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Banerjee P, Chaube R, Joy KP. Catecholamines modulate differentially nonapeptide precursor mRNA expression in the preoptic area and ovary of the catfish Heteropneustes fossilis: An in vitro study. Gen Comp Endocrinol 2023; 333:114211. [PMID: 36642230 DOI: 10.1016/j.ygcen.2023.114211] [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: 08/19/2021] [Revised: 11/25/2022] [Accepted: 01/11/2023] [Indexed: 01/15/2023]
Abstract
In the catfish Heteropneustes fossilis, three nonapeptide hormone genes were identified in the brain preoptic area (POA) and ovary: a pro-vasotocin (pro-vt) and two isotocin gene paralogs viz., a novel pro-ita and conventional pro-itb. In the present study, the regulatory role of catecholamines [CA: dopamine (DA), noradrenaline (NA), adrenaline (AD)] on the expression of these genes were investigated in vitro. DA (1, 10, and 100 ng/mL) inhibited significantly the mRNA expression in both the POA and ovary. NA upregulated the POA mRNA expression in a biphasic manner, the lower concentrations (1 ng and 10 ng) scaled up and the higher concentration (100 ng) scaled down the expression of pro-vt and pro-itb, while only the 1 ng NA scaled up the pro-ita expression. In the ovary, NA upregulated the mRNA expressions at all concentrations; the pro-vt expression was stimulated only at 10 and 100 ng. AD stimulated pro-vt and pro-ita expression in the POA at all concentrations but the pro-itb expression was inhibited at 1 and 10 ng, and stimulated at 100 ng concentrations. In the ovary, AD elicited varied effects; no significant change in pro-vt, a stimulation of pro-ita, and an inhibition of pro-itb at 1 ng, and stimulation of pro-itb at the 10 and 100 ng. The incubation of the POA and ovary with α-methylparatyrosine (MPT, 250 µg/mL, a tyrosine hydroxylase inhibitor) for 8 h downregulated the mRNA expression in the POA but unaltered the expression in the ovary. Pre-incubation with MPT for 4 h, followed by co-incubation with DA, NA or AD for 4 h elicited varied effects. In the POA, the co-incubations with the CAs rescued the inhibition due to MPT. The MPT + DA and MPT + AD treatments reduced the magnitude of the inhibition of pro-vt and pro-itb by MPT. But the pro-ita expression was modestly stimulated in the MPT + AD group. On the other hand, the MPT + NA treatment rescued the MPT effect and elicited 10-folds increase in the expression levels. In the ovary, the changes were: an inhibition in the MPT + DA group, no significant alteration in the MPT + NA group, and a mild stimulation in the MPT + AD group. The results suggest that CAs modulate brain and ovarian nonapeptide gene expression differentially, which is important in the neuroendocrine/endocrine integration of reproduction in the catfish.
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Affiliation(s)
- Putul Banerjee
- Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Radha Chaube
- Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Keerikkattil Paily Joy
- Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi 221005, India.
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2
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Mennigen JA, Ramachandran D, Shaw K, Chaube R, Joy KP, Trudeau VL. Reproductive roles of the vasopressin/oxytocin neuropeptide family in teleost fishes. Front Endocrinol (Lausanne) 2022; 13:1005863. [PMID: 36313759 PMCID: PMC9606234 DOI: 10.3389/fendo.2022.1005863] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 09/23/2022] [Indexed: 12/02/2022] Open
Abstract
The vertebrate nonapeptide families arginine vasopressin (AVP) and oxytocin (OXT) are considered to have evolved from a single vasopressin-like peptide present in invertebrates and termed arginine vasotocin in early vertebrate evolution. Unprecedented genome sequence availability has more recently allowed new insight into the evolution of nonapeptides and especially their receptor families in the context of whole genome duplications. In bony fish, nonapeptide homologues of AVP termed arginine vasotocin (Avp) and an OXT family peptide (Oxt) originally termed isotocin have been characterized. While reproductive roles of both nonapeptide families have historically been studied in several vertebrates, their roles in teleost reproduction remain much less understood. Taking advantage of novel genome resources and associated technological advances such as genetic modifications in fish models, we here critically review the current state of knowledge regarding the roles of nonapeptide systems in teleost reproduction. We further discuss sources of plasticity of the conserved nonapeptide systems in the context of diverse reproductive phenotypes observed in teleost fishes. Given the dual roles of preoptic area (POA) synthesized Avp and Oxt as neuromodulators and endocrine/paracrine factors, we focus on known roles of both peptides on reproductive behaviour and the regulation of the hypothalamic-pituitary-gonadal axis. Emphasis is placed on the identification of a gonadal nonapeptide system that plays critical roles in both steroidogenesis and gamete maturation. We conclude by highlighting key research gaps including a call for translational studies linking new mechanistic understanding of nonapeptide regulated physiology in the context of aquaculture, conservation biology and ecotoxicology.
