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Mefenamic acid as a novel activator of L‐type voltage‐dependent Ca 2+ channels in smooth muscle cells from pig proximal urethra
Author(s) -
Teramoto Noriyoshi,
Tomoda Toshihisa,
Ito Yushi
Publication year - 2005
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1038/sj.bjp.0706051
Subject(s) - mefenamic acid , nifedipine , chemistry , depolarization , biophysics , voltage dependent calcium channel , calcium , biology , chromatography , organic chemistry
1 The effects of mefenamic acid and Bay K 8644 on voltage‐dependent nifedipine‐sensitive inward Ba 2+ currents in pig urethral myocytes were investigated by use of conventional whole‐cell configuration patch clamp. 2 Mefenamic acid increased the peak amplitude of voltage‐dependent nifedipine‐sensitive inward Ba 2+ current without shifting the position of the current–voltage relationship. 3 Mefenamic acid (300 μ M ) caused little shift in the activation curve although the voltage dependence of the steady‐state inactivation was shifted to more positive potentials by 11 mV in the presence of mefenamic acid. 4 Bay K 8644 (100 n M ) enhanced voltage‐dependent nifedipine‐sensitive inward Ba 2+ currents in a concentration‐ and voltage‐dependent manner, shifting the maximum of the current–voltage relationship by 10 mV in the hyperpolarizing direction. 5 Bay K 8644 (1 μ M ) significantly shifted the voltage dependence of the activation curve to more negative potentials by approximately 9 mV although Bay K 8644 caused little shift in the steady‐state inactivation curve. 6 These results indicate that mefenamic acid increased voltage‐dependent nifedipine‐sensitive inward Ba 2+ currents through the activation of L‐type Ca 2+ channels with different kinetics from those of Bay K 8644 in pig urethral myocytes.British Journal of Pharmacology (2005) 144 , 919–925. doi: 10.1038/sj.bjp.0706051