aromatase in the olfactory bulb of the highly social African cichlid fish Astatotilapia burtoni. We asked whether these receptor levels changed with reproductive condition in females, or with social status, which regulates reproductive capacity in males. Our results reveal that mRNA levels of multiple sex steroid, GnRH receptor subtypes, and aromatase in the olfactory bulb vary with sex, social status in males, and reproductive condition in females, which highlights the potential importance of changing receptor levels in fine-tuning the olfactory system during the reproductive cycle. Further, steroid receptor mRNA levels were positively correlated with circulating steroid levels in males, but negatively correlated in females, suggesting different regulatory control between sexes. These results provide support for the hypothesis that the first-order olfactory relay station is a substrate for both GnRH and sex steroid modulation, and suggest that changes in receptor levels could be an important mechanism for regulating reproductive, social, and seasonal plasticity in olfactory perception observed across vertebrates.
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Affiliation(s)
- Karen P Maruska
- Biology Department, Stanford University, 371 Serra Mall, Stanford, CA 94305, USA.
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Kawai T, Oka Y, Eisthen H. The role of the terminal nerve and GnRH in olfactory system neuromodulation. Zoolog Sci 2010; 26:669-80. [PMID: 19832678 DOI: 10.2108/zsj.26.669] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Animals must regulate their sensory responsiveness appropriately with respect to their internal and external environments, which is accomplished in part via centrifugal modulatory pathways. In the olfactory sensory system, responsiveness is regulated by neuromodulators released from centrifugal fibers into the olfactory epithelium and bulb. Among the modulators known to modulate neural activity of the olfactory system, one of the best understood is gonadotropin-releasing hormone (GnRH). This is because GnRH derives mainly from the terminal nerve (TN), and the TN-GnRH system has been suggested to function as a neuromodulator in wide areas of the brain, including the olfactory bulb. In the present article we examine the modulatory roles of the TN and GnRH in the olfactory epithelium and bulb as a model for understanding the ways in which olfactory responses can be tuned to the internal and external environments.
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Affiliation(s)
- Takafumi Kawai
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
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Guilgur LG, Strüssmann CA, Somoza GM. mRNA expression of GnRH variants and receptors in the brain, pituitary and ovaries of pejerrey (Odontesthes bonariensis) in relation to the reproductive status. FISH PHYSIOLOGY AND BIOCHEMISTRY 2009; 35:157-166. [PMID: 19189242 DOI: 10.1007/s10695-008-9215-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2008] [Accepted: 03/20/2008] [Indexed: 05/27/2023]
Abstract
The present study examined the differential mRNA expression levels of three forms of GnRH (sGnRH, pjGnRH and cGnRH-II) and two forms of GnRH receptor (pjGnRH-R I and pjGnRH-R II) in the brain, pituitary, and ovaries of pejerrey in relation to the reproductive status. The analysis revealed the presence of significant amounts of mRNA of the three GnRH forms while the ovaries showed only two (sGnRH and pjGnRH). The GnRH receptor II was found ubiquitously in the brain, pituitary, and ovaries while the form I was detected only in the brain. The levels of pjGnRH mRNA in the brain and pjGnRH-R II in the pituitary gland varied in correlation with the ovarian condition. However, brain sGnRH and pjGnRH-R I mRNA levels reached a maximum during early stages of ovarian development. In contrast, the brain levels of cGnRH-II mRNA showed no variation. The present study also shows a good correlation of ovarian sGnRH and pjGnRH-R II mRNA levels with the reproductive condition, suggesting that these molecules are may be involved in the regulation of pejerrey ovarian function.