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Affiliation(s)
- Jan A. Mennigen
- Department of Biology, Faculty of Science, University of Ottawa, ON, Canada
| | - Divya Ramachandran
- Department of Biology, Faculty of Science, University of Ottawa, ON, Canada
| | - Katherine Shaw
- Department of Biology, Faculty of Science, University of Ottawa, ON, Canada
| | - Radha Chaube
- Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Keerikkattil P. Joy
- Department of Biotechnology, Cochin University of Science and Technology, Kochi, India
| | - Vance L. Trudeau
- Department of Biology, Faculty of Science, University of Ottawa, ON, Canada
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3
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Basu S, Mitra S, Singh O, Chandramohan B, Singru PS. Secretagogin in the brain and pituitary of the catfish, Clarias batrachus: Molecular characterization and regulation by insulin. J Comp Neurol 2022; 530:1743-1772. [PMID: 35322425 DOI: 10.1002/cne.25311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 02/02/2022] [Accepted: 02/04/2022] [Indexed: 11/12/2022]
Abstract
Secretagogin (scgn), is a novel hexa EF-hand, phylogenetically conserved calcium-binding protein. It serves as Ca2+ sensor and participates in Ca2+ -signaling and neuroendocrine regulation in mammals. However, its relevance in the brain of non-mammalian vertebrates has largely remained unexplored. To address this issue, we studied the cDNA encoding scgn, scgn mRNA expression, and distribution of scgn-equipped elements in the brain and pituitary of a teleost, Clarias batrachus (cb). The cbscgn cDNA consists of three transcripts (T) variants: T1 (2185 bp), T2 (2151 bp) and T3 (2060 bp). While 816 bp ORF in T1 and T2 encodes highly conserved six EF-hand 272 aa protein fully capable of Ca2+ -binding, 726-bp ORF in T3 encodes 242 aa protein. The T1 showed >90% and >70% identity with scgn of catfishes, and other teleosts and mammals, respectively. The T1-mRNA was widely expressed in the brain and pituitary, while the expression of T3 was restricted to the telencephalon. Application of the anti-scgn antiserum revealed a ∼32 kDa scgn-immunoreactive (scgn-i) band (known molecular weight of scgn) in the forebrain tissue, and immunohistochemically labeled neurons in the olfactory epithelium and bulb, telencephalon, preoptic area, hypothalamus, thalamus, and hindbrain. In the pituitary, scgn-i cells were seen in the pars distalis and intermedia. Insulin is reported to regulate scgn mRNA in the mammalian hippocampus, and feeding-related neuropeptides in the telencephalon of teleost. Intracranial injection of insulin significantly increased T1-mRNA expression and scgn-immunoreactivity in the telencephalon. We suggest that scgn may be an important player in the regulation of olfactory, neuroendocrine system, and energy balance functions in C. batrachus.
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Affiliation(s)
- Sumela Basu
- School of Biological Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, India.,Homi Bhabha National Institute (HBNI), Mumbai, India
| | - Saptarsi Mitra
- School of Biological Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, India.,Homi Bhabha National Institute (HBNI), Mumbai, India
| | - Omprakash Singh
- School of Biological Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, India.,Homi Bhabha National Institute (HBNI), Mumbai, India
| | - Bathrachalam Chandramohan
- School of Biological Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, India
| | - Praful S Singru
- School of Biological Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, India.,Homi Bhabha National Institute (HBNI), Mumbai, India
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4
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Yang W, Zhang N, Wu Y, Zhang L, Zhang L, Zhang W. Oxytocin-like signal regulates Lh cells directly but not Fsh cells in the ricefield eel Monopterus albus†. Biol Reprod 2020; 104:399-409. [PMID: 33141148 DOI: 10.1093/biolre/ioaa202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 10/23/2020] [Accepted: 10/29/2020] [Indexed: 11/12/2022] Open
Abstract
The synthesis and release of LH and FSH in the pituitary of vertebrates are differentially regulated during gonadal development and maturation. However, the underlying neuroendocrine mechanisms remain to be fully elucidated. The present study examined the possible involvement of isotocin (Ist), an oxytocin-like neuropeptide, in the regulation of Lh and Fsh in a teleost, the ricefield eel Monopterus albus. The immunoreactive isotocin receptor 2 (Istr2) was shown to be localized to Lh but not Fsh cells. In contrast, immunoreactive isotocin receptor 1 (Istr1) was not observed in either Lh or Fsh cells in the pituitary. Interestingly, Lh cells in female ricefield eels expressed Istr2 and secreted Lh in response to Ist challenge stage-dependently and in correlation with ovarian vitellogenesis. Moreover, Ist decreased Lh contents in the pituitary of female fish, indicating its stimulatory roles on Lh release in vivo. The induction of Lh release by Ist in dispersed pituitary cells was blocked by a PLC or IP3R inhibitor but not by a PKA or PKC inhibitor, indicating the involvement of the IP3/Ca2+ pathway. Collectively, the above results indicate that isotocin may bind to Istr2 to stimulate Lh release via the IP3/Ca2+ pathway, and play important roles in the ovarian maturation in ricefield eels. Furthermore, the present study suggests a novel neuroendocrine mechanism underlying the differential regulation of Lh and Fsh in vertebrates.
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Affiliation(s)
- Wei Yang
- Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou, P.R. China
| | - Ning Zhang
- Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou, P.R. China
| | - Yangsheng Wu
- Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou, P.R. China
| | - Lanxin Zhang
- Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou, P.R. China
| | - Lihong Zhang
- Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou, P.R. China.,Biology Department, School of Life Sciences, Sun Yat-Sen University, Guangzhou, P.R. China
| | - Weimin Zhang
- Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou, P.R. China.,Biology Department, School of Life Sciences, Sun Yat-Sen University, Guangzhou, P.R. China
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5
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Rawat A, Chaube R, Joy KP. In situ localization of vasotocin receptor gene transcripts in the brain-pituitary-gonadal axis of the catfish Heteropneustes fossilis: a morpho-functional study. FISH PHYSIOLOGY AND BIOCHEMISTRY 2019; 45:885-905. [PMID: 30506436 DOI: 10.1007/s10695-018-0590-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Accepted: 11/19/2018] [Indexed: 06/09/2023]
Abstract
In the catfish Heteropneustes fossilis, three vasotocin (VT) receptor subtype genes, v1a1, v1a2, and v2a, were cloned and characterized previously. In the present study, using RNA probes, we localized the distribution of the gene transcripts in the brain-pituitary-gonadal (BPG) axis. The V1a-type receptor, v1a1 and v1a2, genes showed similar and overlapping distribution in the brain. The gene paralogs are distributed in the radial glial cells (RGCs) of the telencephalic ventricle and around the third ventricle in the hypothalamus and thalamus, olfactory tract, nucleus preopticus, nucleus lateralis tuberis, nucleus recessus lateralis and posterioris, nucleus saccus vasculosi, thalamic nuclei, habenular nucleus, habenular commissure, basal part of pineal stalk, accessory pretectal nucleus, optic tectum, corpus and valvula of the cerebellum, and facial and vagal lobes. The V2a receptor gene (v2a) has restricted distribution and is largely confined to the anterior subependymal region of the telencephalon. The localization pattern shows that the V1a-type receptors are distributed in major sensorimotor processing centers and the neuroendocrine/reproductive centers of the brain. In the pituitary, the receptor genes were localized differentially in the three divisions with the V1a-type receptor genes strongly expressed in the rostral pars distalis compared to the v2a paralog. In the ovary, the V1a-type receptor genes were localized in the follicular layer while v2a was localized in the oocyte membrane. In the testis, v1a2 and v2a are densely distributed in the interstitial tissue and seminiferous epithelium but the v1a1 is lowly expressed. The results suggest that the VT receptor genes have an extensive but differential distribution in the BPG axis. Future experimental studies are required to correlate the cellular localizations with specific functions of VT in the BPG axis.
