Plasma level of dipropylacetamide and dipropylacetic acid and effect of these drugs on 5-hydroxytryptamine metabolism in mouse brain.

After intraperitoneal application of the antiepileptics dipropylacetamide (DPM, 200 mg/kg) and dipropylacetic acid (DPA, 200 mg/kg) in mice their concentration in plasma and their effects on 5-hydroxytryptamine (5-HT) metabolism in the brain were followed during 360 minutes. Peak plasma level of DPA and DPM was observed at 30 minutes, but level of DPM was only about 25% that of DPA. Plasma content of both drugs declined to low levels by 360 minutes. Both drugs increased brain content of the 5-HT metabolite 5-hydroxyindoleacetic acid (5-HIAA). After DPA application 5-HIAA level increased rapidly and had returned to control value by 360 minutes, while following DPM 5-HIAA increase was much more gradual and was more prolonged. Neither DPM nor DPA significantly altered brain 5-HT content. An apparent relationship between DPA plasma level and brain 5-HIAA content was observed while after DPM no association between plasma drug content and effect on cerebral 5-HT metabolism was seen.