<p>Intact CHO cells expressing MT<sub>1</sub> or MT<sub>2</sub> were incubated with [<sup>3</sup>H]melatonin with or without different concentrations of selected tested compounds or unlabeled melatonin. Data represented mean ± SEM of at least 3 different trials performed in duplicates, and normalized to the maximal binding values (in the absence of tested compound). Estimation of maximal displacement and IC<sub>50</sub> and K<sub>i</sub> were shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0113638#pone-0113638-t001" target="_blank">Table 1</a>.</p
