Characterization of 5-HT1D receptor binding sites in post-mortem human brain cortex.
The present study provides further evidence for the presence of serotonin1D (5-HT1D) receptors in post-mortem human brain. Receptor binding parameters in temporal cortex homogenates were assessed using [3H]5-HT in the presence of 100 nM 8-OH-DPAT, 1 microM propranolol and 1 microM mesulergine to prevent labelling of the 5-HT1A, 5-HT1B and 5-HT1C sites, respectively. Under these conditions, [3H]5-HT apparently bound to a class of high affinity (Kd = 5.0 +/- 1.0 nM) low capacity (Bmax = 96 +/- 23 fmol/mg protein) sites. In competition experiments, 5-HT and 5-carboxyamidotryptamine (5-CT), as well as ergotamine, lysergic acid, sumatriptan and RU-24969 exhibited high affinity for these sites. This pharmacological profile is concordant with the ligand selectivity pattern reported for 5-HT1D receptors in other species and thus provides further evidence for its existence in human temporal cortex. In addition, the competition profile of some ligands, particularly of unlabelled 5-HT, 5-CT and ergotamine, revealed the existence of a lower affinity binding site. The latter suggests receptor heterogeneity or the presence of a lower affinity state of 5-HT1D receptors.
Martial
J
J
Douglas Hospital Research Centre, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
de Montigny
C
C
Cecyre
D
D
Quirion
R
R
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001667:Binding, Competitive; D002540:Cerebral Cortex / Q000378:metabolism*; D005260:Female; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D011869:Radioligand Assay; D011985:Receptors, Serotonin / Q000378:metabolism*
D011985:Receptors, Serotonin