ISSN:
1432-1912
Keywords:
Sodium channels
;
3H-Tetracaine binding
;
3H-Batrachotoxinin-A 20-α-benzoate binding
;
Sodium influx
;
Antianginal drugs
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary The effects of antianginal drugs, especially arylalkylamines and structurally related derivatives, on 3H-batrachotoxinin-A 20-α-benzoate (3H-BTX-B) binding and on 3H-tetracaine binding were studied on rat synaptosomal and heart membrane preparations. The effect of the same drugs on the Na+ influx induced by protoveratrine B was studied on the rat synaptosomal preparation. Antianginal drugs tested inhibited 3H-BTX-B binding in rat synaptosomes, arylalkylamine derivatives being the most potent: IC50 values were 27 nM for flunarizine, 32 nM for prenylamine, 79 nM for cinnarizine. Similarly, these drugs were the most potent when tested in cardiac membrane preparations. All the drugs tested were very weak inhibitors of 3H-tetracaine binding (IC50 ranging from 0.01 mM to more than 1 mM) except for guanabenz, which was more potent (IC50: 0.3 μM on the synaptosomal preparation). The various drugs tested inhibited the 22 Na+ influx induced by protoveratrine B, with IC50 values ranging from 15 μM (prenylamine) to 110 μM (verapamil), with the exception of nifedipine which had an IC50 of more than 0.1 mM. The inhibition of 22Na+ influx correlated well with the inhibition of 3H-BTX-B binding. These findings suggest that some antianginal drugs, especially the arylalkylamines may have, in addition to their calcium antagonist activity, direct effects on sodium channels.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00177720
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