Talk:Endocrine - Pineal Development

About Discussion Pages

On this website the Discussion Tab or "talk pages" for a topic has been used for several purposes: References - recent and historic that relates to the topic Additional topic information - currently prepared in draft format Links - to related webpages Topic page - an edit history as used on other Wiki sites Lecture/Practical - student feedback Student Projects - online project discussions. Links: Pubmed Most Recent | Reference Tutorial | Journal Searches Glossary Links Glossary: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers | Symbols | Term Link Cite this page: Hill, M.A. (2024, April 19) Embryology Endocrine - Pineal Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Endocrine_-_Pineal_Development

2012

Fgf signaling governs cell fate in the zebrafish pineal complex

Development. 2013 Jan;140(2):323-32. doi: 10.1242/dev.083709. Clanton JA, Hope KD, Gamse JT.

Source

Department of Biological Sciences, Vanderbilt University, Nashville, TN 37205, USA. Abstract Left-right (L-R) asymmetries in neuroanatomy exist throughout the animal kingdom, with implications for function and behavior. The molecular mechanisms that control formation of such asymmetries are beginning to be understood. Significant progress has been made by studying the zebrafish parapineal organ, a group of neurons on the left side of the epithalamus. Parapineal cells arise from the medially located pineal complex anlage and migrate to the left side of the brain. We have found that Fgf8a regulates a fate decision among anterior pineal complex progenitors that occurs just prior to the initiation of leftward migration. Cell fate analysis shows that in the absence of Fgf8a a subset of cells in the anterior pineal complex anlage differentiate as cone photoreceptors rather than parapineal neurons. Fgf8a acts permissively to promote parapineal fate in conjunction with the transcription factor Tbx2b, but might also block cone photoreceptor fate. We conclude that this subset of anterior pineal complex precursors, which normally become parapineal cells, are bipotential and require Fgf8a to maintain parapineal identity and/or prevent cone identity.

PMID 23250206

The role of melatonin as an antioxidant in the follicle

J Ovarian Res. 2012 Jan 26;5:5.

Tamura H, Takasaki A, Taketani T, Tanabe M, Kizuka F, Lee L, Tamura I, Maekawa R, Aasada H, Yamagata Y, Sugino N. Source Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Minamikogushi 1-1-1, Ube, 755-8505 Japan. hitamura@yamaguchi-u.ac.jp.

Abstract

ABSTRACT: Melatonin (N-acetyl-5-methoxytryptamine) is secreted during the dark hours at night by pineal gland, and it regulates a variety of important central and peripheral actions related to circadian rhythms and reproduction. It has been believed that melatonin regulates ovarian function by the regulation of gonadotropin release in the hypothalamus-pituitary gland axis via its specific receptors. In addition to the receptor mediated action, the discovery of melatonin as a direct free radical scavenger has greatly broadened the understanding of melatonin's mechanisms which benefit reproductive physiology. Higher concentrations of melatonin have been found in human preovulatory follicular fluid compared to serum, and there is growing evidence of the direct effects of melatonin on ovarian function especially oocyte maturation and embryo development. Many scientists have focused on the direct role of melatonin on oocyte maturation and embryo development as an anti-oxidant to reduce oxidative stress induced by reactive oxygen species, which are produced during ovulation process. The beneficial effects of melatonin administration on oocyte maturation and embryo development have been confirmed by in vitro and in vivo experiments in animals. This review also discusses the first application of melatonin to the clinical treatment of infertile women and confirms that melatonin administration reduces intrafollicular oxidative damage and increase fertilization rates. This review summarizes our recent works and new findings related to the reported beneficial effects of melatonin on reproductive physiology in its role as a reducer of oxidative stress, especially on oocyte maturation and embryo development.

PMID 22277103

2011

Melatonin as a central molecule connecting neural development and calcium signaling

Funct Integr Genomics. 2011 Apr 5. [Epub ahead of print]

de Faria Poloni J, Feltes BC, Bonatto D. Source Instituto de Biotecnologia, Universidade de Caxias do Sul (UCS), Caxias do Sul, Rio Grande do Sul, Brazil.

Abstract

Melatonin (MEL) is a neuroendocrine hormone secreted by the pineal gland in association with the suprachiasmatic nucleus and peripheral tissues. MEL has been observed to play a critical role in the reproductive process and in the fetomaternal interface. Extrapineal synthesis has been reported in mammalian models during pregnancy, especially by the placenta tissue. MEL can regulate intracellular processes (e.g., G-proteins) and the activity of second messengers (e.g., cAMP, IP(3,) Ca(2+)). During neurodevelopment, these activities regulated by melatonin have an important role as an intracellular signaling for gene expression regulation. To review the role of MEL in neurodevelopment, we built interactome networks of different proteins that act in these processes using systems biology tools. The analyses of interactome networks revealed that MEL could modulate neurodevelopment through the regulation of Ca(2+) intracellular levels and influencing BMP/SMAD signaling, thus affecting neural gene responses and neuronal differentiation.

