Evidence for Specific Interactions between Kavain and Human Cortical Neurons Monitored by Fluorescence Correlation Spectroscopy

Abstract

Specific interactions between a tetramethylrhodamine-labeled kavain derivative and human cortical neurons were found for the first time using fluorescence correlation spectroscopy (FCS). Human cortical neurons, cultivated in Nunc® chambers, were incubated with 1 nM of the dye-labeled kavain derivative. A total binding of 0.55 nM was found after an incubation period of 60 min. 50 % of the total binding was specifically displaced in the presence of 1 μM non-labeled (+)-kavain. Evidence for these specific interactions was verified by a saturation experiment. Both the non-linear Scatchard plot and the n value of 1.58 ± 0.07 in the sigmoid Hill plot indicate binding sites with different binding affinities.