The Effects of Cinepazide on the Content, Biosynthesis and Turnover of Noradrenaline, Dopamine and 5-Hydroxytryptamine in the Rat Brain under Room Air and Hypoxia

Abstract

The effects of cinepazide, a vasodilator, on the content, biosynthesis and turnover of noradrenaline (NA), dopamine (DA) and 5-hydroxytryptamine (5-FIT) 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-FIIAA), the accumulation of 3,4-dihydroxyphenylalanine (DOPA) and 5-hydroxytryptophan (5-HTP) after central decarboxylase inhibition, and the depletion of NA, DA and 5-FIT after synthesis inhibition. After 2 hr-exposure to hypoxia, the content of NA, 5-FIT and 5-FIIAA 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.