Bold zebrafish (Danio rerio) express higher levels of delta opioid and dopamine D2 receptors in the brain compared to shy fish.
Behav Brain Res
; 359: 927-934, 2019 02 01.
Article
in En
| MEDLINE
| ID: mdl-29935279
ABSTRACT
Individual variation in coping with environmental challenges is a well-known phenomenon across vertebrates, including teleost fish. Dopamine is the major transmitter in the brain reward networks, and important for motivational processes and stress coping. Functions of the endogenous opioid system are not well studied in teleosts. However, in mammals the activity in the brain reward networks is regulated by the endogenous opioid system. This study aimed at investigating if there was a correlation between risk-taking behavior and the expression of dopamine and opioid receptors in the zebrafish (Danio rerio) brain. Risk-taking behavior was assessed in a novel tank diving test, and the most extreme high risk taking, i.e. bold, and low risk taking, i.e. shy, fish were sampled for qPCR analysis of whole brain gene expression. The expression analysis showed a significantly higher expression of the dopamine D2 receptors (drd2a and drd2b) and the delta opioid receptor (DOR; oprd1b) in bold compared to shy fish. Besides reward and reinforcing properties, DORs are also involved in emotional responses. Dopamine D2 receptors are believed to be important for active stress coping in rodents, and taken together the results of the current study suggest similar functions in zebrafish. However, additional experiments are required to clarify how dopamine and opioid receptor activation affect behavior and stress coping in this species.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Social Behavior
/
Brain
/
Gene Expression
/
Receptors, Dopamine D2
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Receptors, Opioid, delta
Type of study:
Etiology_studies
Aspects:
Determinantes_sociais_saude
Limits:
Animals
Language:
En
Journal:
Behav Brain Res
Year:
2019
Document type:
Article