Crayfish Axons Research Articles

Recording of action potentials and polarization of a single crayfish motor axon through a sucrose-gap capillary suction electrode.

A capillary suction electrode was developed which contains in its tip a sucrose-gap. The nerve fiber is pulled by negative pressure through the closely fitting openings of an outer and an inner capillary. The space between these openings is o.1 mm wide and can be perfused with sucrose solution. Because of the small physical size of the electrode tip the electrode can be used to record from single unmyelinated nerve fibers in small preparations in combination with other electrodes or transducers.

Effects of allethrin and Condylactis toxin on the kinetics of sodium conductance of crayfish axon membranes

1. 1. The effects of the insecticide allethrin and Condylactis toxin (CTX) on the kinetics of sodium conductance of crayfish giant axons have been studied by means of sucrose-gap voltage clamp techniques. 2. 2. The time course of the sodium inactivation is greatly prolonged by either of these agents. The steady-state sodium inactivation curve is shifted in the direction of hyper-polarization after application of allethrin or CTX. 3. 3. In the axon treated with allethrin a prolonged sodium tail-current flows after cessation of a depolarizing pulse, whereas in the axon treated with CTX the sodium tail-current is curtailed quickly. 4. 4. The mechanisms underlying these effects are discussed in terms of the rate constants of sodium conductance change.

Effects of scorpion venom on squid axon membranes.

Effects of scorpion venom on squid axon membranes.

Chemical modification of crayfish axons by protein crosslinking aldehydes.

AbstractA series of aldehydes of varying protein crosslinking strengths have been tested on intact and internally perfused crayfish axons. Non‐crosslinking aldehydes have no effect, or cause a gradual decline in resting potential and overshoot with no widening of the spike. Strong crosslinking compounds, such as acrolein, crotonaldehyde, and glutaraldehyde, widen the action potential significantly while reducing its amplitude. Differences in the shapes of the resulting action potentials and accompanying impedance changes suggest that each crosslinking aldehyde exerts different effects on the axon. Glutaraldehyde, the strongest crosslinking agent tested, slows both rising and falling phases of the spike, and also of the impedance change, suggesting a prolongation of the transient increase in sodium conductance. The ability of protein crosslinking agents to alter excitability, and particularly to slow the various phases of the action potential, provides support for the hypothesis that a conformational change in a protein or protein‐phospholipid complex is involved in excitation.

Transient transmembrane water movements in crayfish axons detected by transmitted light interference microscopy.

AbstractTransmitted light interference microscopy is shown to be a sensitive technique for detecting email transient changes in optical path differences of axons during and following electrical stimulation. It is tentatively concluded that water enters the axon during and following tetanizing stimulation and that this event is in accord with earlier findings concerning opacity changes under similar experimental conditions. It was further demonstrated that the membrane of the axon is normally under a hydrostatic pressure difference of approximately 2 cm of H2O and this may be a contributing factor to the optical properties of the axon during the excitation process.

A note on the "split oil drop" technique.

A modification of the “split oil drop” technique was used for determination of water permeability in crayfish axons. To decide how well the oil drops sealed the lumen of the axon different types of control experiments were parformed. The results suggested that the oil drop diameter was only about 94% of the axon diameter. The possible occurrence of such leaks between oil drops and surrounding membrane wall when using similar methods in other organs is discussed.

Internal Perfusion of Crayfish Axons

Acta Physiologica ScandinavicaVolume 72, Issue 4 p. 535-536 Internal Perfusion of Crayfish Axons B. Gunnar Wallin, B. Gunnar Wallin Institute of Physiology and Medical Biophysics, University of Uppsala, SwedenSearch for more papers by this author B. Gunnar Wallin, B. Gunnar Wallin Institute of Physiology and Medical Biophysics, University of Uppsala, SwedenSearch for more papers by this author First published: April 1968 https://doi.org/10.1111/j.1365-201X.1968.tb10863.xCitations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume72, Issue4April 1968Pages 535-536 RelatedInformation

Internal perfusion of crayfish axons.