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Affiliation(s)
- Arpana Rawat
- Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Radha Chaube
- Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
| | - Keerrikkattil P Joy
- Department of Biotechnology, Cochin University of Science and Technology, Kochi, 682022, India.
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Singh O, Pradhan DR, Nagalakashmi B, Kumar S, Mitra S, Sagarkar S, Sakharkar AJ, Lechan RM, Singru PS. Thyrotropin-releasing hormone (TRH) in the brain and pituitary of the teleost, Clarias batrachus and its role in regulation of hypophysiotropic dopamine neurons. J Comp Neurol 2018; 527:1070-1101. [PMID: 30370602 DOI: 10.1002/cne.24570] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 10/18/2018] [Accepted: 10/23/2018] [Indexed: 11/11/2022]
Abstract
Thyrotropin-releasing hormone (TRH) regulates the hypothalamic-pituitary-thyroid axis in mammals and also regulates prolactin secretion, directly or indirectly via tuberoinfundibular dopamine neurons. Although TRH is abundantly expressed in teleost brain and believed to mediate neuronal communication, empirical evidence is lacking. We analyzed pro-TRH-mRNA expression, mapped TRH-immunoreactive elements in the brain and pituitary, and explored its role in regulation of hypophysiotropic dopamine (DA) neurons in the catfish, Clarias batrachus. Partial pro-TRH transcript from C. batrachus transcriptome showed six TRH progenitors repeats. Quantitative real-time polymerase chain reaction (qRT-PCR) identified pro-TRH transcript in a number of different brain regions and immunofluorescence showed TRH-immunoreactive cells/fibers in the olfactory bulb, telencephalon, preoptic area (POA), hypothalamus, midbrain, hindbrain, and spinal cord. In the pituitary, TRH-immunoreactive fibers were seen in the neurohypophysis, proximal pars distalis, and pars intermedia but not rostral pars distalis. In POA, distinct TRH-immunoreactive cells/fibers were seen in nucleus preopticus periventricularis anterior (NPPa) that demonstrated a significant increase in TRH-immunoreactivity when collected during preparatory and prespawning phases, reaching a peak in the spawning phase. Although tyrosine hydroxylase (TH)-immunoreactive neurons in NPPa are hypophysiotropic, none of the TRH-immunoreactive neurons in NPPa accumulated neuronal tracer DiI following implants into the pituitary. However, 87 ± 1.6% NPPa TH-immunoreactive neurons were surrounded by TRH-immunoreactive axons that were seen in close proximity to the somata. Superfused POA slices treated with TRH (0.5-2 μM) significantly reduced TH concentration in tissue homogenates and the percent TH-immunoreactive area in the NPPa. We suggest that TRH in the brain of C. batrachus regulates a range of physiological functions but in particular, serves as a potential regulator of hypophysiotropic DA neurons and reproduction.
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Affiliation(s)
- Omprakash Singh
- School of Biological Sciences, National Institute of Science Education and Research (NISER)-Bhubaneswar, Jatni, India.,Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, India
| | - Dipti R Pradhan
- School of Biological Sciences, National Institute of Science Education and Research (NISER)-Bhubaneswar, Jatni, India.,Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, India
| | - B Nagalakashmi
- Department of Biotechnology, Savitribai Phule Pune University, Pune, India
| | - Santosh Kumar
- School of Biological Sciences, National Institute of Science Education and Research (NISER)-Bhubaneswar, Jatni, India.,Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, India
| | - Saptarsi Mitra
- School of Biological Sciences, National Institute of Science Education and Research (NISER)-Bhubaneswar, Jatni, India.,Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, India
| | - Sneha Sagarkar
- Department of Biotechnology, Savitribai Phule Pune University, Pune, India
| | - Amul J Sakharkar
- Department of Biotechnology, Savitribai Phule Pune University, Pune, India
| | - Ronald M Lechan
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Tupper Research Institute, Tufts Medical Center, Boston, Massachusetts.,Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts
| | - Praful S Singru
- School of Biological Sciences, National Institute of Science Education and Research (NISER)-Bhubaneswar, Jatni, India.,Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, India
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Banerjee P, Chaube R, Joy KP. Molecular cloning and characterisation of an isotocin paralogue ([V8] isotocin) in catfishes (superorder Ostariophysi): Origin traced likely to the fish-specific whole genome duplication. J Neuroendocrinol 2018; 30:e12647. [PMID: 30244515 DOI: 10.1111/jne.12647] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 09/18/2018] [Accepted: 09/19/2018] [Indexed: 11/27/2022]
Abstract
The present study reports the molecular cloning of a previously uncharacterised neurohypophyseal nonapeptide precursor cDNA in two catfish species: Heteropneustes fossilis and Clarias batrachus. The deduced nonapeptide is CYISNCPVG ([V8] isotocin), which has not been reported in any vertebrate till date. Phylogenetic and conserved synteny analyses showed the gene to have originated from the isotocin precursor (pro-it) gene by fish-specific whole genome duplication (3R). The two isotocin lineages have been designated as pro-ita (new gene) and pro-itb (conventional it gene). All teleost groups may not possess both pro-ita and pro-itb and the pattern of losses/retention was found to be lineage-specific. Quantitative reverse transcriptase-polymerase chain reaction studies showed the expression of the pro-ita gene in the brain and ovary of H. fossilis. In situ hybridisation studies localised the pro-ita transcripts in the nucleus preopticus of the hypothalamus and the follicular layer (theca-granulosa) of oocytes, comprising tissues in which pro-itb and vasotocin precursor (pro-vt) mRNA expression was previously reported. The transcript levels varied with the reproductive stage and a high abundance was found in both brain and ovary during the breeding phase. The substitution of valine in place of isoleucine at the eighth position in Ita may have modified the ligand-receptor interaction, leading to sub-functionalisation and the retention of the gene in catfishes.
