The effects of MCC-134 on the ATP-sensitive K+ channels in pig urethra.
We have investigated the effects of MCC-134 (1-[4-(1H-imidazol-1-yl)benzoyl]-N-methyl-cyclobutanecarbothioamide) on membrane currents and ATP-sensitive K(+) channel (K(ATP) channel) opener-induced currents in pig urethra by use of patch-clamp techniques (conventional whole-cell configuration and nystatin perforated patch recordings). Tension measurement was also performed to study the effects of MCC-134 on the resting tone of pig urethral strips. MCC-134 reduced the resting tone of pig urethra in a concentration-dependent manner (EC(50)=6 microM). The MCC-134 (30 microM)-induced relaxation was suppressed by glibenclamide. In voltage-clamp experiments, MCC-134 produced a concentration-dependent inward K(+) current which was suppressed by application of glibenclamide at a holding potential of -50 mV (symmetrical 140 mM K(+) conditions). Application of MCC-134 enhanced diazoxide-induced inward currents and inhibited pinacidil-induced inward currents in a concentration-dependent manner at -50 mV. These results suggest that MCC-134 induces glibenclamide-sensitive K(ATP) currents in pig urethra.
Yunoki
Takakazu
T
Faculty of Medicine, Department of Pharmacology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi Ward, Fukuoka 812-8582, Japan.
Teramoto
Noriyoshi
N
Takano
Naruaki
N
Seki
Narihito
N
Creed
Kate E
KE
Naito
Seiji
S
Ito
Yushi
Y
D000255:Adenosine Triphosphate / Q000502:physiology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D007093:Imidazoles / Q000494:pharmacology*; D066298:In Vitro Techniques; D009126:Muscle Relaxation / Q000187:drug effects / Q000502:physiology; D015221:Potassium Channels / Q000819:agonists / Q000502:physiology*; D013552:Swine; D013854:Thioamides / Q000494:pharmacology*; D014521:Urethra / Q000187:drug effects* / Q000502:physiology
D007093:Imidazoles; C403079:MCC 134; D015221:Potassium Channels; D013854:Thioamides; D000255:Adenosine Triphosphate