chrna3 modulates alcohol response in zebrafish
Alcohol use disorders (AUDs) are complex phenomena governed by genetics, neurophysiology, environment, and societal structures. New methods to understand the underlying neurogenetics are valuable for designing personalised interventional strategies. Here, we used a novel, two-choice self-administration zebrafish assay (SAZA) to isolate the function of nicotinic acetylcholine receptor (nAChR) subunit alpha3 (chrna3) in alcohol response. Juvenile zebrafish exhibited a biphasic response when self-administering alcohol that transitioned from attraction to aversion within minutes, suggesting they can regulate exposure to alcohol. This inverted U-shaped self-administration mirrored the effect alcohol has on shoaling behaviour. Exposure to low concentration of alcohol reduced anxiety-like behaviours, while sedative effects became prominent at higher concentrations resulting in reduced locomotion and uncoordinated swimming. In contrast, these responses are blunted in chrna3 mutants. They exhibit prolonged alcohol self-administration, and increased gregariousness. Transcriptomic analyses suggest that glutamatergic and GABAergic neurotransmission alongside cholinergic signalling is impacted in the mutant brains. Our results thus suggest that chrna3 dysfunction has a systemic change with an increase in alcohol tolerance being one effect. These findings also highlight the use of non-rodent alternatives to understand the neurogenetics of development of AUD. Overall design: We generated CRISPR/Cas-9 mutants in the gene chrna3 called chrna3C246X. For analysis of trancriptomic changes in adult brains, homozygous mutants chrna3C246X and WT were raised to adulthood. RNA-seq analysis performed on whole brains in triplicates. The quality of each sample was verified by gel electrophoresis and bio-analyser. Samples that passed QC were sent for sequencing by Novogene AIT. An mRNA cDNA library made up of Paired-end sequencing reads of 150 bp in length was generated on the Illumina HiSeq instrument.