Noradrenergic modulation of serotonin release in rat dorsal and median raphé nuclei via alpha(1) and alpha(2A) adrenoceptors

The rat rostral raphé nuclei receive catecholaminergic innervation from the locus coeruleus and other areas. In the present study, we investigated noradrenergic modulation of 5-HT release in rat dorsal and median raphé nuclei (DRN and MRN) slices (350 microm thick) superfused with artificial cerebro...

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Bibliographic Details
Published in:Neuropharmacology 2001-09, Vol.41 (4), p.433-442
Main Authors: Hopwood, S E, Stamford, J A
Format: Article
Language:English
Subjects:
Adrenergic alpha-Agonists - pharmacology
Adrenergic alpha-Antagonists - pharmacology
Adrenergic Uptake Inhibitors - pharmacology
Animals
Desipramine - pharmacology
Dexmedetomidine - pharmacology
Electric Stimulation
Electrophysiology
Imidazoles - pharmacology
In Vitro Techniques
Indoles - pharmacology
Isoindoles
Isoquinolines - pharmacology
Male
Norepinephrine - physiology
Phenylephrine - pharmacology
Piperazines - pharmacology
Prazosin - pharmacology
Raphe Nuclei - drug effects
Raphe Nuclei - metabolism
Rats
Rats, Wistar
Receptors, Adrenergic, alpha-1 - drug effects
Receptors, Adrenergic, alpha-1 - metabolism
Receptors, Adrenergic, alpha-2 - drug effects
Receptors, Adrenergic, alpha-2 - metabolism
Serotonin - metabolism
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Summary:The rat rostral raphé nuclei receive catecholaminergic innervation from the locus coeruleus and other areas. In the present study, we investigated noradrenergic modulation of 5-HT release in rat dorsal and median raphé nuclei (DRN and MRN) slices (350 microm thick) superfused with artificial cerebrospinal fluid (aCSF). The raphé was locally stimulated (0.1 ms pulses, 10 mA) and 5-HT release was monitored at carbon fibre microelectrodes using fast cyclic voltammetry. The selective noradrenaline reuptake inhibitor desipramine (50 nM) did not increase stimulated (20 pulses, 100 Hz) 5-HT release but significantly slowed 5-HT reuptake in both DRN and MRN. On short stimulus trains (10 pulses, 200 Hz), the alpha(2)-selective agonist dexmedetomidine (10nM) decreased evoked 5-HT release in DRN and MRN (to 44+/-3 and 43+/-7% of pre-drug values, respectively, at minimum). In both nuclei, this response was antagonised by the selective alpha(2A)-antagonist BRL 44408 (1 microM: P
ISSN:0028-3908