STUDY OF THE INVOLVEMENT OF CB1 RECEPTOR IN ANXIETY LIKE-BEHAVIOUR RELATED TO ACETIC ACID-INDUCED VISCERAL PAIN IN ADOLESCENT MALE AND FEMALE MICE LACKING CB1 RECEPTORS

BALERIO GRACIELA N; CANERO ELIANA M.; PEDRÓN VALERIA T.; AON AMIRA J.

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

CB1 cannabinoid receptors are widely distributed in the central nervous system where they mediate most of the cannabinoid induced responses. Here we evaluated the interaction between the CB1 cannabinoid receptors and the endogenous opioid system by assaying anxiety like-behaviour related to acetic acid-induced visceral pain in adolescent mice of both sexes.The elevated plus maze and acetic acid-induced writhing tests were used in order to evaluate the effect of morphine (MOR) on the anxiety like-behaviour associated to visceral pain in mice lacking CB1 receptors, respectively. CB1 knockout (CB1 KO) and their wild-type (WT) littermates mice were pre-treated with MOR (3 mg/kg or 9 mg/kg i.p.) or saline (SAL) injection 20 minutes before acetic acid (1.5%, 10 ml/kg i.p.) or SAL administration, and immediately after, the total number of writhes or anxiety-like responses were registered for a period of 20 min.We observed significant differences in the effect of MOR on the number of writhes, expressed as percentage of writhing inhibition. MOR (3 mg/kg) decreased and MOR (9 mg/kg) completely blocked the number of writhes compared to their control groups (mice only treated with acetic acid) (p