Neither the 5-HT1A- nor the 5-HT2-Receptor Subtype Mediates the Effect of Fluvoxamine, a Selective Serotonin Reuptake Inhibitor, on Forced-Swimming-Induced Immobility in Mice

Abstract

ABSTRACT-The effect of fluvoxamine, a selective serotonin (5-HT) reuptake inhibitor, was studied in the forced-swimming test, a model of depression, in mice. Fluvoxamine at 60 mg/kg, p.o. significantly decreased the immobility time in the forced-swimming test. A similar effect was observed by the selective norepinephrine reuptake inhibitor desipramine at the same dose. Furthermore, the suppression of immobility time was slightly potentiated by repeated administration of fluvoxamine, and a significant effect was observed at 30 mg/kg, p.o. The effect of fluvoxamine on forced-swimming was unaffected by the 5-HT2 antagonist ritanserin. On the other hand, the 5-HT1A antagonist Selective serotonin (5-HT) reuptake inhibitors (SSRIs; fluvoxamine, fluoxetine, etc.) have established their status as effective antidepressants with effects comparable to the more traditionally used tricyclic and tetracyclic antidepressants (1). Furthermore, it is recognized that the binding sites for the antidepressant imipramine are the 5-HTreuptake pumps (2) and that 5-HT2 receptors are also down-regulated by the repeated administration of antidepressants (3). These lines of evidence support the 5-HT theory of depressive illness, and it is apparent, therefore, that malfunction of 5-HT transmission is involved in depressive illness.The forced-swimming test has been used elsewhere to evaluate the efficacy of antidepressants (4). There is, however, few reports about the effect of fluvoxamine on the forced-swimming test (5). Furthermore, there is no report about the subchronic effect of fluvoxamine on this model or which 5-HT receptor subtype mediates the effect of fluvoxamine on immobility.In the present experiments, therefore, we investigated Male ICR strain mice weighing 20-30 g (Nihon SLC, Atsugi) were used in the experiment. All animals were housed in the animal rooms (temperature, 20-25C; °hu-midity, 60 ±5%; light on at 7 a.m.; light off at 7 p.m.) for

Strain‐dependent serotonin neuron feedback control: role of serotonin2C receptors

“…SB242084 restored citalopram’s effect in the forced swimming test in DBA/2 mice, possibly because this antagonist enhances the effect on extracellular 5‐HT (Calcagno et al. 2009) whereas pharmacological blockade or genetic deletion of 5‐HT 2C receptors had no clear effects in mice and rats already responding to SSRIs (Egawa et al. 1995; Cryan and Lucki 2000; Yamada and Sugimoto 2002).…”

5-HT1A-Receptor Subtype Mediates the Effect of Fluvoxamine, a Selective Serotonin Reuptake Inhibitor, on Marble-Burying Behavior in Mice

“…We have already found that fluvoxamine has suppressive effects on immobility in the depression models of mice, tail-suspension (5) and forced-swimming (6). However, there is as yet no established screening model for OCD.…”

Fluoxetine Potentiation of Omega-3 Fatty Acid Antidepressant Effect: Evaluating Pharmacokinetic and Brain Fatty Acid-Related Aspects in Rodents

“…injections of saline solution (0.9% NaCl). The antidepressant dose of fluoxetine (10 mg/kg day) was chosen according to previous studies that demonstrated a robust effect in the forced swimming test (FST) employing similar conditions . The fluoxetine dose lacking antidepressant effect (1 mg/kg day) was also chosen according to previous studies .…”

“…The antidepressant dose of fluoxetine (10 mg/kg day) was chosen according to previous studies that demonstrated a robust effect in the forced swimming test (FST) employing similar conditions. 17,24,25 The fluoxetine dose lacking antidepressant effect (1 mg/kg day) was also chosen according to previous studies. 17,26 Rats were in- a Values are expressed as g/100 g total fatty acids, determined by gas chromatography according to previous studies.…”