Terminal autoreceptor control of 5-hydroxytryptamine release as measured by in vivo microdialysis in the conscious guinea-pig.
In vivo microdialysis in the frontal cortex of the freely moving guinea-pig was used to measure extracellular 5-hydroxytryptamine (5-HT) and study terminal autoreceptor control of its release. The indoleamine levels were determined by HPLC with electrochemical detection. Release of extracellular 5-HT and, to a lesser extent, 5-hydroxyindoleacetic acid was sensitive to tetrodotoxin, confirming the neuronal origin of measured neurotransmitter levels. Both systemic and local administration of the 5-HT1 agonist 5-carboxamidotryptamine caused inhibition of extracellular 5-HT levels, confirming the regulatory role of the terminal, and possibly also the somatodendritic, 5-HT autoreceptor on neuronal 5-HT release. Levels of extracellular 5-hydroxyindoleacetic acid were not affected by 5-carboxamidotryptamine following either central or peripheral administration.
Lawrence
A J
AJ
Department of Physiology and Pharmacology, Queen's Medical Centre, University Hospital, Nottingham, England, U.K.
Marsden
C A
CA
D000818:Animals; D003956:Dialysis / Q000379:methods; D004305:Dose-Response Relationship, Drug; D005625:Frontal Lobe / Q000166:cytology / Q000378:metabolism*; D006168:Guinea Pigs; D007274:Injections, Intraperitoneal; D008297:Male; D009474:Neurons / Q000378:metabolism; D010477:Perfusion; D011956:Receptors, Cell Surface / Q000378:metabolism*; D012701:Serotonin / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D013779:Tetrodotoxin / Q000378:metabolism
D011956:Receptors, Cell Surface; D012701:Serotonin; D013779:Tetrodotoxin; C047087:5-carboxamidotryptamine