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Affiliation(s)
- Putul Banerjee
- Department of Zoology, Centre of Advanced Study, Banaras Hindu University, Varanasi, India
| | - Radha Chaube
- Department of Zoology, Centre of Advanced Study, Banaras Hindu University, Varanasi, India
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8
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Acharjee A, Chaube R, Joy KP. Reproductive stage- and sex-dependant effects of neurohypophyseal nonapeptides on gonadotropin subunit mRNA expression in the catfish Heteropneustes fossilis: An in vitro study. Gen Comp Endocrinol 2018; 260:80-89. [PMID: 29305879 DOI: 10.1016/j.ygcen.2018.01.001] [Citation(s) in RCA: 6] [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: 08/05/2017] [Revised: 12/11/2017] [Accepted: 01/01/2018] [Indexed: 12/19/2022]
Abstract
In the present study, in vitro effects of synthetic vasotocin (VT), isotocin (4Ser, 8Ile- oxytocin; ITb) and the recently cloned IT gene paralog product (8Val-Isotocin, ITa) were studied on the expression of pituitary gonadotropin (GtH) subunit mRNA levels. In male pituitaries of early (preparatory phase) and late (prespawning phase) recrudescing catfish, Heteropneustes fossilis, VT (10 nM, 100 nM and 1000 nM) stimulated fshβ expression dose-dependently. But in females, the dose-dependent effect was found only in the preparatory phase. In males, VT stimulated lhβ expression only at higher doses. In females, VT produced a significant dose-dependent increase of the lhβ expression only in the prespawning phase. VT stimulated the expression of gpα, dose-dependently in the preparatory phase in males and in the prespawning phase in females. The incubation of the pituitaries with ITb did not alter the fshβ expression in either sex in both preparatory and prespawning phases. In males, ITb stimulated the expression of lhβ and gpα only at the highest concentration (1000 nM) in both phases. In females, ITb stimulated both lhβ and gpα expression only at 1000 nM in the preparatory phase and dose-dependently in the prespawning phase. The incubation of the pituitaries with ITa produced effects similar to ITb on the expression of fshβ, lhβ, and gpα. The results show that the basic peptide VT modulates both fshβ and lhβ expressions, which are influenced by the sex and reproductive stage. The neutral peptide ITA/ITb exerts an insignificant effect on the fshβ expression regardless of sex or season. Both VT and ITa/ITb elicit a significant effect on the lhβ expression in late recrudescent phase especially in females.
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MESH Headings
- Animals
- Catfishes/genetics
- Catfishes/growth & development
- Catfishes/metabolism
- Female
- Follicle Stimulating Hormone, beta Subunit/genetics
- Follicle Stimulating Hormone, beta Subunit/metabolism
- Gene Expression Regulation, Developmental/drug effects
- Gonadotropins, Pituitary/genetics
- Gonadotropins, Pituitary/metabolism
- In Vitro Techniques
- Luteinizing Hormone, beta Subunit/genetics
- Luteinizing Hormone, beta Subunit/metabolism
- Male
- Oxytocin/analogs & derivatives
- Oxytocin/pharmacology
- Pituitary Gland/drug effects
- Pituitary Gland/metabolism
- Pituitary Hormones, Posterior/pharmacology
- RNA, Messenger/drug effects
- RNA, Messenger/metabolism
- Reproduction/drug effects
- Reproduction/genetics
- Seasons
- Sex Characteristics
- Sexual Maturation/drug effects
- Sexual Maturation/genetics
- Vasotocin/pharmacology
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Affiliation(s)
- A Acharjee
- Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi 221005, India.
| | - R Chaube
- Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi 221005, India.
| | - K P Joy
- Department of Biotechnology, Cochin University of Science and Technology, Kochi 682022, India.
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9
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Yang W, Zhang N, Shi B, Zhang S, Zhang L, Zhang W. Isotocin Regulates Growth Hormone but Not Prolactin Release From the Pituitary of Ricefield Eels. Front Endocrinol (Lausanne) 2018; 9:166. [PMID: 29706934 PMCID: PMC5906535 DOI: 10.3389/fendo.2018.00166] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Accepted: 03/28/2018] [Indexed: 12/21/2022] Open
Abstract
The neurohypophyseal hormone oxytocin (Oxt) has been shown to stimulate prolactin (Prl) synthesis and release from the adenohypophysis in rats. However, little is known about the functional roles of Oxt-like neuropeptides in the adenohypophysis of non-mammalian vertebrates. In this study, cDNAs encoding ricefield eel oxytocin-like receptors (Oxtlr), namely isotocin (Ist) receptor 1 (Istr1) and 2 (Istr2), were isolated and specific antisera were generated, respectively. RT-PCR and Western blot analysis detected the presence of both Istr1 and Istr2 in the brain and pituitary, but differential expression in some peripheral tissues, including the liver and kidney, where only Istr1 was detected. In the pituitary, immunoreactive Istr1 and Istr2 were differentially distributed, with the former mainly in adenohypophyseal cell layers adjacent to the neurohypophysis, whereas the latter in peripheral areas of the adenohypophysis. Double immunofluorescent images showed that immunostaining of Istr1, but not Istr2 was localized to growth hormone (Gh) cells, but neither of them was expressed in Prl cells. Ist inhibited Gh release in primary pituitary cells of ricefield eels and increased Gh contents in the pituitary gland of ricefield eels at 6 h after in vivo administration. Ist inhibition of Gh release is probably mediated by cAMP, PKC/DAG, and IP3/Ca2+ pathways. In contrast, Ist did not affect either prl gene expression or Prl contents in primary pituitary cells. Results of this study demonstrated that Ist may not be involved in the regulation of Prl, but inhibit Gh release via Istr1 rather than Istr2 in ricefield eels, and provided evidence for the direct regulation of Gh cells by oxytocin-like neuropeptides in the pituitary of non-mammalian vertebrates.
