The effect of serotonergic agents on haloperidol-induced striatal dopamine release in vivo: opposite role of 5-HT(2A) and 5-HT(2C) receptor subtypes and significance of the haloperidol dose used.
This study investigated, using microdialysis in freely-moving rats, the role of serotonin (5-HT) and 5-HT(2) receptor subtypes in the enhancement of striatal dopamine (DA) release induced by various doses of haloperidol. The subcutaneous injection of 0.01, 0.1 or 1 mg/kg haloperidol dose-dependently increased DA outflow (160, 219 and 230% of baseline, respectively). The effect of 0.01 mg/kg haloperidol was, respectively, potentiated by the 5-HT uptake inhibitor citalopram (1 mg/kg, s.c.; +35%) and reduced by the 5-HT(1A) receptor agonist 8-OH-DPAT (0.025 mg/kg, s.c.; -32%). Also, it was reduced by the 5-HT(2A) antagonist SR 46349B (0.5 mg/kg, s.c. ; -40%) or by the 5-HT(2A/2B/2C) antagonist ritanserin (1.25 mg/kg, i.p.; -34%), and potentiated by the 5-HT(2B/2C) antagonist SB 206553 (5 mg/kg, i.p; +78%). Further, only this latter compound significantly modified basal dopamine release by itself (+26%). Dopamine released by 0.1 mg/kg haloperidol was enhanced (+100%) by citalopram, decreased (-61%) by SR 4634B, but unaltered by SB 206553. Finally, none of the compounds used were able to modify the enhancement of dopamine release induced by 1 mg/kg haloperidol. These results show that central 5-HT(2A) and 5-HT(2C) receptors exert an opposite (respectively excitatory and inhibitory) influence on DA release. Moreover, they suggest that the 5-HT(2A)-dependent modulation depends on the degree of central DA receptor blockade.
Lucas
G
G
Laboratoire de Neuropsychobiologie des Désadaptations, UMR-CNRS 5541, Université Victor Segalen Bordeaux 2, Boîte Postale 31, 146 rue Léo Saignat, 33076, Bordeaux, France.
De Deurwaerdère
P
P
Caccia
S
S
Umberto Spampinato
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000818:Animals; D015283:Citalopram / Q000494:pharmacology; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism*; D018492:Dopamine Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005464:Fluorobenzenes / Q000494:pharmacology; D006220:Haloperidol / Q000008:administration & dosage / Q000494:pharmacology*; D007211:Indoles / Q000494:pharmacology; D008297:Male; D017551:Microdialysis; D010636:Phenols / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D044402:Receptor, Serotonin, 5-HT2A; D044405:Receptor, Serotonin, 5-HT2C; D011985:Receptors, Serotonin / Q000187:drug effects / Q000502:physiology*; D018490:Serotonin Agents / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D015283:Citalopram; D004298:Dopamine; D018492:Dopamine Antagonists; D005464:Fluorobenzenes; D006220:Haloperidol; D007211:Indoles; D010636:Phenols; D011725:Pyridines; D044402:Receptor, Serotonin, 5-HT2A; D044405:Receptor, Serotonin, 5-HT2C; D011985:Receptors, Serotonin; D018490:Serotonin Agents; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D017367:Selective Serotonin Reuptake Inhibitors; C076033:SR 46349B; C094868:SB 206553