Urotensin receptor in GtoPdb v.2021.3

The urotensin-II (U-II) receptor (UT, nomenclature as agreed by the NC-IUPHAR Subcommittee on the Urotensin receptor [26, 36, 93]) is activated by the endogenous dodecapeptide urotensin-II, originally isolated from the urophysis, the endocrine organ of the caudal neurosecretory system of teleost fish [7, 92]. Several structural forms of U-II exist in fish and amphibians [93]. The goby orthologue was used to identify U-II as the cognate ligand for the predicted receptor encoded by the rat gene gpr14 [2, 20, 63, 69, 72]. Human urotensin-II, an 11-amino-acid peptide [20], retains the cyclohexapeptide sequence of goby U-II that is thought to be important in ligand binding [61, 53, 10]. This sequence is also conserved in the deduced amino-acid sequence of rat urotensin-II (14 amino-acids) and mouse urotensin-II (14 amino-acids), although the N-terminal is more divergent from the human sequence [19]. A second endogenous ligand for the UT has been discovered in rat [86]. This is the urotensin II-related peptide, an octapeptide that is derived from a different gene, but shares the C-terminal sequence (CFWKYCV) common to U-II from other species. Identical sequences to rat urotensin II-related peptide are predicted for the mature mouse and human peptides [32]. UT exhibits relatively high sequence identity with somatostatin, opioid and galanin receptors [93].

A full-system study of neuroendocrine regulation of fish reproduction. 1. Development biotech management principles of artificial fish reproduction on the basis of the ecologo-histophysiological scientific approach

A completed full-system (scientific-applied) ecological-histophysiological study of the hypothalamo-hypophysial neurosecretory system (HHNS) participation in fish reproduction was established. With the help of light-, electron-microscopy and immunocytochemistry it is established for the first time that at the beginning migrations of passing fish there is a mass accumulation of neurosecretory products in neurohypophysis, which indicates to the inhibition of the normal level of their excretion into the bloodstream. At the same time, they are actively synthesized in the pericarions of the neurosecretory cells in the preoptic nucleus and excretioned into the cavity of the III brain ventricle. Firstly it is a sign of a violation of their basic osmoregulatory function, which should cause a change in habitat. Secondly, the synchronous excretion of neurohormones into the brain’s liquor should cause their neurotropic effect on the CNS behavior centers in the form of a dominant state of arousal in the form of “migration impulse”. At the beginning of spawning, regardless of its season, HHNS also initiates spawning behavior and completes spawning by participating in the body’s protective-adaptive reactions to natural physiological stress. The functional role of the HHNS in fish reproduction is to initiate energy-intensive reproductive processes of migratory and spawning behaviors, and to complete spawning by suppressing the hyperactivity of the target glands, which ensures the body’s transition to energy-saving plastic exchange. The analysis of this key role of HHNS in the integration of fish reproduction by the principle of self-regulation has allowed to define the principles of effective reproduction and cultivation fish management, primarily in the form of finding the most effective impacts on the centers of integration of managed functions or modeling their effects, which should be carried out in natural periods of functional lability of the body. A constructive working scheme neuroendocrine integration of fish reproduction has been presented and the possibility of applying method of comparative analysis to further develop the system management biotechnics of fish populations reproduction is considered.

The development system of biotech management of reproduction fish populations based on neuroendocrinological research

The participation of the hypothalamo-hypophysial neurosecretory system (HHNS) in fish reproduction was established by ecologo-histophysiological research with the help of light-, electronmicroscopy and immunocytochemistry. At the beginning of migrations of passing fish an active synthesis of neurosecretory products in pericarions of neurosecretory cells and their excretion into the cavity of the III brain ventricle was stated, while a mass accumulation of them in neurohypophysis occurs. Firstly, the excretion of neurohormones into the brain’s liquor should cause their neurotropic effect on the CNS behavior centers in the form of a dominant state of arousal, designated as “migration impulse”. Then HHNS initiates spawning behavior at the beginning of spawning and completes it by participating in overcoming natural physiological stress. In fish reproduction the main functional role of HHNS is to initiate reproductive energy-intensive processes of migratory and spawning behaviors, and to completion spawning by suppressing the hyperactivity of the target glands, ensuring the body’s transition to energysaving plastic metabolic exchange. The analysis of the key role of HHNS in fish reproduction has allowed to present a constructive working scheme of its neuroendocrine integration by the principle of self-regulation and to develop, on this basis, the system management of biotech reproduction of fish populations.

