Central actions of arginine vasopressin and a V1a receptor antagonist on maternal aggression, maternal behavior, and grooming in lactating rats

Abstract

Maternal aggression is a robust type of aggression displayed by lactating female rats. Although arginine vasopressin (AVP) has been implicated in the control of male aggression, its involvement in maternal aggression has not been thoroughly investigated. Previous neuroanatomical studies suggest that AVP may mediate the display of aggression during lactation. In the current study, AVP and an AVP V1a receptor antagonist were centrally administered to primiparous rats on days 5 and 15 of lactation, and aggression, maternal behavior, and grooming were recorded. Although AVP did not affect the number of attacks or duration of aggression, it increased the latency to initiate aggression on day 5, in addition to decreasing maternal behavior and increasing grooming. Conversely, V1a antagonist treatment increased maternal aggression on both days of lactation, decreased maternal behavior on day 15, and decreased grooming on day 5. Thus, it appears that central AVP activity modulates maternal aggression, as well as maternal behavior and grooming behavior during lactation.

Vasopressin V1a and V1b Receptors: From Molecules to Physiological Systems

“…Furthermore, AVP release significantly increases in the medial preoptic area (MPOA) or tends to increase in the BNST during different phases of maternal care (61). Though V1aR-KO mice display normal maternal aggression (532), blocking the V1a receptor by intracerebroventricular infusion of a selective V1a receptor antagonist or local administration of V1a antisense oligonucleotide into the MPOA impairs maternal care (59,370). Moreover, chronic infusion of the V1a receptor antagonist into the MeA impairs maternal memory (369).…”

Using Chronic Social Stress to Model Postpartum Depression in Lactating Rodents

“…While chronic social defeat is effectively used as a model for social stress-induced depression in male rodents 14, this is not an ecologically relevant behavioral model for many maternal rodents if male intruders are used, as a single social defeat of a maternal rodent usually results in cannibalism of the litter by the male intruder. However, acute exposure to a novel male intruder, without social defeat of the dam, elicits robust behavioral and endocrine stress responses in lactating females [15][16][17][18] . There is also evidence that chronic stress during lactation, including exposure to a male intruder, directly impairs milk production 19,20, which may impact pup growth.…”

Behavioral Roles of Oxytocin and Vasopressin

“…V1a antagonist treatment increases maternal aggression in both primiparous and multiparous dams, and AVP injection decreases maternal aggression in highly aggressive multiparous rats [171,172]. An inhibitory role for AVP in females is also supported by multiple experiments in non-maternal female hamsters [173].…”

“…It is known that OXT receptor and AVP V1a antagonists prevent pair bond formation in both males and females [170]. Studies of AVP and maternal behavior indirectly support the hypothesis that AVP is a mediator of female affiliation [48,171], but it is unknown if these effects pertain to adult conspecific affiliation. Additional studies on females are needed to determine if central AVP also is a significant mediator of the female component of pairbonding.…”

“…Both AVP and V1a antagonist treatments decrease maternal care during exposure to a male intruder, with the effects of AVP associated with increased self grooming and the effects of V1a antagonist associated with elevated maternal aggression during resident intruder tests of maternal aggression [171]. Studies focusing specifically on maternal care conclude that central AVP promotes ongoing maternal care [48].…”