Calcium dependent action potentials in skeletal muscle fibres of a beetle larva, Xylotrupes dichotomus

Jun Fukuda, Shunsuke Furuyama, Kazuyoshi Kawa

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

The ionic requirement for generating action potentials in ventral longitudinal muscle fibers dissected from beetle larvae was examined by conventional electrophysiological techniques. Muscle fibers that generated only graded responses in physiological saline were able to generate an all-or-none action potential when the potassium permeability of the membrane was inhibited by tetraethylammonium+ added to the saline. The peak of the action potential thus elicited was intimately related to the external Ca++ concentration. The action potential was blocked by Co++ which is known as a competitive inhibitor of Ca-spikes. Neither tetrodotoxin (3 μM) nor a Na-free condition effectively blocked the generation of the action potential. Mg++ induced a shift in the peak of the action potential; this was, however, due to the stabilizing action of Mg++ but not due to the penetration of Mg++ through the muscle membrane. No action potential was elicited in the muscle fiber when immersed in a Ca-free, EGTA saline even when a high concentration of either Mg++, Na+, or tetraethylammonium+ was present. The action potential of the larval muscle fiber was thus concluded to be a Ca-spike, through the channel of which Na+ or Mg++ did not penetrate.

Original languageEnglish
Pages (from-to)367-374
Number of pages8
JournalJournal of Insect Physiology
Volume23
Issue number3
DOIs
Publication statusPublished - 1977

ASJC Scopus subject areas

  • Physiology
  • Insect Science

Fingerprint Dive into the research topics of 'Calcium dependent action potentials in skeletal muscle fibres of a beetle larva, Xylotrupes dichotomus'. Together they form a unique fingerprint.

  • Cite this