Premium
Extracellular space and diffusion barriers in muscle fibres from Megabalanus psittacus (Darwin).
Author(s) -
Bacigalupo J,
Luxoro M,
Rissetti S,
Vergara C
Publication year - 1979
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.1979.sp012696
Subject(s) - extracellular , intracellular , diffusion , chemistry , extracellular fluid , biophysics , space (punctuation) , membrane , analytical chemistry (journal) , biology , physics , chromatography , thermodynamics , biochemistry , computer science , operating system
1. Muscle fibres from Megabalanus psittacus (Darwin) were used to measure the exchange of Na+ and Ca2+ between intracellular and extracellular compartments. 2. The size of the extracellular space was evaluated directly from electron micrographs at 6.1 +/‐ 0.5% (percentage of the fibre volume). The more conventional estimates using Na+ and 134Cs+ as space markers gave higher values, namely, 8.9 +/‐ 0.7 and 9.5 +/‐ 1.5%. 3. An average value of 9.2% was used to correct the total Na+ and K+ in the muscle fibres and to estimate the intracellular concentrations of Na+ and K+ as 39 +/‐ 4 and 202 +/‐ 11 mM respectively. 4. Na+ (and similar Ca2+) washout curves could be described using a three compartments diffusion model. The data analysed in terms of this model enabled us to estimate membrane permeabilities as PNa+ = 2.7 x 10(‐7) and PCa2+ = 2.7 x 10(‐7) cm/sec.