the effect of benzodia zepines on the stress-induced responses of the nora drenergic a nd serotonergic projections to the rat hippocampus

microdialysis was used to measure the effect of benzodiazepines (bdzs) on basal levels and on stress-induced increases of 5 -hydroxytryptamine (5 -ht), 5 - hydroxyind oleacetic acid (5 -hiaa) , noradrenaline (na), and dihydroxyphenylacetic acid (dop ac). the stressors used were a 5 min tail pinch or a 10 min period of restraint. a subcutaneous injection of 5 mg/kg diazepam decreased basal levels of 5 -ht, 5 -hiaa, and dopac, but not na. there was no effect on the stress-induced increase in 5 -ht, na, and 5 -hiaa, while the increase in dopac was completely abolished. local infusion of 5 µm flurazepam decteased the basal level of 5 - ht but not 5 -hiaa and abolished the stress-induced increase of 5 -hiaa but not 5 -ht. these results suggest that the anxiolytic action of bdzs is unlikely to be attributable to the suppression of stress-induced increases in the release of na or 5 -ht in the hippocampus.