Influence of 5-HT1B/1D receptors on dopamine release in the guinea pig nucleus accumbens: a microdialysis study.
To clarify whether serotonin (5-HT) 5-HT1B/1D receptors are involved in dopamine (DA) release, extracellular levels of DA were monitored by in vivo microdialysis during various conditions. 5-HT (10 microM) alone, and together with the 5-HT1B/1D receptor antagonist. GR127935 (10 microM), or the 5-HT1B/1D agonist, sumatriptan (1 microM), were perfused into the nucleus accumbens of freely moving guinea pigs. A 10-fold increase in the extracellular concentration of DA was obtained during administration of 5-HT alone. The 5-HT-induced DA elevation was not significantly affected by co-administration of sumatriptan (MANOVA; P > 0.05) but markedly attenuated by coperfusion of GR127935 (MANOVA; P = 0.02). Neither GR127935 nor sumatriptan, when administered alone, significantly affected extracellular DA levels. These results suggest that, in the DA-rich nucleus accumbens, 5-HT1B/1D receptors are not involved in the modulation of DA release during normal tonic or basal conditions but may take part in the regulation of DA release when synaptic 5-HT levels are very high.
Hållbus
M
M
Astra Arcus AB, Behavioural and Biochemical Department, Södertälje, Sweden.
Magnusson
T
T
Magnusson
O
O
D000704:Analysis of Variance; D000818:Animals; D004298:Dopamine / Q000378:metabolism*; D006168:Guinea Pigs; D008297:Male; D017551:Microdialysis; D009714:Nucleus Accumbens / Q000378:metabolism*; D010069:Oxadiazoles / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D011985:Receptors, Serotonin / Q000502:physiology*; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D018170:Sumatriptan / Q000494:pharmacology
D010069:Oxadiazoles; D010879:Piperazines; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; C090701:GR 127935; D018170:Sumatriptan; D004298:Dopamine