Action potentials recording

Figure 2.2 Ionic conductances underlying the action potential recorded from a squid axon. gNa = Na conductance gK = K+ conductance. (Adapted from Hodgkin, AL and Huxley, AF (1952) J. Physiol. 117 500-544)...

Figure 2.13 Relation between the action potential recorded intracellularly from a cat spinal motoneuron following antidromic stimulation (int.) and the local field potential recorded with an extracellular electrode (ext.). (Adapted from Terzuolo, AC and Araki, T (1961) Ann. NY Acad. Sci. 94 547-558). Published by NYAS...

Figure 4.5 Influence of oxidant stress on action potentials recorded In an isolated rabbit ventricular myocyte, (a) Control action potential, (b) Action potential recorded 3 min after exposure to oxidant stress induced by the photoactivation of rose bengal (50 nu). (c) Spontaneous and repetitive action potential discharges induced 6.5 min after exposure to rose bengal. Action potentials were recorded via a 2.5 MQ suction electrode and a current-clamp amplifier. The cell was stimulated at 0.1 Hz with a 2 ms suprathreshold current pulse and, when the cell showed automaticity (after 6 min), stimulation was stopped. Redrawn from Matsuura and Shattock (1991b).

Pallandi, R.T., Perry, M.A. and Campbell, T.J. (1987). Proar-rhythmic efects of an oxygen-derived free radical generating system on action potentials recorded from guinea pig ventricular myocardium possible cause of reperfusion-induced arrhythmias. Circ. Res. 61, 50-54. 

Monophasic Action Potential in Anesthetized Guinea Pigs. Epicardia monophasic action potential recording using suction/contact pressure electrodes are emplaced, allowing simultaneous measurement of ECG and heartrate. 

Figure 30-11 (A) Action potential recorded with internal electrode from extruded axon filled with potassium sulfate (16°C). (B) Action potential of an intact axon, with same amplification and time scale (18°C). The voltage scale gives the potential of the internal electrode relative to its potential in the external solution with no correction for junction potential. From A. Hodgkin, Conduction of Nervous Impulses, 1964. Courtesy of Charles C. Thomas, Publisher, Springfield, Illinois.

The action potential recorded from a cardiac Purkinje fiber is shown in Figure 23-1. At rest, the interior of the cell is negative relative to the cell s exterior. As in other excitable tissues (neurons, skeletal muscle), an action potential occurs when the cell interior suddenly becomes positive (depolarizes), primarily because of sodium ion influx. The cell interior then returns to a negative potential (repolarizes), primarily because of... 

FIGURE 23-1 T The cardiac action potential recorded from a Purkinje cell. The effective refractory period is the time during which the cell cannot be depolarized, and the relative refractory period is the time in which a supranormal stimulus is required to depolarize the cell. Action potential phases [0-4] and the ionic basis for each phase are discussed in the text. From Keefe DLD, Kates RE, Harrison DC. New antiarrhythmic drugs their place in therapy. Drugs. 1981 22 363 with permission.]... 

Action potentials recorded from various cardiac cells may vary somewhat from the action potential described previously. Some cells, for instance, totally lack phase 1 and have a slower phase 0. Such cells are said to have a slow response as opposed to the fast response just described. Also, action potentials from the nodal cells (see the next section, Normal Cardiac Rhythm ) differ somewhat from the fast response cells. Nonetheless, the fundamental ionic fluxes occurring during cardiac action potentials are similar in all cardiac cells. This ionic activity is pharmacologically significant because various antiarrhythmic drugs will affect the movement of sodium and other ions in an attempt to establish and maintain normal cardiac rhythm. 

In contractile experiments the time from the stimulation of the nerve to the CMAP recorded in muscle provides an estimate of NCV. The length of the nerve from the stimulating electrode to the muscle can simply be measured and divided by the time. However, the time recorded in this way includes the delay for synaptic transmission, which may be increased in models with synaptic defects. If this is a concern or if the only parameter desired is NCV, then the measurement can be obtained non-invasively with a relatively simple setup (e.g., (3)). Using the sciatic nerve, NCV can be calculated by measuring the latency of compound motor action potentials recorded in the muscle of a rear paw. Action potentials are produced by subcutaneous stimulation at two separate sites proximal stimulation at the sciatic notch and distally at the ankle. NCV is then calculated by using the two latencies and conduction distance. Decreases in nerve conduction velocity most often reflect defects in myelination, but may also be the result of changes in internodal distance, decreased axon diameters, or altered excitability. 

Franz MR (1991) Method and theory of monophasic action potential recording. Progress in Cardiovascular Diseases 6 347-368... 

Franz MR (1994) Bridging the gap between basic and clinical electrophysiology What can be learned from monophasic action potential recordings J Cardiovasc Electrophysiol 5 699-710... 

