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Importance of h5-HT1B receptor selectivity for 5-HT terminal autoreceptor activity: an in vivo microdialysis study in the freely-moving guinea-pig
- Source :
- Neuropharmacology. 36(4-5)
- Publication Year :
- 1997
-
Abstract
- The importance of h5-HT1B receptor selectivity for 5-HT terminal autoreceptor activity was investigated with the selective h5-HT1B receptor ligands SB 219085, SB 220272, SB 224289 and SB 216641. The studies employed measurement of compound affinity and efficacy in vitro and the measurement of extracellular 5-HT in the frontal cortex of the freely-moving guinea-pig using in vivo microdialysis. All compounds had high affinity and selectivity for the h5-HT1B receptor, with SB 224289 the most selective for h5-HT1B over h5-HT1D receptors. Compounds exhibited a range of efficacies at both receptors: SB 224289 and SB 219085 were inverse agonists, SB 220272 was an antagonist and SB 216641 was a partial agonist. SB 220272, SB 216641 and SB 224289 had no effect on extracellular 5-HT following systemic administration, however, SB 219085 produced a significant increase. The SB 219085-induced increase in extracellular 5-HT was attributed to the compounds non-specific releasing properties as it was also demonstrated to increase basal release of [3H]5-HT from pre-loaded guinea-pig cortical slices. The lack of effect of the above h5-HT1B receptor selective compounds and the decrease in extracellular 5-HT elicited by the non-selective compounds GR 127935, GR125743 and methiothepin suggest that antagonism of 5-HT1D receptors may mediate this decrease in 5-HT levels. It is plausible that blockade of 5-HT1D receptors increases 5-HT levels in the raphe, this activates 5-HT1A receptors which results in an overall decrease in terminal 5-HT release. Definitive proof now awaits elucidation of the action of a selective 5-HT1D receptor antagonist. © 1997 Elsevier Science Ltd.
- Subjects :
- Male
Serotonin
medicine.drug_class
Microdialysis
Guinea Pigs
CHO Cells
Pharmacology
Ligands
Cellular and Molecular Neuroscience
chemistry.chemical_compound
SB-216641
Cricetinae
medicine
Electrochemistry
Inverse agonist
Animals
Receptor
GR-127935
5-HT receptor
Chromatography, High Pressure Liquid
Autoreceptors
Brain Chemistry
Cerebral Cortex
Chemistry
Receptor antagonist
Guanosine 5'-O-(3-Thiotriphosphate)
Receptors, Serotonin
Autoreceptor
Raphe Nuclei
5-HT1 receptor
Subjects
Details
- ISSN :
- 00283908
- Volume :
- 36
- Issue :
- 4-5
- Database :
- OpenAIRE
- Journal :
- Neuropharmacology
- Accession number :
- edsair.doi.dedup.....3628354d8a847758dbd014445dd80763