High affinity binding of a potassium channel agonist to intact rat insulinoma cells.
The specific binding of a novel tritiated K+ channel opener, [3H]BAY X 9228, has been characterized in a rat insulinoma (RINm5F) cell line. The KD was 2.1 nM and Bmax 50 fmol/mg total protein as determined by saturation analysis. The high affinity binding to intact cells was inhibited by pinacidil and by a series of BAY X 9228 analogs with an activity sequence correlating well with that for producing glyburide-reversible relaxation of partially depolarized rat aorta. This represents the first report of the specific binding of a K+ channel opener to cultured cells.
Hoffman
F J
FJ
Institute for Preclinical Pharmacology, Miles Inc., West Haven, CT 06516.
Lenfers
J B
JB
Niemers
E
E
Pleiss
U
U
Scriabine
A
A
Janis
R A
RA
D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000502:physiology; D001665:Binding Sites; D001667:Binding, Competitive; D005905:Glyburide / Q000378:metabolism / Q000494:pharmacology; D006146:Guanidines / Q000494:pharmacology; D007340:Insulinoma / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D009574:Nitro Compounds / Q000378:metabolism* / Q000494:pharmacology; D010671:Phenylurea Compounds / Q000378:metabolism* / Q000494:pharmacology; D020110:Pinacidil; D015221:Potassium Channels / Q000502:physiology*; D051381:Rats; D014407:Tumor Cells, Cultured; D014664:Vasodilation / Q000187:drug effects
D006146:Guanidines; D009574:Nitro Compounds; D010671:Phenylurea Compounds; D015221:Potassium Channels; C079478:Bay Q 3111; D020110:Pinacidil; D005905:Glyburide