Nociceptor Generator Potential

2012 ◽  
Keyword(s):  
Generator Potential

scholarly journals Responses of hair cells to statocyst rotation.

1975 ◽  
Vol 66 (4) ◽  
pp. 507-530 ◽  
Author(s):  
D L Alkon
Keyword(s):  
Hair Cell ◽  
Centrifugal Force ◽  
Hair Cells ◽  
New Technique ◽  
Force Vector ◽  
Generator Potential ◽  
Recording Apparatus ◽  
Intracellular Potentials ◽  
A New Technique

A new technique is described for stimulating hair cells of the Hermissenda statocyst. The preparation and recording apparatus can be rotated at up to 78 rpm while recording intracellular potentials. Hair cells in front of the centrifugal force vector depolarize in response to rotation. Hair cells in back of the centrifugal force vector hypoerpolarize in response to rotation. Mechanisms by which the hair cell generator potential might arise are examined.

scholarly journals GENERATOR PROCESSES OF REPETITIVE ACTIVITY IN A PACINIAN CORPUSCLE

1958 ◽  
Vol 41 (4) ◽  
pp. 825-845 ◽  
Author(s):  
Werner R. Loewenstein
Keyword(s):  
Decay Time ◽  
Time Course ◽  
Stimulus Frequency ◽  
Response Patterns ◽  
Myelinated Nerve ◽  
Constant Frequency ◽  
Generator Potential ◽  
Single Generator ◽  
Constant Strength ◽  
Set Up

Response patterns resulting from repetitive mechanical stimulation of the corpuscle depend on (1) the time course of recovery of the generator potential, on (2) the recovery of critical firing height, and on (3) the stimulus strength/generator potential function. By either augmenting stimulus frequency at constant strength, or by reducing strength at constant frequency, a sequence of propagated potentials is turned into a pattern of alternating regenerative and generator responses. In such a pattern an extra impulse can be set up whenever an extra stimulus produces a generator potential of enough amplitude to reach the firing height of the corresponding period. The new requirements of firing height introduced by the refractory trail of the extra impulse determine resetting of periodicity and appearance of a "compensatory pause." The decay time of the single generator potential is independent of stimulus duration. This is interpreted as a factor determining receptor adaptation. Upon repetitive stimulation at intervals above ½ decay time of the single generator potential, a compound generator potential is built up which shows no spontaneous decline. However, in spite of being considerably greater than the firing height for single impulses, the constant level of depolarization of the compound generator potential is unable to produce propagated potentials. A hypothesis is brought forward which considers the generator potential to arise from membrane units with fluctuating excitability scattered over the non-myelinated nerve ending.

Neurodynamic response analysis of anterior semicircular canal afferents in the pigeon

1980 ◽  
Vol 43 (6) ◽  
pp. 1746-1770 ◽  
Author(s):  
J. P. Landolt ◽  
M. J. Correia
Keyword(s):  
Time Constant ◽  
Semicircular Canal ◽  
Angular Acceleration ◽  
Neural Response ◽  
Response Analysis ◽  
Torsion Pendulum ◽  
Generator Potential ◽  
Pendulum Model ◽  
Anterior Semicircular Canal ◽  
Semicircular Canal Afferents

