ml138ML138 is a probe for MLPCN, an agonist of the κ opioid receptor. Popular Searches. Cell Counting Kit-8 (CCK-8) Approved Drug Library MG-132 Ferrostatin-1 Z-VAD-FMK. mole. 1The ML138 is a hh-performance data acquisition module desned for laboratory and research applications. It features multiple analog input channels, dital inputoutput channels,