Effects of acute olanzapine after sustained fluoxetine on extracellular monoamine levels in the rat medial prefrontal cortex

Amargós-Bosch, Mercè; Artigas, Francesc; Adell, Albert

doi:10.1016/j.ejphar.2005.05.004

Cited by 27 publications

(11 citation statements)

References 18 publications

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“…Unpredicted however, was the small but statistically significant effect of the preceding chronic FLX treatment on DA release after the acute challenge in both age groups, just as was seen with 5-HT. Previous studies have shown that FLX can indeed acutely affect DA and NA release in the prefrontal cortex, presumably via the 5-HT2c receptor and/or post-synaptic 5-HT1A receptor [30], [40], but other studies have reported no effects on DA and NA concentrations after an acute challenge [41] or directly after chronic administration [42], [43]. Although this effect of previous FLX treatment on the DA response to an acute 5-HT challenge is thus less easily explained, it is clear that almost all 5-HT receptors are capable of modulating DA release [44] and it is therefore not surprising that, considering the effects seen in the 5-HT system, also the DA system is similarly affected.…”

Section: Discussionmentioning

confidence: 98%

Increased Response to a 5-HT Challenge After Discontinuation of Chronic Serotonin Uptake Inhibition in the Adult and Adolescent Rat Brain

et al. 2014

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Little is known about the effects of chronic fluoxetine on 5-HT transmission in the adolescent brain, even though it is acknowledged that the neuroplasticity of the brain during childhood and adolescence might influence the neurobiological mechanisms underlying treatment response. Also, possible ongoing effects on monoamine function following drug discontinuation are unidentified. We therefore examined the chronic effects of fluoxetine on extracellular 5-HT and dopamine concentrations in the medial prefrontal cortex and studied their responsiveness to an acute 5-HT challenge after a one-week washout period, both in adolescent and adult rats. Noradrenaline was measured in adult animals only. Fluoxetine increased 5-HT to 200–300% of control and DA and NA to 150% of control. Although there were no lasting effects of chronic fluoxetine on basal monoamine levels, we observed a clear potentiating effect of previous treatment on the fluoxetine-induced increase in extracellular 5-HT and, to a lesser extent, extracellular DA. No differential effect was found for noradrenaline. Age-at-treatment did not influence these results. So, after cessation of chronic fluoxetine treatment 5-HT responsiveness remains heightened. This may be indicative of the continuing presence of 5-HT receptor desensitization, at least until one week after drug discontinuation in rats. No apparent age-at-treatment effects on extracellular monoamine concentrations in the medial prefrontal cortex were detected, but age-related differences in 5-HT transmission further down-stream or in the recovery processes cannot be ruled out.

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Section: Discussionmentioning

confidence: 98%

Increased Response to a 5-HT Challenge After Discontinuation of Chronic Serotonin Uptake Inhibition in the Adult and Adolescent Rat Brain

et al. 2014

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“…: transversal probe AP 4.5, VD 2.7; Amargos‐Bosch et al . : AP 3.2, L −0.8, DV −6.0; Dazzi et al . : AP 3.2, ML 0.8, VD −5.3.…”

Section: Discussionmentioning

confidence: 99%

Adaptive dynamics of the 5‐HT systems following chronic administration of selective serotonin reuptake inhibitors: a meta‐analysis

Fritze

Spanagel

Noori

2017

Journal of Neurochemistry

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Selective serotonin reuptake inhibitors (SSRIs) are the most frequently prescribed antidepressants. However, a major concern is their delayed onset of action, which is hypothesized to be associated with the time required for serotonin (5-HT) autoreceptors to desensitize, which should be reflected by actual neurochemical changes. Numerous in vivo microdialysis studies have been published that report on 5-HT levels in different brain sites following SSRI administration. Here, we performed a meta-analysis on dynamic changes of 5-HT neurotransmission during the course of chronic SSRI treatment. We conducted a meta-analysis on research articles of 5-HT neurotransmission measured by in vivo microdialysis in rat brain after subchronic and chronic SSRI administrations. In total, data from 42 microdialysis studies (798 rats) were analyzed. Within the first week of SSRI treatment, extracellular 5-HT concentrations drop in frontal cortex. Over the next 2 weeks of treatment, a linear increase in extracellular 5-HT levels up to 350% of prior treatment baseline is evident (n = 269). However, in hippocampus, prefrontal cortex, nucleus accumbens, and ventral tegmental area we found increased 5-HT levels within the first 3 days of SSRI administration. The time course of 5-HT dynamics in frontal cortex is in line with the hypothesis that 5-HT autoreceptors desensitize over 2-3 weeks of SSRI treatment and thereby enhanced extracellular 5-HT levels ensue. Yet, in other regions we did not find evidence supporting the traditional autoreceptor-mediated feedback loops hypothesis and thus other neurobiological adaptation mechanisms may also play a role in the delayed onset of SSRI action.

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“…Specifically, NMDA receptor antagonists or genetic deletion of the NMDA receptors raises 5-HT release in the mPFC (Amargos-Bosch et al 2005;Ceglia et al 2004;Miyamoto et al 2001), whereas activation of 5-HT 2A receptors raises cortical GLU release (Scruggs et al 2003), enhances GLU-dependent excitatory postsynaptic currents in cortical slices (Aghajanian and Marek 1999) and c-fos expression (Scruggs et al 2000) in the mPFC. The 5-HT 1A receptors mediate the hyperpolarizing action of 5-HT on glutamatergic prefrontal neurons (Aghajanian and Marek 1997;Amargos-Bosch et al 2004;Zhou and Hablitz 1999).…”

Section: Introductionmentioning

confidence: 99%

Effects of aripiprazole, olanzapine, and haloperidol in a model of cognitive deficit of schizophrenia in rats: relationship with glutamate release in the medial prefrontal cortex

et al. 2010

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Effects of acute olanzapine after sustained fluoxetine on extracellular monoamine levels in the rat medial prefrontal cortex

Cited by 27 publications

References 18 publications

Increased Response to a 5-HT Challenge After Discontinuation of Chronic Serotonin Uptake Inhibition in the Adult and Adolescent Rat Brain

Increased Response to a 5-HT Challenge After Discontinuation of Chronic Serotonin Uptake Inhibition in the Adult and Adolescent Rat Brain

Adaptive dynamics of the 5‐HT systems following chronic administration of selective serotonin reuptake inhibitors: a meta‐analysis

Effects of aripiprazole, olanzapine, and haloperidol in a model of cognitive deficit of schizophrenia in rats: relationship with glutamate release in the medial prefrontal cortex

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