scholarly journals Ocular Motoneuron Pools Develop Along a Dorsoventral Axis in Zebrafish, Danio rerio

2016 ◽  
Author(s):  
Marie R. Greaney ◽  
Ann E. Privorotskiy ◽  
Kristen P. D’Elia ◽  
David Schoppik
Keyword(s):  
Danio Rerio ◽  
Functional Organization ◽  
Temporal Organization ◽  
Birth Date ◽  
Primary Role ◽  
Dorsoventral Axis ◽  
Systems Neuroscience ◽  
Larval Zebrafish ◽  
Fluorescent Markers ◽  
Temporal Cues

Both spatial and temporal cues determine the fate of immature neurons. A major challenge at the interface of developmental and systems neuroscience is to relate this spatiotempo-ral trajectory of maturation to circuit-level functional organization. This study examined the development of two ocular cranial motor nuclei (nIII and nIV), structures in which a motoneuron’s identity, or choice of muscle partner, defines its behavioral role. We used retro-orbital dye fills, in combination with fluorescent markers for motoneuron location and birth-date, to probe spatial and temporal organization of the oculomotor (nIII) and trochlear (nIV) nuclei in the larval zebrafish. We described a dorsoventral organization of the four nIII motoneuron pools, in which inferior and medial rectus motoneurons occupy dorsal nIII, while inferior oblique and superior rectus motoneurons occupy distinct divisions of ventral nIII. Dorsal nIII motoneurons are, moreover, born before motoneurons of ventral nIII and nIV. Order of neurogenesis can therefore account for the dorsoventral organization of nIII and may play a primary role in determining motoneuron identity. We propose that the temporal development of ocular motoneurons plays a key role in assembling a functional oculomotor circuit.

Loss of M2 muscarinic receptor function inhibits development of hypoxic bradycardia and alters cardiac β-adrenergic sensitivity in larval zebrafish (Danio rerio)

2009 ◽  
Vol 297 (2) ◽  
pp. R412-R420 ◽  
Author(s):  
Shelby L. Steele ◽  
Kwok Hong Andy Lo ◽  
Vincent Wai Tsun Li ◽  
Shuk Han Cheng ◽  
Marc Ekker ◽  
...  
Keyword(s):  
Heart Rate ◽  
Muscarinic Receptor ◽  
Danio Rerio ◽  
Antisense Oligonucleotides ◽  
Adrenergic Receptor ◽  
Larval Zebrafish ◽  
M2 Muscarinic Receptor ◽  
Β Adrenergic Receptors ◽  
Relative Mrna Expression

Fish exposed to hypoxia develop decreased heart rate, or bradycardia, the physiological significance of which remains unknown. The general muscarinic receptor antagonist atropine abolishes the development of this hypoxic bradycardia, suggesting the involvement of muscarinic receptors. In this study, we tested the hypothesis that the hypoxic bradycardia is mediated specifically by stimulation of the M2 muscarinic receptor, the most abundant subtype in the vertebrate heart. Zebrafish ( Danio rerio) were reared at two levels of hypoxia (30 and 40 Torr Po2) from the point of fertilization. In hypoxic fish, the heart rate was significantly lower than in normoxic controls from 2 to 10 days postfertilization (dpf). At the more severe level of hypoxia (30 Torr Po2), there were significant increases in the relative mRNA expression of M 2 and the cardiac type β-adrenergic receptors ( β1AR, β2aAR, and β2bAR) at 4 dpf. The hypoxic bradycardia was abolished (at 40 Torr Po2) or significantly attenuated (at 30 Torr Po2) in larvae experiencing M2 receptor knockdown (using morpholino antisense oligonucleotides). Sham-injected larvae exhibited typical hypoxic bradycardia in both hypoxic regimens. The expression of β1AR, β2aAR, β2bAR, and M 2 mRNA was altered at various stages between 1 and 4 dpf in larvae experiencing M2 receptor knockdown. Interestingly, M2 receptor knockdown revealed a cardioinhibitory role for the β2-adrenergic receptor. This is the first study to demonstrate a specific role of the M2 muscarinic receptor in the initiation of hypoxic bradycardia in fish.

