Enhancement of the twitch of bull frog sartorius muscle by fluorides.

Effects of 5 kinds of fluorides on the twitch of the sartorius muscle of the bull frog were investigated. All of the fluorides (0.1-2.0 mM) enhanced the twitch evoked by nerve stimulation. The extents of enhancement at 2.0 mM were in the order: stannous fluoride much greater than potassium fluoride greater than sodium silico fluoride greater than sodium fluoride greater than diammine silver fluoride. The extent of each enhancement was larger than that in the case of direct stimulation of the muscle. These findings show that fluorides commonly enhance the twitch of skeletal muscle and that the extent of enhancement is related to the properties of cations included in the fluoride.