PMID: 21465271 http://www.ncbi.nlm.nih.gov/pubmed/21465271

2008

Tbx2b is required for the development of the parapineal organ

Development. 2008 May;135(9):1693-702. Epub 2008 Apr 2.

Snelson CD, Santhakumar K, Halpern ME, Gamse JT. Source Department of Biological Sciences, Vanderbilt University, VU Station B, Box 35-1634, Nashville, TN 37235, USA.

Abstract

Structural differences between the left and right sides of the brain exist throughout the vertebrate lineage. By studying the zebrafish pineal complex, which exhibits notable asymmetries, both the genes and the cell movements that result in left-right differences can be characterized. The pineal complex consists of the midline pineal organ and the left-sided parapineal organ. The parapineal is responsible for instructing the asymmetric architecture of the bilateral habenulae, the brain nuclei that flank the pineal complex. Using in vivo time-lapse confocal microscopy, we find that the cells that form the parapineal organ migrate as a cluster of cells from the pineal complex anlage to the left side of the brain. In a screen for mutations that disrupted brain laterality, we identified a nonsense mutation in the T-box2b (tbx2b) gene, which encodes a transcription factor expressed in the pineal complex anlage. The tbx2b mutant makes fewer parapineal cells, and they remain as individuals near the midline rather than migrating leftward as a group. The reduced number and incorrect placement of parapineal cells result in symmetric development of the adjacent habenular nuclei. We conclude that tbx2b functions to specify the correct number of parapineal cells and to regulate their asymmetric migration.

PMID: 18385257 http://www.ncbi.nlm.nih.gov/pubmed/18385257

2000

Induction of photosensitivity in neonatal rat pineal gland

Proc Natl Acad Sci U S A. 2000 Oct 10;97(21):11540-4.

Tosini G, Doyle S, Geusz M, Menaker M. Source Neuroscience Institute, Morehouse School of Medicine, 720 Westview Drive, SW, Atlanta, GA 30310, USA. tosinig@msm.edu

Abstract

Pineal glands removed from neonatal rats at 5, 7, and 9 days of age and explanted into short-term culture, synthesized melatonin when stimulated with norepinephrine (NE); their melatonin synthesis could not be suppressed with bright white light. Dispersed pineal cell cultures or pineal explants prepared from 1-day-old neonates and held in culture for 7 or 9 days also synthesized melatonin when stimulated with NE, but in these cases melatonin synthesis was significantly suppressed by light, demonstrating that the pineals had become photosensitive while in culture. The development of photosensitivity in culture could be partially or completely abolished by the continuous presence of 1 or 10 microm of NE in the culture medium. The pineals of all nonmammalian vertebrates are photoreceptive, whereas those of mammals do not normally respond to light. We hypothesize that a mechanism to suppress pineal photosensitivity by using NE released from sympathetic nerve endings evolved early in the history of mammals.

PMID: 11005846

1996

Factors influencing the development of melatonin rhythmicity in humans

J Clin Endocrinol Metab. 1996 Apr;81(4):1525-32.

Kennaway DJ, Goble FC, Stamp GE. Source Department of Obstetrics and Gynecology, University of Adelaide, Australia.

Abstract

The emergence of melatonin rhythmicity was studied in 163 infants between 46-55 weeks postconception by monitoring the excretion of the urinary melatonin metabolite 6-sulfatoxymelatonin (aMT.6S). From this population, we examined the effects of gender, season, multiple birth, home birth, previous sudden infant death syndrome in the family, premature labor, spontaneous rupture of membranes, preeclampsia, intrauterine growth restriction, and nursery lighting on pineal rhythmicity. As previously reported, rhythmic excretion of aMT.6S appeared between 49-55 weeks postconception (9-15 weeks of age) in singleton babies born at term in the hospital. Full-term infants who had a sibling die of sudden infant death syndrome had a pattern of melatonin rhythm development no different from that of the control full-term infants. In contrast, full-term infants born at home and full-term twins born in the hospital had significantly lower aMT.6S excretion than hospital-born singleton infants at the same ages despite similar body weights (e.g. at 52 weeks postconception; 1.8 +/- 0.4, 1.1 +/- 0.3, and 3.6 +/ -0.5 nmol/day, respectively). In full-term infants, there was no difference in the development of melatonin rhythmicity between the sexes, with season or method of delivery (vaginal vs. caesarean). The premature infants were divided into 5 groups (babies born after premature labor, premature rupture of membranes, preeclampsia, intrauterine growth restriction, and fetal distress). All premature infants had a delay in the appearance of aMT.6S rhythms in the urine in relation to chronological age. When the infants were compared on the basis of weeks since conception, those infants born after spontaneous premature labor excreted amounts of aMT.6S no different from those of full-term singleton infants during the period of study. In contrast, the premature rupture of membranes, preeclampsia, and fetal distressed infants excreted 50% less aMT.6S, and intrauterine growth restricted infants excreted 67% less at the same postconceptional ages. These differences were due to reduced nocturnal excretion of the metabolite. In an attempt to accelerate the development of melatonin rhythmicity, premature labor and premature rupture of membranes infants were randomly assigned to be totally deprived of light (using phototherapy eye shields) or partially deprived of light by moving them to a dimly lit room each night for the last 3-8 weeks of their stay in the hospital nursery. Babies born after premature labor produced normal amounts of aMT.6S between 46-52 weeks postconception, and this pattern was not affected by the nocturnal light deprivation. Infants born after premature rupture of membranes and totally deprived of light at night had aMT.6S excretion rhythms at 52 weeks postconception no different from those of full-term hospital-born infants or premature labor infants, whereas those in infants placed in dim light were similar to those in untreated premature rupture of membranes infants. These results suggest that premature birth alone is not the sole cause of altered rhythm development; other factors, such as preeclampsia, growth restriction, and nursery lighting, play an important role. The consequences of the delayed appearance of melatonin in infants are not known, but deserve further study.

