Fast cyclic voltammetry can be used to measure stimulated endogenous 5-hydroxytryptamine release in untreated rat brain slices.
Fast cyclic voltammetry at a carbon fibre microelectrode was used to monitor the time course of 5-hydroxytryptamine (5-HT) overflow in slices of rat dorsal raphe (DRN) and suprachiasmatic nuclei (SCN), incubated in a brain slice chamber for over 6 h. 5-HT overflow was detected in response to electrical brain stimulation in both regions. Voltammetric evidence showed that the released substance was identical to exogenously applied 5-HT. Overflow was reversibly abolished when Ca2+ was removed from the incubating medium or when TTX was added. Ro4-1284, a reserpine like agent, irreversibly abolished 5-HT overflow from both nuclei. The 5-HT uptake blockers, citalopram, clomipramine, fenfluramine and fluvoxamine dose dependently increased overflow and slowed the rate of removal of 5-HT from the extracellular space in both regions. Benztropine had no effect on overflow in the DRN and SCN whereas it caused a significant increase in dopamine overflow in slices of caudate putamen (CPu). Xylamine had no effect on 5-HT overflow in the DRN and SCN. This evidence indicates that the release of endogenous 5-HT can be measured reliably for long periods and that FCV can be used in brain slices for quantitative studies of 5-HT release and uptake.
Department of Pharmacology, Queen Mary and Westfield College, London, U.K.
J J
JJ
O'Connor
Z L
ZL
Kruk
D000818:Animals; D001921:Brain / Q000378:metabolism*; D018492:Dopamine Antagonists; D004558:Electric Stimulation; D004563:Electrochemistry / Q000379:methods*; D066298:In Vitro Techniques; D008297:Male; D009474:Neurons / Q000378:metabolism; D009638:Norepinephrine / Q000037:antagonists & inhibitors; D011903:Raphe Nuclei / Q000166:cytology / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000378:metabolism*; D012702:Serotonin Antagonists / Q000494:pharmacology; D013493:Suprachiasmatic Nucleus / Q000166:cytology / Q000378:metabolism; D013997:Time Factors
D018492:Dopamine Antagonists; D012702:Serotonin Antagonists; D012701:Serotonin; D009638:Norepinephrine