Serotonin enhances striatal dopamine outflow in vivo through dopamine uptake sites.
Serotonin (5-HT) administered at 1, 3, and 10 microM into the striatum of halothane-anesthetized rats by in vivo microdialysis increased extracellular dopamine (DA) in a concentration-dependent manner (approximately 65, 190, and 440%, respectively). These effects were reduced by 50% in the presence of 1 microM tetrodotoxin (TTX) or in the absence of Ca2+ ions. The DA uptake blocker nomifensine (0.1 microM) significantly lowered (by 50%) the enhancement of DA outflow induced by 3 microM 5-HT. Nomifensine (1 microM) coperfused with 1 microM TTX abolished the 1 and 3 microM 5-HT-induced DA outflow, whereas the effect of 10 microM 5-HT was significantly reduced by 1 (-55%) and 10 micro M (-70%) nomifensine. These data demonstrate that, in vivo, striatal DA uptake sites are partially involved in the DA-releasing action of 5-HT.
De Deurwaerdère
P
P
Université de Bordeaux II, INSERM U. 259, Bordeaux, France.
Bonhomme
N
N
Lucas
G
G
Le Moal
M
M
Spampinato
U
U
D000818:Animals; D002118:Calcium / Q000494:pharmacology / Q000502:physiology; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism*; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology; D008297:Male; D017551:Microdialysis; D008959:Models, Neurological; D009627:Nomifensine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011954:Receptors, Dopamine / Q000187:drug effects* / Q000502:physiology; D011985:Receptors, Serotonin / Q000502:physiology; D012701:Serotonin / Q000494:pharmacology*; D015222:Sodium Channels / Q000187:drug effects; D013779:Tetrodotoxin / Q000494:pharmacology
D018765:Dopamine Uptake Inhibitors; D011954:Receptors, Dopamine; D011985:Receptors, Serotonin; D015222:Sodium Channels; D009627:Nomifensine; D012701:Serotonin; D013779:Tetrodotoxin; D002118:Calcium; D004298:Dopamine