Development of a 5-hydroxytryptamine(2A) receptor binding assay for high throughput screening using 96-well microfilter plates.
J Biomol Screen
; 5(4): 269-78, 2000 Aug.
Article
en En
| MEDLINE
| ID: mdl-10992048
ABSTRACT
A high throughput screening method for the analysis of 5-hydroxytryptamine(2A) (5-HT(2A)) receptor binding parameters has been developed, using 96-well filter plates of the Millipore MultiScreen system in combination with a MicroBeta PLUS microplate scintillation counter. MAFB filter plates (GF/B filter over a Durapore membrane) were used because of the lower nonspecific binding of the radioligand to GF/B filter material than to GF/C filters. Comparing different scintillation cocktails, highest counting efficiency and shortest equilibration time were detected with Betaplatescint, after drying the plates at 50 degrees C for 2 h. Measuring the plates without the plastic underdrain increased the counting efficiency by about 39% as compared with counting the plate with the underdrain intact. Presoaking the wells with 0.5% polyethyleneimine for 2 h reduced the nonspecific binding to the filter material by about 50%. A linear relationship of protein concentration and radioligand binding was established up to a protein concentration of 165 microg of protein/well. In the assays, 70 microg of protein/well was generally used, which has turned out to be favorable with respect to the number of counts obtained. When a higher concentration of protein was used, the period of time needed to aspirate the plate was too long because of obstruction of the filter material. Receptor-radioligand equilibration was reached after about 20 min at concentrations less than 0.05 nM [(3)H]ketanserin-HCl; at higher concentrations it was reached after about 10 min. Saturation analysis of [(3)H]ketanserin-HCl resulted in a mean B(max) of 393 fmol/mg protein and a K(D) of 2.0 nM using rat frontal cortex as a receptor source. Competition experiments with known 5-HT(2A) receptor ligands-DOB-HCl (K(i) = 59 nM), DOET-HCl (K(i) = 137 nM), DOM-HCl (K(i) = 533 nM), DMT (K(i) = 1,985 nM), and TMA-HCl (K(i) = 22,340 nM)-were in accordance with literature values.
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Bases de datos:
MEDLINE
Asunto principal:
Ensayo de Unión Radioligante
/
Receptores de Serotonina
/
Evaluación Preclínica de Medicamentos
Tipo de estudio:
Diagnostic_studies
/
Evaluation_studies
/
Screening_studies
Idioma:
En
Revista:
J Biomol Screen
Año:
2000
Tipo del documento:
Article
País de afiliación:
Alemania