Electric Low-Frequency Stimulation of the Tongue Induces Long-Term Depression of the Jaw-Opening Reflex in Anesthetized Mice

2004 ◽  
Vol 92 (6) ◽  
pp. 3332-3337 ◽  
Author(s):  
Jens Ellrich

Long-term depression (LTD) of somatosensory processing has been demonstrated in slice preparations of the spinal dorsal horn. Although LTD could be reliably induced in vitro, inconsistent results were encountered when the same types of experiments were conducted in adult animals in vivo. We addressed the hypothesis that LTD of orofacial sensorimotor processing can be induced in mice under general anesthesia. The effects of electric low- and high-frequency conditioning stimulation of the tongue on the sensorimotor jaw-opening reflex (JOR) elicited by electric tongue stimulation were investigated. Low-frequency stimulation induced a sustained decrease of the reflex integral for ≥1 h after the end of conditioning stimulation. After additional high-frequency stimulation, the reflex partly recovered from LTD. High-frequency stimulation alone induced a transient increase of the JOR integral for <10 min. The LTD of the sensorimotor jaw-opening reflex in anesthetized mice may be an appropriate model to investigate the central mechanisms and the pharmacology of synaptic plasticity in the orofacial region. The application of electrophysiological techniques in mice provides the opportunity to include adequate knock-out models to elucidate the neurobiology of LTD.

2000 ◽  
Vol 83 (4) ◽  
pp. 2412-2420 ◽  
Author(s):  
Hiroshi Ikeda ◽  
Tatsuya Asai ◽  
Kazuyuki Murase

We investigated the neuronal plasticity in the spinal dorsal horn and its relationship with spinal inhibitory networks using an optical-imaging method that detects neuronal excitation. High-intensity single-pulse stimulation of the dorsal root activating both A and C fibers evoked an optical response in the lamina II (the substantia gelatinosa) of the dorsal horn in transverse slices of 12- to 25-day-old rat spinal cords stained with a voltage-sensitive dye, RH-482. The optical response, reflecting the net neuronal excitation along the slice-depth, was depressed by 28% for more than 1 h after a high-frequency conditioning stimulation of A fibers in the dorsal root (3 tetani of 100 Hz for 1 s with an interval of 10 s). The depression was not induced in a perfusion solution containing an NMDA antagonist,dl-2-amino-5-phosphonovaleric acid (AP5; 30 μM). In a solution containing the inhibitory amino acid antagonists bicuculline (1 μM) and strychnine (3 μM), and also in a low Cl−solution, the excitation evoked by the single-pulse stimulation was enhanced after the high-frequency stimulation by 31 and 18%, respectively. The enhanced response after conditioning was depotentiated by a low-frequency stimulation of A fibers (0.2–1 Hz for 10 min). Furthermore, once the low-frequency stimulation was applied, the high-frequency conditioning could not potentiate the excitation. Inhibitory transmissions thus regulate the mode of synaptic plasticity in the lamina II most likely at afferent terminals. The high-frequency conditioning elicits a long-term depression (LTD) of synaptic efficacy under a greater activity of inhibitory amino acids, but it results in a long-term potentiation (LTP) when inhibition is reduced. The low-frequency preconditioning inhibits the potentiation induction and maintenance by the high-frequency conditioning. These mechanisms might underlie robust changes of nociception, such as hypersensitivity after injury or inflammation and pain relief after electrical or cutaneous stimulation.


2019 ◽  
Vol 116 (13) ◽  
pp. 6397-6406 ◽  
Author(s):  
Xi Chen ◽  
Xiao Li ◽  
Yin Ting Wong ◽  
Xuejiao Zheng ◽  
Haitao Wang ◽  
...  

Memory is stored in neural networks via changes in synaptic strength mediated in part by NMDA receptor (NMDAR)-dependent long-term potentiation (LTP). Here we show that a cholecystokinin (CCK)-B receptor (CCKBR) antagonist blocks high-frequency stimulation-induced neocortical LTP, whereas local infusion of CCK induces LTP. CCK−/−mice lacked neocortical LTP and showed deficits in a cue–cue associative learning paradigm; and administration of CCK rescued associative learning deficits. High-frequency stimulation-induced neocortical LTP was completely blocked by either the NMDAR antagonist or the CCKBR antagonist, while application of either NMDA or CCK induced LTP after low-frequency stimulation. In the presence of CCK, LTP was still induced even after blockade of NMDARs. Local application of NMDA induced the release of CCK in the neocortex. These findings suggest that NMDARs control the release of CCK, which enables neocortical LTP and the formation of cue–cue associative memory.


