These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: [3H]dopamine and [3H]serotonin release in vitro induced by electrical stimulation in A9 and A10 dopamine regions of rat brain: characterization and responsiveness to cocaine.
    Author: Chen NH, Reith ME.
    Journal: J Pharmacol Exp Ther; 1993 Oct; 267(1):379-89. PubMed ID: 8229765.
    Abstract:
    The present study investigated [3H]dopamine (DA) and [3H]5-hydroxytryptamine (5-HT) release evoked by electrical stimulation in superfused ventral mesencephalon (VM) slices containing A9 and A10 DA neurons. Electrically induced [3H]DA release from VM was, at least, of two origins: one was from DA somatodendrites, regulated by DA autoreceptors, and increased by DA uptake blockers; another was from 5-HT terminals, modulated by 5-HT autoreceptors, and could be minimized by the copresence of fluoxetine during the labeling of the slices. Release of both origins was Ca(++)-dependent and tetrodotoxin-sensitive. Cocaine (10 and 100 microM) modestly increased electrically induced [3H]DA release from DA somatodendrites and concentration-dependently inhibited that from 5-HT terminals. Electrically induced [3H]5-HT release from VM was exclusively from 5-HT terminals, dependent on Ca++, partly blocked by tetrodotoxin, increased by 5-HT uptake blockers and regulated by 5-HT autoreceptors. The autoregulation of [3H]5-HT release partly counteracted the stimulatory effect of cocaine (10 microM) on [3H]5-HT release. Inhibition of 5-HT uptake by cocaine reduced the effectiveness of 5-methoxytryptamine to suppress electrically induced [3H]5-HT release. No evidence was found to support the notion that postsynaptic 5-HT receptors modulate somatodendritic DA release. 5-HT facilitated spontaneous [3H]DA release from VM via a 5-HT/DA transporter-dependent exchange process and inhibited electrically induced [3H]DA release from 5-HT terminals via a 5-HT autoreceptor-mediated mechanism. The dual effects of cocaine on electrically induced [3H]DA release from VM may be attributed to the complex 5-HT/DA and 5-HT autoreceptor/cocaine interactions as well as the relative densities of 5-HT/DA transporters in this region, indicating a possible involvement of the 5-HT system in cocaine's behavioral effects.
    [Abstract] [Full Text] [Related] [New Search]