Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2006 Feb;127(2):183–190. doi: 10.1085/jgp.200509389

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

Copyright © 2006, The Rockefeller University Press

This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).

PMC Copyright notice

Figure 4. — VIC can be blocked independently of I_h. (A) Current traces recorded from a patch expressing spHCN-464C in response to repeated voltage steps to +60 mV and −120 mV. The black trace is the current in the presence of 100 μM cAMP, the blue trace shows the rapid reduction in VIC as 20 μM Cd²⁺ was applied for 5 s, as indicated by the black bar. (B) Average time course of block of VIC and I_h in spHCN-464C after a single 1-s application of 20 μM Cd²⁺ at +60 mV (arrow) in the protocol illustrated in A, with voltage steps given every 12 s. The zero baseline for VIC was taken as the minimum current after Cd²⁺ application. Currents were normalized to the maximum current before Cd²⁺ application. Little recovery of VIC occurred during ∼2 min of repeated pulsing and washing. (C) In the constant presence of 100 μM cAMP, 100 μM ZD7288 was applied to a patch containing spHCN channels during a voltage pulse to +60 mV. Shown are a trace before the application of ZD7288 (black line) and the first trace where ZD7288 was applied (blue line). After a holding period of 8 s at +10 mV, during which all the ZD7288 was washed from the bath, the channels were then stepped to −120 mV to assay the blockade of I_h (note that the block of VIC is also apparent from the initial current at −120 mV, after ZD7288 has been removed). (D) Time course of block of VIC and I_h in response to repeated applications of 100 μM ZD7288 at +60 mV using the protocol illustrated in C, repeated every 15 s. The plotted symbols for VIC represent the current at the start of each pulse to +60 mV, before application of ZD7288; this isolates the irreversible component of block. Complete blockade was elicited after ∼5 min by changing to constant application of ZD7288 (solid bar). Note that no further block of VIC occurred. Net VIC was calculated by subtracting the lowest current measured after blocker application.