Effect of romifidine on the nociceptive withdrawal reflex and temporal summation in conscious horses.
Abstract: To investigate the action of a single IV administration of romifidine on the thresholds of the nociceptive withdrawal reflex (NWR) and temporal summation in conscious horses. Methods: 10 adult horses. Methods: Single electrical stimulations were applied on the digital nerves to evoke NWR from the left forelimb and hind limb. Repeated electrical stimulations (10 stimuli, 5 Hz) were given to obtain temporal summation. Surface electromyographic reflex activity was recorded from the common digital extensor and cranial tibial muscles. After baseline assessment of NWR and temporal summation thresholds, romifidine (80 microg x kg(-1), IV) was administered. Successive determinations of NWR and temporal summation thresholds were performed 5, 25, and 55 minutes after administration. Results: Romifidine significantly increased the current intensities necessary to evoke NWR and temporal summation in forelimbs and hind limbs of horses. Values were significantly higher than baseline values 55 minutes after romifidine administration. After administration of romifidine, a facilitation of reflex components of tactile origin was observed when repeated stimulations were applied. Conclusions: Results confirm antinociceptive activity of romifidine and may represent an objective demonstration of the well-known hypersensitivity to tactile stimuli observed in horses receiving alpha2-adrenoreceptor agonists in clinical practice. Romifidine can be included in analgesic and anesthetic protocols to provide additional analgesia in horses.
Publication Date: 2005-12-13 PubMed ID: 16334961DOI: 10.2460/ajvr.2005.66.1992Google Scholar: Lookup
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- Journal Article
Summary
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This research paper studies the effect of the drug romifidine on the sensitivity of horses to pain. It was found that romifidine significantly increased the amount of electrical stimulation required to provoke pain response and repeated stimulation (temporal summation) in horses.
Research Methodology
- The study was conducted on 10 adult horses. A single intravenous administration of romifidine was given to each subject.
- To test the pain reflexes of the horses, single electrical stimulations were applied on the digital nerves of their left forelimb and hind limb. This was done to evoke Nervous Withdrawal Reflex (NWR).
- To achieve temporal summation, repeated electrical stimulations (10 stimuli, 5 Hz) were given.
- The muscular reflex activity in response to these stimuli was recorded using electromyography, focusing on the common digital extensor and cranial tibial muscles.
- Pain thresholds were tested before drug administration to establish baseline values, then again 5, 25, and 55 minutes after romifidine administration.
Research Findings
- It was observed that applying romifidine significantly increased the electrical current intensities necessary to provoke NWR and temporal summation. Both forelimb and hind limb of the horses exhibited this behavior.
- This elevated threshold was found to continue even 55 minutes after romifidine administration, indicating a significant and sustained antinociceptive (pain-blocking) effect of the drug.
- It was also noted that romifidine facilitated reflex components originating from touch when repeated stimulations were applied. This could be the reason for increased sensitivity to tactile stimuli commonly observed in clinical practice among horses that receive alpha2-adrenoreceptor agonists.
Conclusions
- The findings confirm the antinociceptive activity of romifidine and provide an objective demonstration of the well-known hypersensitivity to tactile stimuli in horses receiving alpha2-adrenoreceptor agonists in a clinical setting.
- This study suggests that romifidine can be included in analgesic and anesthetic protocols for horses to provide additional pain relief.
Cite This Article
APA
Spadavecchia C, Arendt-Nielsen L, Andersen OK, Spadavecchia L, Schatzmann U.
(2005).
Effect of romifidine on the nociceptive withdrawal reflex and temporal summation in conscious horses.
Am J Vet Res, 66(11), 1992-1998.
https://doi.org/10.2460/ajvr.2005.66.1992 Publication
Researcher Affiliations
- Anesthesiology Section, Department of Clinical Veterinary Sciences, Vetsuisse Faculty, University of Berne, Switzerland.
MeSH Terms
- Adrenergic alpha-Agonists / administration & dosage
- Adrenergic alpha-Agonists / pharmacology
- Animals
- Electromyography / veterinary
- Female
- Forelimb
- Hindlimb
- Horses / physiology
- Imidazoles / administration & dosage
- Imidazoles / pharmacology
- Injections, Intravenous / veterinary
- Male
- Pain Measurement / drug effects
- Pain Measurement / veterinary
- Reflex / drug effects
Citations
This article has been cited 5 times.- Mühlemann S, Leandri M, Risberg ÅI, Spadavecchia C. Comparison of Threshold and Tolerance Nociceptive Withdrawal Reflexes in Horses. Animals (Basel) 2021 Nov 26;11(12).
- Siegenthaler J, Pleyers T, Raillard M, Spadavecchia C, Levionnois OL. Effect of Medetomidine, Dexmedetomidine, and Their Reversal with Atipamezole on the Nociceptive Withdrawal Reflex in Beagles. Animals (Basel) 2020 Jul 21;10(7).
- Petrucci M, Spadavecchia C, Bachmann KF, Berger D, Mirra A, Casoni D. The nociceptive withdrawal reflex during spinal analgesia in pigs undergoing veno-arterial extracorporeal membrane oxygenation: a prospective observational study. Front Vet Sci 2024;11:1449297.
- Mascaró Triedo CE, Karar S, Abunemeh M, Portier K. Effect of nose twitching on the pupillary dilation in awake and anesthetized horses. Front Vet Sci 2024;11:1412755.
- Maidanskaia EG, Mirra A, Marchionatti E, Levionnois OL, Spadavecchia C. Antinociceptive, Sedative and Excitatory Effects of Intravenous Butorphanol Administered Alone or in Combination with Detomidine in Calves: A Prospective, Randomized, Blinded Cross-Over Study. Animals (Basel) 2023 Jun 9;13(12).
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