Abstract
We studied the blocking effects of 4-aminopyridine (4-AP) on a Kv1.4 K+ channel. A permanently charged 4-AP derivative only produced block when applied intracellularly. 4-AP block accumulated from pulse to pulse indicating trapping of 4-AP in deactivated channels. For long trains of depolarizing pulses, 4-AP block increased with decreasing pulse duration. This increase took many pulses (>10) to accumulate and was relieved by two to three subsequent pulses of 500 msec duration. We conclude that the time- and voltage-dependence of 4-AP block can not be accounted for solely by either simple pure open channel or pure closed channel blocking schemes. We propose that the data can be explained by a model in which 4-AP binding is most stable when the channel has a symmetric arrangement in the binding regions.
Original language | English (US) |
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Pages (from-to) | 11-22 |
Number of pages | 12 |
Journal | Advances in Experimental Medicine and Biology |
Volume | 382 |
State | Published - 1995 |
Externally published | Yes |
ASJC Scopus subject areas
- General Biochemistry, Genetics and Molecular Biology