Mechanisms underlying the M-current block by barium in bullfrog sympathetic neurons.
Whole-cell/voltage-clamp recordings were made from dissociated bullfrog sympathetic neurons to examine the channel blocking actions of barium (3-2000 microM) on an M-type potassium current (I(M)). Barium (IC(50) approximately 105 microM) blocked I(M) without affecting the 50%-activation voltage ( approximately -35 mV) and the slope factor ( approximately 11 mV) of the activation curve. The results indicate that the barium block is independent of the kinetics of I(M).
Kotani
S
S
Department of Physiology, Tokai University School of Medicine, Bohseidai, Isehara, Japan.
Hirasawa
T
T
Suzuki
T
T
Sato
K
K
Sakakibara
M
M
Tokimasa
T
T
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001340:Autonomic Nerve Block / Q000379:methods; D001464:Barium / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism; D011892:Rana catesbeiana; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000502:physiology*; D013565:Sympatholytics / Q000494:pharmacology
D026902:Potassium Channel Blockers; D015221:Potassium Channels; D013565:Sympatholytics; D001464:Barium