Role of 5-HT1A receptors in the effects of acute and chronic fluoxetine on extracellular serotonin in the frontal cortex

Invernizzi, Roberto William; Bramante, Mario; Samanin, R.

doi:10.1016/0091-3057(95)02159-0

Cited by 124 publications

(97 citation statements)

References 20 publications

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“…However, other studies using SSRIs (Hjorth and Auerbach 1994;Bosker et al 1995a,b;Invernizzi et al 1995Invernizzi et al , 1996 or clomipramine (Gur et al 1999) failed to show any change in 5-HT 1A autoreceptor subsensitivity by this method. An increase in basal 5-HT levels after chronic SSRI administration, taken to be due to pre-synaptic 5-HT 1A and 5-HT 1B receptor desensitization, has been observed in cortex (Bel and Artigas 1993), hippocampus (Auerbach and Hjorth 1995) diencephalon (Rutter et al 1994) and prefrontal cortex (Tanda et al 1996) and, after chronic administration of clomipramine, in frontal cortex but not hippocampus (Gur et al 1999).…”

Section: Serotonergic Receptors Of the 5-ht 1a Subtype Have Been Suggmentioning

confidence: 75%

“…Evidence for subsensitivity of somatodendritic 5-HT 1A autoreceptors after chronic administration of SSRIs has been provided by microdialysis experiments in which 5-HT levels are measured in vivo in response to a challenge dose of the 5-HT 1A receptor agonist, 8-hydroxy-2 (di-n-propylamino) tetralin (8-OH-DPAT) (Rutter et al 1994, Kreiss andLucki 1995;Invernizzi et al 1994). However, other studies using SSRIs (Hjorth and Auerbach 1994; Bosker et al 1995a,b;Invernizzi et al 1995Invernizzi et al , 1996 or clomipramine (Gur et al 1999) failed to show any change in 5-HT 1A autoreceptor subsensitivity by this method. An increase in basal 5-HT levels after chronic SSRI administration, taken to be due to pre-synaptic 5-HT 1A and 5-HT 1B receptor desensitization, has been observed in cortex (Bel and Artigas 1993), hippocampus (Auerbach and Hjorth 1995) diencephalon (Rutter et al 1994) and prefrontal cortex (Tanda et al 1996) and, after chronic administration of clomipramine, in frontal cortex but not hippocampus (Gur et al 1999).…”

Section: Serotonergic Receptors Of the 5-ht 1a Subtype Have Been Suggmentioning

confidence: 99%

Section: Serotonergic Receptors Of the 5-ht 1a Subtype Have Been Suggmentioning

confidence: 99%

“…An increase in basal 5-HT levels after chronic SSRI administration, taken to be due to pre-synaptic 5-HT 1A and 5-HT 1B receptor desensitization, has been observed in cortex (Bel and Artigas 1993), hippocampus (Auerbach and Hjorth 1995) diencephalon (Rutter et al 1994) and prefrontal cortex (Tanda et al 1996) and, after chronic administration of clomipramine, in frontal cortex but not hippocampus (Gur et al 1999). A number of other studies have failed, however, to show increases in basal 5-HT levels in terminal areas after chronic administration of 5-HT uptake blocking drugs (unless the measurements were performed less than 24 hr after the last administration of the drug, in which case the effect is very likely due to the persistence of residual drug) (e.g., Hjorth and Auerbach 1994;Bosker et al 1995a,b;Invernizzi et al 1995Invernizzi et al , 1996.…”

Section: Serotonergic Receptors Of the 5-ht 1a Subtype Have Been Suggmentioning

confidence: 99%

“…A number of other studies have failed, however, to show increases in basal 5-HT levels in terminal areas after chronic administration of 5-HT uptake blocking drugs (unless the measurements were performed less than 24 hr after the last administration of the drug, in which case the effect is very likely due to the persistence of residual drug) (e.g., Hjorth and Auerbach 1994; Bosker et al. 1995a,b;Invernizzi et al 1995Invernizzi et al , 1996.There is relatively little evidence from binding studies for changes in the number of 5-HT 1A receptors after chronic SSRI administration. Welner et al (1989) observed a reduction in the dorsal raphe and decreased binding in midbrain was observed by Li et al (1994) after chronic fluoxetine.…”

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confidence: 99%

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5-HT1A Receptor Function in Normal Subjects on Clinical Doses of Fluoxetine Blunted Temperature and Hormone Responses to Ipsapirone Challenge

