The role of serotonin in modulating common waxbill behaviour

Abstract

Serotonin or 5-hydroxytryptamine (5-HT) is a monoaminergic neurotransmitter that is known to influence behaviour in various animal species. Its actions, however, are complex and not well-understood yet. Here, we tested whether and how two 5-HT receptor agonists and a 5-HT receptor antagonist influence behaviour in common waxbills (Estrilda astrild), focusing on aggression, movement and feeding. We applied acute administration of either 8-OH-DPAT (a 5-HT1A receptor agonist), fluoxetine (a selective serotonin reuptake inhibitor; SSRI) or WAY 100,635 (a 5-HT1A receptor antagonist), and then quantified behaviour in the context of competition for food. Waxbills treated with the SSRI fluoxetine showed an overall decrease of aggressive behaviour, activity and feeding, while we found no significant effects of treatment with the other serotonergic enhancer (8-OH-DPAT) or with the antagonist WAY 100,635. Since both 8-OH-DPAT and WAY 100,635 act mainly on 5-HT1A receptor pathways, while fluoxetine more generally affects 5-HT pathways, our results suggest that receptors other than 5-HT1A are important for serotonergic modulation of waxbill behaviour. Significance statement The serotonergic system is of interest for current behavioural research due to its influence on a range of behaviours, including aggression, affiliative behaviour, feeding and locomotion in various species. There are, however, numerous discrepancies regarding the behavioural effects of serotonin across studies. We used acute pharmacological manipulations of the serotonergic system in common waxbills, using two serotonin enhancers (8-OH-DPAT and fluoxetine) and a serotonin blocker (WAY 100,635). Behavioural effects of these pharmacological manipulations on aggressiveness, movement and feeding, during tests of competition over food, indicated an anxiogenic-like effect of fluoxetine, but not of 8-OH-DPAT and WAY 100,635. This suggests a distinct role for different serotonergic pathways on waxbill behaviour.

Changes in Induced-Antipredation Defense Traits and Transcriptome Regulations of Daphnia magna in Response to 5-HT1A Receptor Antagonist

“…37,38 It is often used as a pharmaceutical treatment in laboratory studies to explore biological processes related to serotonin. 39 Given that its action mechanism is similar to most PDs that regulate the serotonin system by modulating serotonin signaling, it is strategic to select WAY-100635 for experiments at concentrations that simulate both high natural levels and extreme levels after biomagnification or accumulated concentration. Therefore, appropriately setting a higher test concentration in our experiments will be helpful to comprehensively evaluate the potential risks of the abnormal regulation of the serotonin signaling system to cladocerans due to the effects of bioaccumulation and multiple-PD accumulation.…”

“…WAY-100635 is a selective 5-HT 1A receptor antagonist and a novel atypical antianxiety drug. It produces antidepressant and anxiolytic effects by preventing excessive activation of 5-HT 1A receptors and promoting the transmission of serotonin between neurons. , It is often used as a pharmaceutical treatment in laboratory studies to explore biological processes related to serotonin . Given that its action mechanism is similar to most PDs that regulate the serotonin system by modulating serotonin signaling, it is strategic to select WAY-100635 for experiments at concentrations that simulate both high natural levels and extreme levels after biomagnification or accumulated concentration.…”