Internal perfusion of crayfish axons.

Effects of temperature and caclcium variation on membrane potentials of crayfish axons.

ARTICLESEffects of temperature and caclcium variation on membrane potentials of crayfish axonsX Machne, and R OrozcoX Machne, and R OrozcoPublished Online:01 Mar 1968https://doi.org/10.1152/ajplegacy.1968.214.3.672MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInEmailWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited ByLocalization of short-term memory in the brain of the bee, Apis melliferaPhysiological Entomology, Vol. 5, No. 4The Influence of Temperature on Membrane Processes More from this issue > Volume 214Issue 3March 1968Pages 672-676 Copyright & PermissionsCopyright © 1968 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1968.214.3.672PubMed5638998History Published online 1 March 1968 Published in print 1 March 1968 Metrics

The relation between external potassium concentration, membrane potential and internal ion concentrations in crayfish axons.

AbstractIn single crayfish axons simultaneous determinations were made of membrane potential and intracellular concentrations of sodium, potassium and chloride at different external potassium concentrations. When the external potassium level was varied from 2–150 mM. internal potassium concentration remained fairly constant. At the same time internal sodium concentration decreased with more than 50 % whereas internal chloride level increased 10 times. These ion changes were accompanied by a considerable volume increase. From the data it was calculated that a net inward movement of potassium, chloride and water had occurred while a slight outward transport of sodium was noted at lower external potassium levels. When axon volume increased, observations were made indicating an increased intracellular hydrostatic pressure. In terms of the constant field equation, it appears as if the ratio Pc1: Pk and possibly also Pna: Pk increares when the axon is potassium depolarized.

Intracellular ion concentrations in single crayfish axons.

AbstractA method for simultaneous determination of membrane potential and intracellular concentrations of sodium, potassium and chloride in single nerve axons is described in detail. Only 3–5 × 10‐‐9 liter axoplasm is required for the ion analyzes and consequently it has been possible to take 2 samples from the same axon. This allows for a comparison of the intracellular ion compositions at different external conditions with good accuracy. The normal ion concentrations in crayfish giant axons are found to be (in mM ± S. E.) Na 17A k 0A, K 265 ± 1.8 and C1 12.7 ± 0.4, indicating that probably none of the ions is distributed in electrochemical equilibrium. It is also shown that the distributions of sodium and potassium are directly dependent on an ouabain sensitive metabolic pathway but that this does not seem to be the case for chloride.

Impulse propagation at the septal and commissural junctions of crayfish lateral giant axons.

Transmission across the septal junctions of the segmented giant axons of crayfish is accounted for quantitatively by a simple equivalent circuit. The septal membranes are passive, resistive components and transmission is ephaptic, by the electrotonic spread of the action current of the pre-septal spike. The electrotonic spread appears as a septal potential, considerably smaller than the pre-septal spike, but usually still large enough to initiate a new spike in the post-septal segments. The septal membranes do not exhibit rectification, at least over a range of +/- 25 mv polarization and this accounts for their capacity for bidirectional transmission. The commissural branches, which are put forth by each lateral axon, make functional connections between the two axons. Transmission across these junctions can also be bidirectional and is probably also ephaptic. Under various conditions, the ladder-like network of cross-connections formed by the commissural junctions can give rise to circus propagation of impulses from one axon to the other. This can give rise to reverberatory activity of both axons at frequencies as high as 400/sec.

GIANT NERVE FIBER SYSTEM OF THE CRAYFISH. A CONTRIBUTION TO COMPARATIVE PHYSIOLOGY OF SYNAPSE

GIANT NERVE FIBER SYSTEM OF THE CRAYFISH. A CONTRIBUTION TO COMPARATIVE PHYSIOLOGY OF SYNAPSE