To furnish direct evidence which the peculiar enhancement of catecholaminergic action in the brain in animals addressed with a small dose of (−)deprenyl is unrelated to MAO inhibition, we made inside the early '90s a family of deprenyl analogues devoid on the MAO-B inhibitory effect (Knoll et al PPAP 23 https://stephenhhcys.angelinsblog.com/29703334/facts-about-ppap-hcl-revealed