Investigation of the facilitation of the nociceptive withdrawal reflex evoked by repeated transcutaneous electrical stimulations as a measure of temporal summation in conscious horses

Spadavecchia, Claudia; Andersen, Ole Kæseler; Arendt‐Nielsen, Lars; Spadavecchia, L.; Doherr, Marcus G.; Schatzmann, U.

doi:10.2460/ajvr.2004.65.901

Cited by 24 publications

(42 citation statements)

References 45 publications

(47 reference statements)

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“…The basic physiology of temporal summation has been evaluated in conscious horses using the NWR (Spadavecchia et al 2004). The final purpose was to define a method to study the pathophysiology and pharmacological modulation of central integrative processes in horses.…”

Section: Temporal Summation: Background and Experiences In Horsesmentioning

confidence: 99%

“…The total stimulation time was set at 2 s, as in most human experiments, and the EMG response was recorded for 4 s: 500 ms prestimulation, 2000 ms during stimulation and 1500 ms poststimulation (Spadavecchia et al 2004). The experience collected over the last years indicates that the best method to quantify the NWR facilitation consists in the determination of the RMS amplitude of the reflex response within the 40 -200 ms window following each stimulus (Risberg et al 2014).…”

Section: Temporal Summation: Background and Experiences In Horsesmentioning

confidence: 99%

“…During the post-stimulation window between 2500 and 4000 ms, a certain degree of EMG activity persisted (Figure 3). This most probably reflects the voluntary muscle activation following the end of stimulation, as if the horse would still show annoyance and delayed limb lifting (Spadavecchia et al 2004).…”

Section: Temporal Summation: Background and Experiences In Horsesmentioning

confidence: 99%

“…As an alternative, the Nociceptive Withdrawal Reflex (NWR) model has been proposed to investigate the physiology of nociception and to evaluate its modulation by analgesic and anaesthetic drugs in horses (Spadavecchia et al 2002, Spadavecchia et al 2003, Spadavecchia et al 2007, Rohrbach et al 2009). This model not only allows a more reliable definition of the nociceptive threshold through neurophysiological characterization of the elicited response (Spadavecchia et al 2002), but also allows to plot a stimulus-response curve together with the assessment of temporal summation mechanisms (Spadavecchia et al 2004). Aim of this review is to summarize the experience and results obtained using the NWR model in horses over the last 15 years.…”

Section: Introductionmentioning

confidence: 99%

“…Temporal summation in humans is both frequency and intensity dependent, so different frequencies and intensities of stimulation were applied to find the best settings capable of evoking summation in horses. In a first methodological study (Spadavecchia et al 2004), repeated stimuli (each stimulus being a train of 5 pulses as previously…”

Section: Temporal Summation: Background and Experiences In Horsesmentioning

confidence: 99%

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The model of the Nociceptive Withdrawal Reflex in horses

Spadavecchia¹,

Rohrbach²,

Levionnois³

et al. 2016

PHK

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Summary: In equine pain research, the Nociceptive Withdrawal Reflex (NWR) model has been proposed as an alternative to classical thermal, mechanical and electrical models to investigate the physiology of nociception. This model does not only allow a more reliable definition of the nociceptive threshold through neurophysiological characterization of the elicited response , but also consents plotting a stimulus-response curve as well as the evaluation of temporal summation mechanisms. Aim of this report is to summarize the experience and results obtained using the NWR model in horses over the last 15 years, firstly with the purpose of describing its physiological characteristics and secondly with the aim of evaluating its pharmacological modulation through analgesic and anaesthetic compounds. The NWR can be elicited in horses through electrical transcutaneous stimulation of a peripheral sensory nerve and is recorded through electromyographic electrodes from the muscles involved in the withdrawal reaction. As the non-nociceptive fibres have lower threshold to electrical stimuli than the nociceptive one, it is impossible to differentiate between the two groups on the stimulus side. So, the only guidance to assess the quality of the stimulus and the recruitment of nociceptive afferents should rely on the characteristics of the electromyographic response, most of all on the timing of its various components. A reflex response can be considered to be a true NWR only if it appears within a time epoch compatible with the conduction velocity of the A fibers. Furthermore a clearly recognizable EMG burst in the epoch of interest has to be accompanied by a consistent aversive behavioural reaction, thus allowing the definition of a reliable NWR threshold. Responses to stimulation intensities below and above thresholds can be quantified to draw a stimulus response curve. Furthermore, through repeated stimulation at subthreshold intensities, it is possible to elicit the phenomenon of temporal summation, considered to be the early phase of the wind up phenomenon and of relevant interest to study central integrative mechanisms of pain processing. Alpha-2 agonists, opioids, systemic lidocaine, ketamine and inhalation anaesthetics have been investigated using the NWR model in horses. Drug-specific modulation of NWR threshold, stimulus-response curves and temporal summation are summarized for each tested compound.

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Section: Temporal Summation: Background and Experiences In Horsesmentioning

confidence: 99%

Section: Temporal Summation: Background and Experiences In Horsesmentioning

confidence: 99%

Section: Temporal Summation: Background and Experiences In Horsesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Temporal Summation: Background and Experiences In Horsesmentioning

confidence: 99%

See 3 more Smart Citations

The model of the Nociceptive Withdrawal Reflex in horses

Spadavecchia¹,

Rohrbach²,

Levionnois³

et al. 2016

PHK

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show abstract

Perioperative Pain Management

Lerche¹,

Muir²

2009

Equine Anesthesia

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Quantitative assessment of the nociceptive withdrawal reflex in healthy, non-medicated experimental sheep

Rohrbach

Zeiter

Andersen

et al. 2014

Physiology & Behavior

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20This study aimed to characterize the nociceptive withdrawal reflex (NWR) and to define the 21 nociceptive threshold in 25 healthy, non-medicated experimental sheep in standing posture. 22Electrical stimulation of the dorsal lateral digital nerves of the right thoracic and the pelvic limb 23 was performed and surface-electromyography (EMG) from the deltoid (all animals) and the 24 femoral biceps (18 animals) or the peroneus tertius muscles (7 animals) was recorded. The 25 behavioural reaction following each stimulation was scored on a scale from 0 (no reaction) to 5 26 (strong whole body reaction). A train-of-five 1 ms constant-current pulse was used and current 27 intensity was stepwise increased until NWR threshold intensity was reached. The NWR 28 threshold intensity (I t ) was defined as the minimal stimulus intensity able to evoke a reflex with 29 a minimal Root-Mean-Square amplitude (RMS A ) of 20 µV, a minimal duration of 10 ms and a 30 minimal reaction score of 1 (slight muscle contraction of the stimulated limb) within the time 31 window 20 to 130 ms post-stimulation. Based on this value, further stimulations were 32 performed below (0.9I t ) and above threshold (1.5I t and 2I t ). The stimulus-response curve was 33 described. Data are reported as medians and interquartile ranges. 34At the deltoid muscle I t was 4.4 mA (2.9-5.7) with an RMS A of 62 µV (30-102

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Investigation of the facilitation of the nociceptive withdrawal reflex evoked by repeated transcutaneous electrical stimulations as a measure of temporal summation in conscious horses

Cited by 24 publications

References 45 publications

The model of the Nociceptive Withdrawal Reflex in horses

The model of the Nociceptive Withdrawal Reflex in horses

Perioperative Pain Management

Quantitative assessment of the nociceptive withdrawal reflex in healthy, non-medicated experimental sheep

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