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Knockout of histamine receptor H3 alters adaptation to sudden darkness and monoamine levels in the zebrafish
Author(s) -
Puttonen H. A. J.,
Sundvik M.,
Semenova S.,
Shirai Y.,
Chen YC.,
Panula P.
Publication year - 2018
Publication title -
acta physiologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 116
eISSN - 1748-1716
pISSN - 1748-1708
DOI - 10.1111/apha.12981
Subject(s) - knockout mouse , zebrafish , monoaminergic , biology , monoamine neurotransmitter , serotonin , dopamine , darkness , receptor , medicine , microbiology and biotechnology , endocrinology , biochemistry , gene , botany
Aim Histamine receptor H3 (HRH3) has substantial neuropharmacological potential. Currently, knockout models of this receptor have been investigated only in mice. We characterized the expression of this receptor in the zebrafish and generated a zebrafish HRH3 knockout line. Using this model, we studied the role of HRH3 in important behaviours. We also analysed the effect of HRH3 knockout on monoaminergic systems, which has not been thoroughly studied in any animal model. Methods Generation of a mutant zebrafish line using the CRISPR ‐Cas9 system. Analysis of locomotor and social behaviour. Expression of HRH3 was characterized using in situ hybridization. Analysis of monoamine networks using HPLC , immunohistochemistry and quantitative PCR . Results We found that HRH3 knockout zebrafish larvae showed a shorter period of increased locomotion after a sudden onset of darkness, while the knockout larvae had a wild‐type‐like acute response to sudden darkness. Adult knockout fish showed decreased swimming velocity, although locomotor activity of knockout larvae was unaltered. Additionally, levels of dopamine and serotonin were significantly decreased in the knockout fish, while monoamine‐related gene expression and immunohistochemistry patterns were unchanged. Conclusions Our results show that HRH3 knockout larvae adapt faster to sudden darkness, suggesting a role for this receptor in regulating responses to changes in the environment. The decreased levels of dopamine and serotonin provide the first direct evidence that knockout of HRH3 alters these systems.