On the effects of iron ore tailings micro/nanoparticles in embryonic and larval zebrafish (Danio rerio)

2021 ◽  
Vol 759 ◽  
pp. 143456
Author(s):  
Vítor Otacílio de Almeida ◽  
Talita Carneiro Brandão Pereira ◽  
Lilian de Souza Teodoro ◽  
Manuella Escobar ◽  
Carolina Junqueira Ordovás ◽  
...  
Keyword(s):  
Danio Rerio ◽  
Iron Ore ◽  
Larval Zebrafish ◽  
Iron Ore Tailings

scholarly journals The restless brain: how intrinsic activity organizes brain function

2015 ◽  
Vol 370 (1668) ◽  
pp. 20140172 ◽  
Author(s):  
Marcus E. Raichle
Keyword(s):  
Brain Function ◽  
Functional Organization ◽  
Sensory Information ◽  
Intrinsic Activity ◽  
Systems Neuroscience ◽  
Brain Functions ◽  
Molecular Neuroscience ◽  
Constant State ◽  
Health And Disease ◽  
The Brain

Traditionally studies of brain function have focused on task-evoked responses. By their very nature such experiments tacitly encourage a reflexive view of brain function. While such an approach has been remarkably productive at all levels of neuroscience, it ignores the alternative possibility that brain functions are mainly intrinsic and ongoing, involving information processing for interpreting, responding to and predicting environmental demands. I suggest that the latter view best captures the essence of brain function, a position that accords well with the allocation of the brain's energy resources, its limited access to sensory information and a dynamic, intrinsic functional organization. The nature of this intrinsic activity, which exhibits a surprising level of organization with dimensions of both space and time, is revealed in the ongoing activity of the brain and its metabolism. As we look to the future, understanding the nature of this intrinsic activity will require integrating knowledge from cognitive and systems neuroscience with cellular and molecular neuroscience where ion channels, receptors, components of signal transduction and metabolic pathways are all in a constant state of flux. The reward for doing so will be a much better understanding of human behaviour in health and disease.

scholarly journals Fumonisin B1 Production by Fusarium Species and Mycotoxigenic Effect on Larval Zebrafish

2020 ◽  
Vol 31 (3) ◽  
pp. 91-107 ◽  
Author(s):  
Najihah Azman ◽  
Nur Ain Izzati Mohd Zainudin ◽  
Wan Norhamidah Wan Ibrahim
Keyword(s):  
Liquid Chromatography ◽  
Danio Rerio ◽  
Morphological Changes ◽  
Fusarium Species ◽  
Fumonisin B1 ◽  
Larval Zebrafish ◽  
Zebrafish Larvae ◽  
Significant Difference ◽  
Successful Amplification ◽  
Fast Liquid Chromatography

Fumonisin B1 (FB1) is a common mycotoxin produced by Fusarium species particularly F. proliferatum and F. verticillioides. The toxin produced can cause adverse effects on humans and animals. The objectives of this study were to detect the production of FB1 based on the amplification of FUM1 gene, to quantify FB1 produced by the isolates using Ultra-fast Liquid Chromatography (UFLC) analysis, to examine the embryotoxicity effect of FB1 and to determine EC50 toward the larvae of zebrafish (Danio rerio). Fifty isolates of Fusarium species were isolated from different hosts throughout Malaysia. Successful amplification of the FUM1 gene showed the presence of this gene (800 bp) in the genome of 48 out of 50 isolates. The highest level of FB1 produced by F. proliferatum isolate B2433 was 6677.32 ppm meanwhile F. verticillioides isolate J1363 was 954.01 ppm. From the assessment of embryotoxicity test of FB1 on larvae of zebrafish, five concentrations of FB1 (0.43 ppm, 0.58 ppm, 0.72 ppm, 0.87 ppm and 1.00 ppm) were tested. Morphological changes of the FB1 exposed-larvae were observed at 24 to 168 hpf. The mortality rate and abnormality of zebrafish larvae were significantly increased at 144 hpf exposure. Meanwhile, the spontaneous tail coiling showed a significant difference. There were no significant differences in the heartbeat rate. As a conclusion, the presence of FUM1 in every isolate can be detected by FUM1 gene analysis and both of the species produced different concentrations of FB1. This is the first report of FB1 produced by Fusarium species gave a significant effect on zebrafish development.

Joint acute and endocrine disruptive toxicities of malathion, cypermethrin and prochloraz to embryo-larval zebrafish, Danio rerio

Chemosphere ◽  
2017 ◽  
Vol 166 ◽  
pp. 63-71 ◽  
Author(s):  
Dongmei Guo ◽  
Yanhua Wang ◽  
Yongzhong Qian ◽  
Chen Chen ◽  
Bining Jiao ◽  
...  
Keyword(s):  
Danio Rerio ◽  
Larval Zebrafish

The pyrethroid esfenvalerate induces hypoactivity and decreases dopamine transporter expression in embryonic/larval zebrafish (Danio rerio)

Chemosphere ◽  
2020 ◽  
Vol 243 ◽  
pp. 125416 ◽  
Author(s):  
Xiao H. Wang ◽  
Christopher L. Souders ◽  
Priscilla Xavier ◽  
Xiao Y. Li ◽  
Bing Yan ◽  
...  
Keyword(s):  
Dopamine Transporter ◽  
Danio Rerio ◽  
Larval Zebrafish ◽  
Transporter Expression
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