Rodent Nonapeptides

Cross references:  Rodent 5-HT1R      Rodent 5-HT3R    
Rodent Hormone-Nerve Interaction

Nonapeptides and the Evolutionary Patterning of Sociality (PubMed) 
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Neuropeptides of the arginine vastocin (AVT) family, which include the mammalian peptides arginine vasopressin (AVP) and oxytocin (OXT), comprise neuroendocrine circuits that range from being evolutionarily conserved to evolutionarily diverse. For instance, the functions and anatomy of the AVT/AVP projections to the pituitary (which arise in the preoptic area and hypothalamus) are strongly conserved, whereas those of extrahypothalamic AVT/AVP circuits are species-specific and change rapidly over evolutionary time.



Molecular genetic studies of the arginine vasopression 1a receptor (AVPR1a) ... (OTXR) ... (PubMed) 
Only abstract available online.
"Converging evidence from both human and animal studies has highlighted the pervasive role of two neuropeptides, oxytocin (OXT) and arginine vasopressin (AVP), in mammalian social behaviours. ... associated with two other social domains in Homo sapiens: music and altruism. AVPR1a was associated with dance and musical cognition which we theorize as reflecting the ancient role of this hormone in social interactions executed by vocalization, ritual movement and dyadic (mother-offspring) and group communication.



Impact of prosocial neuropeptides on human brain f... (PubMed) 
Only abstract available online. 
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Oxytocin and vasopressin are key effectors of social behaviour. Oxytocin effects in humans were recently demonstrated by a behavioural study showing selectively increased trust after hormone administration. Since this suggested involvement of the amygdala, which is linked to trust - presumably because of its role in danger monitoring - and highly expresses oxytocin receptors, we studied amygdala circuitry after double-blind crossover intranasal application of placebo or oxytocin. Oxytocin potently reduced amygdala activation and decreased coupling to brainstem regions implicated in autonomic and behavioural manifestations of fear, indicating a neural mechanism for the effects of oxytocin in social cognition in humans and providing a potential therapeutic approach to social anxiety currently being tested in social phobia and autism. ... Preliminary findings from our laboratory using imaging genetics indeed implicate genetic variants for both AVPR1A, encoding the primary receptor of vasopressin in brain, and the oxytocin receptor, OXTR, in amygdala regulation and activation.



Oxytocin: the great facilitator of life (PubMed) 
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 Although Oxt is implicated in a variety of "non-social" behaviors, such as learning, anxiety, feeding and pain perception, it is Oxt's roles in various social behaviors that have come to the fore recently. Oxt is important for social memory and attachment, sexual and maternal behavior, and aggression. Recent work implicates Oxt in human bonding and trust as well. Human disorders characterized by aberrant social interactions, such as autism and schizophrenia, may also involve Oxt expression. Many, if not most, of Oxt's functions, from social interactions (affiliation, aggression) and sexual behavior to eventual parturition, lactation and maternal behavior, may be viewed as specifically facilitating species propagation.


Brain oxytocin: a key regulator of emotional and s... (PubMed) 
Only abstract available online. 
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In addition to various reproductive stimuli, the neuropeptide oxytocin (OXT) is released both from the neurohypophysial terminal into the blood stream and within distinct brain regions in response to stressful or social stimuli. Brain OXT receptor-mediated actions were shown to be significantly involved in the regulation of a variety of behaviours. ... Also, in male rats, activation of the brain OXT system is essential for the regulation of sexual behaviour, and increased OXT system activity during mating is directly linked to an attenuated anxiety-related behaviour.



Oxytocin, vasopressin and pair bonding: implications for autism (PubMed) 
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Oxytocin and vasopressin contribute to a wide variety of social behaviours, including social recognition, communication, parental care, territorial aggression and social bonding. ... Prairie voles are socially monogamous; males and females form long-term pair bonds, establish a nest site and rear their offspring together. In contrast, montane and meadow voles do not form a bond with a mate and only the females take part in rearing the young. Species differences in the density of receptors for oxytocin and vasopressin in ventral forebrain reward circuitry differentially reinforce social-bonding behaviour in the two species. High levels of oxytocin receptor (OTR) in the nucleus accumbens and high levels of vasopressin 1a receptor (V1aR) in the ventral pallidum contribute to monogamous social structure in the prairie vole. While little is known about the genetic factors contributing to species-differences in OTR distribution, the species-specific distribution pattern of the V1aR is determined in part by a species-specific repetitive element, or ‘microsatellite’, in the 5′ regulatory region of the gene encoding V1aR (avpr1a). This microsatellite is highly expanded in the prairie vole (as well as the monogamous pine vole) compared to a very short version in the promiscuous montane and meadow voles. These species differences in microsatellite sequence are sufficient to change gene expression in cell culture. Within the prairie vole species, intraspecific variation in the microsatellite also modulates gene expression in vitro as well as receptor distribution patterns in vivo and influences the probability of social approach and bonding behaviour.



Pheromones enhance somatosensory processing in newt brains through a vasotocin-dependent mechanism  (PubMed) 
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In summary, we have shown that social stimuli processed within one sensory modality can affect how sensory information coming in through other sensory modalities is processed in male roughskin newt brains, most likely by inducing endogenous VT release.
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