1. The neurodynamic responses to sinusoidal and pulse angular accelerations were studied in anterior semicircular canal afferents in the barbiturate-anesthetized pigeon. 2. The resting discharge frequency, aS, varied from 7.4 to 149.0 impulses/s. For most units, aS remained fairly constant for long periods of time during the experiment. 3. The neural-response harmonic distortion, resulting from stimulation by sinusoidal angular accelerations, varied in different units. Percent distortions from as low as 3% to those as high as 57% were determined. 4. Intensity-function plots of peak first harmonic neural response as a function of the peak sinusoidal angular acceleration (with frequency, f, as a parameter) are of two types: one has a linear relationship between the variables; the other demonstrates pronounced nonlinearities ("saturation," particularly for low values of f). In saturation-type units, the data of which fit a power law function, the exponent of the function is frequency dependent, becoming closer and closer to unity with increasing f. 5. Data for all units fit the transfer function, G'(s) = Csk/(tauLS + 1), where G'(s) relates the unit response to angular acceleration, C is a gain constant, 0 < k < 1, and tauL is the so-called long time constant of the classical torsion pendulum model. tauL varied from 4.45 to 22.17 S (mean +/- SE = 10.24 +/- 1.20 S). This may be interpreted as an indication of a regional distribution of tauL'S within the neuroepithelium. Arguments are advanced to show that this is consistent with our present understanding of the ampullary end organ. 6. The degree of regularity of the spontaneous discharge (as determined by the coefficient of variation, CV) was significantly correlated with the parameter k in G'(S). The larger the CV, the larger is the corresponding k. Further work indicated that the larger the value of k, the more adaptation a unit exhibited (k varied from 0.017 to 0.66). 7. The time-domain response of G(S) = G'(S)/(tauSS + 1) to different durations of pulse angular acceleration stimuli agreed well with the neural response to these stimuli (tauS = 2.27 ms is the short time constant of the torsion pendulum model). 8. The term Sk was decomposed into an expression containing a series of polynomials in S in the numerator and denominator. The first term in this expansion K0tau1S/(tau1S + 1), has previously been shown to describe so-called adaptation properties in the dynamics of the semicircular canals. A mean (+/-SE) tau1 = 71.56 (+/-10.01) S was determined. Evidence is presented that Sk probably represents a relaxation phenomenon comprised of a time-varying intracellular Na+/K+-transport process, components of which are summed with the generator potential in the afferent terminal(S) of the receptor hair cell.

Estimation of generator potential waveform elicited in muscle spindles by various inputs

1985 ◽  
pp. 377-383 ◽  
Author(s):  
Saburo Homma ◽  
Yoshio Nakajima
Keyword(s):  
Muscle Spindles ◽  
Generator Potential ◽  
Potential Waveform

An intracellular study of chemosensory fibers and endings

1980 ◽  
Vol 44 (6) ◽  
pp. 1077-1088 ◽  
Author(s):  
Y. Hayashida ◽  
H. Koyano ◽  
C. Eyzaguirre
Keyword(s):  
Carotid Body ◽  
Action Potentials ◽  
Physiological Saline ◽  
Mean Amplitude ◽  
Nerve Fibers ◽  
Chemical Stimulation ◽  
Nerve Terminals ◽  
Generator Potential ◽  
Single Nerve ◽  
Frequency Changes

1. The carotid body and its nerve, removed from anesthetized cats, were placed in physiological saline flowing under paraffin oil. The nerve, lifted into the oil, was used for either electrical stimulation or recording of the total afferent discharge. Intracellular recordings were obtained from individual nerve fibers and endings within the carotid body. The recording sites were identified by injecting Procion yellow through the intracellular electrodes; the tissues were then prepared for histology and observed with episcopic fluorescence or Nomarski optics. 2. Intracellularly recorded chemosensory fibers conducted at 1.1-30 m/s and usually displayed action potentials of regular amplitude. At times, however, some spikes become partially blocked while others maintained their original amplitude. "Natural" (hypoxia) or chemical (ACh or NaCN) stimulation induced different patterns of frequency changes of the large and small action potentials. This indicated nerve fiber branching at some distance from the recording site. 3. Intra- and extracellularly recorded spikes were blocked in 0 [Na+]0 by tetrodotoxin (TTX) or procaine. 4. During chemical stimulation, a slowly occurring depolarization (receptor or generator potential) was recorded intracellularly from the afferent fibers. It developed concomitantly with the increase in discharge. 5. Impalement of single nerve terminals (histologically identified) showed numerous "spontaneous" depolarizing potentials (SDPs) that had a mean amplitude of 5.6 mV, a mean duration of 46.1 ms, and nearly random distribution. They increased in frequency and summated during chemical stimulation. SDPs originated from either the site of recording or from neighboring areas. When the SDPs attained a certain amplitude, they seemed to give rise to action potentials. Also, relatively well developed or partially blocked spikes (apparently originating elsewhere) were recorded from single nerve terminals. 6. The receptor (generator) potential of chemosensory receptors appears to be an integrated response formed by multiple activity originating in different nerve endings.

scholarly journals Effects of Lithium on Different Membrane Components of Crayfish Stretch Receptor Neurons

