KSK67 is a selective dual antagonist of sigma-2 and histamine H3 receptors with inhibitory effects on H3 receptors, sigma-1, and sigma-2 receptors, with Ki values of 3.2, 1531, and 101 nM, respectively.

Sigma-1 receptor antagonist 3 is a more potent and selective antagonist of Sigma-1 (σ1) receptor (Ki = 1.14 nM) than σ2 receptor(Ki = 1239 nM).

S1R agonist 2 is a selective S1R agonist with a Ki of 88 nM for S2R and 1.1 nM for S1R and is protective against ROS and NMDA-induced neurotoxicity.