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Affiliation(s)
- Wei Yang
- School of Life Sciences, Institute of Aquatic Economic Animals, Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou, China
| | - Ning Zhang
- School of Life Sciences, Institute of Aquatic Economic Animals, Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou, China
| | - Boyang Shi
- School of Life Sciences, Institute of Aquatic Economic Animals, Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou, China
| | - Shen Zhang
- School of Life Sciences, Institute of Aquatic Economic Animals, Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou, China
| | - Lihong Zhang
- School of Life Sciences, Institute of Aquatic Economic Animals, Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou, China
- Biology Department, School of Life Sciences, Sun Yat-Sen University, Guangzhou, China
- *Correspondence: Lihong Zhang, ; Weimin Zhang,
| | - Weimin Zhang
- School of Life Sciences, Institute of Aquatic Economic Animals, Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou, China
- Biology Department, School of Life Sciences, Sun Yat-Sen University, Guangzhou, China
- *Correspondence: Lihong Zhang, ; Weimin Zhang,
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10
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Distribution of tyrosine hydroxylase-immunoreactive neurons in the brain of the viviparous fish Gambusia affinis. J Chem Neuroanat 2017; 85:1-12. [DOI: 10.1016/j.jchemneu.2017.05.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 05/14/2017] [Accepted: 05/19/2017] [Indexed: 11/18/2022]
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Kumar S, Singh U, Singh O, Goswami C, Singru PS. Transient receptor potential vanilloid 6 (TRPV6) in the mouse brain: Distribution and estrous cycle-related changes in the hypothalamus. Neuroscience 2016; 344:204-216. [PMID: 28039038 DOI: 10.1016/j.neuroscience.2016.12.025] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 11/28/2016] [Accepted: 12/16/2016] [Indexed: 12/28/2022]
Abstract
Transient receptor potential vanilloid (TRPV) subfamily of cationic channels have emerged as novel players in neural regulation. Unlike other members of TRPV subfamily, TRPV5 and TRPV6 are highly Ca2+-selective. Although TRPV5/TRPV6 transcripts are expressed in mouse brain, understanding the full functional spectrum of these ion channels in the brain is however limited due to the lack of information on their neuroanatomical distribution. We have studied TRPV6 in mouse brain in further detail. In the hypothalamus, while Western blot analysis using TRPV6 specific antiserum showed a distinct ∼95 kDa band corresponding to the molecular weight of TRPV6, transcripts for TRPV6 were detected with RT-PCR. TRPV6-immunoreactive cells/fibers were observed in vascular organ of the lamina terminalis, olfactory bulb, amygdala, hippocampus, septohypothalamic, supraoptic, arcuate (ARC), dorsomedial, and subincertal nuclei. TRPV6-immunoreactive cells/fibers were also observed in the brainstem and cerebellum. Estrogen has emerged as a potential regulator of TRPV6 in peripheral tissues. TRPV6 gene promoter contains estrogen-response element, estrogen activates TRPV6 via estrogen receptor alpha (ERα), and ERα-expressing ARC neurons in mediobasal hypothalamus (MBH) serve as primary site for estradiol feedback. Using double immunofluorescence, co-expression of TRPV6 and ERα was observed in several ARC neurons. MBH of mice during different phases of estrous cycle were subjected to Western blot analysis of TRPV6. Compared to proestrus, a significant reduction (P<0.01) in intensity of TRPV6-immunoreactive band was observed in MBH during metestrus and diestrus phases. While the wide distribution of TRPV6-expressing elements in the brain suggests its role in a range of CNS functions, the ion channel may serve as novel component of the neural pathway mediating effects of estradiol in MBH.
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Affiliation(s)
- Santosh Kumar
- School of Biological Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, Odisha 752050, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Uday Singh
- School of Biological Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, Odisha 752050, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Omprakash Singh
- School of Biological Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, Odisha 752050, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Chandan Goswami
- School of Biological Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, Odisha 752050, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Praful S Singru
- School of Biological Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, Odisha 752050, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India.