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Affiliation(s)
- L G Guilgur
- Laboratorio de Ictiofisiología y Acuicultura, Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico Chascomús, Chascomús, Buenos Aires, Argentina
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Neurosecretory neurons of the nucleus preopticus (NPO) express salmon GnRH mRNA and show reproduction phase-related variation in the female Indian major carp, Cirrhinus cirrhosus. Comp Biochem Physiol A Mol Integr Physiol 2008; 151:247-52. [DOI: 10.1016/j.cbpa.2008.07.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Revised: 07/03/2008] [Accepted: 07/07/2008] [Indexed: 11/22/2022]
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Bhute YV, Baile VV. Organization of the olfactory system of the Indian major carp Labeo rohita (Ham.): A scanning and transmission electron microscopy study. J EVOL BIOCHEM PHYS+ 2007. [DOI: 10.1134/s002209300703009x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Mazumdar M, Sakharkar AJ, Singru PS, Subhedar N. Reproduction phase-related variations in neuropeptide Y immunoreactivity in the olfactory system, forebrain, and pituitary of the female catfish,Clarias batrachus (Linn.). J Comp Neurol 2007; 504:450-69. [PMID: 17701999 DOI: 10.1002/cne.21462] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The aim of this study was to determine whether neuropeptide Y (NPY) immunoreactivity in the cells and fibers in the forebrain and pituitary of Clarias batrachus is linked to the annual reproductive cycle. A steady rise in luteinizing hormone (LH) immunoreactivity was seen in the pituitary through preparatory (February-April) and prespawning (May-June) phases; it was greatly reduced during spawning (July-August; P < 0.001) and partially replenished during postspawning (September-November; P < 0.01) through resting (December-January) phases. Although NPY immunoreactivity in olfactory receptor neurons and olfactory nerve layer in olfactory bulb was gradually augmented during resting through prespawning phases (P < 0.001), attaining a peak in spawning phase (P < 0.001), a dramatic decline was encountered during postspawning phase (P < 0.001). A similar pattern was also observed in NPY-containing fibers of the medial olfactory tract (MOT) and pituitary. However, a different pattern of NPY immunoreactivity was observed in the neurons of nucleus entopeduncularis (NE) and nucleus preopticus periventricularis (NPP). Whereas these neurons and fibers in the forebrain showed significant augmentation during the resting through prespawning phases (P < 0.001), the immunoreactivity dramatically declined during spawning (P < 0.001) and was partially replenished in the postspawning phase. Testosterone injection of juveniles significantly augmented (P < 0.001) NPY immunoreactivity in NE neurons. We suggest that NPY cells of NE and NPP, and related fiber systems, might be involved in processing of sex steroid-borne information and regulation of the gonadotropin-releasing hormone-LH axis.
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Affiliation(s)
- Minakshi Mazumdar
- Department of Pharmaceutical Sciences, R.T.M. Nagpur University Campus, Nagpur-440033, India
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Sakharkar AJ, Singru PS, Mazumdar M, Subhedar N. Reproduction phase-related expression of beta-endorphin-like immunoreactivity in the nucleus lateralis tuberis of the female Indian major carp Cirrhinus mrigala: correlation with the luteinising hormone cells-ovary axis. J Neuroendocrinol 2006; 18:319-29. [PMID: 16629830 DOI: 10.1111/j.1365-2826.2006.01421.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The present study aimed to determine whether beta-endorphin immunoreactivity (bEP-ir) in the neurones of the nucleus lateralis tuberis (NLT) is linked to the seasonal cycle and shows correlation with the number of luteinising hormone (LH) cells in the pituitary gland and ovaries in the teleost, Cirrhinus mrigala. Although LH cells were moderately immunostained during the resting phase (December to January), the morphological profile suggested increased synthetic and secretory activity during the preparatory (February to April) and prespawning (May to June) phases. However, LH immunoreactivity was greatly reduced (P < 0.001) in the spawning (July to August) phase, suggesting massive discharge of the hormone; this pool was partly replenished in the postspawning (September to November) phase. The ovaries grew rapidly in the preparatory and prespawning phases; maximal size was attained during spawning, when ovulation occurred. Thereafter, the ovaries regressed. The NLT of C. mrigala is divisible into the pars lateralis (NLTl) and medialis (NLTm). During the postspawning and resting phases, bEP-ir was readily detectable in the NLTm as well as NLTl neurones. However, a steady reduction in the immunoreactivity was observed in the NLTm neurones during the preparatory through spawning phases (P < 0.001), suggesting a negative correlation with the LH cells-ovary axis. Thus, the inhibitory influence of beta-endorphin on the gonadotrophin-releasing hormone (GnRH)-LH axis appears to be attenuated during the preparatory through spawning phases. This may be necessary for the rapid stimulation of the axis culminating in spawning. Neurones of the NLTl also showed a gradual reduction in bEP-ir during the preparatory and prespawning phases (P < 0.01) and may therefore play a similar role. However, significant augmentation of the immunoreactivity was noticed in these neurones during the spawning phase (P < 0.001), the physiological significance of which is unknown. Although the present study demonstrated a temporal correlation between the beta-endorphin in the NLT, LH cells and the ovary, we suggest that the peptide in the NLTl and NLTm may show functional duality during the spawning phase.
