title: Assessments of the effects of nicotine and ketamine using tyrosine hydroxylase-green fluorescent protein transgenic zebrafish as biosensors.
abstract: Transgenic zebrafish are a common vertebrate model system for the study of addictive behavior. In the present study, plasmid constructs containing green fluorescent protein (GFP) and the promoter of tyrosine hydroxylase (TH), a key synthetic enzyme for catecholamines, were produced. The TH-GFP constructs were microinjected into zebrafish embryonic cells. Three days post-fertilization, GFP began expressing in distinct catecholaminergic areas. The TH-GFP transgenic zebrafish were employed as live biosensors to test the effects of the commonly abused drugs nicotine and ketamine. First, locomotion assays were used to study the general excitatory effects of the drugs. Maximal locomotor activity was obtained after treatment with a high concentration of nicotine (10 μM), but with a much lower concentration of ketamine (0.1 μM). Second, TH protein levels in zebrafish brains were assessed by Western blot. TH protein levels were significantly increased, with maximal protein levels found after treatment with the same drug concentrations that gave maximal locomotor activity. Importantly, analysis of GFP in the zebrafish catecholaminergic areas revealed the same expression patterns as was obtained by Western blot. The present results indicate that increased locomotor activity can be correlated to TH protein expression, as indicated by Western blot and expression of TH-GFP. We have shown that TH-GFP expression is a reliable method to show the effects of drugs on TH expression that may be employed as a novel high-throughput live biosensor for screening drugs of abuse.
authors.affiliation: Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong.
authors.forename: Miranda F K
authors.initials: MF
authors.lastname: Suen
authors.forename: W S
authors.initials: WS
authors.lastname: Chan
authors.forename: Karen W Y
authors.initials: KW
authors.lastname: Hung
authors.forename: Y F
authors.initials: YF
authors.lastname: Chen
authors.forename: Z X
authors.initials: ZX
authors.lastname: Mo
authors.forename: Ken K L
authors.initials: KK
authors.lastname: Yung
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D015374:Biosensing Techniques / Q000379:methods*; D049452:Green Fluorescent Proteins / Q000737:chemistry*; D013287:Illicit Drugs; D007649:Ketamine / Q000008:administration & dosage; D008124:Locomotion / Q000187:drug effects*; D009538:Nicotine / Q000008:administration & dosage; D011401:Promoter Regions, Genetic; D014446:Tyrosine 3-Monooxygenase / Q000737:chemistry*; D015027:Zebrafish / Q000196:embryology / Q000235:genetics
chemical_list: D013287:Illicit Drugs; D049452:Green Fluorescent Proteins; D007649:Ketamine; D009538:Nicotine; D014446:Tyrosine 3-Monooxygenase