Attention-dependent reductions in burstiness and action-potential height in macaque area V4

The functional relationship between sinusal distension and the sympathetic innervation of the feline carotid sinus was investigated by neurophysiological techniques. A balloon catheter was used to distend the sinus region while recording evoked postganglionic activity from the superior cervical ganglion. When the SCG was stimulated at 1.0 or 10.0/s, balloon inflation reduced postganglionic action potential height by 25-50% and increased ganglionic negativity. These effects were subsequently abolished by section of one of the remaining intact postganglionic trunks. This evidence suggests that a pressure-modulated reflex arc, similar to the intestinointestinal reflex, might exist between the carotid sinus and superior and cervical ganglion.

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Effect of Detergent on Electrical Properties of Squid Axon Membrane

The Journal of General Physiology ◽

10.1085/jgp.47.5.975 ◽

1964 ◽

Vol 47 (5) ◽

pp. 975-986 ◽

Cited By ~ 27

Author(s):

Uichiro Kishimoto ◽

William J. Adelman

Keyword(s):

Action Potential ◽

Potassium Conductance ◽

Tween 80 ◽

Giant Axon ◽

Resting Potential ◽

Temporary Increase ◽

Lauryl Sulfate ◽

Axon Membrane ◽

Ionic Detergent ◽

Potential Height

The effects of detergents on squid giant axon action and resting potentials as well as membrane conductances in the voltage clamp have been studied. Anionic detergents (sodium lauryl sulfate, 0.1 to 1.0 mM; dimethyl benzene sulfonate, 1 to 20 mM, pH 7.6) cause a temporary increase and a later decrease of action potential height and the value of the resting potential. Cationic detergent (cetyl trimethyl ammonium chloride, 6 x 10-5M or more, pH 7.6) generally brings about immediate and irreversible decreases in the action and resting potentials. Non-ionic detergent (tween 80, 0.1 M, pH 7.6) causes a slight reversible reduction of action potential height without affecting the value of the resting potential. Both anionic and cationic detergents generally decrease the sodium and potassium conductances irreversibly. The effect of non-ionic detergent is to decrease the sodium conductance reversibly, leaving the potassium conductance almost unchanged.

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How to sample the entire length of a single muscle fiber quick-frozen after electrical point stimulation for high resolution EM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100124288 ◽

1992 ◽

Vol 50 (1) ◽

pp. 776-777

Author(s):

Joachim R. Sommer ◽

Teresa High ◽

Betty Scherer ◽

Isaiah Taylor ◽

Rashid Nassar

Keyword(s):

Skeletal Muscle ◽

High Resolution ◽

Action Potential ◽

Muscle Fiber ◽

Freeze Fracture ◽

Freeze Substitution ◽

Electrical Field Stimulation ◽

Skeletal Muscle Fiber ◽

Freeze Dried ◽

Quick Freezing

We have developed a model that allows the quick-freezing at known time intervals following electrical field stimulation of a single, intact frog skeletal muscle fiber isolated by sharp dissection. The preparation is used for studying high resolution morphology by freeze-substitution and freeze-fracture and for electron probe x-ray microanlysis of sudden calcium displacement from intracellular stores in freeze-dried cryosections, all in the same fiber. We now show the feasibility and instrumentation of new methodology for stimulating a single, intact skeletal muscle fiber at a point resulting in the propagation of an action potential, followed by quick-freezing with sub-millisecond temporal resolution after electrical stimulation, followed by multiple sampling of the frozen muscle fiber for freeze-substitution, freeze-fracture (not shown) and cryosectionmg. This model, at once serving as its own control and obviating consideration of variances between different fibers, frogs etc., is useful to investigate structural and topochemical alterations occurring in the wake of an action potential.

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