Evolution of skeletal muscle excitation-contraction coupling and the appearance of dihydropyridine-sensitive intramembrane charge movement

I. Inoue*, I. Tsutsui, Q. Bone, E. R. Brown

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)

Abstract

Excitation-contraction (E-C) coupling was studied in the striated muscle fibres of lower chordates and invertebrates. In the agnathan Lampetra, twitches in response to electrical stimulation were unchanged after Ca2+ influx was blocked by the addition of Co2+. In the invertebrates examined (Branchiostoma, Oikopleura, Doliolum, Diphyes, Patinopecten and Sagitta), Ca2+ influx was necessary to cause a twitch. Whole-cell voltage clamp on muscle fibres of Lampetra revealed that intramembrane charge movement was partly blocked by 5 μM nifedipine, a dihydropyridine (DHP) derivative. Charge movement in fibres from Branchiostoma and Patinopecten was insensitive to nifedipine, although the Ca2+ current was 75% blocked by 5 μM nifedipine. The results suggest that the vertebrate type of E-C coupling was acquired between cephalochordates and agnathans, and was accompanied by the appearance of the DHP-sensitive component of intramembrane charge movement.

Original languageEnglish
Pages (from-to)181-187
Number of pages7
JournalProceedings of the Royal Society B: Biological Sciences
Volume255
Issue number1343
DOIs
Publication statusPublished - 22 Feb 1994

ASJC Scopus subject areas

  • General Biochemistry,Genetics and Molecular Biology
  • General Immunology and Microbiology
  • General Environmental Science
  • General Agricultural and Biological Sciences

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