Parental experience is linked with lower vasopressin receptor 1a binding and decreased postpartum androgens in titi monkeys

• Published in: Journal of neuroendocrinology 2023-07, Vol.35 (7), p.e13304-n/a
• Main Authors: Baxter, Alexander, Karaskiewicz, Chloe L., Campbell, Lindsey A., Kinnally, Erin L., Ferrer, Emilio, Seelke, Adele H. M., Freeman, Sara M., Bales, Karen L.
• Format: Article
• Language: English
• Subjects: Androgens; Androgens - metabolism; Animals; Argipressin; Argipressin receptors; Autoradiography; AVPR1a binding; Brain; Brain - metabolism; Callicebus; Callicebus - metabolism; Cognition; Female; Forebrain; Hippocampus; Humans; infant care; Male; Neuroplasticity; pair bonding; parental androgen suppression; Parental behavior; parental brain; Parents & parenting; Postpartum; Postpartum Period; Pregnancy; Preoptic area; Preoptic area (medial); Receptors, Vasopressin - metabolism; Superior colliculus; Vasopressin; Vasopressin receptors
• ISSN: 0953-8194; 1365-2826
• DOI: 10.1111/jne.13304

Parenting induces many neurological and behavioral changes that enable parents to rear offspring. Vasopressin plays an important role in this process via its effects on cognition, affect, and neuroplasticity, and in some cases, via interactions with decreased parental androgens. Thus far, the role of these hormones has been primarily studied in rodents. To address this gap, we explored vasopressin receptors and androgens in titi monkeys, a pair‐bonding and biparental primate species. In Studies 1 and 2, we used receptor autoradiography to correlate arginine vasopressin receptor 1a (AVPR1a) binding in the hippocampus (Study 1, n = 10) and the rest of the forebrain (Study 2, n = 23) with parental status, parental experience, parity, infant carrying, and pair affiliation. We found that parents exhibited lower AVPR1a binding than non‐parents throughout most brain regions assessed, with especially strong effects in the hippocampus (β = −.61), superior colliculus (β = −.88), lateral septum (β = −.35), and medial preoptic area (β = −.29). The other measures of parental experience also tended to be negatively associated with AVPR1a binding across different brain regions. In Study 3 (n = 44), we compared pre‐ and postpartum urinary androgen levels in parents and non‐parents and found that mothers exhibited a sustained androgen decrease across 3–4 months postpartum (relative to 3 months prepartum; β ranged from −.72 to −.62 for different comparisons). For males, we found that multiparous fathers exhibited decreased androgen levels at 1–2 weeks postpartum (β = −.25) and at 3–4 months postpartum (β = −.40) compared to the prepartum, indicating both immediate and long‐term reductions with subsequent paternal experience. Together, the results of this study suggest that decreases in AVPR1a binding and circulating androgens are associated with parental behavior and physiology in titi monkeys. We investigated whether parenting was associated with AVPR1a binding (postmortem brain tissue) and circulating androgen levels (postpartum urine samples) in titi monkeys, a biparental primate. In Studies 1 and 2, parents exhibited globally decreased AVPR1a binding compared to non‐parents; reduced AVPR1a binding was also associated with greater parental experience and pair affiliation. In Study 3, parents showed decreased androgen levels across 3 months postpartum, with different trajectories based on sex and parity.