Functional New World monkey oxytocin forms elicit an altered signaling profile and promotes parental care in rats.
Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, 14040-900 Ribeirão Preto, São Paulo, Brazil.
The neurohormone oxytocin is a key player in the modulation of reproductive and social behavioral traits, such as parental care. Recently, a correlation between different forms of oxytocin and behavioral phenotypes has been described in the New World Monkeys (NWMs). Here, we demonstrate that, compared with the Leu(8)OXT found in most placental mammals, the Cebidae Pro(8)OXT and Saguinus Val(3)Pro(8)OXT taxon-specific variants act as equi-efficacious agonists for the Gq-dependent pathway but are weaker agonists for the β-arrestin engagement and subsequent endocytosis toward the oxytocin receptor (OXTR). Upon interaction with the AVPR1a, Pro(8)OXT and the common Leu(8)OXT yielded similar signaling profiles, being equally efficacious on Gq and β-arrestin, while Val(3)Pro(8)OXT showed reduced relative efficacy toward β-arrestin. Intranasal treatment with either of the variants increased maternal behavior and also promoted unusual paternal care in rats, as measured by pup-retrieval tests. We therefore suggest that Val(3)Pro(8)OXT and Pro(8)OXT are functional variants, which might have been evolutionarily co-opted as an essential part of the adaptive genetic repertoire that allowed the emergence of taxon-specific complex social behaviors, such as intense parental care in the Cebidae and the genus Saguinus.
Proc. Natl. Acad. Sci. U.S.A. 2017;114(34):9044-9049.
Pubmed ID: 28784762