“Sucrose gap” technique applied to single-nerve-fiber preparation

1962 ◽  
Vol 60 (3) ◽  
pp. 648-650
Author(s):  
Wolf-D. Dettbarn ◽  
Floyd A. Davis
Keyword(s):  
Nerve Fiber ◽  
Gap Technique ◽  
Single Nerve ◽  
Sucrose Gap

scholarly journals Pressure-clamped single-fiber recording technique: A new recording method for studying sensory receptors

2020 ◽  
Vol 16 ◽  
pp. 174480692092785 ◽  
Author(s):  
Mayumi Sonekatsu ◽  
Hiroshi Yamada ◽  
Jianguo G Gu
Keyword(s):  
Nerve Fiber ◽  
Single Unit ◽  
Single Fiber ◽  
Single Unit Recording ◽  
Sensory Receptors ◽  
Unit Recording ◽  
Recording Technique ◽  
C Fibers ◽  
Recording Method ◽  
Single Nerve

An electrophysiological technique that can record nerve impulses from a single nerve fiber is indispensable for studying modality-specific sensory receptors such as low threshold mechanoreceptors, thermal receptors, and nociceptors. The teased-fiber single-unit recording technique has long been used to resolve impulses that are likely to be from a single nerve fiber. The teased-fiber single-unit recording technique involves tedious nerve separation procedures, causes nerve fiber impairment, and is not a true single-fiber recording method. In the present study, we describe a new and true single-fiber recording technique, the pressure-clamped single-fiber recording method. We have applied this recording technique to mouse whisker hair follicle preparations with attached whisker afferents as well as to skin-nerve preparations made from mouse hindpaw skin and saphenous nerves. This new approach can record impulses from rapidly adapting mechanoreceptors (RA), slowly adapting type 1 mechanoreceptors (SA1), and slowly adapting type 2 mechanoreceptors (SA2) in these tissue preparations. We have also applied the pressure-clamped single-fiber recordings to record impulses on Aβ-fibers, Aδ-fibers, and C-fibers. The pressure-clamped single-fiber recording technique provides a new tool for sensory physiology and pain research.

AN ANALYSIS OF CONTROL OF THE VENTRICLE OF THE MOLLUSC MERCENARIA MERCENARIA

1993 ◽  
Vol 179 (1) ◽  
pp. 63-75
Author(s):  
C. L. Devlin
Keyword(s):  
Critical Role ◽  
Chloride Concentration ◽  
Mercenaria Mercenaria ◽  
Maximal Effect ◽  
Entry Blocker ◽  
Gap Technique ◽  
High K ◽  
Ionic Mechanisms ◽  
Excitatory Action ◽  
Sucrose Gap

This study focuses on the ionic mechanisms involved in serotonergic control of the ventricle from the mollusc Mercenaria mercenaria. The effects of calcium (Ca2+), sodium (Na+), potassium (K+), magnesium (Mg2+) and chloride (Cl-) ions on the action of 5-hydroxytryptamine (5-HT) were tested using a sucrose-gap technique. 5-HT increased the amplitude and frequency of the cardiac action potentials (APs) and coupled systolic force in a range of concentrations from the threshold, at 10–10 mol l-1, to 10-6 mol l-1. Low, physiological doses of 5-HT increased the rate of rise and amplitude of the fast rising phase of the AP, and hastened the process of repolarization. Doses of 5-HT higher than 10-5 mol l-1 caused systolic arrest. The action of 5-HT was highly dependent on the presence of physiological levels of extracellular Ca2+. It had a maximal effect on systolic activity in a calcium chloride concentration range of 9–18 mmol l-1. The activity of 5-HT was blocked by treatment with Ca2+-free saline, with inorganic Ca2+ blockers (lanthanum or cobalt) or with an organic Ca2+ entry blocker (verapamil). The effects of 5- HT were potentiated by treatment with barium ions (Ba2+), by a dihydropyridine-sensitive Ca2+ agonist, Bay K 8644, or by a vertebrate Ca2+ entry blocker, diltiazem. Removal of extracellular Na+ or treatment with a Na+ ionophore, monensin, did not significantly affect excitation by 10-6 mol l-1 5-HT; nor did the removal of Cl- or Mg2+. Unlike Ca2+, these three ions probably did not have a critical role during the excitatory action of 5-HT. The excitatory action of 5-HT was not significantly altered by treatment with K+-free saline. When the membrane was depolarized by high-K+ salines, however, 5-HT was unable to elicit any APs or systolic contractions, suggesting that its mechanism may involve voltage-sensitive channels.

scholarly journals Membrane Potentials of the Lobster Giant Axon Obtained by Use of the Sucrose-Gap Technique

