Figure 1

Effects of PCPA-induced serotonin depletion on antidepressant stimulation of CDP-diacylglycerol synthesis in brain tissue. Brain slices were prepared from the frontal cortex or hippocampus tissues of saline-injected control rats or animals that had been administered p-chlorophenylalanine (PCPA) to deplete endogenous serotonin stores. The tissue slices were labeled with [³H]cytidine and then incubated with predetermined concentrations of the antidepressant drugs fluoxetine (FLX, 100 μM), imipramine (IMI, 300 μM), or maprotiline (MAP, 100 μM). After 90 min, accumulated [³H]CDP-diacylglycerol was measured. Data were calculated as percentages relative to the respective basal accumulations in the control or PCPA group. Each bar represents the mean ± SEM (N = 6). PCPA treatment had no significant effect on basal [³H]CDP-diacylglycerol accumulation in either tissue; such basal effects being, respectively, 8194+806 v. 8555+1657 for control versus PCPA in frontal cortex, and 8026+1295 v. 8139+1642 for control versus PCPA in hippocampus. Each drug induced significant accumulations of [³H]CDP-diacylglycerol in either the control or PCPA tissues (ANOVA, p < 0.0001 for each drug). PCPA partially reduced FLX and MAP effects but did not eliminate any of the drug effects: ***p < 0.001, compared by posthoc Tukey tests.