The Pharmacological Profile of Second Generation Pyrovalerone Cathinones and Related Cathinone Derivative

Pyrovalerone cathinones, a class of potent psychoactive substances, were tested for their effects on monoamine transporters and receptors. All tested compounds strongly inhibited the dopamine and norepinephrine transporters, with IC50 values in the low micromolar range, but showed no activity at the serotonin transporter at concentrations below 10 µM. None of the substances triggered monoamine efflux. Two compounds, 4F-PBP and NEH, were particularly selective for the dopamine transporter, suggesting they likely produce strong psychostimulant effects and have high abuse potential. Extending the alkyl chain increased inhibition potency at dopamine and norepinephrine transporters, while a 3,4-methylenedioxy group enhanced serotonin transporter inhibition.

Study at a glance

Abstract

Pyrovalerone cathinones are potent psychoactive substances that possess a pyrrolidine moiety. Pyrovalerone-type novel psychoactive substances (NPS) are continuously detected but their pharmacology and toxicology are largely unknown. We assessed several pyrovalerone and related cathinone derivatives at the human norepinephrine (NET), dopamine (DAT), and serotonin (SERT) uptake transporters using HEK293 cells overexpressing each respective transporter. We examined the transporter-mediated monoamine efflux in preloaded cells. The receptor binding and activation potency was also assessed at the 5-HT1A, 5-HT2A, 5-HT2B, and 5-HT2C receptors. All pyrovalerone cathinones were potent DAT (IC50 = 0.02–8.7 μM) and NET inhibitors (IC50 = 0.03–4.6 μM), and exhibited no SERT activity at concentrations < 10 μM. None of the compounds induced monoamine efflux. NEH was a potent DAT/NET inhibitor (IC50 = 0.17–0.18 μM). 4F-PBP and NEH exhibited a high selectivity for the DAT (DAT/SERT ratio = 264–356). Extension of the alkyl chain enhanced NET and DAT inhibition potency, while presence of a 3,4-methylenedioxy moiety increased SERT inhibition potency. Most compounds did not exhibit any relevant activity at other monoamine receptors. In conclusion, 4F-PBP and NEH were selective DAT/NET inhibitors indicating that these substances likely produce strong psychostimulant effects and have a high abuse liability.