Using an endocardial monophasic action potential recording, the incidence of early after depolarizations can be determined. The catheter (e.g. Franz combination catheter, EPT No. 1650) can be placed through the jugular vein or carotid artery under fluoroscopic guidance. 

Lang RJ, Zhang Y, Exintaris B, Vogalis F (1995) Effects of nerve stimulation on the spontaneous action potentials recorded in the proximal renal pelvis of the guinea pig. Urol Res 23 343-350... 

Yuan S, Wohlfart B, Rasmussen HS, Olsson S, Blomstrom-Lundqvist C. Effect of dofetilide on cardiac repolarization in patients with ventricular tachycardia. A study using simultaneous monophasic action potential recordings from two sites in the right ventricle. Eur Heart J 1994 15(4) 514-22. 

Stoelzle S, Haythomthwaite A, Haarmann C et al (2011) Automated patch clamp with current clamp action potential recordings from stem cell derived cardiomyocytes. Biophys J 100(3) 196... 

Trains of action potentials recorded extracellularly from a neuron in the rostral portion of the nucleus of the solitary tract (NST) of a rat. About 10s of activity is shown for each stimulus, the application of which is indicated by the arrowheads. This cell did not respond to the sweet-tasting stimuli (sucrose and fructose), but showed robust responses to sodium salts, nonsodium salts, acids, and all the 10 bitter stimuli applied to the tongue and palate. Arrowheads indicated the time of stimulus application. The interspike interval histogram shown at the lower left indicates that no spikes fell within the neuron s refractory period, demonstrating that the spikes are recorded from a single neuron. Data from Lemon and Smith (2005)... 

Figure 3. Action potentials recorded from Purkinje and SA nodal fibers. Note the absence of phase 1 and slurring together of phases 2 and 3 in the recording from...

Figure 4. Action potentials recorded from Purkinje fibers before (A) and after 1 X 10 6M(B), 1 X 10 5 M (C), and 1 X 10 4 M (D) 2-n-butyl MDl (top) and quaternary 2-n-butyl MDl (bottom). Note the obvious prolongation in APD100...

Huxley, A L., Sc Huxley, A F. (1939). Action potentials recorded from inside a nerve fibre. Nature, 144, 710—711. 

Figure 8.1-5. (A) The shape of a single action potential is shown. (B) The top trace shows the action potentials recorded from the trigeminal ganglion. The bottom trace shows an increase in the force applied with an electronic von Frey (VF) hair on the masseter muscle until the fiber started firing action potentials. The threshold of the fiber (7.71 g) was determined by subtracting the baseline from the minimum force required to activate the fiber.

Fig. 26.9. Cardiac action potential recorded from a Purkinje fiber.

Fig. 3 Spontaneous action potentials recorded from freshly-isolated single Tbxl8-VMs (n=5, middle panel) with perforated-patch current-clamp technique, showing robust and rhythmic APs with prominent diastolic depolarization recapitulating the electrophysiological hallmark of native SAN myocytes (left panel). The same recordings are expanded in the lower panel to show prominent diastolic depolarization in Tbxl8-VMs and native SAN myocytes. Right panel GFP-VMs displayed stable resting membrane potential and fired single action potential only upon electrical stimulation.

Draper MH Weidmann S (1951). Cardiac resting and action potentials recorded with an intracellular electrode. J Physiol 115 74-94. 

In our hands (Assaf et ai, 1981), depolarizing as opposed to hyper-polarizing after-potentials, 15-20 msec in duration, are a conspicuous feature of action potentials recorded in granule cells with resting mem-... 

Pollack, V., 1971, The waveshape of action potentials recorded with different types of electromyographic needles, Med. Biol. Eng. 9 657-664,... 

Figure 2 ACh-induced responses in the cat petrosal ganglion and in isolated neurons in culture, (a) Increases in the carotid sinus nerve frequency discharge ( csn) evoked by the application of increasing AQi doses (2-500 pg) to the ganglion (arrowhead), (b) Dose-response relationship for the significant increases in csn (Afew) observed in (a), (c) Depolarization and firing of multiple action potentials, recorded with intracellular microelectrode, elicited by application of an ACh (200 pM) bolus (arrowhead), (d) Inwardly directed inactivating current, recorded in whole-cell voltage-clamp configuration at Vm = —60 my induced by a 4-sec ACb (500 pM) pulse (continuous line).

More recently, a GRN housed within sensilla on the labeUa of Aedes aegypti was shown to respond to deet and other repellents including 1R3535, picaridin, and citronellal. At least three GRNs (Figure 2.1d) occurred in these sensilla based on the size and shape of the action potentials recorded. A large amplitude action potential was activated by increasing concentrations of salt (NaCl). A somewhat smaller amplitude action potential with a different shape was activated by... 

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