1. An electrophysiological method was used to estimate the half-times for sodium and potassium entry to, and efflux from, the extra-axonal space in peripheral nerve and central nervous connectives of two species of crustacean. Results from crab (marine) and crayfish (fresh water) were qualitatively similar. 2. Peripheral nerve showed no evidence for diffusion barriers, potassium entry and efflux being rapid, and proceeding at comparable rates. 3. In connective, potassium entry was extremely slow, with a half-time greater than 100 min, while potassium efflux was relatively rapid (T 1/2 = 6 min). Sodium movements were less restricted, but sodium entry was more rapid than sodium efflux. 4. The potassium experiments were compared with the behaviour of a theoretical model system. Evidence is presented for diffusional restriction to potassium at the connective perineurial layer. The mechanism of restriction may involve changes in permeability or activation of an ion pump in the perineurial layer. 5. The physiological significance of these findings is discussed.
JOURNAL ARTICLE| 01 August 1975
Electrophysiological analysis of potassium and sodium movements in crustacean nervous system
N. J. Abbott
R. B. Moreton
Online Issn: 1477-9145
Print Issn: 0022-0949
© 1975 by Company of Biologists
J Exp Biol (1975) 63 (1): 85–115.
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N. J. Abbott, R. B. Moreton, Y. Pichon; Electrophysiological analysis of potassium and sodium movements in crustacean nervous system. J Exp Biol 1 August 1975; 63 (1): 85–115. doi: https://doi.org/10.1242/jeb.63.1.85
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