Effects of 5,6-Dihydroxytryptamine on Brain Monoamine Neurons in the Rat

Baumgarten, H. G.; Schlossberger, H.

doi:10.1016/b978-0-12-078150-8.50032-3

Cited by 26 publications

(19 citation statements)

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“…The findings of this study indicate that 5-HT, either endogenously or exogenously applied, can facilitate the release of ␤-endorphin in the arcuate nucleus and nucleus accumbens. 5,7-DHT-induced destruction of 5-HT neurons, at a dose that does not affect dopaminergic neurons (Baumgarten et al, 1971;Yadid et al, 1994; present study, Table 1), caused a 60 -80% decrease in basal extracellular levels of ␤-endorphin. This may indicate that endogenous 5-HT not only facilitates endogenous ␤-endorphin release, but is also involved in its tonic release in both the arcuate nucleus and nucleus accumbens.…”

Section: Discussionsupporting

confidence: 46%

Serotonin‐Mediated Increases in the Extracellular Levels of β‐Endorphin in the Arcuate Nucleus and Nucleus Accumbens : A Microdialysis Study

Zangen

Nakash

Yadid

1999

Journal of Neurochemistry

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Although the involvement of both endogenous opioid and serotonergic systems in modulation of pain and emotion was suggested, the neurochemical interaction between these systems in the brain has not previously been studied directly. Herein, the effects of the local application of serotonin (5-HT) and fluoxetine (a 5-HT reuptake inhibitor) on extracellular levels of ␤-endorphin in the arcuate nucleus and nucleus accumbens were assessed in freely moving rats using in vivo microdialysis. The mean basal concentrations of ␤-endorphin in dialysates obtained from the arcuate nucleus and nucleus accumbens were 259.9 and 143.3 pM, respectively. Specific lesion of the serotonergic system by 5,7-dihydroxytryptamine (5,7-DHT) caused a significant decrease in these dialysate ␤-endorphin levels. When 5-HT (0.25-5 M) was added to the perfusion solution, the levels of ␤-endorphin in the dialysate from the arcuate nucleus increased (186 -296% of baseline), in a concentrationdependent manner. In the nucleus accumbens, 0.5 and 2 M 5-HT in the perfusion fluid did not affect the levels of ␤-endorphin in the dialysate, whereas 5 and 10 M 5-HT caused an increase of ϳ190% of baseline. When fluoxetine (250 M) was present in the perfusing solution, the levels of ␤-endorphin in the dialysates from the arcuate nucleus and nucleus accumbens increased two-to threefold. This effect was not obtained in the 5,7-DHT-lesioned rats. Thus, 5-HT, either endogenously or exogenously delivered, appears to facilitate the release of ␤-endorphin in the arcuate nucleus and nucleus accumbens. This indication of an interaction between serotonergic and endorphinic systems may be relevant for assessing pain and mood disorder circuits and the mode of action of antidepressant drugs. Key Words: ␤-EndorphinFluoxetine-Microdialysis-Serotonin-Nucleus accumbens-Arcuate nucleus.

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Section: Discussionsupporting

confidence: 46%

Serotonin‐Mediated Increases in the Extracellular Levels of β‐Endorphin in the Arcuate Nucleus and Nucleus Accumbens : A Microdialysis Study

Zangen

Nakash

Yadid

1999

Journal of Neurochemistry

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“…Control animals received only the ascorbic acid solution (vehicle). To protect noradrenaline-containing neurones from the action of 5,7-DHT (Baumgarten et al, 1973), 30 min before the injection of 5,7-DHT the rats were given desipramine 25 mg kg-intraperitoneally (i.p. ), an inhibitor of noradrenaline uptake into nerve endings (Breese & Cooper, 1975).…”

Section: Methodsmentioning

confidence: 99%

8‐Hydroxy‐2‐(di‐n‐propylamino)tetralin impairs spatial learning in a water maze: role of postsynaptic 5‐HT_1A receptors

