Use-dependent removal of the 4-aminopyridine-induced block of the transient K+ current in rat dorsal root ganglia.
Effects of 4-aminopyridine (4-AP) on the transient K(+) current (I(A)) was studied in rat sensory neurons using the whole cell patch-clamp technique. The amplitude of I(A) was reduced by 4-AP. The steady-state inactivation curve for I(A) was shifted in the positive direction by 4-AP, suggesting that the blocking action of 4-AP may be attenuated by membrane depolarization. When two I(A)s were evoked with variable intervals, the peak amplitude of the I(A) induced by the second pulse was augmented in the presence of 4-AP. These results indicate that the action of 4-AP can be modulated by concurrent neuronal activities.
Ohishi
Yoshiaki
Y
Department of Neurophysiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.
Matsutomi
Tomoya
T
Zheng
Taixing
T
Kakimura
Jun-Ichi
J
Maruyama
Hiroshi
H
Ogata
Nobukuni
N
D015761:4-Aminopyridine / Q000494:pharmacology*; D000818:Animals; D002478:Cells, Cultured; D005727:Ganglia, Spinal / Q000187:drug effects* / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D026902:Potassium Channel Blockers / Q000494:pharmacology*; D015221:Potassium Channels / Q000502:physiology*; D051381:Rats
D026902:Potassium Channel Blockers; D015221:Potassium Channels; D015761:4-Aminopyridine