Article date: 1989/12/1
PubMed ID: 2575444
Journal name: Brain research bulletin (ISSN: 0361-9230)
The effects of microinfusion of serotonin (5-HT) agents as well as glutamate and muscimol into the ventral tegmental area (VTA) on dopamine (DA) release in the ipsilateral nucleus accumbens (ACC) were investigated in freely moving rats, using a push-pull perfusion procedure. The baseline values for DA, 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) were approximately 0.24, 8.4, 2.1 and 2.7 pmol/15 min, respectively, in the push-pull perfusate of the ACC. When microinfused into the VTA, glutamate (0.74 microgram) significantly (p less than 0.05) increased the contents of DOPAC (110%) and HVA (90%) over baseline levels in the perfusate. On the other hand, 0.5 microgram muscimol (a gamma-amino-n-butyric acid, GABA, agonist) significantly, (p less than 0.05) decreased both DA (40%) and DOPAC (20%) levels relative to baseline values. Administration of 2 micrograms 5-HT into the VTA caused a significant (p less than 0.05) elevation in the perfusate levels of DOPAC (80%) and HVA (70%) over baseline values. A similar effect was obtained with a nonselective 5-HT1 agonist but not with a selective 5-HT1A agonist. The results suggest that 5-HT innervations in the VTA may have an excitatory action possibly via 5-HT1B rather than 5-HT1A receptors on the mesolimbic DA system projecting to the ACC and that this DA system may also be regulated by glutamatergic and GABAergic (via GABAA receptors) inputs.
Author List: Guan X M, McBride W J
Publication Types: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.
Substances mentioned in the article: Glutamates; 3,4-Dihydroxyphenylacetic Acid; Muscimol; Serotonin; Glutamic Acid; Dopamine;
Mesh terms: 3,4-Dihydroxyphenylacetic Acid/metabolism; Animals; Dopamine/metabolism; Functional Laterality; Glutamates/pharmacology; Glutamic Acid; Male; Muscimol/pharmacology; Nucleus Accumbens/metabolism; Rats; Rats, Inbred Strains; Septal Nuclei/metabolism; Serotonin/pharmacology; Tegmentum Mesencephali/drug effects;