A novel depolarizing activity of scorpion venom fraction M1 due to activation of skeletal muscle nicotinic receptors

A depolarizing activity following interaction with nicotinic acetylcholine receptors (nAchRs) in skeletal muscle cells, was observed for the first time in the non-toxic venom fraction (M1) of the yellow scorpion Buthus occitanus tunetanus (Bot). The effects of M1 fraction were tested on cultured rat myotubes by recording changes in [Ca2+]i. When applied, M1 (10 μg/mL) induced a transient increase of [Ca2+]i which could be blocked by a prior application of α-Bungarotoxin (α-Bg-Tx).