Hyperpolarizing shift by quinine in the steady-state inactivation curve of delayed rectifier-type potassium current in bullfrog sympathetic neurons.
Whole-cell recordings were made from dissociated bullfrog sympathetic neurons to examine the actions of quinine (1-100 microM) on the steady-state activation and inactivation curves of a delayed rectifier-type potassium current (I(K)). Quinine (EC50 approximately 8 microM) caused a hyperpolarizing shift (approximately 31 mV with 30 microM) in the inactivation curve of I(K) without significantly affecting its activation curve. Quinine (20 microM) was without effects on the voltage-dependence of a rapidly-inactivating A-type potassium current (I(A)). It is concluded that quinine can selectively modulate the voltage-dependence of I(K) in amphibian autonomic neurons.
Kotani
S
S
Department of Physiology, Tokai University School of Medicine, Bohseidai, Isehara, Japan.
Hasegawa
J
J
Meng
H
H
Suzuki
T
T
Sato
K
K
Sakakibara
M
M
Takiguchi
M
M
Tokimasa
T
T
D000818:Animals; D002462:Cell Membrane / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005728:Ganglia, Sympathetic / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects* / Q000502:physiology; D009125:Muscle Relaxants, Central / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D015221:Potassium Channels / Q000187:drug effects* / Q000378:metabolism; D011803:Quinine / Q000494:pharmacology*; D011892:Rana catesbeiana
D009125:Muscle Relaxants, Central; D015221:Potassium Channels; D011803:Quinine