Changes in Synaptic Properties in Cortical-Limbic Communications Induced by Repeated Treatments With Fluvoxamine in Rats

• Main Authors: Satoshi Ohashi (Author), Hiroko Togashi (Author), Machiko Matsumoto (Author), Kiyoshi Mori (Author), Ken-ichi Ueno (Author), Mitsuhiro Yoshioka (Author)
• Format: Book
• Published: Elsevier, 2003-01-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 1347-8613; 10.1254/S1347-8613(19)32671-4
• Keywords: Therapeutics. Pharmacology; RM1-950
• Source: Journal of Pharmacological Sciences, Vol 92, Iss 2, Pp 100-107 (2003)

There is evidence indicating that dysregulation of coordinated interactions of the cortical-limbic circuitry is associated with anxiety and mood disorders. Our previous study has reported that an enhancement of long-term plasticity in the "limbic-cortical" pathway produced by repeated treatments with fluvoxamine may be involved in the clinical effects of a selective serotonin (5-HT) reuptake inhibitor (SSRI). Here we assessed the effects of single and repeated treatments with fluvoxamine on the synaptic transmission and plasticity in the "cortical-limbic" pathway in vivo. The evoked potentials in the basolateral amygdaloid complex (BLA) by stimulation of the medial prefrontal cortex (mPFC) in halothane-anesthetized rats were recorded. Single administration of fluvoxamine (10 and 30 mg/kg, i.p.) enhanced the efficacy of synaptic transmission at the mPFC-BLA synapses dose-dependently. The enhanced synaptic efficacy induced by 30 mg/kg fluvoxamine was suppressed after long-term administration of fluvoxamine (30 mg/kg per day × 21 days, orally). Repeated treatments with fluvoxamine affected short-term, but not long-term, synaptic plasticity in the mPFC-BLA pathway. These findings indicate that the 5-HTergic system contributes to modulation of synaptic changes in this pathway. Our results also suggest that different changes in synaptic properties in cortical-limbic communications induced by repeated treatments with fluvoxamine may be associated with therapeutic effects of SSRI.