Central V1b Receptor Antagonism in Lactating Rats: Impairment of Maternal Care But Not of Maternal Aggression

Abstract

Maternal behaviour in rodents is mediated by the central oxytocin and vasopressin systems, amongst others. The role of vasopressin, acting via the V1a receptor (V1aR), on maternal care and maternal aggression has recently been described. However, a potential involvement of the V1b receptor (V1bR) in maternal behaviour has only been demonstrated in knockout mice. The present study aimed to examine the effects of central pharmacological manipulation of the V1bR on maternal behaviour in lactating Wistar rats. On pregnancy day 18, female rats were implanted with a guide cannula targeting the lateral ventricle. After parturition, dams received an acute central infusion of a specific V1bR agonist (d[Leu4,Lys8]VP) or V1bR antagonist (SSR149415) once daily, followed by observations of maternal care [lactation day (LD) 1], maternal motivation in the pup retrieval test (LD 2), anxiety-related behaviour on the elevated plus-maze (LD 3) and maternal aggression in the maternal defence test followed by maternal care monitoring (LD 4). Our data demonstrate that, under nonstress conditions, the V1bR antagonist decreased the occurrence of both nursing and mother-pup interaction, whereas the V1bR agonist did not affect either parameter. Under stress conditions (i.e. after the maternal defence test), mother-pup interaction was decreased by infusion of the V1bR antagonist. During the maternal defence test, neither treatment affected aggressive or non-aggressive behaviour. Finally, neither treatment altered maternal motivation or anxiety. In conclusion, central V1bR antagonism modulates aspects of maternal care but not of maternal aggression or maternal motivation in lactating rats. These findings further extend our knowledge on the vasopressin system as a vital mediator of maternal behaviour.

Brain vasopressin signaling modulates aspects of maternal behavior in lactating rats

“…In addition to V1a receptors, V1b receptors are also involved in mediating maternal care. In lactating NAB dams, acute central blockade of V1b receptors using the selective receptor antagonist SSR149415 impairs the display of nursing and the amount of mother‐pup interaction, whereas the V1bc receptor‐specific agonist d[Leu 4 ,Lys 8 ]VP has no effect . Hence, these data suggest a crucial role for both V1 receptor subtypes in maternal care.…”

“…In daily acutely stressed lactating rats, chronic central infusion of vasopressin decreases the time until retrieval of all pups in mid but not early lactation . Interestingly, in lactating NAB rats, central V1b receptor agonism or antagonism has no effect on pup retrieval . Therefore, these studies hint towards a dominant role of V1a receptors over V1b receptors to promote maternal motivation (for overview see Table ).…”

“…Hence, these data suggest a crucial role for both V1 receptor subtypes in maternal care. Furthermore, our additional finding that after stressor‐exposure, that is, 10‐min maternal defense test, central V1b receptor antagonism leads to impaired nursing and mother‐pup interaction suggests that V1b receptors might be necessary for the reinstatement of adequate maternal care after disruption of the homeostasis …”

Brain CRF-binding protein modulates aspects of maternal behavior under stressful conditions and supports a hypo-anxious state in lactating rats

“…Maternal care was monitored on lactation day (LD) 1 before and after substance infusion (non-stress condition) as well as on LD 5 before and after substance infusion, which was combined with a psychosocial stressor (i.e. the maternal defense test; stress condition Bayerl et al, 2014;Klampfl et al, 2014Klampfl et al, , 2016Klampfl et al, 2013)). Observations were conducted for 10 s every 2 nd min in 30 min blocks according to an established protocol (Bosch and Neumann, 2008).…”

Effects of Chronic Social Stress and Maternal Intranasal Oxytocin and Vasopressin on Offspring Interferon-γ and Behavior

“…AVP is an established mediator of social recognition (37), which may explain its effectiveness in ameliorating the social stress-induced deficits in social interaction through changes in investigatory behaviors, but not allogrooming. In maternal rats, AVP is a key mediator of maternal care, maternal aggression, maternal memory, and self-grooming (38–44), and chronic central infusion of AVP enhances maternal care in CSS-exposed F0 dams (19). The preventative effects of AVP on F2 juveniles indicate that it may be an effective treatment for both depressed maternal care and the adverse effects of deficient care on offspring.…”