Study of CB1 cannabinoid receptors involvement in the anxiety like-behaviour and memory consolidation associated to acetic acid-induced visceral pain in CB1 knockout adolescent mice

PEDRÓN VALERIA T.; BALERIO GRACIELA N.; CANERO ELIANA M.; BALERIO GRACIELA N

Mar del Plata

Congreso; Reunión Anual de Sociedades de Biociencias. S A I C. S A F E. S A B. SAP 2 0 1 9. AACYTAL. NANOMED-AR. HCS; 2019

SAIC

Study of CB1 cannabinoid receptors involvement in the anxiety like-behaviour and memory consolidation associated to acetic acid-induced visceral pain in CB1 knockout adolescent mice.In previous studies we evaluated the interaction between the CB1 cannabinoid receptors and the endogenous opioid system studying the antinociceptive effect of morphine (MOR) by using the acetic acid (AA)-induced writhing test in CB1 knockout (KO) adolescent male and female mice. The aim of the present study was to evaluate the motivational (anxiety like-behaviour) and cognitive (memory consolidation) responses associated to the AA-induced visceral pain model in adolescent CB1 KO mice of both sexes. The anxiety like-behaviour associated to visceral pain was measured by the elevated plus maze (EPM). CB1 KO and WT mice were pre-treated with MOR (1, 3 or 9 mg/kg i.p.) or saline (SAL) injection, 20 minutes before the AA (1.5%, 10 ml/kg i.p.) or SAL administration. Immediately after, the time spent and number of entries to the open arms were registered during 20 min.The memory consolidation associated to visceral pain was determined using the novel object recognition (NOR) test and expressed as a differentiation index (DI). During the training phase of NOR test, CB1 KO and WT mice were placed in an open field with two identical objects for 9 minutes and right after, mice were pretreated with MOR (1, 3 or 9 mg/kg) or SAL injection 20 minutes before AA or SAL administration. On the test phase, 24 hs after, one of the two identical objects was randomly replaced by a different object. Time spent exploring either novel or familiar object, were measured and the DI was calculated.In the EPM test only MOR 1 mg/kg attenuated the AA-induced anxiogenic like effect expressed as the % of time in the open arms in CB1 KO (p