Identification of the Neuropeptide Precursor Genes Potentially Involved in the Larval Settlement in the Echiuran Worm Urechis unicinctus

Background: In marine invertebrate life cycles, which often consist of planktonic larval and benthonic adult stages, settlement of the free-swimming larva to the sea floor in response to environmental cues is a key life cycle transition. Settlement is regulated by a specialized sensory–neurosecretory system, the larval apical organ. The neuroendocrine mechanisms through which the apical organ transduces environmental cues into behavioral responses during settlement are not fully understood yet.Results: In this study, a total of 54 neuropeptide precursors (pNPs) were identified in the Urechis unicinctus larva and adult transcriptome databases using local BLAST and NpSearch prediction, of which 10 pNPs belonging to the ancient eumetazoa, 24 pNPs belonging to the ancient bilaterian, 3 pNPs belonging to the ancient protostome, 9 pNPs exclusive in lophotrochozoa, 3 pNPs exclusive in annelid, and 5 pNPs only found in U. unicinctus. Furthermore, four pNPs (MIP, FRWamide, FxFamide and FILamide) which may be associated with the settlement and metamorphosis of U. unicinctus larvae were analysed by qRT-PCR. Whole-mount in situ hybridization results showed that all the four pNPs were expressed in the region of the apical organ of the larva, and the positive signals were also detected in the ciliary band and abdomen chaetae. We speculated that these pNPs may regulate the movement of larval cilia and chaeta by sensing external attachment signals.Conclusions: This study represents the first comprehensive identification of neuropeptides in Echiura, and would contribute to a complete understanding on the roles of various neuropeptides in larval settlement of most marine benthonic invertebrates.

Identification of the neuropeptide precursor genes potentially involved in the larval settlement in the Echiuran worm Urechis unicinctus

Background In marine invertebrate life cycles, which often consist of planktonic larval and benthonic adult stages, settlement of the free-swimming larva to the sea floor in response to environmental cues is a key life cycle transition. Settlement is regulated by a specialized sensory–neurosecretory system, the larval apical organ. The neuroendocrine mechanisms through which the apical organ transduces environmental cues into behavioral responses during settlement are not fully understood yet. Results In this study, a total of 54 neuropeptide precursors (pNPs) were identified in the Urechis unicinctus larva and adult transcriptome databases using local BLAST and NpSearch prediction, of which 10 pNPs belonging to the ancient eumetazoa, 24 pNPs belonging to the ancient bilaterian, 3 pNPs belonging to the ancient protostome, 9 pNPs exclusive in lophotrochozoa, 3 pNPs exclusive in annelid, and 5 pNPs only found in U. unicinctus. Furthermore, four pNPs (MIP, FRWamide, FxFamide and FILamide) which may be associated with the settlement and metamorphosis of U. unicinctus larvae were analysed by qRT-PCR. Whole-mount in situ hybridization results showed that all the four pNPs were expressed in the region of the apical organ of the larva, and the positive signals were also detected in the ciliary band and abdomen chaetae. We speculated that these pNPs may regulate the movement of larval cilia and chaeta by sensing external attachment signals. Conclusions This study represents the first comprehensive identification of neuropeptides in Echiura, and would contribute to a complete understanding on the roles of various neuropeptides in larval settlement of most marine benthonic invertebrates.

Identification of the Neuropeptide Precursor Genes Potentially Involved in the Larval Settlement in the Echiuran Worm Urechis unicinctus

Background: In marine invertebrate life cycles, which often consist of planktonic larval and benthonic adult stages, settlement of the free-swimming larva to the sea floor in response to environmental cues is a key life cycle transition. Settlement is regulated by a specialized sensory–neurosecretory system, the larval apical organ. The neuroendocrine mechanisms through which the apical organ transduces environmental cues into behavioral responses during settlement are not fully understood yet.Results: In this study, a total of 54 neuropeptide precursors (pNPs) were identified in the Urechis unicinctus larva and adult transcriptome databases using local BLAST and de novo prediction, of which 10 pNPs belonging to the ancient eumetazoa, 23 pNPs belonging to the ancient bilaterian, 3 pNPs belonging to the ancient protostome, 10 pNPs exclusive in lophotrochozoa, 3 pNPs exclusive in annelid, and 5 pNPs only found in U. unicinctus. Furthermore, four pNPs (MIP, FRWamide, FxFamide and FILamide) which may be associated with the settlement and metamorphosis of U. unicinctus larvae were verified successfully by qRT-PCR. Whole-mount in situ hybridization results showed that all the four pNPs were expressed in the region of the apical organ of the larva, and the positive signals were also detected in the ciliary band and abdomen chaetae. We speculated that these pNPs may regulate the movement of larval cilia and chaeta by sensing external attachment signals.Conclusions: This study represents the first comprehensive identification of neuropeptides in Echiura, and would contribute to a complete understanding on the roles of various neuropeptides in larval settlement of most marine benthonic invertebrates.