1968 ◽  
Vol 51 (5) ◽  
pp. 635-654 ◽  
Author(s):  
Shosaku Obara ◽  
Harry Grundfest
Keyword(s):  
Significant Role ◽  
Specific Effect ◽  
Stretch Receptor ◽  
Receptor Neuron ◽  
Generator Potential ◽  
Crayfish Stretch Receptor ◽  
Soma Membrane ◽  
Receptor Neurons ◽  
Membrane Components

Unlike several other varieties of input membrane, that of the crayfish stretch receptor develops a generator potential in response to stretch when all the Na of the medium is replaced with Li. However, Li depolarizes the receptor neuron, the soma membrane becoming more depolarized than that of the axon. During exposure to Li the cell usually fires spontaneously for a period, and when it becomes quiescent spike electrogenesis fails in the soma but persists in the axon. These effects are seen in the rapidly adapting as well as the slowly adapting cells. The block of spike electrogenesis of the soma membrane is only partly due to the Li-induced depolarization and a significant role must be ascribed to a specific effect of Li.

Summative Action of Acetylcholine with Physiological Stimulus on the Generator Potential in the Lateral Eye of the Horseshoe Crab

Nature ◽  
1960 ◽  
Vol 187 (4743) ◽  
pp. 1118-1119 ◽  
Author(s):  
R. KIKUCHI ◽  
K. NAITO ◽  
S. MINAGAWA
Keyword(s):  
Horseshoe Crab ◽  
Generator Potential ◽  
Lateral Eye

scholarly journals Responses of Photoreceptors in Hermissenda

1972 ◽  
Vol 60 (6) ◽  
pp. 631-649 ◽  
Author(s):  
Daniel L. Alkon ◽  
M. G. F. Fuortes
Keyword(s):  
Generator Potential ◽  
Two Phases

The five photoreceptors in the eye of the mollusc Hermissenda crassicornis respond to light with depolarization and firing of impulses. The impulses of any one cell inhibit other cells, but the degree of inhibition differs in different pairs. Evidence is presented to show that the interactions occur at terminal branches of the photoreceptor axons, inside the cerebropleural ganglion. Properties of the generator potential are examined and it is shown that the depolarization develops in two phases which are affected differently by extrinsic currents. Finally, it is shown that by enhancing the differences in the responses of individual cells to a variety of stimuli, the interactions may facilitate a number of simple discriminations.

scholarly journals PROCESSES OF EXCITATION IN THE DENDRITES AND IN THE SOMA OF SINGLE ISOLATED SENSORY NERVE CELLS OF THE LOBSTER AND CRAYFISH

1955 ◽  
Vol 39 (1) ◽  
pp. 87-119 ◽  
Author(s):  
Carlos Eyzaguirre ◽  
Stephen W. Kuffler
Keyword(s):  
Membrane Potential ◽  
Cell Body ◽  
Action Potentials ◽  
Sensory Nerve ◽  
Resting Potential ◽  
Cell Soma ◽  
Appreciable Change ◽  
Generator Potential ◽  
Receptor Cells ◽  
Wide Range

