Skeletal muscle fibers of beetle larvae, Xylotrupes dichotomus L., which were inexcitable in the standard saline solution at pH 7.4 became capable of generating all-or-none spikes when a certain amount of acetate was added to a low pH saline solution. The optimum condition for the spike initiation was the presence of 20-30 mM acetate at pH 6. The spikes thus elicited were pure Ca-spikes as they were dependent on the external Ca++ concentration but were not inhibited either by removal of the external Na+ or by application of tetrodotoxin. This facilitation of the Ca-spike generation was probably due to a combined action of acetate and of the low pH upon the muscle membrane.
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Pharmacology, Toxicology and Pharmaceutics(all)