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Effects of 5,7‐dihydroxytryptamine depletion of tissue serotonin levels on extracellular serotonin in the striatum assessed with in vivo microdialysis: Relationship to behavior
Author(s) -
Hall F.S.,
DeVries A.C.,
Fong G.W.,
Huang S.,
Pert A.
Publication year - 1999
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/(sici)1098-2396(199907)33:1<16::aid-syn2>3.0.co;2-8
Subject(s) - serotonin , microdialysis , extracellular , 5,7 dihydroxytryptamine , endocrinology , medicine , dopamine , striatum , extracellular fluid , chemistry , neurotransmitter , p chloroamphetamine , biology , serotonergic , central nervous system , biochemistry , receptor
Effects of i.c.v. administration of 5,7‐dihydroxytryptamine (5,7‐DHT) on biochemistry and behavior were studied in awake Sprague‐Dawley rats. It was found that 5,7‐DHT depletion of striatal tissue levels of serotonin (5‐HT) does not diminish extracellular levels until substantial depletions occur. This finding is similar to those observed after 6‐hydroxydopamine lesions of the brain dopamine systems. Although varying amounts of 5,7‐DHT produced serotonin depletions in striatal tissue, decreases in extracellular levels were only observed at tissue depletions greater than 60% compared to saline‐injected control subjects. Thus, the effects of serotonin lesions which produce only moderate depletions may not be the result of decreased extracellular serotonin, but instead may be the result of compensatory changes in remaining neurons which maintain normal extracellular serotonin concentrations. Different degrees of striatal serotonin depletion were associated with opposite behavioral effects. Moderate levels of serotonin depletion (50–75%) produced evidence of increased anxiety, while these effects were no longer seen in rats with more severe 5‐HT depletions (>75%). Synapse 33:16–25, 1999. © 1999 Wiley‐Liss, Inc.