Osmometrically determined characteristics of the cell membrane of squid and lobster giant axons.
Lobster and squid giant nerve fibers respond differently when subjected to osmotic challenges. The axons proper, as distinct from the total (fiber) complex formed by the axon and connective sheath, both behave as "fast" osmometers for changes in the concentration of NaCl, but the maximum degree of swelling in hyposmotic media is by about 60% in lobster and only by 20% in squid. The relative volume intercepts of the van't Hoff relation are about 0.2 for lobster and 0.4 for squid. The sheaths of both axons undergo only small, apparently passive changes in volume. Lobster axons are permeable to Cl, but squid axons are impermeable to this anion. Lobster axons are also permeable to glycerol. The implications of the data as to the nature of volume regulation of cells are discussed.
Freeman
A R
AR
Laboratory of Neurophysiology, Department of Neurology and Department of Anatomy, College of Physicians and Surgeons, Columbia University, New York, USA.
Reuben
J P
JP
Brandt
P W
PW
Grundfest
H
H
D000818:Animals; D001369:Axons / Q000378:metabolism* / Q000648:ultrastructure; D003451:Cryoprotective Agents / Q000494:pharmacology; D049832:Decapodiformes; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D005990:Glycerol / Q000494:pharmacology; D007552:Isotonic Solutions / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008854:Microscopy, Electron; D008121:Nephropidae; D009997:Osmotic Pressure; D011189:Potassium Chloride / Q000493:pharmacokinetics; D011422:Propionates / Q000494:pharmacology; D012462:Saline Solution, Hypertonic / Q000494:pharmacology; D012965:Sodium Chloride / Q000493:pharmacokinetics*; D014882:Water-Electrolyte Balance / Q000187:drug effects / Q000502:physiology*
D003451:Cryoprotective Agents; D007552:Isotonic Solutions; D011422:Propionates; D012462:Saline Solution, Hypertonic; D012965:Sodium Chloride; D011189:Potassium Chloride; D005990:Glycerol