Characteristics of specific 125I-omega-conotoxin GVIA binding in rat whole brain.
Characteristics of specific 125I-omega-conotoxin (omega-CgTX) binding were systematically investigated in crude membranes from rat whole brain. Kd and Bmax Values for the binding were 49.7 pM and 181.5 fmol/mg of protein, respectively. The effects of various types of Ca channel antagonists on the binding were investigated. Dynorphin A (1-13), in particular, specifically inhibited 125I-omega-CgTX binding, but not that of [3H](+)PN200-110. Spider venom from Plectreurys tristes did not specifically inhibit specific binding of 125I-omega-CgTX, because the venom also inhibited the binding of [3H](+)PN200-110 to a similar degree. The amount of specific binding of 125I-omega-CgTX was less in the cerebellum than that in any other area of whole brain. The cross-linker disuccinimidyl suberate did not label with 125I-omega-CgTX and its binding sites in rat whole brain, although it did in chick whole brain, which was used as a positive control. These findings suggested that dynorphine A (1-13) was a selective blocker of omega-CgTX-sensitive Ca channels in crude membranes from rat whole brain and that omega-CgTX-sensitive Ca channels were mainly present a rat brain except cerebellum.
Ichida
S
S
Department of Biological Chemistry, Faculty of Pharmacy, Kinki University, Higashi-Osaka, Japan.
Wada
T
T
Sekiguchi
M
M
Kishino
H
H
Okazaki
Y
Y
Akimoto
T
T
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002412:Cations; D002462:Cell Membrane / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004399:Dynorphins / Q000494:pharmacology; D005260:Female; D007457:Iodine Radioisotopes; D007700:Kinetics; D008297:Male; D010446:Peptide Fragments / Q000494:pharmacology; D010455:Peptides / Q000378:metabolism* / Q000494:pharmacology; D011494:Protein Kinases / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013111:Spider Venoms / Q000494:pharmacology; D013388:Succinimides / Q000494:pharmacology; D020866:omega-Conotoxin GVIA
D002412:Cations; D003432:Cross-Linking Reagents; D007457:Iodine Radioisotopes; D010446:Peptide Fragments; D010455:Peptides; D013111:Spider Venoms; D013388:Succinimides; C026843:dynorphin (1-13); D004399:Dynorphins; D020866:omega-Conotoxin GVIA; D011494:Protein Kinases; C019358:disuccinimidyl suberate