Abstract
Electrophysiological and pharmacological studies have shown that peripheral-type benzodiazepine receptors modulate voltage-sensitive calcium channels in the heart. We have compared these binding sites with binding sites for [3H]dihydropyridines, which are believed to label such channels. Although no direct or allosteric interaction could be demonstrated between the two sites, their subcellular distribution--sarcolemma and ryanodine-sensitive sarcoplasmic reticulum--was parallel. Size determination of the two sites suggests that the receptors for these two classes of compounds are separate molecules packaged in the same membrane compartment.
MeSH terms
-
Animals
-
Benzodiazepinones / metabolism
-
Benzodiazepinones / pharmacology
-
Binding Sites
-
Calcium / metabolism
-
Calcium Channel Blockers / metabolism*
-
Calcium Channels
-
Cell Fractionation
-
Dogs
-
Ion Channels
-
Isoquinolines / metabolism
-
Isoquinolines / pharmacology
-
Isradipine
-
Male
-
Molecular Weight
-
Myocardium / metabolism
-
Myocardium / ultrastructure*
-
Nifedipine / analogs & derivatives
-
Nifedipine / metabolism
-
Nifedipine / pharmacology
-
Nitrendipine
-
Oxadiazoles / metabolism
-
Rats
-
Rats, Inbred Strains
-
Receptors, GABA-A / metabolism*
-
Receptors, Nicotinic / metabolism*
-
Sarcolemma / metabolism*
-
Sarcoplasmic Reticulum / metabolism*
-
Verapamil / metabolism
-
Verapamil / pharmacology
Substances
-
Benzodiazepinones
-
Calcium Channel Blockers
-
Calcium Channels
-
Ion Channels
-
Isoquinolines
-
Oxadiazoles
-
Receptors, GABA-A
-
Receptors, Nicotinic
-
4'-chlorodiazepam
-
Nitrendipine
-
Verapamil
-
Nifedipine
-
Calcium
-
PK 11195
-
Isradipine