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

. 2002 Oct;120(4):567–579. doi: 10.1085/jgp.20028665

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

Copyright © 2002, 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 1. — The effect of HCl injection on pH_i and steady-state [Ca²⁺]_i in a voltage-clamped snail neuron. (A) Record of membrane potential, clamp and HCl injection current, pH_i and V_Ca, during a short experiment. V_Ca values of −100, −120, and 140 mV correspond, respectively, to [Ca²⁺]_i values of 1.7 μM, 300 nM, and 60 nM. The Ca²⁺-sensitive microelectrode was inserted first, then the membrane potential and clamp electrodes (both filled with KCl, the latter pushed against the cell membrane before being zapped in by switching on the clamp) and then the pH-sensitive microelectrode. The membrane potential was clamped at −60 mV except for one brief hyperpolarization and six brief depolarizations. After the first four depolarizations the HCl electrode was inserted (arrow) and used to lower pH_i to ∼6.3. The injection current, shown as a downward deflection between a and b on the current trace, was then switched off and pH_i allowed to start recovering. 3 min after the injection current was switched off a solution with 5 mM bicarbonate was superfused (shown as bar under pH_i record) for 7 min to accelerate pH_i recovery. (B) Graph of V_Ca versus pH_i for the period (shown as within dashed box on Fig. 1 A) from the start of the HCl injection to the end of the bicarbonate superfusion. Arrows show direction in which time passed.

Figure 1. — The effect of HCl injection on pH_i and steady-state [Ca²⁺]_i in a voltage-clamped snail neuron. (A) Record of membrane potential, clamp and HCl injection current, pH_i and V_Ca, during a short experiment. V_Ca values of −100, −120, and 140 mV correspond, respectively, to [Ca²⁺]_i values of 1.7 μM, 300 nM, and 60 nM. The Ca²⁺-sensitive microelectrode was inserted first, then the membrane potential and clamp electrodes (both filled with KCl, the latter pushed against the cell membrane before being zapped in by switching on the clamp) and then the pH-sensitive microelectrode. The membrane potential was clamped at −60 mV except for one brief hyperpolarization and six brief depolarizations. After the first four depolarizations the HCl electrode was inserted (arrow) and used to lower pH_i to ∼6.3. The injection current, shown as a downward deflection between a and b on the current trace, was then switched off and pH_i allowed to start recovering. 3 min after the injection current was switched off a solution with 5 mM bicarbonate was superfused (shown as bar under pH_i record) for 7 min to accelerate pH_i recovery. (B) Graph of V_Ca versus pH_i for the period (shown as within dashed box on Fig. 1 A) from the start of the HCl injection to the end of the bicarbonate superfusion. Arrows show direction in which time passed.