PMID: 8636362

1995

The pineal gland: a comparative MR imaging study in children and adults with respect to normal anatomical variations and pineal cysts

Pediatr Radiol. 1995;25(4):245-8.

Sener RN. Source Department of Radiology, Ege University Hospital, Bornova, Izmir, Turkey.

Abstract

This study was undertaken to evaluate the variations in appearance of the normal pineal gland. The findings of 1000 consecutive MR imaging examinations obtained at 0.5 T were studied. The age of the patients ranged from 1 day to 83 years, and findings in children and adults were compared. In all age groups the pineal gland appeared mainly in three forms: (1) nodule-like, (2) crescent-like and (3) ring-like. Overall prevalences of these forms were 52%, 26% and 22%, respectively. Apparent differences in frequencies were evident in children and adults with respect to the crescent- and ring-like types. Cystiform pineal lesions 5 mm or larger in one diameter (anteroposterior, sagittal or transverse) were taken to be true pineal cysts, when compared with the gland's ring-like appearance (less than 5 mm). Pineal cysts had a prevalence of 0.6% in children and 2.6% in adults. No symptomatic pineal cyst with mass effect on the lamina tecti was detected in the series. Besides identifying the three anatomical types of the pineal gland as seen on MR imaging and addressing the potential significance of differences in their frequencies in children and adults, the author tries to explain the previous discrepancy between the MR imaging and autopsy series findings with respect to frequencies of the pineal cysts.

PMID: 7567225

1992

Fine structure of the pinealopetal innervation of the mammalian pineal gland

Microsc Res Tech. 1992 May 1;21(3):188-204.

Møller M. Source Department B, University of Copenhagen, Denmark.

Abstract

The mammalian pineal gland is innervated by peripheral sympathetic and parasympathetic nerve fibers as well as by nerve fibers originating in the central nervous system (central innervation). The perikarya of the sympathetic fibers are located in the superior cervical ganglia, while the fibers terminate in boutons containing small granular vesicles and a few large granular vesicles. Both noradrenaline and neuropeptide Y are contained in these neurons. The parasympathetic fibers originate from perikarya in the pterygopalatine ganglia. The neuropeptides, vasoactive intestinal peptide and peptide histidine isoleucine, are present in these fibers, the boutons of which contain small clear transmitter vesicles and larger granular vesicles. The fibers of the central innervation originate predominantly from perikarya located in hypothalamic and limbic forebrain structures as well as from perikarya in the optic system. These fibers terminate in boutons containing small clear and, in certain fibers, an abundant number of large granular vesicles. In rodents, the majority of the central fibers terminate in the deep pineal gland and the pineal stalk. From these areas impulses might be transmitted further caudally to the superficial pineal gland via neuronal structures or processes from pinealocytes. Several hypothalamic neuropeptides and monoamines might be contained in the central fibers. The intrapineal nerve fibers are located both in the perivascular spaces and intraparenchymally. The majority of the intraparenchymally located fibers terminate freely between the pinealocytes. However, some nerve terminals make synaptic contacts with the pinealocytes and in some species with intrapineal neurons. In fetal mammals, sympathetic, parasympathetic, and central fibers are also present. In addition, an unpaired nerve, connecting the caudal part of the pineal gland with the extreme rostral part of the mesencephalon, is present. This nerve is a homologue to the pineal nerve (nervus pinealis) observed in lower vertebrates.

PMID: 1606315