RATS were tested in an elevated plus-maze on two consecutive days. Bas
ed on the percentage of time spent in the open arms on the Ist day, th
ey were divided into two subgroups with either low or high anxiety lev
els. A post-mortem neurochemical analysis showed that animals with hig
h anxiety had lower ventral striatal tissue levels of 5-HT. No such di
fferences were found for 5-HT in other brain areas or in dopamine and
norepinephrine levels. The ventral striatal 5-HT levels correlated wit
h plus-maze behavior on the 2nd but not Ist day. These data suggest th
at individual differences in ventral striatal 5-HT interact with plus-
maze behavior, which may help to explain why serotonergic drugs can ha
ve inconsistent effects in this paradigm. (C) 1998 Rapid Science Ltd.