Activation of maternal behavior of albino rats after combined treatment with dopamine and opioid receptor antagonists in low doses

Abstract

We studied the effect of D1/D2 antagonist haloperidol on maternal motivation in nursing albino rats. Haloperidol in a dose of 0.2 mg/kg significantly attenuated parental reactions and motor and exploratory activities. In a lower dose (0.1 mg/kg) the drug produced the same effect on maternal behavior (number of approaches to newborns) without reducing motor activity. The effect of low-dose haloperidol was different after naloxone treatment (0.2 mg/kg intranasally): the number of pup transfers increased significantly. The detected phenomenon indicates good prospects of combined treatment with agents modifying the cerebral dopaminergic and opioid systems as the method for correction of disorders in maternal behavior.

Effect of Single and Repeated Injections of Selective D2-Antagonist Clebopride on Maternal Behavior of Albino Rats

“…We previously showed that under stress conditions, the inhibitory effect of some drugs (e.g. agonists of opioid receptors) increases and outweighs the parental care despite additional activation of this care by a stressor [1]. In series III with repetitive (cumulative) administration of clebopride, we used a dose of 0.2 mg/kg, which according to the above experiments (series II) produced practically no behavioral effects after two injections made with a 2-day interval.…”

“…We measured the latency of the fi rst approach to the pups, the number of visits, the latency of transferring the pups, the number of transfers, etc. The methodical details are described somewhere [1,2,5].…”

“…Anatomically, the parental care originates from such structures as the medial preoptic area, n. ac cumbens, and the ventral tegmental area (VTA) [3,8,9]. The neurotransmitter basis of maternal beha vior is mostly composed of dopaminergic and the brain opioid receptor systems [1,4,11]. The agonists and antagonists of the corresponding receptors are considered as promising agents to cope with disturbances in parental care (post partum depression) [14] and to model the related symptoms in experimental animals [1,5].…”

“…In high doses it suppressed both parental care of albino rats and their motor activity. In contrast, the low doses of haloperidol specifi cally affected only the paternal care [1]. In this study, the same method was used to examine clebopride, a selective D 2 -antagonist, after its single and repetitive administration for 6 days.…”

“…The neurotransmitter basis of maternal beha vior is mostly composed of dopaminergic and the brain opioid receptor systems [1,4,11]. The agonists and antagonists of the corresponding receptors are considered as promising agents to cope with disturbances in parental care (post partum depression) [14] and to model the related symptoms in experimental animals [1,5]. This problem is also examined in the studies that analyze the effects of antipsychotic preparations and antidepressants administered to women during postpartum (PP) period [7,10].…”