Morphine attenuated the anxiety-like behaviour associated to acetic acid-induced visceral pain in adolescent male, but not in female mice lacking CB1 receptors

CANERO E.M.; PEDRÓN V.T.; AON AJ; VARANI A. P; BALERIO G. N

CABA

Congreso; IV International Congress in Translational Medicine.; 2018

Morphine attenuated the anxiety-like behaviour associated to acetic acid-induced visceral pain in adolescent male, but not in female mice lacking CB1 receptors.The aim of the present study was to evaluate 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 lacking CB1 receptors.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. CB1 knockout (CB1 KO) and wild-type (WT) 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% 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.MOR (3 mg/kg) decreased and MOR (9 mg/kg) completely blocked the nociceptive response (expressed as percentage of writhing inhibition) compared to their control groups (mice only treated with acetic acid) (p