Comparison of binding affinities of omega-conotoxin and amlodipine to N-type Ca2+ channels in rat brain.
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Qu YL, Sugiyama K, Ohnuki T, Hattori K, Watanabe K, Nagatomo T
Comparison of binding affinities of omega-conotoxin and amlodipine to N-type Ca2+ channels in rat brain.
Zhongguo Yao Li Xue Bao. 1998 Mar;19(2):97-100.
- PubMed ID
- 10374627 [ View in PubMed]
- 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.
DrugBank Data that Cites this Article
- Drug Targets
Drug Target Kind Organism Pharmacological Action Actions Amlodipine Voltage-dependent calcium channel subunit alpha-2/delta-3 Protein Humans UnknownInhibitorDetails Amlodipine Voltage-dependent L-type calcium channel subunit beta-1 Protein Humans UnknownInhibitorDetails Amlodipine Voltage-dependent N-type calcium channel subunit alpha-1B Protein Humans UnknownInhibitorDetails Nilvadipine Voltage-dependent calcium channel subunit alpha-2/delta-3 Protein Humans UnknownInhibitorDetails