1962 ◽  
Vol 45 (6) ◽  
pp. 1195-1216 ◽  
Author(s):  
Fred J. Julian ◽  
John W. Moore ◽  
David E. Goldman
Keyword(s):  
Membrane Potential ◽  
Action Potential ◽  
Sea Water ◽  
Sucrose Solution ◽  
Chloride Concentration ◽  
Giant Axon ◽  
Membrane Resistance ◽  
Resting Potential ◽  
Gap Technique ◽  
Sucrose Gap

A method similar to the sucrose-gap technique introduced be Stäpfli is described for measuring membrane potential and current in singly lobster giant axons (diameter about 100 micra). The isotonic sucrose solution used to perfuse the gaps raises the external leakage resistance so that the recorded potential is only about 5 per cent less than the actual membrane potential. However, the resting potential of an axon in the sucrose-gap arrangement is increased 20 to 60 mv over that recorded by a conventional micropipette electrode when the entire axon is bathed in sea water. A complete explanation for this effect has not been discovered. The relation between resting potential and external potassium and sodium ion concentrations shows that potassium carries most of the current in a depolarized axon in the sucrose-gap arrangement, but that near the resting potential other ions make significant contributions. Lowering the external chloride concentration decreases the resting potential. Varying the concentration of the sucrose solution has little effect. A study of the impedance changes associated with the action potential shows that the membrane resistance decreases to a minimum at the peak of the spike and returns to near its initial value before repolarization is complete (a normal lobster giant axon action potential does not have an undershoot). Action potentials recorded simultaneously by the sucrose-gap technique and by micropipette electrodes are practically superposable.

Specific effects of α-D,L-aminoadipic acid on synaptic transmission in frog spinal cord

1980 ◽  
Vol 58 (6) ◽  
pp. 692-698 ◽  
Author(s):  
Ante L. Padjen ◽  
Peter A. Smith
Keyword(s):  
Amino Acids ◽  
Spinal Cord ◽  
Dorsal Root ◽  
Lateral Column ◽  
Specific Effects ◽  
Acidic Amino Acids ◽  
Frog Spinal Cord ◽  
Gap Technique ◽  
Root Potential ◽  
Sucrose Gap

The sucrose gap technique was employed to investigate both synaptic and amino acid evoked responses from motoneurones or primary afferents of frog spinal cord. α-D,L-Aminoadipic acid (α-D,L-AAD) selectively antagonized responses to acidic amino acids, especially aspartate. The drug was most effective in antagonizing the polysynaptic components of synaptic potentials evoked by dorsal root or lateral column stimulation but had little effect on their monosynaptic components. The ventral root dorsal root potential which is thought to be mediated by a pathway that does not involve acidic amino acids was insensitive to α-D,L-AAD. These data, which were confirmed by intracellular recording from motoneurones, provided further evidence for the role of acidic amino acids in polysynaptic pathways in frog spinal cord.

scholarly journals The diffusion of oxygen and lactic acid through tissues

1928 ◽  
Vol 104 (728) ◽  
pp. 39-96 ◽  
Keyword(s):  
Lactic Acid ◽  
Aqueous Solutions ◽  
Nerve Fiber ◽  
Living Cell ◽  
Diffusion Constant ◽  
Fatigued Muscle ◽  
Single Nerve ◽  
Capillary Circulation ◽  
Determining Factor

The diffusion of dissolved substances through cells and tissues is a determining factor in many vital processes. The slowness of diffusion on the scale of ordinary sensible objects gives to the unaided imagination an imperfect realisation of its speed and importance in systems of the dimensions of the living cell. The diffusion constant k is expressed in terms of the number of unit quantities of substance which diffuse per minute across an area of 1 sq. cm. in a gradient of concentration per cm. of 1 unit quantity per c. c. For aqueous solutions of ordinary substances k is usually of the order of 2 to 10 times 10 -4 . The diffusion constant is of the dimensions L 2 T -1 , 2 in length, -1 in time. Expressing it in units of 1μ (0·0001 cm.) instead of 1 cm., and of 1σ (0·001 sec.) instead of minutes, k is of the order of unity, instead of multiple of 10 -4 . Thus the diffusion constant is a fairly large quantity for systems involving distances of the order of 1μ and times of the order of 1σ. A cylinder 1 cm. in diameter composed of material similar to frog's nerve, if suddenly placed in oxygen, would take 185 minutes to attain 90 per cent. of is full saturation with that gas. An actual nerve 0·7 mm. thick would take 54 seconds for the same stage of saturation to be reached. A single nerve fiber 7μ thick would take only 5·4 σ. Again, the rapidity of diffusion attainable in systems of small dimensions is the basis of the capillary circulation, and therewith of the whole design of the larger animals; and the rate at which diffusion an supply oxygen to a fatigued muscle for the removal of lactic acid is an important factor in determining the speed at which recovery can occur.

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