1991 ◽  
Vol 65 (6) ◽  
pp. 1313-1320 ◽  
Author(s):  
H. R. Koerber ◽  
L. M. Mendell

1. Monosynaptic excitatory postsynaptic potentials (EPSPs) were evoked in medial gastrocnemius motoneurons by maximal group Ia stimulation of the heteronymous lateral gastrocnemius-soleus nerve in anesthetized cats. Three different patterns of high-frequency stimulation were delivered to the nerve, and the EPSPs were averaged in register (1, 2, . . ., n) for each. 2. One pattern ("Burst") consisted of 32 shocks delivered every 2 s at an interstimulus interval of 6 ms (167 Hz). The second pattern ("Stepping") was a frequency-modulated burst of 52 shocks derived from a recording of a spindle during stepping and was delivered every 2 s. The third pattern ("Paw Shake") was from an extensor spindle afferent recorded during rapid paw shake and was delivered in groups of six bursts with an interburst interval of 75 ms and a 3-s pause between groups of six bursts. The EPSPs in each burst were averaged in register (1, 2, . . ., n) so that the relative amplitude of each EPSP in the burst could be ascertained. The EPSP produced by low-frequency stimulation of the nerve (18 Hz) was also recorded for each motoneuron. 3. The initial EPSP in most bursts was larger than the EPSP measured as a result of low-frequency stimulation. This potentiation, defined as the ratio of the amplitude of the initial EPSP of the response to that of the low-frequency control, was found to vary systematically as a function of amplitude of the control EPSP as well as the stimulus paradigm used.(ABSTRACT TRUNCATED AT 250 WORDS)


1990 ◽  
Vol 258 (5) ◽  
pp. H1334-H1338 ◽  
Author(s):  
A. Ohlen ◽  
M. G. Persson ◽  
L. Lindbom ◽  
L. E. Gustafsson ◽  
P. Hedqvist

Intravital microscopy was used to study the effect of motor nerve stimulation on microvessel diameters in the rabbit tenuissimus muscle. Stimulation of the motor nerve (0.5-5 ms, 2-20 Hz, 5-15 V) evoked pulse duration- and frequency-dependent constriction of transverse and terminal arterioles. The vasoconstriction induced by low-frequency stimulation (2 Hz) was abolished by the alpha-adrenoceptor antagonist phentolamine, whereas high-frequency stimulation (10-20 Hz) resulted in a response that was only partially inhibited by phentolamine. However, desensitization of the tissue to the vasoconstrictor effects of neuropeptide Y (NPY) changed the response remaining after phentolamine into vasodilatation. Independent of stimulation parameters, pretreatment of the tissue with the adrenergic neuron blocker guanethidine reversed the constriction into dilatation that was resistant to propranolol, atropine, and indomethacin. The results document the functional presence of both vasoconstrictor and vasodilator fibers in the rabbit tenuissimus muscle motor nerve, and they suggest that part of the nerve-induced vasoconstriction at higher stimulation frequencies is caused by neuronally released NPY.


1991 ◽  
Vol 19 (4) ◽  
pp. 597-601 ◽  
Author(s):  
J. Tibballs

Electrical percutaneous stimulation of the phrenic nerves was first employed in 1948 by Sarnoff to provide temporary artificial ventilation in patients with respiratory failure.1 However, the technique was limited by development of infection around the electrode. Short-term radio frequency stimulation of the phrenic nerves was first utilised by Glenn in 19641 and adapted to long-term use in patients with central hypoventilation in 19683 and with traumatic quadriplegia in 1972.4 The technique employed alternate pacing of each hemi-diaphragm with high frequency stimulation (25–30 Hz) with a respiratory rate of 12 to 17 per minute which, in a series of 17 quadriplegic adults, although initially successful, was self-limiting because of eventual damage to the nerves and diaphragms. More recently, continuous bilateral simultaneous low frequency (up to 8 Hz) stimulation with a respiratory rate of 5 to 9 per minute has not induced myopathic changes.5 This phenomenon has been attributed to: 1. the conversion of the mixture of slow and fast twitch fibres in the diaphragm to a uniform population of fatigue resistant fibres induced by low frequency stimulation, and 2. the reduction in the total current necessary to achieve adequate gas exchange when both diaphragms contract simultaneously with the less frequent stimulation at lower energy. Diaphragmatic pacing has been applied to infants and children6–8 with emphasis on the selection of patients and optimum setting of stimulus parameters.9 This communication presents a case report of diaphragmatic pacing in a child with a review of the principles of application. The advantages and disadvantages compared to mechanical ventilation are also discussed.


