Effects of quinine on three different types of potassium currents in bullfrog sympathetic neurons.
Whole-cell/voltage-clamp recordings were made from dissociated bullfrog sympathetic neurons to examine the sensitivity of potassium currents to a potassium channel blocker quinine (1-500 microM). Among three currents tested, a rapidly inactivating A-type current (I(A)) was the most sensitive to the block by quinine (IC50 approximately 22 microM). A non-inactivating M-type current (I(M)) was the least sensitive (IC50 approximately 445 microM), and the sensitivity of a slowly inactivating delayed rectifier-type current (I(K)) was in between (IC50 approximately 115 microM). Results suggest that the ability of quinine to block different types of potassium currents such as I(A) and I(M) with significantly different IC50 values would be of help for the potassium channel pharmacology in amphibian autonomic ganglion cells.
Imai
S
S
Department of Physiology, Tokai University School of Medicine, Bohseidai, Isehara, Japan.
Suzuki
T
T
Sato
K
K
Tokimasa
T
T
D000818:Animals; D005728:Ganglia, Sympathetic / Q000166:cytology / Q000502:physiology*; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000187:drug effects*; D011803:Quinine / Q000494:pharmacology*; D011892:Rana catesbeiana
D015221:Potassium Channels; D011803:Quinine