The effects of
cinepazide, a
vasodilator, on the content, biosynthesis and turnover of
noradrenaline (NA),
dopamine (DA) and
5-hydroxytryptamine (5-HT) in the rat brain were examined under room air and
hypoxia (10% O2, 90% N2). Under room air,
cinepazide had no significant effects on the content of NA, DA,
5-HT and 5-hydroxyindoleacetic
acid (5-HIAA), the accumulation of
3,4-dihydroxyphenylalanine (
DOPA) and
5-hydroxytryptophan (5-HTP) after central
decarboxylase inhibition, and the depletion of NA, DA and
5-HT after synthesis inhibition. After 2 hr-exposure to
hypoxia, the content of NA,
5-HT and
5-HIAA was decreased, whereas the content of DA was unchanged. The accumulation of
DOPA and
5-HTP was decreased. The depletion of DA and
5-HT was inhibited by
hypoxia, whereas the depletion of NA was unaffected. Under hypoxic conditions,
cinepazide had no effects on the content of NA, DA and
5-HT, the accumulation of
DOPA and
5-HTP, and the depletion of NA and DA, whereas
cinepazide increased both the rate of
5-HT depletion and the content of
5-HIAA. The present data suggest that
cinepazide selectively stimulates the functional activities of
5-HT neurons in the brain, which are depressed by
hypoxia.