Immediate and long-term effects of 5,7-dihydroxytryptamine on rat striatal serotonergic neurons measured using in vivo voltammetry.
The immediate and long-term effects of the selective serotonergic neurotoxin 5,7-dihydroxytryptamine (5,7-DHT) on rat striatal serotonergic neurons were examined after its intracerebroventricular administration using in vivo voltammetry. Extracellular concentration of 5-hydroxyindoles increased immediately following intracerebroventricular 5,7-DHT injection (200 microg in 24 microl, 18 min), peaked at 1.5-2 h, and returned to normal by 4 h. 5,7-DHT diffused to the contralateral striatum in detectable amounts 9 to 12 min after the start of injection and returned to basal levels by 1.5 h. Three to 6 days after 5,7-DHT lesions, 5-hydroxytryptophan administration produced an increase in striatal 5-hydroxyindoles that was greater than that produced in pre-lesioned rats. This effect was maximal at 14 to 17 days post-lesion, and remained even after 50 days. The short-term effect of 5,7-DHT may be attributable to increased serotonin release, inhibition of uptake, or monoamine oxidase inhibition. The long-term effect of 5,7-DHT lesions may attributable to increased synthesis of serotonin or decreased reuptake in remaining serotonergic neurons.
Nakazato
T
T
Department of Physiology, Juntendo University School of Medicine, Tokyo, Japan. nakazato@med.juntendo.ac.jp
Akiyama
A
A
D015116:5,7-Dihydroxytryptamine / Q000008:administration & dosage / Q000494:pharmacology*; D006916:5-Hydroxytryptophan / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects / Q000502:physiology*; D004567:Electrodes, Implanted; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D007276:Injections, Intraventricular; D008297:Male; D009474:Neurons / Q000187:drug effects* / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000378:metabolism*
D015116:5,7-Dihydroxytryptamine; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D006916:5-Hydroxytryptophan