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Rats with persistently high exploratory activity have both higher extracellular dopamine levels and higher proportion of D 2 High receptors in the striatum
Author(s) -
Alttoa Aet,
Seeman Philip,
Kõiv Kadri,
Eller Marika,
Harro Jaanus
Publication year - 2009
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/syn.20620
Subject(s) - striatum , dopamine , extracellular , receptor , amphetamine , sensitization , behavioral sensitization , psychology , medicine , dopamine receptor , endocrinology , dopamine receptor d2 , neuroscience , chemistry , biology , nucleus accumbens , biochemistry
Increases in both striatal dopamine release and the proportion of the D 2 receptors in the high affinity state (D 2 High ) accompany the behavioral sensitization to psychostimulants, but it is not known whether the physiological substrate of the interindividual differences locomotor and exploratory behavior is similar. Thus, we examined whether persistently high spontaneous exploratory activity is associated with extracellular dopamine as well as the proportion of D 2 Highin the striatum. Extracellular dopamine levels were found to be significantly higher in rats with high exploratory activity (high explorers, HE) as compared with low explorers (LE) in baseline conditions as well as after administration of amphetamine (0.5 mg/kg, i.p.). Also, the HE animals had significantly higher proportion of striatal D 2 Highreceptors than the LE‐rats (43.8 ± 4.4% and 22.5 ± 1.5%, respectively). Thus, the present findings support the notion that concomitant higher extracellular dopamine levels and the proportion of D 2 Highreceptors in the striatum, whether naturally occurring and persistent or pharmacologically induced, are causally related to high behavioral activity. Synapse 63:443–446, 2009. © 2009 Wiley‐Liss, Inc.