Jpn. J. Pharmacol. 83 (4), 344-347 (2000)

Day/Night Variation of 5-Hydroxyindole Acetic Acid Concentration in Rat Cerebrospinal Fluid After Acute and Long-Term Administration of a Selective Serotonin Reuptake Inhibitor, Fluvoxamine

Toru Egashira¹, Fusako Takayama¹, Yasumitsu Yamanaka¹, Kaori Takada², Hiroshi Takeda² and Teruhiko Matsumiya<sup>2


1</sup>Departmentﾊof Pharmacology, Oita Medical University, 1-1, Idaigaoka, Hasama-machi, Oita 879-5593, Japan
²Departmentﾊof Pharmacology, Tokyo Medical College, 6-1-1, Shinjuku, Tokyo 160-8402, Japan

Abstract: When 30ﾊmg/kg, p.o. of fluvoxamine, a selective serotonin reuptake inhibitor, was administered, significant increases of 3-methoxy-4-hydroxyphenylglycol (MHPG) and 5-hydroxy indole-3-acetic acid (5-HIAA) contents in rat cerebrospinal fluid (CSF) were observed from two days after administration of fluvoxamine in both the light and dark periods and in the dark period of the light/dark cycle, respectively. In long-term treatment with 15ﾊmg/kg, p.o. of fluvoxamine, the level of MHPG in CSF exhibited no difference, whereas the levels of 5-HIAA showed a significant increase during the light periods. These results suggest that fluvoxamine enhances the 5-HT system, but only with long-term treatment.

Keywords: Selective serotonin reuptake inhibitor, Monoamine metabolite, Cerebrospinal fluid