Phenelzine (Synonyms: NSC 170957)

Phenelzine is an inhibitor of monoamine oxidase (MAO; IC50 = 0.9 μM using rat brain mitochondrial preparations).[1] It potentiates the effects of tryptamine on isolated rat fundus (EC50 = 90 nM) and increases tryptamine toxicity in mice with LD50 values of 85 and 500 mg/kg in the presence and absence of phenelzine, respectively. Phenelzine (20 mg/kg) increases GABA, dopamine, serotonin, and norepinephrine levels in the hippocampus and cortex of socially isolated rats and rats treated with the NMDA receptor antagonist (+)-MK-801.[2] It also increases 5-HT levels in the ventral horn of the spinal cord, improves gross motor ability in a rotarod test, and increases locomotor activity in an open field test in mice with experimental autoimmune encephalomyelitis when administered at a dose of 30 mg/kg.[3]

Reference:
[1]. Maxwell, D.R., Gray, W.R., and Taylor, E.M. Relative activity of some inhibitors of mono-amine oxidase in potentiating the action of tryptamine in vitro and in vivo. Br. J. Pharmacol. Chemother. 17(3), 310-320 (1961).
[2]. Simpson, S.M., Hickey, A.J., Baker, G.B., et al. The antidepressant phenelzine enhances memory in the double Y-maze and increases GABA levels in the hippocampus and frontal cortex of rats. Pharmacol. Biochem. Behav. 102(1), 109-117 (2012).
[3]. Musgrave, T., Benson, C., Wong, G., et al. The MAO inhibitor phenelzine improves functional outcomes in mice with experimental autoimmune encephalomyelitis (EAE). Brain Behav. Immun. 25(8), 1677-1688 (2011).