Peptides of love and fear: vasopressin and oxytocin modulate the integration of information in the amygdala

Abstract

Neuropeptides vasopressin and oxytocin regulate a variety of behaviors ranging from maternal and pair bonding to aggression and fear. Their role in modulating fear responses has been widely recognized, but not yet well understood. Animal and human studies indicate the major role of the amygdala in controlling fear and anxiety. The amygdala is involved in detecting threat stimuli and linking them to defensive behaviors. This is accomplished by projections connecting the central nucleus of the amygdala (CeA) to the brain stem and to hypothalamic structures, which organize fear responses. A recent study by Huber et al demonstrates that vasopressin and oxytocin modulate the excitatory inputs into the CeA in opposite manners. Therefore this finding elucidates the mechanisms through which these neuropeptides may control the expression of fear.

Attachment, aggression and affiliation: The role of oxytocin in female social behavior

“…While OT inhibits aggression directed towards the pups, it simultaneously enhances attacks on intruders (Debiec, 2005;Pedersen, 2004). Maternal aggression is typically studied experimentally in rodents by introducing a strange conspecific of either sex into the mother"s home cage in the presence of her pups.…”

Chronic methamphetamine treatment induces oxytocin receptor up-regulation in the amygdala and hypothalamus via an adenosine A2A receptor-independent mechanism

“…Accumulating evidence showing a strong interaction between neuronal markers of social behaviour and those of stress and mood regulation (Dabrowska et al , 2011, Debiec, 2005, Di Simplicio et al , 2009, Heinrichs and Gaab, 2007, Windle et al , 2004) and of drug reward/withdrawal (Liu et al , 2011, suggest that the "social" neuropeptide oxytocin (OT) and its receptor (OTR) may be implicated in the modulation of at least some of these methamphetamine-induced effects. OT is primarily synthesized by the magnocellular neurons of the supraoptic (SON) and paraventricular (PVN) 5 nuclei of the hypothalamus projecting to the posterior pituitary gland where it is stored in vesicles and it is released into the bloodstream to exert its peripheral effects (Fig.…”

“…There is considerable evidence demonstrating abnormalities in the amygdala following chronic MAP use (Kim et al , 2011, London et al , 2004 which is likely to be at least partly responsible for the development of anxiety, stress, depression (Dawe et al , 2009, Goeldner et al , 2011, Morley et al , 2001, Thompson et al , 2004) and social cognitive deficits (Dawe et al, 2009, Volkow et al , 2011. Given that OT is known to stimulate oxytocinergic neurons in the amygdala (Carson et al, 2010c) and that the amygdala is partly responsible for the prosocial, antidepressant and anxiolytic properties of OT (Baumgartner et al, 2008, Debiec, 2005, Domes et al , 2007, Febo et al , 2005, Febo et al , 2009, it would be intriguing to speculate that the upregulation of OTRs in this regions, following chronic MAP administration, may be involved in the modulation of the behavioural consequences of chronic MAP use including depression, anxiety and social deficits. Interestingly, Thompson et al, (2007) strongly implicated the oxytocinergic system of the central medial amygdala in the prosocial effect of the drug MDMA ("ecstasy").…”

Cloning and identification of an oxytocin/vasopressin-like receptor and its ligand from insects

“…Vasopressin has antidiuretic actions in mammals by stimulating water reabsorption from the renal collecting ducts. It also increases blood pressure and is involved in various aspects of reproduction, such as male/female pair bonding and parental care (14)(15)(16). Oxytocin induces contractions of the uterus during birth and milk ejection from the mammary glands during lactation.…”