Dopaminergic Regulation of Brain Gonadotropin-Releasing Hormone in Male Goldfish during Spawning Behavior

Yu, Kei Li; Peter, Richard

doi:10.1159/000125598

Cited by 49 publications

(24 citation statements)

References 18 publications

(37 reference statements)

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“…Beside these direct pituitary effects, DA was also shown in the goldfish to exert additional inhibitory effects on GnRH neurons, blocking the synthesis of the peptide or inhibiting its release from the pituitary nerve terminals [51,52]. In the eel, our data demonstrate that DA exerts a major inhibitory action at the level of pituitary gonadotrophs, antagonizing the actions of GnRH even if we cannot rule out the possibility of additional targets of DA inhibition at the level of GnRH neurons, either directly or through other interneurons.…”

Section: Discussionmentioning

confidence: 99%

Dopamine Inhibits Luteinizing Hormone Synthesis and Release in the Juvenile European Eel: A Neuroendocrine Lock for the Onset of Puberty1

Vidal¹,

Pasqualini²,

Belle³

et al. 2004

Biology of Reproduction

154

113

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In various adult teleost fishes, LH ovulatory peak is under a dual neurohormonal control that is stimulatory by GnRH and inhibitory by dopamine (DA). We investigated whether DA could also be involved in the inhibitory control of LH at earlier steps of gametogenesis by studying the model of the European eel, Anguilla anguilla, which remains at a prepubertal stage until the oceanic reproductive migration. According to a protocol previously developed in the striped bass, eels received sustained treatments with GnRH agonist (GnRHa), DA-receptor antagonist (pimozide), and testosterone (T) either alone or in combination. Only the triple treatment with T, GnRHa, and pimozide could trigger dramatic increases in LH synthesis and release as well as in plasma vitellogenin levels and a stimulation of ovarian vitellogenesis. Thus, in the prepubertal eel, removal of DA inhibition is required for triggering GnRH-stimulated LH synthesis and release as well as ovarian development. To locate the anatomical support for DA inhibition, the distribution of tyrosine hydroxylase (TH) in the brain and pituitary was studied by immunocytochemistry. Numerous TH-immunoreactive cell bodies were observed in the preoptic anteroventral nucleus, with a dense tract of immunoreactive fibers reaching the pituitary proximal pars distalis, where the gonadotrophs are located. This pathway corresponds to that mediating the inhibition of LH and ovulation in adult teleosts. To our knowledge, this is the first demonstration of a pivotal role for DA in the control of LH and puberty in a juvenile teleost. These data support the view that DA inhibition on LH secretion is an ancient evolutionary component in the neuroendocrine regulation of reproduction that may have been partially maintained throughout vertebrate evolution.

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Section: Discussionmentioning

confidence: 99%

Dopamine Inhibits Luteinizing Hormone Synthesis and Release in the Juvenile European Eel: A Neuroendocrine Lock for the Onset of Puberty1

Vidal¹,

Pasqualini²,

Belle³

et al. 2004

Biology of Reproduction

154

113

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“…The acute direct effect of DA induces the disruption of intracellular GnRH signal transduction pathways (Chang et al, 1993), whereas the long-term effects account for a reduction in the number of GnRH receptors on the sur-face of LH tropic cells ) and a reduction in GnRH peptide release from nerve terminals in the pituitary (Yu and Peter, 1992). DA inhibitory effects are reflected also in the preoptic region, where it disrupts GnRH peptide synthesis in GnRH neurons (Yu and Peter, 1990). Moreover, treatment with a DA antagonist causes an increase in the numbers of LH-like gonadotrophs and is directly proportional to time and the dose of the antagonist (Osornio et al, 2004).…”

Section: Inhibition Factor Of Lh Secretiondopaminementioning

confidence: 99%

Induction of final oocyte maturation in Cyprinidae fish by hypothalamic factors: a review

Podhorec¹,

Kouřil²

2009

Vet. Med.

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Gonadotropin-releasing hormone in Cyprinidae as in other Vertebrates functions as a brain signal which stimulates the secretion of luteinizing hormone from the pituitary gland. Two forms of gonadotropin-releasing hormone have been identified in cyprinids, chicken gonadotropin-releasing hormone II and salmon gonadotropinreleasing hormone. Hypohysiotropic functions are fulfilled mainly by salmon gonadotropin-releasing hormone. The only known factor having an inhibitory effect on LH secretion in the family Cyprinidae is dopamine. Most cyprinids reared under controlled conditions exhibit signs of reproductive dysfunction, which is manifested in the failure to undergo final oocyte maturation and ovulation. In captivity a disruption of endogenous gonadotropinreleasing hormone stimulation occurs and sequentially that of luteinizing hormone, which is indispensible for the final phases of gametogenesis. In addition to methods based on the application of exogenous gonadotropins, the usage of a method functioning on the basis of hypothalamic control of final oocyte maturation and ovulation has become popular recently. The replacement of natural gonadotropin-releasing hormones with chemically synthesized gonadotropin-releasing hormone analogues characterized by amino acid substitutions at positions sensitive to enzymatic degradation has resulted in a centuple increase in the effectiveness of luteinizing hormone secretion induction. Combining gonadotropin-releasing hormone analogues with Dopamine inhibitory factors have made it possible to develop an extremely effective agent, which is necessary for the successful artificial reproduction of cyprinids.Keywords: reproductive dysfunction; ovulation; luteinizing hormone; gonadotropin-releasing hormone; gonadotropin; dopamine; dopamine antagonist; cyprinids List of abbreviations DA = dopamine; DI = dopamine antagonist; EU = European Union; GnRH = gonadotropin-releasing hormone; GnRHa = gonadotropin-releasing hormone analogue; cGnRH-II = chicken gonadotropin-releasing hormone II; mGnRH = mammalian gonadotropin-releasing hormone; sGnRH = salmon gonadotropin-releasing hormone; GPCR = G-protein coupled receptor; LH = luteinizing hormone; MRL = minimum residual limit; IM = intramuscular injection; IP = intraperitoneal injection; PCC = pericardial cavity injection; IV = intravenous injection