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Affiliation(s)
- A J Sakharkar
- Department of Pharmaceutical Sciences, Nagpur University Campus, Nagpur, India
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Biju KC, Gaikwad A, Sarkar S, Schreibman MP, Subhedar N. Ontogeny of GnRH-like immunoreactive neuronal systems in the forebrain of the Indian major carp, Cirrhinus mrigala. Gen Comp Endocrinol 2005; 141:161-71. [PMID: 15748717 DOI: 10.1016/j.ygcen.2004.12.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2004] [Revised: 12/16/2004] [Accepted: 12/17/2004] [Indexed: 11/18/2022]
Abstract
GnRH immunoreactivity appeared in the medial olfactory placode very early in the development of Cirrhinus mrigala. The immunoreactive elements were divisible into distinct migratory and non-migratory components. The migratory component appeared as a patch of intensely immunoreactive cells located close to the olfactory epithelium in day 6 post-fertilization larvae. Subsequently, these neurons migrate caudally along the ventromedial aspect of the developing forebrain and enroute give rise to GnRH immunoreactive neurons in the (1) nervus terminalis located in ventral and caudal part of the olfactory bulb (day 8), and (2) basal telencephalon (day 9). The non-migratory GnRH immunoreactive component appeared in the olfactory placode of day 1 post-fertilization larvae. It consisted of few olfactory receptor neuron (ORN)-like cells with distinct flask-shaped somata, dendrites that communicate with the periphery and a single axon on the basal side; GnRH immunoreactivity was seen throughout the neuron. Considerable increase in the number of immunoreactive ORNs was encountered in day 2 post-fertilization larvae. On day 3, the dendrites of ORNs sprout bunches of apical cilia, while on the basal side the axonal outgrowths can be traced to the olfactory bulb. GnRH immunoreactive fibers were distributed in the olfactory nerve layer in the periphery of the bulb and glomeruli-like innervation was clearly established in 5 days old larvae. The innervation to the olfactory bulb showed a considerable increase in GnRH immunoreactivity in 9 and 19 days old larvae. However, GnRH immunoreactivity in non-migratory as well as migratory components gradually diminished and disappeared altogether by the age of 68 days. Results of the present study suggest that GnRH may serve a neurotransmitter role in the ORNs during early stages of development in C. mrigala.
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Affiliation(s)
- K C Biju
- Department of Pharmaceutical Sciences, Nagpur University Campus, Nagpur 440 033, India
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Sakharkar A, Singru P, Subhedar N. Reproduction phase-related variations in the GnRH immunoreactive fibers in the pineal of the Indian major carp Cirrhinus mrigala (Ham.). FISH PHYSIOLOGY AND BIOCHEMISTRY 2005; 31:163-166. [PMID: 20035452 DOI: 10.1007/s10695-006-0039-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We studied GnRH immunoreactivity in the pineal gland of the Indian major carp Cirrhinus mrigala during different phases of reproductive cycle. In the resting phase (December-January), GnRH immunoreactive (-ir) fibers were organized as paired fascicles above the posterior commissure that ascend in the stalk and distribute widely in the pineal gland. The GnRH-ir fiber density significantly declined (P<0.001) during the preparatory phase (February-April) and the fibers disappeared thereafter. While no GnRH fibers were seen during the prespawning (May-June) and spawning (July-August), isolated GnRH-ir fibers reappeared in the postspawning phase. Since no GnRH cell bodies were detected in the pineal, these GnRH-ir fibers seem to be of central origin. The results reveal a distinct reciprocal relationship between the GnRH immunoreactivity in the pineal and the status of the ovarian maturity; the fibers appeared in the pineal only during the period of ovarian quiescence. While the functional significance of these cyclic changes in GnRH is yet to be determined, we suggest that the decapeptide may serve as a transmitter of central origin that modulates the activity of the pineal gland.
