Assessment of the wind-up phenomenon in the equine nociceptive trigeminal system.

Veres-Nyéki, Kata O.; Leandri, M.; Spadavecchia, Claudia (2013). Assessment of the wind-up phenomenon in the equine nociceptive trigeminal system. Veterinary journal, 198(1), pp. 81-87. Elsevier 10.1016/j.tvjl.2013.04.012

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Repeated sub-threshold nociceptive electrical stimulation resulting in temporal summation of the limb nociceptive withdrawal reflex is a well-established non-invasive model to investigate the wind-up phenomenon in horses. Due to structural similarities of the trigeminal sensory nucleus to the dorsal horn of the spinal cord, temporal summation should be evoked by repeated transcutaneous electrical stimulation of trigeminal afferents. To evaluate this hypothesis repeated transcutaneous electrical stimulation was applied to the supraorbital and infraorbital nerves of 10 horses. Stimulation intensities varied between 0.5 and 1.3 times the trigemino-cervical reflex threshold defined for single stimulation. Evoked electromyographic activity of the orbicularis oculi, splenius and cleidomastoideus muscles was recorded and the signals analysed in the previously established epochs typical to the early and late component of the blink reflex and to the trigemino-cervical reflex. Behavioural reactions were evaluated with the aid of numerical rating scale. The nociceptive late component and the trigemino-cervical reflex were not elicited by sub-threshold intensity repeated transcutaneous electrical stimulation. Furthermore, the median reflex amplitude for the 10 horses showed a tendency to decline over the stimulation train so temporal summation of afferent trigeminal inputs could not be observed. Therefore, the modulation of trigeminal nociceptive processing attributable to repeated Aδ fibre stimulations seems to differ from spinal processing of similar inputs as it seems to have an inhibitory rather than facilitatory effect. Further evaluation is necessary to highlight the underlying mechanism.

Item Type:	Journal Article (Original Article)
Division/Institute:	05 Veterinary Medicine > Research Foci > NeuroCenter 05 Veterinary Medicine > Department of Clinical Veterinary Medicine (DKV) 05 Veterinary Medicine > Department of Clinical Veterinary Medicine (DKV) > DKV - Anaesthesiology
UniBE Contributor:	Veres, Kata, Spadavecchia, Claudia
Subjects:	600 Technology > 630 Agriculture
ISSN:	1090-0233
Publisher:	Elsevier
Language:	English
Submitter:	Susanne Portner
Date Deposited:	06 Aug 2014 16:13
Last Modified:	05 Dec 2022 14:30
Publisher DOI:	10.1016/j.tvjl.2013.04.012
PubMed ID:	23726819
Uncontrolled Keywords:	Blink reflex, Equine, Repeated stimulation, Temporal summation, Trigemino-cervical reflex
URI:	https://boris.unibe.ch/id/eprint/44708