EFFECT OF STRESS ON RELAPSE OF OPIOID ADDICTIVE BEHAVIOR IN MALE AND FEMALE MICE

HÖCHT CHRISTIAN; PEREZ VIRGINIA SILVANA; BALERIO GRACIELA NOEMÍ; VILLALOBOS-VASQUEZ JESUS; OPEZZO JAVIER

Mar del Plata

Congreso; Reunión Anual de Sociedades de Biociencias. LXVIII SAIC. XXV SAB. LV AAFE. VIII AACYTAL; 2023

Previous studies from our laboratory have shown sex differences in the behavioural, molecular and neurochemical responses to morphine (MOR) withdrawal syndrome. In addition, stress is an important factor to trigger relapse in substance use disorders. The aim of our study was to evaluate patterns of extinction and relapse of opioid addictive behaviour under stress conditions and to correlate these patterns with neurochemical changes in brain nuclei related to brain reward circuitry in prepubertal CD1 male and female mice. The paradigm used was conditioned place preference (CPP) which consists of 3 phases: preconditioning, conditioning and postconditioning (test). On the test day, the reinforcing effects of MOR (10 mg/kg, s.c.) were tested and 24 h later, the extinction phase was carried out by 10 sessions of CPP administrating only saline (SAL) (0.10 ml/g, s.c.) in each session. The test was performed 24 h after the last extinction session, and CPP to MOR was considered extincted if the preference score was less than 15% of that obtained during the first test. After the extinction, animals were induced to relapse CPP by stress (immobilized for 15 min). Immediately after, brains were rapidly removed and homogenates were obtained. The supernatants were used for electrochemical detection coupled to HPLC of DA, 5-HT and their metabolites. Our results showed that MOR was able to induce reinforcing effects in mice of both sexes (p