Lerer¹,

Gelfin²,

Gorfine

et al. 1999

Neuropsychopharmacology

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Serotonergic receptors of the 5-HT 1A subtype have been suggested to play a pivotal role in the mechanism of action of antidepressant drugs, including specific serotonin reuptake inhibitors (SSRIs). We examined the effect of clinical doses of the SSRI, fluoxetine, on 5-HTThere is considerable interest in the role of serotonergic (5-HT) receptors of the 5-HT 1A subtype in the therapeutic action of antidepressant drugs. 5-HT 1A receptors are located presynaptically on serotonergic cell bodies in the raphe nuclei where they serve as autoreceptors which inhibit cell firing and reduce 5-HT release by a negative feedback mechanism, and post-synaptically in the hippocampus, cortex and other brain areas, including the hypothalamus. Based on electrophysiological studies in rats, De Montigny and colleagues Mongeau et al. 1997) proposed that each major class of antidepressants increases 5-HT neurotransmission by a distinct mechanism involving either From the Biological Psychiatry Laboratory, Department of Psychiatry, Hadassah-Hebrew University Medical Center (BL, YG, MEN) and the Laboratory of Applied Statistics, Hebrew University (MG), Jerusalem, Israel; the Endocrine Laboratory, Department of Medicine (BA) and Department of Psychiatry (KPL), University of Wuerzburg, Wuerzburg, Germany.Address correspondence to: Prof. Bernard Lerer, Biological Psychiatry Laboratory, Dept. of Psychiatry, Hadassah-Hebrew University Medical Center, Ein Karem, Jerusalem 91120, Israel.Received May 15, 1998; accepted August 25, 1998. N EUROPSYCHOPHARMACOLOGY 1999 -VOL . 20 , NO . 6 Ipsapirone Challenge in Normal Subjects on Fluoxetine 629pre-or post-synaptic 5-HT 1A receptors. The selective serotonin re-uptake inhibitors (SSRIs), which raise 5-HT synaptic levels when given acutely, were proposed to increase 5-HT transmission on repeated administration by inducing desensitization of somatodendritic 5-HT 1A autoreceptors in the raphe nuclei and nerve terminal 5-HT 1B autoreceptors, which also mediate feedback inhibition of 5-HT release. These effects would lead to a slow increase in 5-HT levels which corresponds to the delayed clinical effect of the drugs. Evidence for subsensitivity of somatodendritic 5-HT 1A autoreceptors after chronic administration of SSRIs has been provided by microdialysis experiments in which 5-HT levels are measured in vivo in response to a challenge dose of the 5-HT 1A receptor agonist, 8-hydroxy-2 (di-n-propylamino) tetralin (8-OH-DPAT) (Rutter et al. 1994, Kreiss andLucki 1995;Invernizzi et al. 1994). However, other studies using SSRIs (Hjorth and Auerbach 1994; Bosker et al. 1995a,b;Invernizzi et al. 1995Invernizzi et al. , 1996 or clomipramine (Gur et al. 1999) failed to show any change in 5-HT 1A autoreceptor subsensitivity by this method. An increase in basal 5-HT levels after chronic SSRI administration, taken to be due to pre-synaptic 5-HT 1A and 5-HT 1B receptor desensitization, has been observed in cortex (Bel and Artigas 1993), hippocampus (Auerbach and Hjorth 1995) diencephalon (Rutter et al. 1994) an...

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Section: Serotonergic Receptors Of the 5-ht 1a Subtype Have Been Suggmentioning

confidence: 75%

Section: Serotonergic Receptors Of the 5-ht 1a Subtype Have Been Suggmentioning

confidence: 99%

Section: Serotonergic Receptors Of the 5-ht 1a Subtype Have Been Suggmentioning

confidence: 99%

Section: Serotonergic Receptors Of the 5-ht 1a Subtype Have Been Suggmentioning

confidence: 99%

mentioning

confidence: 99%

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5-HT1A Receptor Function in Normal Subjects on Clinical Doses of Fluoxetine Blunted Temperature and Hormone Responses to Ipsapirone Challenge

Lerer¹,

Gelfin²,

Gorfine

et al. 1999

Neuropsychopharmacology

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In vivo microdialysis assessment of extracellular serotonin and dopamine levels in awake monkeys during sustained fluoxetine administration

Smith

Kuczenski

George-Friedman

et al. 2000

Synapse

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Fluoxetine (FLU) rapidly enhances extracellular (EC) serotonin (5‐HT) in rodent brain, whereas the antidepressant effects of this drug in humans are typically not observed for 2–3 weeks. Thus, the effects of chronic oral FLU administration on neocortical and hippocampal EC 5‐HT, and on caudate EC 5‐HT and dopamine (DA), were examined in awake monkeys (Macaca fascicularis) using in vivo microdialysis (10.0 mg/kg; 3, 7, 14, and 21 days). On day 3, 5‐HT was significantly increased above baseline levels in hippocampus (HC) and caudate. There was a trend for an increase in neocortex EC 5‐HT levels. However, by day 7 5‐HT remained significantly elevated only in HC, although 5‐HT levels elsewhere had not completely returned to baseline. In contrast, levels of the 5‐HT metabolite, 5‐HIAA, were significantly reduced in all brain regions at all time points. Caudate DA levels tended to be decreased throughout FLU treatment. Local FLU and K+ infusion were also used at various times during chronic systemic FLU administration to evaluate changes in functional synaptic regulation. In general, these results, along with the significant decrease in 5‐HIAA levels and the tendency for basal EC 5‐HT levels to remain modestly elevated only in HC during sustained FLU administration, suggest a reduction in releasable pools of 5‐HT. Taken together with the trend for a decrease in caudate EC DA levels, these results do not appear to support the current hypothesis regarding the mechanism of action of SSRI antidepressants—that monoaminergic neurotransmission is progressively augmented during chronic treatment. Synapse 38:460–470, 2000. © 2000 Wiley‐Liss, Inc.

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Neuropharmacology of venlafaxine

Roseboom¹,

Kalin²

2000

Depress. Anxiety

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Role of 5-HT1A receptors in the effects of acute and chronic fluoxetine on extracellular serotonin in the frontal cortex

Cited by 124 publications

References 20 publications

5-HT1A Receptor Function in Normal Subjects on Clinical Doses of Fluoxetine Blunted Temperature and Hormone Responses to Ipsapirone Challenge

5-HT1A Receptor Function in Normal Subjects on Clinical Doses of Fluoxetine Blunted Temperature and Hormone Responses to Ipsapirone Challenge

In vivo microdialysis assessment of extracellular serotonin and dopamine levels in awake monkeys during sustained fluoxetine administration

Neuropharmacology of venlafaxine

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