Role of venlafaxine in relapse to methamphetamine seeking

Experimental design A) Wistar rats were randomly assigned into four groups: 1) Saline-Saline-animals received saline during the conditioning, extinction, and reinstatement phases; 2) Saline-VEN-animals received saline in the conditioning, VEN (10 mg/kg, i.p.) in the extinction, and saline in the reinstatement phase; 3) METH-Saline, rats received METH (1 mg/kg, i.p.) in the conditioning, saline in the extinction, and METH (1 mg/kg, i.p.) in the reinstatement phase; 4) METH-VEN group in which METH (1 mg/kg, i.p.) was administered in the conditioning phase, VEN (10 mg/kg, i.p.) during the extinction phase, and METH (1 mg/kg, i.p.) was administered in the reinstatement phase. Time spent in each chamber during pre-conditioning and before any treatment. B) No significant changes in time spent were found in chamber 1 and chamber 2 during the preconditioning phase. Values shown as means ± S.E.M.

Time spent in the conditioning chambers during phases of post-conditioning, extinction, and reinstatement in A) Saline-Saline and B) Saline-VEN treated groups. No significant changes in time spent were found in Chamber 1 and Chamber 2 during all tested phases. Values shown as means ± S.E.M.

Time spent in the conditioning chambers during phases of post-conditioning, extinction, and reinstatement in A) METH-Saline and B) METH-VEN. In METH-Saline group, rats spent time in the METH-paired chamber that was significantly elevated during the reinstatement test compared to the extinction test. VEN blocked reinstatement induced by re-exposure to METH. Values shown as means ± S.E.M. ^***p<0.001 and ^****p<0.0001. (^@p<0.05 and ^@@p<0.01 compared to post-conditioning, while ^$$p<0.01 as compared to the extinction test).