Comparative analysis of the effect of acute (local or systemic) or chronic treatment with SSRIs. Fluvoxamine (72 pmol) was applied locally into the CA3 region of hippocampus of rats that received vehicle chronically, as described in Materials and Methods. It was pressure-ejected 90 sec before application of 5-HT (10.4 pmol). Data from these experiments (local fluvoxamine) were performed at the same time as the experiments on rats treated for 15 d with sertraline shown in the last two rows of the table. Paroxetine (10 mg/kg, i.p.) was given to naive rats and induced a decrease in clearance of 5-HT (18.2 ± 4.6 pmol) that reached a maximum at 40–60 min after injection, which is when the values shown in this table were measured. The data shown were obtained using amounts of 5-HT to produce comparable peak signal amplitudes before SSRI administration to that measured in the rats treated chronically with vehicle.

F1-a Mean ± SEM.

*p<0.05, paired t test comparing postdrug treatment with the corresponding pretreatment value.

**p<0.05, Student's t test comparing values in animals chronically treated with sertraline with those in animals chronically treated with vehicle.

F1-b Values in parentheses are the percentage of increase produced by the SSRI in comparison with the pre or control value.

***p < 0.05 in comparison with the other percentage increases, Mann–Whitney U test.