Naloxone-precipitated morphine withdrawal syndrome: Behavioural and biochemical studies in adolescent male and female mice lacking CB1 receptors

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

Berlín

Congreso; 11th FENS Forum of European Neuroscience; 2018

CB1 cannabinoid receptor deficient (CB1KO) mice showed lower intensity in naloxone (NAL)-precipitated MOR withdrawal syndrome than wild-type (WT) mice. On the other hand, previous studies from our laboratory have shown sex differences in the expression of NAL-precipitated MOR withdrawal syndrome in WT Swiss Webster Albino mice. The aim of the present study was: I) to explore the presence of sex differences in the expression of MOR withdrawal syndrome in CB1KO mice, II) to evaluate the c-Fos expression of certain brain areas in CB1KO mice during MOR withdrawal syndrome.CB1KO and WT mice from day 25 postnatal forward, were treated for 9 days with MOR (2 mg/kg, i.p.) or saline (SAL) twice daily. On tenth day, animals received NAL (6 mg/kg, i.p.) or SAL 60 min after the last injection in order to precipitate the withdrawal syndrome, and immediately after somatic sings were counted during 30 minutes. At the end of the behavioral test, mice were transcardially perfused with 4% paraformaldehyde solution. Brains were removed and coronal sections were made at 30 μm to perform c-Fos immunohistochemistry.No sex differences were observed during MOR abstinence syndrome. In addition, It was observed an increase in the number of c-Fos positive nuclei in the Nucleus Accumbens Core, Habenula Lateral (p