Isolation and characterization of a fraction from brain that inhibits 1,4-[3H]dihydropyridine binding and L-type calcium channel current.
Bovine brain was subjected to acid extraction and several purification steps. A fraction from brain that eluted from C18 reverse-phase columns at 30-35% acetonitrile inhibited [3H]nitrendipine binding to cardiac membranes. Further purification of this fraction on a sizing column in the presence of 40% acetonitrile yielded a low molecular mass fraction (less than 1 kDa) that produced a time- and voltage-dependent inhibition of L-type (but not T-type) Ca2+-channel current in GH3 cells. The results suggest that this fraction contains an endogenous substance that binds directly to slowly-inactivating Ca2+ channels and thereby inhibits current flow.
Janis
R A
RA
Institute for Preclinical Pharmacology, Miles Inc., West Haven, CT 06516.
Shrikhande
A V
AV
Johnson
D E
DE
McCarthy
R T
RT
Howard
A D
AD
Greguski
R
R
Scriabine
A
A
D000818:Animals; D001921:Brain / Q000502:physiology*; D002121:Calcium Channel Blockers / Q000378:metabolism*; D015220:Calcium Channels / Q000502:physiology*; D002417:Cattle; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000302:isolation & purification* / Q000494:pharmacology; D009568:Nitrendipine / Q000378:metabolism*; D011978:Receptors, Nicotinic / Q000187:drug effects / Q000378:metabolism*; D012016:Reference Values
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D009419:Nerve Tissue Proteins; D011978:Receptors, Nicotinic; D009568:Nitrendipine