Effects of a selective 5-HT2 agonist, DOI, on 5-HT neuronal firing in the dorsal raphe nucleus and 5-HT release and metabolism in the frontal cortex.
Systemic administration of the 5-HT2 agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) (50 and 100 micrograms kg-1, i.v.) inhibited dorsal raphe neuronal firing. DOI (100 micrograms kg-1, i.v.) also produced a decrease in extracellular 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in the frontal cortex measured by microdialysis. However, local administration of DOI into the frontal cortex produced no change in extracellular 5-HT and 5-HIAA at any dose given (1, 10 and 100ng). The results demonstrate that DOI is a potent inhibitor of 5-HT neuronal firing and terminal release and that the effects on release are not mediated by an action within the terminal region. The site of action and the receptor involved in the inhibition remains to be determined.
Department of Physiology and Pharmacology, Medical School, Queen's Medical Centre, Nottingham.
I K
IK
Wright
J C
JC
Garratt
C A
CA
Marsden
D000662:Amphetamines / Q000494:pharmacology*; D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003956:Dialysis; D004594:Electrophysiology; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D008297:Male; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D011903:Raphe Nuclei / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000378:metabolism / Q000502:physiology*
D000662:Amphetamines; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; C015952:4-iodo-2,5-dimethoxyphenylisopropylamine