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EFFECT OF NEOMYCIN ON PHOSPHOINOSITIDE LABELLING AND CALCIUM BINDING IN GUINEA‐PIG INNER EAR TISSUES IN VIVO AND IN VITRO 1
Author(s) -
Orsulakova Angela,
Stockhorst Eva,
Schacht Jochen
Publication year - 1976
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1976.tb04478.x
Subject(s) - neomycin , phosphatidylinositol , inositol , guinea pig , biochemistry , in vivo , organ of corti , phospholipid , calcium , inner ear , chemistry , labelling , biology , endocrinology , receptor , anatomy , membrane , signal transduction , microbiology and biotechnology , organic chemistry , antibiotics
—Phospholipids of guinea‐pig inner ear tissues were labelled in vivo by perilymphatic perfusion of the cochlea with [ 32 P]orthophosphate or myo‐[ 3 H]inositol. After 20‐40 min the most highly labelled 32 P‐lipids were phosphatidylinositol phosphate and diphosphate. Incorporation of [ 3 H]inositol proceeded in the order phosphatidylinositol > phosphatidylinositol phosphate > phosphatidylinositol diphosphate. After treatment of animals with neomycin for 3 weeks, 32 P‐incorporation into phosphatidylinositol diphosphate, but not into other lipids, was significantly decreased in the preparations of the organ of Corti and stria vascularis. In homogenates of inner ear tissues, the labelling of the polyphosphoinositides by [γ‐ 32 P]ATP was increased and the hydrolysis of these lipids was blocked in the presence of 10 −4 m ‐neomycin. Neomycin also competitively inhibited the binding of 45 Ca 2+ to homogenates of these tissues.