Interfering with somatosensory stimulation from pups sensitizes experienced, postpartum rat mothers to oxytocin antagonist inhibition of maternal behavior.

Abstract

Proximal separation (PS) refers to isolating pups in small cages so dams can hear, smell, and see pups but have very limited physical contact with them. Six days of PS diminished the number of discernible oxytocin- (OT) immunostaining perikarya in forebrain areas of rat dams compared with 6 days of total separation (TS) or no separation (NS) from pups. Dams exhibited a more rapid resurgence of maternal behavior after 4-6 days of PS than after 4-6 days of TS. Bilateral infusion of the OT antagonist (OTA; 1 microgram/microliter/side) into the ventral tegmental area blocked the resurgence of maternal behavior after 3-6 days of PS but not after 2 days of PS or 4-6 days of NS. The conclusion was that PS for 3 or more days reinstates OT as necessary and sufficient for the activation of maternal behavior in experienced rat mothers. These findings suggest that some aspects of somatosensory stimulation from pups regulate the role of OT in the control of maternal behavior.

Functional Magnetic Resonance Imaging Shows Oxytocin Activates Brain Regions Associated with Mother–Pup Bonding during Suckling

“…However, it is possible that a longterm disruption of central oxytocinergic effects would be more disruptive (Pedersen et al, 1995;Pedersen and Boccia, 2003). It should also be mentioned that the central release of OT might be related to maternal aggression.…”

Sex differences and developmental effects of manipulations of oxytocin on alloparenting and anxiety in prairie voles

“…OTA has been shown to decrease maternal care when administered centrally in adult rats (Pedersen et al, 1982;Pedersen et al, 1995); however, there are no previous reports of either immediate or long-lasting effects of OTA on male parental care. AVP, a hormone closely related to OT in structure, has been linked to male parental care (Bamshad et al, 1994;Wang et al, 1994;reviews in Wang & Insel, 1996;Ziegler, 2000); however, the exact role of AVP remains to be understood.…”

“…Oxytocin (OT), in particular, is released during sexual behavior, labor, and lactation, and has been associated with the onset of maternal behavior (Fahrbach, Morrell, & Pfaff, 1985;Kendrick et al, 1997;Kendrick, Keverne, Hinton, & Goode, 1992;Pedersen, 1997;Pedersen et al, 1982;Pedersen, et al, 1995), pair bonding, and other positive social behaviors (Carter, 1998;Carter & Keverne, 2002). OTalso may play a role in homeostatic responses to stressors (Uvnas-Moberg, 1998).…”

Hormonal and non-hormonal bases of maternal behavior: The role of experience and epigenetic mechanisms

“…CREB and ERK signaling pathways may have particular functional relevance to these sensory-mediated effects (Putignano et al, 2007). Somatosensory inputs from pups likely contribute to the expression of maternal behavior (hormonal or nonhormonal) and deprivation of this contact can impact the maternal brain (Pedersen et al, 1995). Tactile-mediated sensory input may also be critical to the epigenetic impact of the experience of maternal care during postnatal development (Hellstrom et al, 2012).…”