Synchronized diurnal and circadian expressions of four subtypes of melatonin receptor genes in the diencephalon of a puffer fish with lunar-related spawning cycles

Ikegami, Taro; Motohashi, Eiji; Doi, Hiroyuki; Hattori, Atsuhiko; Ando, Hironori

doi:10.1016/j.neulet.2009.06.076

Cited by 34 publications

(35 citation statements)

References 19 publications

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“…The inhibitory effects of light may be mediated by melatonin, which may stimulate the expression of LPXRFa and LPXRFa‐R genes like quail. Similar results were observed in the case of melatonin receptor genes in the diencephalon of grass puffer (41). Four subtypes of melatonin receptor genes exhibited synchronised diurnal and circadian expressions, with one peak at ZT15 and CT18, respectively, and the levels of expression were higher under DD conditions.…”

Section: Discussionsupporting

confidence: 85%

Synchronised Expressions of LPXRFamide Peptide and its Receptor Genes: Seasonal, Diurnal and Circadian Changes During Spawning Period in Grass Puffer

Shahjahan

Ikegami

Osugi

et al. 2010

Journal of Neuroendocrinology

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Among the RFamide peptide family, the LPXRFamide peptide (LPXRFa) group regulates the release of various pituitary hormones and, recently, LPXRFa genes were found to be regulated by photoperiod via melatonin. As a first step towards investigating the role of LPXRFa on reproductive function in grass puffer (Takifugu niphobles), which spawns in semilunar cycles, genes encoding LPXRFa and its receptor (LPXRFa-R) were cloned, and seasonal, diurnal and circadian changes in their absolute amounts of mRNAs in the brain and pituitary were examined by quantitative real-time polymerase chain reaction. The grass puffer LPXRFa precursor contains two putative RFamide peptides and one possible RYamide peptide. LPXRFa and LPXRFa-R genes were extensively expressed in the diencephalon and pituitary. The expression levels of both genes were significantly elevated during the spawning periods in both sexes in the brain and pituitary, although they were low in the spawning fish just after releasing eggs and sperm. The treatment of primary pituitary cultures with goldfish LPXRFa increased the amounts of follicle-stimulating hormone β- and luteinising hormone β-subunit mRNAs. In the diencephalon, LPXRFa and LPXRFa-R genes showed synchronised diurnal and circadian variations with one peak at zeitgeber time 3 and circadian time 15, respectively. The correlated expression patterns of LPXRFa and LPXRFa-R genes in the diencephalon and pituitary and the possible stimulatory effects of LPXRFa on gonadotrophin subunit gene expression suggest the functional significance of the LPXRFa and LPXRFa-R system in the regulation of lunar-synchronised spawning of grass puffer.

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Section: Discussionsupporting

confidence: 85%

Synchronised Expressions of LPXRFamide Peptide and its Receptor Genes: Seasonal, Diurnal and Circadian Changes During Spawning Period in Grass Puffer

Shahjahan

Ikegami

Osugi

et al. 2010

Journal of Neuroendocrinology

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“…The inhibitory effects of light may be mediated by melatonin which may stimulate the expression of LPXRFa and LPXRFa-R genes. Similar results were observed in the case of melatonin receptor genes in the diencephalon of grass puffer [56]. Four subtypes of melatonin receptor genes exhibited synchronised diurnal and circadian expressions with one peak at ZT15 and CT18, respectively, and the levels of expression were higher under the DD conditions.…”

Section: Regulatory Mechanism Of Lpxrfa Biosynthesissupporting

confidence: 83%

Role of LPXRFamide peptide in the neuroendocrine regulation of reproduction in fish

Shahjahan¹,

Ando²

2011

Open Life Sciences

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The decapeptide gonadotropin-releasing hormone (GnRH) is the primary factor responsible for the hypothalamic control of gonadotropin (GTH) secretion. This review focuses on a family of neuropeptides, LPXRFamide (LPXRFa) peptides, which have been implicated in the regulation of GTH secretion. LPXRFa acts on the pituitary via a G protein-coupled receptor, LPXRFa-R, to enhance gonadal development and maintenance by increasing gonadotropin release and synthesis. Because LPXRFa exists and functions in several fish species, LPXRFa is considered to be a key neurohormone in fish reproduction control. The precursors to LPXRFamide peptides encoded plural LPXRFamide peptides and were highly divergent in vertebrates, particularly in lower vertebrates. Tissue distribution analyses indicated that LPXRFamide peptides were highly concentrated in the hypothalamus and other brainstem regions. In view of the localization and expression of LPXRFamide peptides in the hypothalamo-hypophysial system, LPXRFamide peptide in fish increase GTH release in vitro and in vivo. This review summarizes the advances made in our understanding of the biosynthesis, mode of action and functional significance of LPXRFa, a newly discovered key neurohormone.

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“…Receptors for melatonin showed diurnal and circadian expression in the brain and retina of the golden rabbitfish (Park et al, 2007). In grass puffer, we previously showed that four subtypes of melatonin receptor genes were synchronously expressed in the diencephalon with diurnal and circadian variations (Ikegami et al, 2009). The moonlight cue might be involved in the entrainment of the endogenous semilunar rhythm through melatonin in grass puffer.…”

Section: Discussionmentioning

confidence: 98%

Aggregating Behavior of the Grass Puffer,Takifugu niphobles, Observed in Aquarium During the Spawning Period

et al. 2010

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Synchronized diurnal and circadian expressions of four subtypes of melatonin receptor genes in the diencephalon of a puffer fish with lunar-related spawning cycles

Cited by 34 publications

References 19 publications

Synchronised Expressions of LPXRFamide Peptide and its Receptor Genes: Seasonal, Diurnal and Circadian Changes During Spawning Period in Grass Puffer

Synchronised Expressions of LPXRFamide Peptide and its Receptor Genes: Seasonal, Diurnal and Circadian Changes During Spawning Period in Grass Puffer

Role of LPXRFamide peptide in the neuroendocrine regulation of reproduction in fish

Aggregating Behavior of the Grass Puffer,Takifugu niphobles, Observed in Aquarium During the Spawning Period

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