[3H]9-Methyl-7-bromoeudistomin D, a caffeine-like powerful Ca2+ releaser, binds to caffeine-binding sites distinct from the ryanodine receptors in brain microsomes.
[3H]9-Methyl-7-bromoeudistomin D ([3H]MBED), the most powerful Ca2+ releaser from sarcoplasmic reticulum, specifically bound to the brain microsomes. Caffeine competitively inhibited [3H]MBED binding. [3H]MBED binding was markedly blocked by procaine, whereas that was enhanced by adenosine-5'-(beta,gamma-methylene)triphosphate. The Bmax value was 170 times more than that of [3H]ryanodine binding. The profile of sucrose-density gradient centrifugation of solubilized microsomes indicated that [3H]MBED binding protein was different from [3H]ryanodine binding protein. These results suggest that there are MBED/caffeine-binding sites in brain that are distinct from the ryanodine receptor and that MBED becomes an essential molecular probe for characterizing caffeine-binding protein in the central nervous system.
Yoshikawa
K
K
Department of Pharmaceutical Molecular Biology, Faculty of Pharmaceutical Sciences, Tohoku University, Sendai, Japan.
Furukawa
K
K
Yamamoto
M
M
Momose
K
K
Ohizumi
Y
Y
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D001921:Brain / Q000378:metabolism*; D002110:Caffeine / Q000378:metabolism* / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D015220:Calcium Channels / Q000378:metabolism*; D002243:Carbolines / Q000378:metabolism*; D002793:Cholic Acids / Q000494:pharmacology; D006152:Cyclic GMP / Q000378:metabolism; D003902:Detergents / Q000494:pharmacology; D006168:Guinea Pigs; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology; D007700:Kinetics; D008861:Microsomes / Q000378:metabolism*; D009124:Muscle Proteins / Q000378:metabolism*; D011343:Procaine / Q000494:pharmacology; D012430:Ruthenium Red / Q000494:pharmacology; D012433:Ryanodine / Q000378:metabolism / Q000494:pharmacology; D019837:Ryanodine Receptor Calcium Release Channel
D015220:Calcium Channels; D002243:Carbolines; D002793:Cholic Acids; D003902:Detergents; D009124:Muscle Proteins; D019837:Ryanodine Receptor Calcium Release Channel; D012430:Ruthenium Red; C060741:9-methyl-7-bromoeudistomin D; D012433:Ryanodine; C005147:5'-adenylyl (beta,gamma-methylene)diphosphonate; D002110:Caffeine; D011343:Procaine; D015544:Inositol 1,4,5-Trisphosphate; D000255:Adenosine Triphosphate; D006152:Cyclic GMP; C002630:alpha,beta-methyleneadenosine 5'-triphosphate; C028213:3-((3-cholamidopropyl)dimethylammonium)-1-propanesulfonate; D002118:Calcium