Effects of Reproductive Experience on Central Expression of Progesterone, Oestrogen α, Oxytocin and Vasopressin Receptor mRNA in Male California Mice (Peromyscus californicus)

Abstract

Fatherhood in biparental mammals is accompanied by distinct neuroendocrine changes in males, involving some of the same hormones involved in maternal care. In the monogamous, biparental California mouse (Peromyscus californicus), paternal care has been linked to changes in the central and/or peripheral availability of oestrogen, progesterone, vasopressin and oxytocin, although it is not known whether these endocrine fluctuations are associated with changes in receptor availability in the brain. Thus, we compared mRNA expression of oestrogen receptor (ER)α, progesterone receptor (PR), vasopressin receptor (V1a) and oxytocin receptor (OTR) in brain regions implicated in paternal care [i.e. medial preoptic area (MPOA)], fear [i.e. medial amygdala (MeA)] and anxiety [i.e. bed nucleus of the stria terminalis (BNST)] between first-time fathers (n = 8) and age-matched virgin males (n = 7). Males from both reproductive conditions behaved paternally towards unrelated pups, whereas fathers showed significantly shorter latencies to behave paternally and less time investigating pups. Furthermore, fathers showed significantly lower PR, OTR and V1a receptor mRNA expression in the BNST compared to virgins. Fathers also showed a marginally significant (P = 0.07) reduction in progesterone receptor mRNA expression in the MPOA, although fatherhood was not associated with any other changes in receptor mRNA in the MPOA or MeA. The results of the present study indicate that behavioural and endocrine changes associated with the onset of fatherhood, and/or with cohabitation with a (breeding) female, are accompanied by changes in mRNA expression of hormone and neuropeptide receptors in the brain.

Aging and estradiol effects on gene expression in the medial preoptic area, bed nucleus of the stria terminalis, and posterodorsal medial amygdala of male rats

“…Decreased oxytocin receptor expression and binding in the BnST have been reported to be associated with decreased aggression. Rats who were first time fathers exhibited facilitated parental care compared to virgins, and lower oxytocin receptor expression in the BnST, but not the MeA or POA (Perea-Rodriguez et al, 2015). On the other hand, when introduced to a novel male intruder, rats classified as excessively aggressive also showed the highest levels of oxytocin receptor binding in the BnST (Calcagnoli et al, 2014).…”

Exposure to extrinsic stressors, social defeat or bisphenol A, eliminates sex differences in DNA methyltransferase expression in the amygdala

“…Frozen brains were shipped to UC Davis where they were sliced on a cryostat at a thickness of 500 μm at −10°C and immediately immersed into RNAlater for approximately 24 hours at 4°C . A 0.36‐mm diameter punch tool was used to collect bilateral samples of BLA and CeA.…”

The birth of new neurons in the maternal brain: Hormonal regulation and functional implications

“…Fathers of biparental species, such as the California mouse and prairie vole, engage in all aspects of parental behaviors displayed by the mother, except nursing (Lonstein and DeVries, 2000). Evidence to date suggests that the neural circuitry underlying paternal behavior is similar to that for maternal behavior (Bales and Saltzman, 2015; Perea-Rodriguez et al, 2015). Moreover, the endocrine changes experienced by fathers typically involve testosterone but also some of the same hormones and neuropeptides that regulate maternal care and lactation including estrogen, progesterone, prolactin, oxytocin and vasopressin, although often with notable species variations (Saltzman and Ziegler, 2014; Bales and Saltzman, 2015; Perea-Rodriguez et al, 2015).…”