Yohimbine A – Equine Care Pharmacy

Yohimbine A, an alpha-2 adrenergic receptor antagonist, is an indole alkaloid found in numerous botanical sources. It is the predominant alkaloid in extracts from the bark of the Pausinystalia yohimbe tree, and can also be found in Rauwolfia root. It has two stereoisomers (rauwolscine and corynanthine) that differ little in their physical properties or in their effects on serotonin and dopamine receptors. The three isomers, however, do differ significantly in their affinity for the alpha-1 and alpha-2 adrenergic receptor subtypes. It was one of the first radioligands developed for selectively labeling alpha-2 adrenergic receptors.