Franz Birke

WAL 2014 FU (Talsaclidine) : A preferentially neuron activating muscarinic agonist for the treatment of Alzheimer's disease

The functional selectivity of WAL 2014 FU with regard to stimulation of the neuronal muscarinic M1 receptor subtype in vitro and in vivo is shown in different receptor preparations, isolated organ models, whole animal testing, and finally humans. From receptor binding experiments in membrane preparations from rat tissues and from Chinese hamster ovary cells expressing human muscarinic receptor subtypes, it can be delineated that the ratio between M1 and M2 (hm1 and hm2) is shifted in favour of the M1 receptor affinity, when compared to several classic muscarinic agonists such as carbachol, arecoline, and oxotremorine. The intermediate GTP‐shift of 7.5 for WAL 2014 FU in a M2 muscarinic receptor preparation (rat heart) indicates only partial agonistic activity at this subtype, carbachol (e.g., shows a shift of 51). Moreover, the ratio from agonist to antagonist receptor binding comparing the affinities using [3H]cis‐methyldioxolane and [3H]N‐methylscopolamine as radioligands, suggests only a partial agonist behaviour at M2 receptors, too.