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Singh O, Kumar S, Singh U, Bhute Y, Singru PS. Role of Isotocin in the Regulation of the Hypophysiotropic Dopamine Neurones in the Preoptic Area of the Catfish, Clarias batrachus. J Neuroendocrinol 2016; 28. [PMID: 27805784 DOI: 10.1111/jne.12441] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 10/28/2016] [Accepted: 10/28/2016] [Indexed: 11/28/2022]
Abstract
Dopamine (DA) has emerged as a potent inhibitory neuromodulator of luteinsing hormone (LH) secretion and reproduction in teleosts. The DA neurones located in the anterior subdivision of nucleus preopticus periventricularis (NPPa) in the preoptic area (POA) innervate the pituitary gland and regulate LH cells. Although a reduction in the inhibitory DAergic tone is crucial for stimulatory action of gonadotrophin-releasing hormone (GnRH) on LH cells, the role of other hypothalamic factors is suggested but not fully understood. Nonapeptide, isotocin (IST) has emerged as a likely candidate that may also influence the LH cell function. IST neurones reside in the nucleus preopticus and innervate LH cells. While IST treatment dramatically elevated LH secretion, the IST levels in brain peaked during spawning. In a pilot study on the catfish, Clarias batrachus, we observed a dense network of IST-immunoreactive (IST-IR) fibres in the NPPa, the region known to harbour hypophysiotropic DA neurones. Application of the double immunofluorescence method showed a dense IST-IR fibre network around the tyrosine hydroxylase-immunoreactive (TH-IR) neurones in the NPPa region. A great majority of the TH-IR neurones in the NPPa were contacted by IST-IR fibres during the spawning phase. The NPPa therefore appears to be a site for the intense interaction of DA and IST. IST-IR fibre innervation in NPPa showed reproduction phase-dependent changes. The percent fluorescent area of IST-IR fibres showed a gradual increase from the resting through prespawning phases (resting: 7.5 ± 1.04; preparatory: 8.6 ± 0.8; prespawning: 15.5 ± 1.4), reaching a peak in the spawning phase (28 ± 2.3; P < 0.001). Compared to the spawning phase, a drastic reduction in IST-IR fibres in the NPPa was observed during the postspawning phase (8.4 ± 0.9; P < 0.001). Superfused slices of the POA of C. batrachus treated with IST peptide resulted in a significant reduction in TH immunoreactivity in the NPPa (Control: 45.3 ± 4.2; IST peptide, 5 μm: 29.4 ± 4.7; P < 0.05). We suggest that the intense interaction between IST and DA in the NPPa, most probably of an inhibitory nature, may be critical for the regulation of LH cells and reproduction in teleosts.
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Affiliation(s)
- O Singh
- School of Biological Sciences, National Institute of Science Education and Research (NISER)-Bhubaneswar, Jatni, Odisha, India
- Training School Complex, Homi Bhabha National Institute, Mumbai, India
| | - S Kumar
- School of Biological Sciences, National Institute of Science Education and Research (NISER)-Bhubaneswar, Jatni, Odisha, India
- Training School Complex, Homi Bhabha National Institute, Mumbai, India
| | - U Singh
- School of Biological Sciences, National Institute of Science Education and Research (NISER)-Bhubaneswar, Jatni, Odisha, India
- Training School Complex, Homi Bhabha National Institute, Mumbai, India
| | - Y Bhute
- Department of Zoology, DRB Sindhu Mahavidyalaya, Nagpur, India
| | - P S Singru
- School of Biological Sciences, National Institute of Science Education and Research (NISER)-Bhubaneswar, Jatni, Odisha, India
- Training School Complex, Homi Bhabha National Institute, Mumbai, India
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Singh O, Kumar S, Singh U, Kumar V, Lechan RM, Singru PS. Cocaine- and amphetamine-regulated transcript peptide (CART) in the brain of zebra finch,Taeniopygia guttata: Organization, interaction with neuropeptide Y, and response to changes in energy status. J Comp Neurol 2016; 524:3014-41. [DOI: 10.1002/cne.24004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 03/21/2016] [Accepted: 03/24/2016] [Indexed: 01/21/2023]
Affiliation(s)
- Omprakash Singh
- School of Biological Sciences; National Institute of Science Education and Research (NISER)-Bhubaneswar; Odisha India
| | - Santosh Kumar
- School of Biological Sciences; National Institute of Science Education and Research (NISER)-Bhubaneswar; Odisha India
| | - Uday Singh
- School of Biological Sciences; National Institute of Science Education and Research (NISER)-Bhubaneswar; Odisha India
| | - Vinod Kumar
- DST-IRHPA Centre for Excellence in Biological Rhythms Research and Indo-US Centre for Biological Timing, Department of Zoology; University of Delhi; Delhi India
| | - Ronald M. Lechan
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Tupper Research Institute; Tufts Medical Center; Boston Massachusetts USA
- Department of Neuroscience; Tufts University School of Medicine; Boston Massachusetts USA
| | - Praful S. Singru
- School of Biological Sciences; National Institute of Science Education and Research (NISER)-Bhubaneswar; Odisha India
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Singh U, Kumar S, Shelkar GP, Yadav M, Kokare DM, Goswami C, Lechan RM, Singru PS. Transient receptor potential vanilloid 3 (TRPV3) in the ventral tegmental area of rat: Role in modulation of the mesolimbic-dopamine reward pathway. Neuropharmacology 2016; 110:198-210. [PMID: 27084697 DOI: 10.1016/j.neuropharm.2016.04.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 04/04/2016] [Accepted: 04/10/2016] [Indexed: 12/29/2022]
Abstract
While dopamine (DA) neurons in the ventral tegmental area (VTA) drive the mesolimbic-reward pathway, confluent lines of evidence underscore the importance of transient receptor potential vanilloid (TRPV) channels as novel regulators of these neurons. Among the TRPV-subfamily, TRPV3 is of particular interest in reward, since active ingredients of flavour-enhancing spices in food serve as TRPV3 agonists and modulate DAergic neurotransmission. The nature of TRPV3 elements in the VTA and their role in driving the mesolimbic-DA-reward pathway has however, remained unexplored. We observed TRPV3 mRNA as well as TRPV3-immunoreactive neurons in the VTA of Wistar rats. We therefore explored whether these ion channels participate in modulating mesolimbic-DA reward pathway. In the posterior VTA (pVTA), 82 ± 2.6% of the TRPV3 neurons co-express tyrosine hydroxylase and 68 ± 5.5% of these neurons project to the nucleus accumbens shell (Acb shell). While ex vivo treatment of midbrain slices with TRPV3-agonist, thymol increased [Ca(2+)]i-activity in pVTA neurons, intra-pVTA injections of thymol in freely-moving, satiated rats enhanced positive reinforcement for active lever pressings in an operant chamber to self-administer sweet pellets. This behavior was attenuated by prior treatment with intra-Acb shell DA D1- and D2-like receptor antagonists. These results demonstrate a role for TRPV3 in driving mesolimbic-DA food-reward pathway, and underscores the importance of these channels in the VTA as key components processing reward.
