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Effects of bipyridylium compounds on calcium release from triadic vesicles isolated from rabbit skeletal muscle
Author(s) -
Kang J.J.,
Hsu K.S.,
LinShiau S.Y.
Publication year - 1994
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1994.tb13213.x
Subject(s) - ryanodine receptor , calcium , chemistry , caffeine , skeletal muscle , vesicle , muscle contraction , biophysics , stimulation , endoplasmic reticulum , endocrinology , biochemistry , biology , membrane , organic chemistry
1 The effects of 1,1′‐diheptyl‐4,4′‐bipyridinium dibromide (DHBP), a viologen for electrochromic memory display agent, on calcium release and ryanodine binding were studied with triad‐rich sarcoplasmic reticulum (SR) vesicles isolated from rabbit skeletal muscle. 2 DHBP inhibited the calcium release induced by 2 mM caffeine and 2 μg ml −1 polylysine with an IC 50 value of 5 μg ml −1 and 4 μg ml −1 respectively. 3 DHBP inhibited [ 3 H]‐ryanodine binding in a dose‐dependent manner with an IC 50 of 2.5 μg ml −1 and 90–100% inhibition at 20–30 μg ml −1 . 4 Calcium uptake by SR was inhibited in the presence of caffeine and this inhibition was antagonized by concomitant addition of DHBP. 5 The effect of DHBP on muscle twitches was studied on the mouse diaphragm. Muscle twitches elicited by direct electrical muscle stimulation and contractions induced by either 10 mM caffeine or 1 μ m ryanodine were blocked by pretreatment with DHBP. 6 Data from this study provided evidence that DHBP blocked the calcium release from SR by direct interaction with the calcium release channel, also known as the ryanodine receptor. A possible use of this agent as a specific inhibitor for calcium release and as a muscle relaxant was suggested.