Skip to main content
NCBI home page
The Journal of General Physiology logoLink to The Journal of General Physiology
. 1971 May 1;57(5):623–637. doi: 10.1085/jgp.57.5.623

Nonelectrolyte Permeability, Sodium Influx, Electrical Potentials, and Axolemma Ultrastructure in Squid Axons of Various Diameters

Raimundo Villegas 1, Gloria M Villegas 1, Reinaldo DiPolo 1, Jorge Villegas 1
PMCID: PMC2203113  PMID: 5553105

Abstract

The penetration of 14C-labeled ethylene glycol, erythritol, mannitol, and sucrose was measured in giant axons of various diameters isolated from the hindmost stellar nerves of Doryteuthis plei squid. Axon diameter depends mainly on the age of the squid. The influx of 22Na, some electrical properties, and the ultrastructure of the axolemma were also studied. The results confirm our previous observation that in medium sized axons of D. plei stimulation causes an increase in the permeability to the penetration of erythritol, mannitol, and sucrose. They also demonstrate that the magnitude of the increase in the penetration of these probing molecules diminishes progressively as the axon diameter increases. The diminution in permeability may be due to a reduction in size of the pathways used by nonelectrolytes to enter the axon. No effect of stimulation on the ethylene glycol permeability is observed. The sodium influx and electrical properties are independent of axon size. The ultrastructural study shows that the axolemma thickness increases with axon diameter. The present experiments indicate that the nonelectrolyte permeability of stimulated axons depends on nerve fiber properties related to axon diameter and on the size of the hydrophilic nonelectrolyte probe.

Full Text

The Full Text of this article is available as a PDF (963.3 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. BRINLEY F. J., Jr, MULLINS L. J. ION FLUXES AND TRANSFERENCE NUMBER IN SQUID AXONS. J Neurophysiol. 1965 May;28:526–544. doi: 10.1152/jn.1965.28.3.526. [DOI] [PubMed] [Google Scholar]
  2. ELFVIN L. G. Electron microscopic investigation of the plasma membrane and myelin sheath of autonomic nerve fibers in the cat. J Ultrastruct Res. 1961 Aug;5:388–407. doi: 10.1016/s0022-5320(61)80015-4. [DOI] [PubMed] [Google Scholar]
  3. Hidalgo C., Latorre R. Effect of stimulation and hyperpolarization on non-electrolyte and sodium permeability in perfused axons of squid. J Physiol. 1970 Nov;211(1):193–202. doi: 10.1113/jphysiol.1970.sp009274. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. KEYNES R. D., LEWIS P. R. The sodium and potassium content of cephalopod nerve fibers. J Physiol. 1951 Jun;114(1-2):151–182. doi: 10.1113/jphysiol.1951.sp004609. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. KEYNES R. D. The ionic movements during nervous activity. J Physiol. 1951 Jun;114(1-2):119–150. doi: 10.1113/jphysiol.1951.sp004608. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Mullins L. J. Ion and molecule fluxes in squid axons. Ann N Y Acad Sci. 1966 Jul 14;137(2):830–836. doi: 10.1111/j.1749-6632.1966.tb50203.x. [DOI] [PubMed] [Google Scholar]
  7. SHANES A. M., BERMAN M. D. Kinetics of ion movement in the squid giant axon. J Gen Physiol. 1955 Nov 20;39(2):279–300. doi: 10.1085/jgp.39.2.279. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. VILLEGAS R., CAPUTO C., VILLEGAS L. Diffusion barrieres in the squid nerve fiber. The axolemma and the Schwann layer. J Gen Physiol. 1962 Nov;46:245–255. doi: 10.1085/jgp.46.2.245. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. VILLEGAS R., VILLEGAS L., GIMENEZ M., VILLEGAS G. M. Schwann cell and axon electrical potential differences. Squid nerve structure and excitable membrane location. J Gen Physiol. 1963 May;46:1047–1064. doi: 10.1085/jgp.46.5.1047. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Villegas G. M., Villegas R. Ultrastructural studies of the squid nerve fibers. J Gen Physiol. 1968 May;51(5 Suppl):44S+–44S+. [PubMed] [Google Scholar]
  11. Villegas R., Bruzual I. B., Villegas G. M. Equivalent pore radius of the axolemma of resting and stimulated squid axons. J Gen Physiol. 1968 May;51(5 Suppl):81S+–81S+. [PubMed] [Google Scholar]
  12. Villegas R., Villegas G. M., Blei M., Herrera F. C., Villegas J. Nonelectrolyte penetration and sodium fluxes through the axolemma of resting and stimulated medium sized axons of the squid Doryteuthis plei. J Gen Physiol. 1966 Sep;50(1):43–59. doi: 10.1085/jgp.50.1.43. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from The Journal of General Physiology are provided here courtesy of The Rockefeller University Press

RESOURCES