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Role of Striatal Serotonin 2A and Serotonin 2C Receptor Subtypes in the Control of In Vivo Dopamine Outflow in the Rat Striatum
Author(s) -
Lucas Guillaume,
Spampinato Umberto
Publication year - 2000
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.2000.740693.x
Subject(s) - ritanserin , microdialysis , endocrinology , chemistry , medicine , dopamine , serotonin , striatum , haloperidol , agonist , 3,4 dihydroxyphenylacetic acid , antagonist , receptor antagonist , 5 ht receptor , pharmacology , receptor , biology , homovanillic acid
This study investigated, using in vivo microdialysis in the striatum of freely moving rats, the role of striatal serotonin 2A (5‐HT 2A ) and 5‐HT 2C receptor subtypes in the modulation of dopamine (DA) and 3, 4‐dihydroxyphenylacetic acid (DOPAC) outflow, both in basal conditions and under activation induced by subcutaneous administration of 0.01 mg/kg haloperidol. The different 5‐HT 2 agents used were applied intrastriatally at a 1 μ M concentration through the microdialysis probe. Basal DA efflux was enhanced (27%) by the 5‐HT 2A/2B/2C agonist 1‐(4‐iodo‐2,5‐dimethoxyphenyl)‐2‐aminopropane (DOI) and reduced (‐30%) by the 5‐HT 2B/2C antagonist SB 206553. It was unaffected by infusion of the 5‐HT 2A antagonist SR 46349B. The effect of DOI was abolished by SB 206553 but not modified by SR 46349B. Haloperidol‐stimulated DA efflux (65‐70%) was reduced by both SR 46349B (‐32%) and the 5‐HT 2A/2B/2C antagonist ritanserin (‐30%) but not affected by SB 206553. Conversely, the effect of haloperidol was potentiated (22%) when DOI was coperfused with SB 206553. Also, haloperidol‐stimulated DOPAC outflow (40‐45%) was reduced (‐20%) by SR 46349B and potentiated (25%) by the combination of SB 206553 with DOI. These results indicate that striatal 5‐HT 2A receptors, probably through activation of DA synthesis, positively modulate DA outflow only under activated conditions. In contrast, striatal 5‐HT 2C receptors exert a facilitatory control on basal DA efflux, which appears to be both tonic and phasic.