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Phosphoinositide breakdown in isolated myelin is stimulated by GTP analogues and calcium
Author(s) -
Golly F.,
Larocca J. N.,
Ledeen R. W.
Publication year - 1990
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.490270313
Subject(s) - inositol , inositol phosphate , gtp' , chemistry , carbachol , calcium , incubation , phosphatase , biophysics , in vivo , endocrinology , medicine , biochemistry , biology , receptor , enzyme , organic chemistry , microbiology and biotechnology
Purified myelin from rat brainstem, prelabeled in vivo by intracerebral injection of [ 3 H]myoinositol, showed enhanced breakdown of phosphoinositides on treatment with 5'‐guanylylimidodiphosphate [Gpp‐(NH)p] and Ca 2+ . Concentration variation of the former in the presence of Ca 2+ snowed a dose‐dependent release of inositol 1,4‐bisphosphate (IP 2 ) and inositol 1,4,5‐trisphosphate (IP 3 ), while inositol 1‐phosphate (IP) release was erratic. Concentration‐dependent release of IP 2 and IP 3 was also observed with Ca 2+ as the variable in the presence of Gpp(NH)p. Carbachol, when present, did not enhance the stimulatory effect of Gpp(NH)p alone. Addition of diphosphoglycerate during incubation enhanced IP 3 at the expense of IP 2 , suggesting the presence of IP 3 phosphatase in mylein.