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Affiliation(s)
- Amul Sakharkar
- Department of Pharmaceutical Sciences, R.T.M. Nagpur University, Nagpur, 440 033, India
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Von Bartheld CS. The terminal nerve and its relation with extrabulbar "olfactory" projections: lessons from lampreys and lungfishes. Microsc Res Tech 2005; 65:13-24. [PMID: 15570592 DOI: 10.1002/jemt.20095] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The definition of the terminal nerve has led to considerable confusion and controversy. This review analyzes the current state of knowledge as well as diverging opinions about the existence, components, and definition of terminal nerves or their components, with emphasis on lampreys and lungfishes. I will argue that the historical terminology regarding this cranial nerve embraces a definition of a terminal nerve that is compatible with its existence in all vertebrate species. This review further summarizes classical and more recent anatomical, developmental, neurochemical, and molecular evidence suggesting that a multitude of terminalis cell types, not only those expressing gonadotropin-releasing hormone, migrate various distances into the forebrain. This results in numerous morphological and neurochemically distinct phenotypes of neurons, with a continuum spanning from olfactory receptor-like neurons in the olfactory epithelium to typical large ganglion cells that accompany the classical olfactory projections. These cell bodies may lose their peripheral connections with the olfactory epithelium, and their central projections or cell bodies may enter the forebrain at several locations. Since "olfactory" marker proteins can be expressed in bona fide nervus terminalis cells, so-called extrabulbar "olfactory" projections may be a collection of disguised nervus terminalis components. If we do not allow this pleiomorphic collection of nerves to be considered within a terminal nerve framework, then the only alternative is to invent a highly species- and stage-specific, and, ultimately, thoroughly confusing nomenclature for neurons and nerve fibers that associate with the olfactory nerve and forebrain.
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Affiliation(s)
- Christopher S Von Bartheld
- Department of Physiology and Cell Biology, Mailstop 352, University of Nevada School of Medicine, Reno, NV 89557, USA.
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Pinelli C, D'Aniello B, Polese G, Rastogi RK. Extrabulbar olfactory system and nervus terminalis FMRFamide immunoreactive components in Xenopus laevis ontogenesis. J Chem Neuroanat 2004; 28:37-46. [PMID: 15363489 DOI: 10.1016/j.jchemneu.2004.06.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2003] [Revised: 02/12/2004] [Accepted: 06/01/2004] [Indexed: 11/28/2022]
Abstract
The extrabulbar olfactory system (EBOS) is a collection of nerve fibers which originate from primary olfactory receptor-like neurons and penetrate into the brain bypassing the olfactory bulbs. Our description is based upon the application of two neuronal tracers (biocytin, carbocyanine DiI) in the olfactory sac, at the cut end of the olfactory nerve and in the telencephalon of the developing clawed frog. The extrabulbar olfactory system was observed already at stage 45, which is the first developmental stage compatible with our techniques; at this stage, the extrabulbar olfactory system fibers terminated diffusely in the preoptic area. A little later in development, i.e. at stage 50, the extrabulbar olfactory system was maximally developed, extending as far caudally as the rhombencephalon. In the metamorphosing specimens, the extrabulbar olfactory system appeared reduced in extension; caudally, the fiber terminals did not extend beyond the diencephalon. While a substantial overlapping of biocytin/FMRFamide immunoreactivity was observed along the olfactory pathways as well as in the telencephalon, FMRFamide immunoreactivity was never observed to be colocalized in the same cellular or fiber components visualized by tracer molecules. The question whether the extrabulbar olfactory system and the nervus terminalis (NT) are separate anatomical entities or represent an integrated system is discussed.
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Affiliation(s)
- Claudia Pinelli
- Department of Life Sciences, Second University of Naples, I-81100 Caserta, Italy
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