brain regional 5-ht ( 5-hydroxytryptamine ) and 5-hiaa ( 5-hydroxyindole-3-acetic acid ) concentrations in male le rats at three times were measured by a fluorescence method , to evaluate effects of intracranial surgery and administration of melatonin on the changes in these compounds during the first part of the dark phase of the daily cycle in a fixed 12:12 l : d photoperiod .
C0006104
brain
C0086045
concentrations