β2 -Adrenoceptor Agonist Activity of Higenamine.

Higenamine was included in the World Antidoping Agency (WADA) Prohibited Substances and Methods List as a β2 -adrenoceptor agonist in 2017, thereby resulting in its prohibition both in- and out-of-competition. The present mini-review describes the physiology and pharmacology of adrenoceptors, summarizes the literature addressing the mechanism of action of higenamine, and extends these findings with previously unpublished in-silico and in-vitro work. Studies conducted in isolated in vitro systems, whole animal preparations, and a small number of clinical studies suggest that higenamine acts in part as a β2 -adrenoceptor agonist. In silico predictive tools indicated that higenamine and possibly a metabolite has a high probability of interacting with the β2 -receptor as an agonist. Stable expression of human β2 -receptors in Chinese Hamster Ovary (CHO) cells to measure agonist activity confirmed not only the activity of higenamine at β2 , but also closely agreed with the in-silico prediction of potency for this compound. These data confirm and extend literature findings supporting the inclusion of higenamine in the Prohibited List. This article is protected by copyright. All rights reserved.