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Affiliation(s)
- Uday Singh
- School of Biological Sciences, National Institute of Science Education and Research (NISER)-Bhubaneswar, 752050, Odisha, India
| | - Santosh Kumar
- School of Biological Sciences, National Institute of Science Education and Research (NISER)-Bhubaneswar, 752050, Odisha, India
| | - Gajanan P Shelkar
- Department of Pharmaceutical Sciences, R.T.M. Nagpur University, Nagpur, 440033, Maharashtra, India
| | - Manoj Yadav
- School of Biological Sciences, National Institute of Science Education and Research (NISER)-Bhubaneswar, 752050, Odisha, India
| | - Dadasaheb M Kokare
- Department of Pharmaceutical Sciences, R.T.M. Nagpur University, Nagpur, 440033, Maharashtra, India
| | - Chandan Goswami
- School of Biological Sciences, National Institute of Science Education and Research (NISER)-Bhubaneswar, 752050, Odisha, India
| | - Ronald M Lechan
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Tupper Research Institute, Tufts Medical Center, Boston, MA, USA; Department of Neuroscience, Tufts University School of Medicine, Boston, MA, USA
| | - Praful S Singru
- School of Biological Sciences, National Institute of Science Education and Research (NISER)-Bhubaneswar, 752050, Odisha, India.
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Saha S, Patil S, Singh U, Singh O, Singru PS. Sexual dimorphism in the hypophysiotropic tyrosine hydroxylase-positive neurons in the preoptic area of the teleost, Clarias batrachus. Biol Sex Differ 2015; 6:23. [PMID: 26557978 PMCID: PMC4640419 DOI: 10.1186/s13293-015-0042-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 10/30/2015] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Dopamine (DA) neurons in the anteroventral periventricular nucleus (AVPV) in the preoptic area (POA) of mammals express estrogen receptors, regulate luteinizing hormone (LH) secretion, and show distinct sexual dimorphism. In teleosts, hypophysiotropic DA neurons of the nucleus preopticus periventricularis (NPP), located in the anteroventral POA, express estrogen receptors, innervate LH cells, and emerged as a neuroanatomical substrate for inhibiting LH cells. Interestingly, the NPP and AVPV seem to share several similarities. Whether DAergic neurons in the NPP show sexual dimorphism is, however, not known. Based on the proposed homology to AVPV and previous studies showing greater tyrosine hydroxylase (TH) mRNA and enzyme activity levels in the brain of female catfish, we hypothesize that females have greater number of DAergic neurons in the NPP and correspondingly more TH-immunoreactive fiber innervation of the pituitary. METHODS Adult, male and female Clarias batrachus collected during the prespawning phase of their reproductive cycle were used. Fish were anesthetized and perfused transcardially with phosphate-buffered saline (pH 7.4) and 4 % paraformaldehyde in phosphate buffer. Sections through the rostro-caudal extent of the POA and pituitary were processed for TH immunofluorescence. Using double immunofluorescence, the association between TH-immunoreactive fibers and LH cells in the pituitary was explored. Sections were analyzed using semiquantitative analysis. RESULTS NPP in POA of C. batrachus has two distinct subdivisions, viz, anterior (NPPa) and posterior (NPPp), and TH neurons were observed in both the subdivisions. Compared to that in the males, a significantly higher (P < 0.05) number of TH neurons was consistently observed in the NPPa of females. TH neurons in NPPp, however, showed no difference in the number or immunoreactivity. Since DA neurons in NPPa are hypophysiotropic, we compared TH-fiber innervation of the pituitary in both sexes. Compared to males, proximal pars distalis and LH cells in this region of the pituitary in females were densely innervated by TH fibers. CONCLUSIONS Neurons of NPPa and their innervation to the pituitary seem to be a distinct sexually dimorphic DAergic system in C. batrachus. The DAergic system may serve as a component of the neural mechanisms controlling the sexually dimorphic LH surge in teleosts. Given the similarities shared by NPPa and AVPV, homology between these two nuclei is suggested.
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Affiliation(s)
- Soham Saha
- School of Biological Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, 751 005 Odisha India ; Present address: Institut Pasteur, Affiliated to: Ecole des neurosciences Paris (ENP) Graduate program, 28, rue du docteur Roux, 75724 Paris, Cedex 15 France
| | - Saurabh Patil
- School of Biological Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, 751 005 Odisha India
| | - Uday Singh
- School of Biological Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, 751 005 Odisha India
| | - Omprakash Singh
- School of Biological Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, 751 005 Odisha India
| | - Praful S Singru
- School of Biological Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, 751 005 Odisha India
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Golan M, Zelinger E, Zohar Y, Levavi-Sivan B. Architecture of GnRH-Gonadotrope-Vasculature Reveals a Dual Mode of Gonadotropin Regulation in Fish. Endocrinology 2015; 156:4163-73. [PMID: 26261873 DOI: 10.1210/en.2015-1150] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The function and components of the hypothalamic-pituitary axis are conserved among vertebrates; however, in fish, a neuroglandular mode of delivery (direct contact between axons and endocrine cells) was considered dominant, whereas in tetrapods hypothalamic signals are relayed to their targets via the hypophysial portal blood system (neurovascular delivery mode). By using a transgenic zebrafish model we studied the functional and anatomical aspects of gonadotrope regulation thus revisiting the existing model. FSH cells were found to be situated close to the vasculature whereas the compact organization of LH cells prevented direct contact of all cells with the circulation. GnRH3 fibers formed multiple boutons upon reaching the pituitary, but most of these structures were located in the neurohypophysis rather than adjacent to gonadotropes. A close association was observed between FSH cells and GnRH3 boutons, but only a fifth of the LH cells were in direct contact with GnRH3 axons, suggesting that FSH cells are more directly regulated than LH cells. GnRH3 fibers closely followed the vasculature in the neurohypophysis and formed numerous boutons along these tracts. These vessels were found to be permeable to relatively large molecules, suggesting the uptake of GnRH3 peptides. Our findings have important implications regarding the differential regulation of LH and FSH and contradict the accepted notion that fish pituitary cells are mostly regulated directly by hypothalamic fibers. Instead, we provide evidence that zebrafish apply a dual mode of gonadotrope regulation by GnRH3 that combines both neuroglandular and neurovascular components.