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“…It inhibits gonadotropin LH secretion by activating dopamine D2 receptors found on gonadotropic cells of the pituitary gland (Peter et al 1986, Omeljaniuk et al 1987. The inhibiting effect of dopamine is not limited to the pituitary gland, because studies with crucian carp proved its inhibitory effect on both LHRH synthesis and secretion (Yu and Peter 1990). This hypothesis was also confirmed by in vitro studies (Yu et al 1991, Yu andPeter 1992).…”

Section: Introductionmentioning

confidence: 97%

Effect of the pineal gland and melatonin on dopamine release from perifused hypothalamus of mature female carp during spawning and winter regression

Popek¹,

Łuszczek‐Trojnar²,

Drąg‐Kozak³

et al. 2005

Acta Ichthyol. Piscat.

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Epler P. 2005. Effect of the pineal gland and melatonin on dopamine release from perifused hypothalamus of mature female carp during spawning and winter regression. Acta Ichthyol. Piscat. 35 (2): 65-71.Background. Melatonin regulates various physiological and neuroendocrinological processes that occur rhythmically, and stimulates or inhibits endocrine activity of various body glands. This acts on the hypothalamic-pituitary-gonadal axis by synchronizing animals with their reproductive cycles. The proximity of melatonin receptors and dopamine and gonadoliberin production sites has led to a hypothesis that dopamine may be a link between melatonin and hypothalamic LHRH. Melatonin may have an indirect influence on animal reproduction through dopaminergic structures of the hypothalamus, but the mechanism involved remains unknown, also in fish, for this reason, the present experiment was conducted. The aim of the study was to determine the effect of melatonin on dopamine release from hypothalamic cells of mature female carp in vitro. Material and Methods. Hypothalami were perifused with a mineral medium containing melatonin (group 1), in the presence of implanted pineal glands (group 2), and with a pure mineral medium (control). Perifusion was 180 min long and samples of the effluent perifusate were collected at 15-minute intervals. Dopamine concentration in the medium was analysed radioenzymatically. The experiment was carried out in the summer during spawning and in the winter during regression. Results.The results indicate that melatonin inhibits the release of dopamine from hypothalamic cells. This effect was only noticeable in the experiment conducted during the spawning period. Conclusion. The present findings show that melatonin may have a role in the hypothalamic control of hypophyseal activity during the spawning period of carp.Key words: pineal gland, melatonin, dopamine, perifusion, carp, fish their reproductive cycles (Reiter 1991a, b, Zachmann et al. 1991.In looking for a link between the pineal gland and the hypothalamus, Zisapel and Laudon (1983) and Zisapel et al. (1985) showed that melatonin is able to inhibit dopamine secretion from the hypothalamic cells of the rat. The results of other studies, which showed that even picomolal concentrations of melatonin can inhibit dopamine release from the retina of birds and mammals (Cardinali et al. 1979, Dubocovich 1983, 1985, seemed to support this theory. Also in humans, the high nocturnal level of melatonin reduces dopaminergic activity in the hypothalamus (Rao and Mager 1987). In the brain of mammals, melatonin receptors are most abundant in the hypothalamus and in the anterior lobe of the pituitary gland, and much less abundant in the other parts of the brain (Weaver et al. 1991, Stankov et al. 1993. It is therefore conjectured that the hypothalamus acts as a functional link between melatonin and the endocrine system (Maywood et al. 1996). In the hypothalamus, the highest concentration of melatonin receptors is found in the medial eminence, next to the ...

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Dopaminergic Regulation of Brain Gonadotropin-Releasing Hormone in Male Goldfish during Spawning Behavior

Cited by 49 publications

References 18 publications

Dopamine Inhibits Luteinizing Hormone Synthesis and Release in the Juvenile European Eel: A Neuroendocrine Lock for the Onset of Puberty1

Dopamine Inhibits Luteinizing Hormone Synthesis and Release in the Juvenile European Eel: A Neuroendocrine Lock for the Onset of Puberty1

Induction of final oocyte maturation in Cyprinidae fish by hypothalamic factors: a review

Effect of the pineal gland and melatonin on dopamine release from perifused hypothalamus of mature female carp during spawning and winter regression

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