Rostral hypothalamic microinfusions of 5,7 dihydroxytryptamine produce anatomically and neurochemically selective depletions of hippocampal serotonin and increase the influence of estrogen and food deprivation on locomotor activity.
Ovariectomized Long-Evans rats received bilateral rostral hypothalamic infusions of 5,7-dihydroxytryptamine (5,7-DHT). Neurochemical determination of catecholamines (CA) and indoleamines in the hippocampus, hypothalamus and mesencephalon revealed that 5,7-DHT infusions had no effect on CA content in these areas nor in mesencephalic serotonin or 5-hydroxyindoleacetic acid (5-HIAA). However, the neurotoxin produced significant decreases in hippocampal serotonin and 5-HIAA. Serotonin-depleted animals exhibited an increase in both spontaneous and estradiol-induced wheel running. In addition it was found that serotonin-depleted animals exhibit an enhanced activity response to starvation. Because estrogen is thought to decrease serotonergic transmission, the enhanced activity response to estrogen may be secondary to an estrogen-related exaggeration of the 5,7-DHT-induced serotonin depletion. The increased activity effect of starvation may indicate that serotonin-depleted animals do not effectively mobilize energy stored as lipid.
D015116:5,7-Dihydroxytryptamine / Q000494:pharmacology*; D000818:Animals; D004102:Dihydroxytryptamines / Q000494:pharmacology*; D004347:Drug Interactions; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D005508:Food Deprivation; D006624:Hippocampus / Q000032:analysis*; D007031:Hypothalamus / Q000187:drug effects*; D008845:Microinjections; D009043:Motor Activity / Q000187:drug effects*; D051381:Rats; D012701:Serotonin / Q000032:analysis*
D004102:Dihydroxytryptamines; D015116:5,7-Dihydroxytryptamine; D012701:Serotonin; D004958:Estradiol