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Affiliation(s)
- Matan Golan
- Department of Animal Sciences (M.G., B.L.-S.) and The Interdepartmental Equipment Unit (E.Z.), The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel; and Department of Marine Biotechnology (Y.Z.), University of Maryland Baltimore County and Institute of Marine and Environmental Technology, Baltimore, Maryland 21202
| | - Einat Zelinger
- Department of Animal Sciences (M.G., B.L.-S.) and The Interdepartmental Equipment Unit (E.Z.), The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel; and Department of Marine Biotechnology (Y.Z.), University of Maryland Baltimore County and Institute of Marine and Environmental Technology, Baltimore, Maryland 21202
| | - Yonathan Zohar
- Department of Animal Sciences (M.G., B.L.-S.) and The Interdepartmental Equipment Unit (E.Z.), The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel; and Department of Marine Biotechnology (Y.Z.), University of Maryland Baltimore County and Institute of Marine and Environmental Technology, Baltimore, Maryland 21202
| | - Berta Levavi-Sivan
- Department of Animal Sciences (M.G., B.L.-S.) and The Interdepartmental Equipment Unit (E.Z.), The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel; and Department of Marine Biotechnology (Y.Z.), University of Maryland Baltimore County and Institute of Marine and Environmental Technology, Baltimore, Maryland 21202
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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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Chabbi A, Ganesh CB. Evidence for the involvement of dopamine in stress-induced suppression of reproduction in the cichlid fish Oreochromis mossambicus. J Neuroendocrinol 2015; 27:343-56. [PMID: 25712855 DOI: 10.1111/jne.12269] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 02/02/2015] [Accepted: 02/19/2015] [Indexed: 01/23/2023]
Abstract
In the present study, we examined whether stress-induced suppression of reproduction is mediated through the catecholaminergic neurotransmitter dopamine (DA) in the female cichlid fish Oreochromis mossambicus. In the first experiment, application of antibody against tyrosine hydroxylase (TH; a marker for DA) in brain sections revealed the presence of intensely stained TH immunoreactive cells in the preoptic area (POA) and nucleus preopticus (NPO) during the previtellogenic phase. These cells showed weak immunoreactivity during the vitellogenic and prespawning phases concomitant with darkly stained luteinising hormone (LH) immunoreactive content in the proximal pars distalis (PPD) of the pituitary gland and fully ripened follicles (stage V) in the ovary of control fish. However, in fish exposed to aquacultural stressors, TH secreting cells remained intensely stained in POA and NPO regions during the prespawning phase, indicating increased synthetic and secretory activity, which was reflected by a significantly higher DA content compared to controls. Increased DA activity as a result of stress was associated with a decrease in the LH immunoreactive content in the PPD and an absence of stage V follicles in the ovary. In the second experiment, administration of DA caused effects similar to those in stressed fish, whereas DA receptor antagonist domperidone (DOM) treatment significantly increased the LH content in the PPD and the number of stage V follicles in unstressed fish. On the other hand, treatment of stressed fish with DOM resulted in dark accumulations of LH immunoreactive content in the PPD accompanied by the presence of stage V follicles in the ovary. Taken together, these results suggest an additional pathway for the inhibitory effects of stress through dopaminergic neurones along the reproductive axis.
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Affiliation(s)
- A Chabbi
- Neuroendocrinology Research Lab, Department of Studies in Zoology, Karnatak University, Dharwad, Karnataka, India
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Chabbi A, Ganesh CB. Glucocorticoid synthesis inhibitor metyrapone blocks stress-induced suppression along luteinizing hormone secreting cells–ovary axis in the fish Oreochromis mossambicus. ACTA ACUST UNITED AC 2014; 321:125-34. [PMID: 24639434 DOI: 10.1002/jez.1842] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 09/24/2013] [Accepted: 10/15/2013] [Indexed: 12/14/2022]
Abstract
We showed previously that exposure to mild acute stressors leads to inhibition of follicular development and luteinizing hormone (LH) secretion in tilapia. In this study, we examined whether the hypothalamo–pituitary–interrenal axis was involved in such inhibition. Administration (i.p.) of corticotropin-releasing hormone (CRH) to stripped Oreochromis mossambicus (eggs manually removed from mouth brooder) during the ovarian cycle for 22 days resulted in a significant increase in the serum levels of cortisol, and significantly lower gonadosomatic and hepatosomatic indices concomitant with complete absence of stage V (vitellogenic) follicles in the ovary compared to controls. Furthermore, the LH secreting cells at the proximal pars distalis (PPD) in the pituitary gland showed weak immunostaining in contrast to the intensely stained immunoreactive cells in controls during prespawning phase. On the other hand, while exposure of fish to aquacultural stressors produced effects similar to that of CRH treatment, treatment of glucocorticoid synthesis inhibitor metyrapone to stressed fish during the ovarian cycle did not show significant serum cortisol response. The LH secreting cells in these fish showed intense immunostaining at the PPD in the pituitary gland, and the ovary contained stage V follicles similar to that of controls prior to spawning phase. These results suggest that the inhibitory effects of CRH treatment on LH secretion and recruitment of follicles for vitellogenic growth are mediated through the stress hormone cortisol in O. mossambicus.
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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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Differential and reproductive stage-dependent regulation of vasotocin secretion by catecholamines in the catfish Heteropneustes fossilis. Comp Biochem Physiol A Mol Integr Physiol 2013; 166:619-26. [DOI: 10.1016/j.cbpa.2013.09.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 09/04/2013] [Accepted: 09/05/2013] [Indexed: 12/15/2022]
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