PT  - JOURNAL ARTICLE
AU  - P A Maguire
AU  - J I Mechanick
AU  - M F Davies
AU  - D M Ellis
AU  - D B Meredith
AU  - G H Loew
TI  - Resolving receptor heterogeneity using Fourier-derived affinity spectrum analysis and LIGAND: benzodiazepine receptors in the rat spinal cord.
DP  - 1995 May 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 842--849
VI  - 273
IP  - 2
4099  - http://jpet.aspetjournals.org/content/273/2/842.short
4100  - http://jpet.aspetjournals.org/content/273/2/842.full
SO  - J Pharmacol Exp Ther1995 May 01; 273
AB  - In the present study, we combined a powerful and novel receptor binding data analysis technique. Fourier-derived affinity spectrum analysis (FASA), with the nonlinear regression analysis program LIGAND to resolve benzodiazepine receptor heterogeneity in rat spinal cord. With FASA, we identified three distinct [3H]Ro15-1788 binding populations: two high-affinity sites (0.4 and 5 nM) for the radioligand and a lower-affinity site (150 nM) that is insensitive to the imidazopyridine alpidem. With the affinities for the radioligand determined with FASA, the Ki values of 13 competing ligands were calculated with LIGAND. All of the ligands studied displayed the highest affinity for site 1 (the highest-affinity [3H]Ro15-1788 binding site), with the exception of AHR 11797. Site 2 had high affinity for Ro15-1788, lower affinity for flunitrazepam and beta-CCM and very low, but measurable, affinity for zolpidem. The alpidem-insensitive binding site, studied in isolation by performing competitive binding assays in the presence of 65 microM alpidem, showed relatively low affinity for all of the ligands studied, and its physiological relevance is not yet known.