An opiate receptor on frog sciatic nerve axons

1979 ◽  
Vol 57 (10) ◽  
pp. 1171-1174 ◽  
Author(s):  
E. G. Hunter ◽  
G. B. Frank
Keyword(s):  
Sciatic Nerve ◽  
Action Potential ◽  
Maximum Rate ◽  
Opiate Receptor ◽  
Resting Potential ◽  
Amplitude Maximum ◽  
Gap Technique ◽  
Sucrose Gap ◽  
Frog Sciatic Nerve ◽  
Maximum Rate Of Rise

The effect of meperidine (3 × 10−4 M) on the action potential of frog sciatic nerve was examined by means of the double sucrose gap technique. Meperidine decreased the amplitude, maximum rate of depolarization, and maximum rate of repolarization of the action potential but had no effect on the resting potential. This depression in amplitude and maximum rate of rise was partially blocked by naloxone (1 × 10−8 M) while the maximum rate of depolarization was further depressed. The data suggest that the effect of meperidine is due to two mechanisms, a nonspecific local anaesthetic like effect and an opiate receptor mediated effect.

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.

scholarly journals Membrane Currents in Mammalian Ventricular Heart Muscle Fibers Using a Voltage-Clamp Technique

1971 ◽  
Vol 57 (3) ◽  
pp. 290-296 ◽  
Author(s):  
Gerhard Giebisch ◽  
Silvio Weidmann
Keyword(s):  
Action Potential ◽  
Outward Current ◽  
Time Dependent ◽  
Resting Potential ◽  
Equilibrium Potential ◽  
Initial Amplitude ◽  
Inward Current ◽  
Gap Technique ◽  
Sucrose Gap

Bundles of sheep ventricular fibers were voltage-clamped utilizing a modified sucrose gap technique and intracellular voltage control. An action potential was fired off in the usual way, and the clamp circuit was switched on at preselected times during activity. Clamping the membrane back to its resting potential during the early part of an action potential resulted in a surge of inward current. The initial amplitude of this current surge decreased as the clamp was switched on progressively later during the action potential. Inward current decreasing as a function of time was also recorded if the membrane potential was clamped beyond the presumed K equilibrium potential (to -130 mv). Clamping the membrane to the inside positive range (+40 mv to +60 mv) at different times of an action potential resulted in a step of outward current which was not time-dependent. The results suggest that normal repolarization of sheep ventricle depends on a time-dependent decrease of inward current (Na, Ca) rather than on a time-dependent increase of outward current (K).

scholarly journals Electrophysiological Actions of Oxytocin on the Rabbit Myometrium

1969 ◽  
Vol 53 (6) ◽  
pp. 758-780 ◽  
Author(s):  
A. L. Kleinhaus ◽  
C. Y. Kao
Keyword(s):  
Maximum Rate ◽  
Resting Potential ◽  
Spike Amplitude ◽  
Electrode Recording ◽  
Pregnant Rabbit ◽  
Sucrose Gap ◽  
The Mean ◽  
Electrical Activities ◽  
Maximum Rate Of Rise ◽  
Duration Of Pregnancy

The electrical activities of myometrial cells of the pregnant rabbit uterus have been studied by means of sucrose-gap and intracellular micro-electrode recording techniques. The resting potential of the myometrial cell was about -50 mv, and it is unaffected by the duration of pregnancy or placental attachment. Action potentials of the myometrium, although dependent on external Na+, were not always of the regenerative type; preparations from nonparturient uteri often produce mainly small spikes. The mean spike amplitude was 35 mv, rising at a mean maximum rate of 3 v/sec. Oxytocin, in concentrations less than 500 µU/ml, increased the mean spike amplitude to 48 mv and the mean maximum rate of rise to 7 v/sec, without affecting the resting potential. The relation between membrane potential and dV/dt of the spike was steepened by oxytocin, suggesting that oxytocin increased the number of normally sparse sodium gates in the myometrial membrane. By this action, oxytocin is believed to increase the probability of successful regenerative spikes and thereby initiate electrical activity in quiescent preparations, increase the frequency of burst discharges, the number of spikes in each burst, and the amplitude of spikes in individual cells.

scholarly journals Comparison of Tetrodotoxin and Procaine in Internally Perfused Squid Giant Axons

1967 ◽  
Vol 50 (5) ◽  
pp. 1413-1428 ◽  
Author(s):  
Toshio Narahashi ◽  
Nels C. Anderson ◽  
John W. Moore
Keyword(s):  
Steady State ◽  
Action Potential ◽  
Ionic Current ◽  
Transient Current ◽  
Resting Potential ◽  
Giant Axons ◽  
Time To Peak ◽  
Sucrose Gap ◽  
High Concentrations ◽  
Very High

Squid giant axons were internally perfused with tetrodotoxin and procaine, and excitability and electrical properties were studied by means of current-clamp and sucrose-gap voltage-clamp methods. Internally perfused tetrodotoxin was virtually without effect on the resting potential, the action potential, the early transient membrane ionic current, and the late steady-state membrane ionic current even at very high concentrations (1,000–10,000 nM) for a long period of time (up to 36 min). Externally applied tetrodotoxin at a concentration of 100 nM blocked the action potential and the early transient current in 2–3 min. Internally perfused procaine at concentrations of 1–10 mM reversibly depressed or blocked the action potential with an accompanying hyperpolarization of 2–4 mv, and inhibited both the early transient and late steady-state currents to the same extent. The time to peak early transient current was increased. The present results and the insolubility of tetrodotoxin in lipids have led to the conclusion that the gate controlling the flow of sodium ions through channels is located on the outer surface of the nerve membrane.

Effects of Static Magnetic Field on Compound Action Potential of Isolated Frog Sciatic Nerve

2019 ◽  
Vol 24 (4) ◽  
pp. 668-673
Author(s):  
Serkan Cizmeciogullari ◽  
Yasar Keskin ◽  
N. Hale Saybasili ◽  
Selcuk Paker
Keyword(s):  
Magnetic Field ◽  
Sciatic Nerve ◽  
Action Potential ◽  
Static Magnetic Field ◽  
Compound Action Potential ◽  
Frog Sciatic Nerve ◽  
Compound Action

Effects of moderate hypoxia on premature action potentials of rabbit papillary muscle

1984 ◽  
Vol 62 (5) ◽  
pp. 596-599
Author(s):  
Julio Alvarez ◽  
Francisco Dorticós ◽  
Jesús Morlans
Keyword(s):  
Action Potential ◽  
Action Potential Duration ◽  
Action Potentials ◽  
Potassium Current ◽  
Maximum Rate ◽  
Resting Potential ◽  
Papillary Muscles ◽  
Premature Response ◽  
Coupling Interval ◽  
Control Response

Experiments were performed to study the effects of hypoxia on the characteristics of premature action potentials of rabbit papillary muscles. At normal resting potential, the duration of the premature action potential at the shortest coupling intervals was always greater than that of the control response. As the coupling interval was increased beyond 150 ms, the duration of the premature action potential regained control values. In cells depolarized to −70 mV by KCl, early lengthening of the premature response was attenuated. After 60 min of hypoxia, recovery of action potential duration at normal and reduced resting potentials was accelerated. The maximum rate of depolarization and its reactivation time constant were not affected by 60 min of hypoxia. It is suggested that intracellular free Ca is important in the control of action potential duration via the outward background potassium current.

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