PUBLICATION
Motoneuron axon pathfinding errors in zebrafish: Differential effects related to concentration and timing of nicotine exposure
- Authors
- Menelaou, E., Paul, L.T., Perera, S.N., Svoboda, K.R.
- ID
- ZDB-PUB-150211-1
- Date
- 2015
- Source
- Toxicology and applied pharmacology 284(1): 65-78 (Journal)
- Registered Authors
- Svoboda, Kurt
- Keywords
- axonal pathfinding, dual labeling, embryonic spinal cord, muscle degeneration
- MeSH Terms
-
- Animals
- Animals, Genetically Modified
- Axons/drug effects*
- Axons/metabolism
- Biomarkers/metabolism
- Dose-Response Relationship, Drug
- Genotype
- Larva/drug effects
- Larva/metabolism
- Morphogenesis
- Motor Neurons/drug effects*
- Motor Neurons/metabolism
- Nervous System/drug effects*
- Nervous System/embryology
- Nervous System/metabolism
- Nicotine/toxicity*
- Nicotinic Agonists/toxicity*
- Phenotype
- Receptors, Nicotinic/metabolism
- Time Factors
- Zebrafish/embryology*
- Zebrafish/genetics
- Zebrafish/metabolism
- Zebrafish Proteins/metabolism
- PubMed
- 25668718 Full text @ Tox. App. Pharmacol.
- CTD
- 25668718
Citation
Menelaou, E., Paul, L.T., Perera, S.N., Svoboda, K.R. (2015) Motoneuron axon pathfinding errors in zebrafish: Differential effects related to concentration and timing of nicotine exposure. Toxicology and applied pharmacology. 284(1):65-78.
Abstract
Nicotine exposure during embryonic stages of development can affect many neurodevelopmental processes. In the developing zebrafish, exposure to nicotine was reported to cause axonal pathfinding errors in the later born secondary motoneurons (SMN). These alterations in SMN axon morphology coincided with muscle degeneration at high nicotine concentrations (15-30µM). Previous work showed that the paralytic mutant zebrafish known as sofa potato, exhibited nicotine-induced effects onto SMN axons at these high concentrations but in the absence of any muscle deficits, indicating that pathfinding errors could occur independent of muscle effects. In this study, we used varying concentrations of nicotine at different developmental windows of exposure to specifically isolate its effects onto subpopulations of motoneuron axons. We found that nicotine exposure can affect SMN axon morphology in a dose-dependent manner. At low concentrations of nicotine, SMN axons exhibited pathfinding errors, in the absence of any nicotine-induced muscle abnormalities. Moreover, the nicotine exposure paradigms used affected the 3 subpopulations of SMN axons differently, but the dorsal projecting SMN axons were primarily affected. We then identified morphologically distinct pathfinding errors that best described the nicotine-induced effects on dorsal projecting SMN axons. To test whether SMN pathfinding was potentially influenced by alterations in the early born primary motoneuron (PMN), we performed dual labeling studies, where both PMN and SMN axons were simultaneously labeled with antibodies. We show that only a subset of the SMN axon pathfinding errors coincided with abnormal PMN axonal targeting in nicotine-exposed zebrafish. We conclude that nicotine exposure can exert differential effects depending on the levels of nicotine and developmental exposure window.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping