@article{APS8897,
author = {Ying-Li Qu and Kentaro Sugiyama and Toshio Ohnuki and Kaoru Hattori and Kenichi Watanabe and Takafumi Nagatomo},
title = {Comparison of binding affinities of omega-conotoxin and amlodipine to N-type Ca2+ channels in rat brain.},
journal = {Acta Pharmacologica Sinica},
volume = {19},
number = {2},
year = {2016},
keywords = {},
abstract = {AIM: To compare the binding affinities of omega-conotoxin (CTX) and amlodipine to N-type Ca2+ channels in rat brains. METHODS: Whole rat brains were homogenized in HEPES buffer 50 mmol.L-1 (pH 7.4) and centrifuged at 40,000 x g to obtain the membrane-entriched fraction. 125I-omega-conotoxin (125I-omega-CTX) was used as a radioligand. Using radioligand binding assay Kd and Bmax values of the radioligand were determined by Scatchard analysis. The IC50 value for each drug was obtained from displacement experiments. RESULTS: No differences in Bmax values of 125I-omega-CTX binding sites between frozen and fresh tissues were observed. Values of Kd and Bmax of N-type Ca2+ channels were 0.02 +/- 0.01 nmol.L-1 and 1029 +/- 108 pmol/g protein, respectively. The pKi values of omega-CTX and amlodipine were 9.57 and less than 4, respectively. The pKi values of propranolol, prazosin, atropine, and histamine were very low. CONCLUSION: The binding affinity of the L-type Ca(2+)-antagonist amlodipine to N-type Ca2+ channels in the rat brain was very low.},
issn = {1745-7254}, url = {http://www.chinaphar.com/article/view/8897}
}