Role of CB1 receptor in vulnerability to morphine dependence in adolescent mice prenatally exposed to a cannabinoid agonist

BRUSCO HA; BALERIO G. N.; PEDRÓN V; SORIANO D.; VARANI A; CALTANA L

Dubrovnik

Congreso; International Drug Abuse Reseaarch Society (6th Biennial IDARS meeting).; 2017

Cannabinoids and opioids are psychoactive drugs with similar pharmacological effects, as both produce analgesia, catalepsy, hypothermia, motor depression, hypotension and reward effects. CB1 receptor is involved in the motivational properties of opiates and in the development of dependence. The close relationship between cannabinoid and opioid systems is critical during morphine (MOR) withdrawal. CD1 mice deficient in cannabinoid receptor type 1 (CB1 knockout) have a lower intensity of somatic signals to MOR withdrawal induced by naloxone (NAL) as compared to wild-type CD1 mice (WT).The current work studied: 1) gender differences in the somatic syndrome during MOR withdrawal induced by NAL in CB1 knockout and WT; 2) the effect of prenatal exposure to WIN 55.212-2 (WIN) on the expression of MOR withdrawal in adolescent CB1 knockout and WT. Primiparous pregnant CB1 knockout and WT received WIN or vehicle from gestational day 5; after delivery, dams were replaced by naive substitutes. The MOR dependence and withdrawal protocol was implemented in pups at postnatal day 25.Results: 1) No gender-specific differences were detected between pups; 2) Prenatal exposure to WIN reduced MOR withdrawal expression in WT but not in CB1 knockout, whose MOR withdrawal expression levels showed no significant differences from their vehicle counterparts (p