Changes in Thyroid Hormone Activity Disrupt Photomotor Behavior of Larval Zebrafish.

Changes in Thyroid Hormone Activity Disrupt Photomotor Behavior of Larval Zebrafish. Neurotoxicology. 2019 May 20;: Authors: Walter KM, Miller GW, Chen X, Harvey DJ, Puschner B, Lein PJ Abstract High throughput in vitro, in silico, and computational approaches have identified numerous environmental chemicals that interfere with thyroid hormone (TH) activity, and it is posited that human exposures to such chemicals is a contributing factor to neurodevelopmental disorders. However, whether hits in TH activity screens are predictive of developmental neurotoxicity (DNT) has yet to be systematically addressed. The zebrafish has been proposed as a second tier model for assessing the in vivo DNT potential of TH active chemicals. As an initial evaluation of the feasibility of this proposal, we determined whether an endpoint often used to assess DNT in larval zebrafish, specifically photomotor behavior, is altered by experimentally induced hyper- and hypothyroidism. Developmental hyperthyroidism was simulated by static waterborne exposure of zebrafish to varying concentrations (3-300 nM) of thyroxine (T4) or triiodothyronine (T3) beginning at 6 hours post-fertilization (hpf) and continuing through 5 days post-fertilization (dpf). Teratogenic effects and lethality were observed at 4 and 5 dpf in fish exposed to T4 or T3 at concentrations > 30 nM. However, as early as 3 dpf, T4 (> 3 nM) and T3 (> 10 nM) significantly increased swimming...
Source: Neurotoxicology - Category: Neurology Authors: Tags: Neurotoxicology Source Type: research