Premium
Intracellular pH of snail neurones measured with a new pH‐sensitive glass micro‐electrode
Author(s) -
Thomas R. C.
Publication year - 1974
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1974.sp010516
Subject(s) - intracellular ph , chemistry , bicarbonate , intracellular , biophysics , electrode , ion , ammonia , membrane potential , azide , ammonium , membrane , inorganic chemistry , biochemistry , biology , organic chemistry
1. The construction and properties of a new design of pH‐sensitive micro‐electrode are described. The electrodes are very durable, and have a recessed configuration so that only the extreme tip, which can be as small as 1 μm in diameter, needs to enter the cell. 2. The average intracellular pH in thirty‐two snail neurones was 7·4. This was not in accord with a passive distribution of H + ions across the cell membrane. 3. Changing membrane potential or external pH had only slow effects on internal pH. 4. Removing external K had no effect, and removing external Na had only slow and variable effects on intracellular pH. 5. Anoxia, azide and DNP all caused a slow fall in internal pH. 6. External CO 2 caused large and rapid decreases in internal pH, which external bicarbonate appeared to offset slowly. Injected bicarbonate increased internal pH. 7. The size of the pH changes caused by CO 2 suggested a minimum intracellular buffering power of 25 m‐equiv H + /unit pH per l., equivalent to that of 150 m M Tris maleate, pH 7·4. 8. External ammonia caused a large and rapid increase in internal pH, while the injection of ammonium ions had the opposite effect.