1957 ◽  
Vol 40 (3) ◽  
pp. 435-450 ◽  
Author(s):  
David P. C. Lloyd

An assemblage of individual motoneurons constituting a synthetic motoneuron pool has been studied from the standpoint of relating monosynaptic reflex responses to frequency of afferent stimulation. Intensity of low frequency depression is not a simple function of transmitter potentiality. As frequency of stimulation increases from 3 per minute to 10 per second, low frequency depression increases in magnitude. Between 10 and approximately 60 per second low frequency depression apparently diminishes and subnormality becomes a factor in causing depression. At frequencies above 60 per second temporal summation occurs, but subnormality limits the degree of response attainable by summation. At low stimulation frequencies rhythm is determined by stimulation frequency. Interruptions of rhythmic firing depend solely upon temporal fluctuation of excitability. At high frequency of stimulation rhythm is determined by subnormality rather than inherent rhythmicity, and excitability fluctuation leads to instability of response rhythm. In short, whatever the stimulation frequency, random excitability fluctuation is the factor disrupting rhythmic response. Monosynaptic reflex response latency is stable during high frequency stimulation as it is in low frequency stimulation provided a significant extrinsic source of random bombardment is not present. In the presence of powerful random bombardment discharge may become random with respect to monosynaptic afferent excitation provided the latter is feeble. When this occurs it does so equally at low frequency and high frequency. Thus temporal summation is not a necessary factor. There is, then, no remaining evidence to suggest that the agency for temporal summation in the monosynaptic system becomes a transmitting agency in its own right.


1981 ◽  
Vol 51 (2) ◽  
pp. 317-320 ◽  
Author(s):  
S. R. Garfin ◽  
C. M. Tipton ◽  
S. J. Mubarak ◽  
S. L. Woo ◽  
A. R. Hargens ◽  
...  

The effect of fasciotomy on muscle tension (measured by a force transducer attached to the tendon) and interstitial fluid pressure (measured by Wick catheters in the muscle belly) was studied in the anterolateral compartments of 13 dog hindlimbs. Muscle tension and pressure were monitored in the tibialis cranialis muscle after low- and high-frequency stimulation of the peroneal nerve to produce twitch- and tetanic-type contractions. Fasciotomy decreased muscle force during the low-frequency stimulation by 16% (35.3 +/- 4.9 to 28.4 +/- 3.9 N) and during the high-frequency stimulation by 10% (60.8 %/- 4.9 to 54.8 +/- 3.9 N). Muscle pressure decreased 50% after fasciotomy under both conditions, 15 +/- 2 to 6 +/- 1 mmHg and 84 +/- 17 to 41 +/- 8 mmHg), respectively. Repeated functional evaluations during the testing procedure indicated that muscle fatigue was not a major factor in these results. It was concluded that fascia is important in the development of muscle tension and changes in interstitial pressure. Furthermore, the results raised questions concerning the merits of performing a fasciotomy for athletes with a compartment syndrome.


1983 ◽  
Vol 58 (1) ◽  
pp. 92-100 ◽  
Author(s):  
Thomas E. Ciesielski ◽  
Yoshitaka Fukuda ◽  
William W. L. Glenn ◽  
Jack Gorfien ◽  
Kathryn Jeffery ◽  
...  

✓ The histological, histochemical, and ultrastructural features of canine diaphragms subjected to pacing by high-frequency electrical stimulation (27 to 33 Hz) of the phrenic nerve are compared with unstimulated diaphragms and with diaphragms subjected to pacing by low-frequency stimulation (11 to 13 Hz). The high-frequency group showed a reduced tidal volume (fatigue) after long-term stimulation, and myopathic changes which included enlarged internal and sarcolemmal nuclei, ring fibers, moth-eaten fibers with irregular histochemical staining, core/targetoid fibers, and smearing and aggregation of Z-band material with electron microscopy. The low-frequency group did not develop a significant degree of fatigue or pathological changes, and showed histochemical evidence of transformation to fast-twitch (type II) fibers. Possible pathogenic mechanisms and their similarity to those in certain human neuromuscular diseases are discussed. The application of the findings resulting from high- and low-frequency stimulation to long-term diaphragm pacing in humans with chronic ventilatory insufficiency is also discussed.


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