Effects of (+) and (-) enantiomers of calcium channel agonist, Bay K 8644, on mechanical and electrical responses of frog skeletal muscle

M. Oz, Y. Tchugunova, M. Dinc

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

The effects of (+) and (-) enantiomers of Bay K 8644, a Ca2+ channel agonist, on the mechanical and electrical properties of frog skeletal muscle fibers were investigated. In the concentration range of 10-6 to 10-5 M, both (+) and (-) enantiomers of Bay K 8644 significantly increased the maximum amplitudes of twitch responses. Both (+) and (-) enantiomers of Bay K 8644, at higher concentrations such as 10-4 M, greatly depressed the amplitudes of twitches. Potentiating and depressing effects of (-) enantiomer of Bay K 8644 on twitch responses were significantly greater than those of the (+) enantiomer. At all concentrations used, both (+) and (-) enantiomers of Bay K 8644 significantly decreased the area under the tetanic force x time curve. In intracellular recordings, it was found that the depressing effects of both (+) and (-)-Bay K 8644 on tetanic contractions and twitch responses were due to the inhibition of action potentials. The inhibitory effect of (-) enantiomer of Bay K 8644 on action potentials also was significantly greater than that of the (+) enantiomer. In conclusion, present results suggest that, in contrast with cardiac muscle fibers, (+) and (-) enantiomers of Bay K 8644 have similar inhibitory effects on the electrical and mechanical properties of frog skeletal muscle fibers.

Original languageEnglish
Pages (from-to)649-655
Number of pages7
JournalCanadian Journal of Physiology and Pharmacology
Volume78
Issue number8
DOIs
Publication statusPublished - Jan 1 2000

Keywords

  • Bay K 8644
  • Calcium channels
  • Skeletal muscle
  • Sodium channels

ASJC Scopus subject areas

  • Physiology
  • Pharmacology
  • Physiology (medical)

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