Involvement of CB1 receptor in morphine withdrawal of adolescent mice prenatally treated with a cannabinoid agonist

CANERO ELIANA M.; PEDRÓN VALERIA T.; VARANI ANDRÉS P.; AON AMIRA J.; SORIANO DELIA B.; CALTANA LAURA R.; BRUSCO HERMINIA A; BALERIO GRACIELA N.

Congreso; Sociedad Argentina de Investigación Clínica (SAIC), la Sociedad Argentina de Inmunología (SAI) y la Sociedad Argentina de Farmacología Experimental (SAFE),; 2016

In previous studies from our laboratory performed in adolescent CB1 receptor knockout mice (CB1 KO), we reported a decrease in the expression of naloxone (NAL) precipitated morphine (MOR) withdrawal syndrome compared to their wild-type (WT) littermates, in both male and female mice. On the other hand, there is evidence that prenatal exposure to cannabinoid agonists induces long-term alterations in the opioid system.The aim of the present study was to evaluate the effect of the prenatal exposure to the cannabinoid agonist WIN 55,212-2 (WIN) in c-Fos expression of certain brain areas of MOR withdrawn CB1 KO and WT adolescent mice.Pregnant female CB1 KO and WT mice received WIN (0.75 mg/kg, s.c.) or vehicle (VEH) once daily from 5th to 15th gestational day. From 25th postnatal day forward, mice were treated for 9 days with MOR (2 mg/kg, i.p.) or saline (SAL) twice daily. On the tenth day, the animals received NAL (6 mg/kg, i.p.) or SAL 60 min after the last injection and 30 min after precipitating the withdrawal, mice were perfused with a PFA 4% solution and brains were removed and coronal frozen sections were made at 30 μm on a freezing microtome to perform the c-Fos immunohistochemistry (IHC).WT but not KO adolescent mice prenatally treated with VEH show a c-Fos expression decrease during MOR withdrawal syndrome in Cg (p