Tissue- and subcellular-distribution of the binding site of [3H]9- methyl-7-bromoeudistomin D, a potent caffeine-like Ca2+ releaser, in rabbits.
Tissue and subcellular distribution of the binding site of 3H-labelled 9-methyl-7-bromoeudistomin D ([3H]MBED), a powerful caffeine-like Ca2+ releaser, were investigated in rabbits. The order of specific activities of total homogenates was liver > brain > other tissues. All binding was completely suppressed by 10 mM caffeine, indicating that all [3H]MBED binding sites are modulated by caffeine. [3H]MBED binding sites distributed mainly in membrane fractions rather than soluble fractions in most tissues. In lung and liver, [3H]MBED binding was enriched in microsomes. [3H]MBED may be useful as a probe to investigate the actions of caffeine at the molecular level not only in muscles but also in a variety of tissues including liver, kidney and lung.
Department of Pharmaceutical Molecular Biology, Tohoku University, Sendai, Japan.
M
M
Adachi
M
M
Kakubari
Y
Y
Ohizumi
D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive / Q000187:drug effects; D002110:Caffeine / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002243:Carbolines / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D008297:Male; D009928:Organ Specificity; D011817:Rabbits; D013347:Subcellular Fractions
D002243:Carbolines; C060741:9-methyl-7-bromoeudistomin D; D002110:Caffeine; D002118:Calcium