The neurotransmitter serotonin (5-HT) reduces aggressive behaviour in a number of vertebrates, and the 5-HT_1A receptor is known to be involved in this regulation. However, the role of this receptor in the modulation of sociopositive behaviour remains largely unknown. Here we investigated the role of the 5-HT_1A receptor in the regulation of aggressive, submissive and affiliative behaviour in the cooperatively-breeding cichlid Neolamprologus pulcher. In two experiments, we performed intramuscular injections of a 5-HT_1A agonist (8-OH-DPAT) and antagonist (Way-100635) followed by recordings of social behaviour of injected fish within their social groups. We determined the concentrations and post-injection times when the drugs had the greatest effect on social behaviour. We recorded spontaneous social behaviour in both experiments. In the second experiment we also recorded behaviour after social groups received a territorial challenge by live presentations of either conspecifics or egg predators. The 5-HT_1A agonist caused an increase in aggression and a decrease in submission and affiliation, whereas the antagonist had the opposite effects. Thus, the 5-HT_1A receptor plays an important regulatory role not only for aggressive but also sociopositive behaviour.

神经递质血清素 (5-HT) 可减少许多脊椎动物的攻击行为，并且已知5-HT _1A受体参与此调节。然而，这种受体在调节社会积极行为中的作用在很大程度上仍然未知。在这里，我们研究了 5-HT _1A受体在调节合作繁殖慈鲷Neolamprologus pulcher的攻击性、顺从性和亲和性行为中的作用。在两个实验中，我们进行了 5-HT _{1A 的}肌肉注射激动剂 (8-OH-DPAT) 和拮抗剂 (Way-100635) 然后记录注射鱼在其社会群体中的社会行为。我们确定了药物对社会行为产生最大影响时的浓度和注射后时间。我们在两个实验中都记录了自发的社会行为。在第二个实验中，我们还记录了社会群体通过对同种动物或卵食肉动物的现场演示而受到领土挑战后的行为。5-HT _1A激动剂引起攻击性增加和服从和从属关系的减少，而拮抗剂具有相反的作用。因此，5-HT _1A受体不仅对攻击性行为而且对社会积极行为都起着重要的调节作用。