Harmane-D is the deuterated form of Harmane. Harmane, a β-carboline alkaloid (BCA), acts as a potent neurotoxin, inducing marked tremors and psychiatric symptoms. It exhibits a high affinity for the I1 imidazoline receptor (IC50=30 nM), showing 1000 times more selectivity than for the α2-adrenergic receptor (IC50=18 μM). Additionally, Harmane (T3158) is an efficient and selective monoamine oxidase inhibitor, with IC50 values of 0.5 μM and 5 μM for MAO A and B, respectively.