The stretch receptor organs of Alexandrowicz in lobster and crayfish possess sensory neurons which have their cell bodies in the periphery. The cell bodies send dendrites into a fine nearby muscle strand and at the opposite pole they give rise to an axon running to the central nervous system. Mechanisms of excitation between dendrites, cell soma, and axon have been studied in completely isolated receptor structures with the cell components under visual observation. Two sensory neuron types were investigated, those which adapt rapidly to stretch, the fast cells, and those which adapt slowly, the slow cells. 1. Potentials recorded from the cell body of the neurons with intracellular leads gave resting potentials of 70 to 80 mv. and action potentials which in fresh preparations exceeded the resting potentials by about 10 to 20 mv. In some experiments chymotrypsin or trypsin was used to make cell impalement easier. They did not appreciably alter resting or action potentials. 2. It has been shown that normally excitation starts in the distal portion of dendrites which are depolarized by stretch deformation. The changed potential within the dendritic terminals can persist for the duration of stretch and is called the generator potential. Secondarily, by electrotonic spread, the generator potential reduces the resting potential of the nearby cell soma. This excitation spread between dendrites and soma is seen best during subthreshold excitation by relatively small stretches of normal cells. It is also seen during the whole range of receptor stretch in neurons in which nerve conduction has been blocked by an anesthetic. The electrotonic changes in the cells are graded, reflecting the magnitude and rate of rise of stretch, and presumably the changing levels of the generator potential. Thus in the present neurons the resting potential and the excitability level of the cell soma can be set and controlled over a wide range by local events within the dendrites. 3. Whenever stretch reduces the resting membrane potential, measured in the relaxed state in the cell body, by 8 to 12 mv. in slow cells and by 17 to 22 mv. in fast cells, conducted impulses are initiated. It is thought that in slow cells conducted impulses are initiated in the dendrites while in fast cells they arise in the cell body or near to it. In fresh preparations the speed of stretch does not appreciably influence the membrane threshold for discharges, while during developing fatigue the firing level is higher when extension is gradual. 4. Some of the specific neuron characteristics are: Fast receptor cells have a relatively high threshold to stretch. During prolonged stretch the depolarization of the cell soma is not well maintained, presumably due to a decline in the generator potential, resulting in cessation of discharges in less than a minute. This appears to be the basis of the relatively rapid adaptation. A residual subthreshold depolarization can persist for many minutes of stretch. Slow cells which resemble the sensory fibers of vertebrate spindles are excited by weak stretch. Their discharge rate remains remarkably constant for long periods. It is concluded that, once threshold excitation is reached, the generator potential within slow cell dendrites is well maintained for the duration of stretch. Possible reasons for differences in discharge properties between fast and slow cells are discussed. 5. If stretch of receptor cells is gradually continued above threshold, the discharge frequency first increases over a considerable range without an appreciable change in the firing level for discharges. Beyond that range the membrane threshold for conducted responses of the cell soma rises, the impulses become smaller, and partial conduction in the soma-axon boundary region occurs. At a critical depolarization level which may be maintained for many minutes, all conduction ceases. These overstretch phenomena are reversible and resemble cathodal block. 6. The following general scheme of excitation is proposed: stretch deformation of dendritic terminals → generator potential → electrotonic spread toward the cell soma (prepotential) → dendrite-soma impulse → axon impulse. 7. Following release of stretch a transient hyperpolarization of slow receptor cells was seen. This off effect is influenced by the speed of relaxation. 8. Membrane potential changes recorded in the cell bodies serve as very sensitive detectors of activity within the receptor muscle bundles, indicating the extent and time course of contractile events.

scholarly journals II. Post-Tetanic Potentiation and Depression of Generator Potential in a Single Non-Myelinated Nerve Ending

1959 ◽  
Vol 43 (2) ◽  
pp. 347-376 ◽  
Author(s):  
Werner R. Loewenstein ◽  
Stanley Cohen
Keyword(s):  
Mechanical Stimulation ◽  
Sense Organ ◽  
Critical Parameters ◽  
Resting Membrane Potential ◽  
Ranvier Node ◽  
Generator Potential ◽  
After Effects ◽  
Receptor Membrane ◽  
Post Tetanic Potentiation ◽  
Stimulation Of

Repetitive activity at the non-myelinated ending of Pacinian corpuscles leaves the following after-effects: (1) With certain parameters of repetitive mechanical stimulation of the ending a depression in generator potential is produced. The effect is fully reversible and has low energy requirements. The effect is a transient decrease in responsiveness of the receptor membrane which is unrelated to changes in resting membrane potential. It appears to reflect an inactivation process of the receptor membrane. Within certain limits, the depression increases as a function of strength, frequency, and train duration of repetitive stimuli. (2) With other, more critical parameters of repetitive stimulation a hyperpolarization of the ending and of the first intracorpuscular Ranvier node may be produced. This leads to respectively post-tetanic potentiation of generator potential and increase in nodal firing threshold. The balance of these after-effects determines the threshold for the production of nerve impulses by adequate (mechanical) stimulation of the sense organ. The after-effects of activity at the node can be elicited by dromic (mechanical) stimulation of the ending, as well as by antidromic (electric) stimulation of the axon; the after-effects at the ending can only be produced by dromic and not by antidromic stimulation.

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