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Acute and chronic effects of citalopram on postsynaptic 5‐hydroxytryptamine 1A receptor‐mediated feedback: a microdialysis study in the amygdala
Author(s) -
Bosker F. J.,
Cremers T. I. F. H.,
Jongsma M. E.,
Westerink B. H. C.,
Wikström H. V.,
Den Boer J. A.
Publication year - 2001
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.1471-4159.2001.00194.x
Subject(s) - microdialysis , citalopram , agonist , amygdala , medicine , endocrinology , chemistry , 5 ht receptor , neurotransmitter , serotonin , pharmacology , postsynaptic potential , receptor , dopamine
Microdialysis was used to assess the involvement of postsynaptic 5‐hydroxytryptamine 1A (5‐HT 1A ) receptors in the regulation of extracellular 5‐HT in the amygdala. Local infusion of the 5‐HT 1A receptor agonist flesinoxan (0.3, 1, 3 µ m ) for 30 min into the amygdala maximally decreased 5‐HT to 50% of basal level. Systemic administration of citalopram (10 µmol/kg) increased 5‐HT to 175% of basal level. Local infusion of 1 µ m of the 5‐HT 1A receptor antagonist WAY 100.635 into the amygdala augmented the effect of citalopram to more than 500% of basal 5‐HT level. 5‐HT 1A receptor responsiveness after chronic citalopram treatment was determined in two ways. First, by local infusion of 1 µ m flesinoxan for 30 min into the amygdala, which showed a significant 63% reduction in response (area under the concentration–time curve; AUC) for the citalopram group compared to the saline group. Second, by systemic administration of citalopram (10 µmol/kg), which increased 5‐HT to 350% of basal level. The effect was larger than in untreated animals, but more important, local infusion of 1 µ m WAY 100.635 into the amygdala now failed to augment the effect of citalopram. Both the flesinoxan and WAY 100.635 data suggest an involvement of postsynaptic 5‐HT 1A receptor‐mediated feedback in the amygdala, which diminishes following chronic citalopram treatment.