Participação dos receptores purinérgicos P2 no comportamento maternal e nas funções neuroendócrinas de ratas lactantes

Abstract

Maternal behavior consists of a series of behaviors displayed by the female that specifically support the development, the growth of her offspring and in the propagation of its species. Previous studies have demonstrated the participation of several neurotransmitters and neuromodulators in the modulation of this behavior. However, to date, has not been established the participation of P2 purinergic receptors in maternal behavior in rodents. Although it has already been found the widespread presence of these P2 receptors in the central nervous system and its involvement in various processes, including the secretion of hypothalamic neuropeptides involved in lactation Therefore, the aim of our study was to investigate the participation of P2 purinergic receptors on behavioral (maternal care and aggression against the intruder) and neuroendocrine responses during lactation. For this evaluation, rats between the 6th and 7th day of lactation were used under the central infusion of vehicle or non-selective P2 receptors antagonist (Suramin) or P2X receptors antagonist (PPADS) or P2X receptors agonist (α,βMeATP) 30 minutes before starting the experiments. Microinjection of P2 purinergic receptor antagonists has altered the neuroendocrine and behavioral responses of lactating rats since it reduced maternal care as well as the activation of neurons in areas strongly involved with this behavior (medial preoptic area, bed nucleus of the stria terminalis and oxytocinergic neurons in paraventricular nucleus and in the supraoptic nucleus); reduced plasma oxytocin concentration and milk consumption by pups; reduced aggressive behavior as well as neuronal activation of neurons in the ventromedial hypothalamus, hypothalamic attack area, anterior hypothalamus, medial amygdala and ventrolateral periaqueductal gray. However, no change was found in the assessment of locomotor activity. Our results suggest the participation of purinergic P2 receptors in the behavioral and neuroendocrine responses of lactating rats.