Carli

Samanin

1992

British J Pharmacology

147

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1 The effect of 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), a 5-HT1A receptor agonist, on place navigation was studied by use of two spatial tasks in a water maze. 2 In the first experiment, rats treated subcutaneously with 100 and 300 (but not 30) p1gkg-1 8-OH-DPAT were impaired in their ability to locate a hidden platform. The probe test confirmed the impairment of spatial navigation but the effect (time spent in the training quadrant) was quantitatively different, depending on whether 8-OH-DPAT was administered only before each training session, only before the probe test or in both conditions. 3 In the second experiment, rats received 150pg 5,7-dihydroxytryptamine (5,7-DHT) intracerebroventricularly to destroy 5-hydroxytryptamine (5-HT-containing neurones and 24 days later were examined for choice accuracy in a two-platform spatial discrimination task.4 At 100 (but not 30)pgkg-1 8-OH-DPAT impaired rats' accuracy with no effect on latency and no errors of omission. In 5,7-DHT-treated rats, this dose had a greater effect, including errors of omission. Sham-operated rats injected with 300pugkg'-8-OH-DPAT were markedly impaired in accuracy but they had longer latencies and made more errors than controls. All the effects were increased in 5,7-DHT treated rats. 5 The results suggest that, at doses causing no apparent changes in motor behaviour or motivation, 8-OH-DPAT impairs spatial navigation by stimulating postsynaptic 5-HTlA receptors in the rat brain.

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“…Control rats received only the ascorbic acid solution. In order to protect noradrenaline-containing neurones from the action of 5,7-DHT (Baumgarten et al, 1973), 30 min before 5,7-DHT the rats received i.p. 25 mg kg-' desipramine, an inhibitor of noradrenaline uptake into the nerve endings (Samanin et al, 1975).…”

Section: Intraventricular Injections Of 57-dihydroxytryptaminementioning

confidence: 99%

Differential effects of acute and chronic fluoxetine administration on the spontaneous activity of dopaminergic neurones in the ventral tegmental area

Prisco

Esposito

1995

British J Pharmacology

157

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1 Electrophysiological techniques were used to study the effects of fluoxetine and citalopram on the basal activity of dopaminergic neurones in the ventral tegmental area (VTA) and substantia nigra, pars compacta (SNc) of rats.2 Acute i.v. injection of fluoxetine (20-1280 ,ug kg-') caused a dose-dependent inhibition of the firing rate of VTA dopaminergic neurones, but did not affect the activity of dopaminergic cells in the SNc. Citalopram (20-1280 pg kg-', i.v.) inhibited the firing rate of dopaminergic neurones in the VTA, but its effect (maximal inhibition: 14 ± 7%) was less pronounced than that of fluoxetine (maximal inhibition: 34±7%).

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Effects of 5,6-Dihydroxytryptamine on Brain Monoamine Neurons in the Rat

Cited by 26 publications

References 0 publications

Serotonin‐Mediated Increases in the Extracellular Levels of β‐Endorphin in the Arcuate Nucleus and Nucleus Accumbens : A Microdialysis Study

Serotonin‐Mediated Increases in the Extracellular Levels of β‐Endorphin in the Arcuate Nucleus and Nucleus Accumbens : A Microdialysis Study

8‐Hydroxy‐2‐(di‐n‐propylamino)tetralin impairs spatial learning in a water maze: role of postsynaptic 5‐HT_1A receptors

Differential effects of acute and chronic fluoxetine administration on the spontaneous activity of dopaminergic neurones in the ventral tegmental area

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Effects of 5,6-Dihydroxytryptamine on Brain Monoamine Neurons in the Rat

Cited by 26 publications

References 0 publications

Serotonin‐Mediated Increases in the Extracellular Levels of β‐Endorphin in the Arcuate Nucleus and Nucleus Accumbens : A Microdialysis Study

Serotonin‐Mediated Increases in the Extracellular Levels of β‐Endorphin in the Arcuate Nucleus and Nucleus Accumbens : A Microdialysis Study

8‐Hydroxy‐2‐(di‐n‐propylamino)tetralin impairs spatial learning in a water maze: role of postsynaptic 5‐HT1A receptors

Differential effects of acute and chronic fluoxetine administration on the spontaneous activity of dopaminergic neurones in the ventral tegmental area

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Product

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8‐Hydroxy‐2‐(di‐n‐propylamino)tetralin impairs spatial learning in a water maze: role of postsynaptic 5‐HT_1A receptors