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Equine veterinary journal2020; 53(3); 549-557; doi: 10.1111/evj.13305

Localisation of cannabinoid and cannabinoid-related receptors in the equine dorsal root ganglia.

Abstract: Growing evidence recognises cannabinoid receptors as potential therapeutic targets for pain. Consequently, there is increasing interest in developing cannabinoid receptor agonists for treating pain. As a general rule, to better understand the actions of a drug, it would be of extreme importance to know the cellular distribution of its specific receptors. The localisation of cannabinoid receptors in the dorsal root ganglia of the horse has not yet been investigated. Objective: To localise the cellular distribution of canonical and putative cannabinoid receptors in the equine cervical dorsal root ganglia. Methods: Qualitative and quantitative immunohistochemical study. Methods: Cervical (C6-C8) dorsal root ganglia were collected from six horses (1.5 years of age) at the slaughterhouse. The tissues were fixed and processed to obtain cryosections which were used to investigate the immunoreactivity of canonical cannabinoid receptors 1 (CB1R) and 2 (CB2R), and for three putative cannabinoid-related receptors: nuclear peroxisome proliferator-activated receptor alpha (PPARα), transient receptor potential ankyrin 1 (TRPA1) and serotonin 5-HT1a receptor (5-HT1aR). Results: The neurons showed immunoreactivity for CB1R (100%), CB2R (80% ± 13%), PPARα (100%), TRPA1 (74% ± 10%) and 5-HT1aR (84% ± 6%). The neuronal satellite glial cells showed immunoreactivity for CB2R, PPARα, TRPA1 and 5-HT1aR. Conclusions: The low number of horses included in the study. Conclusions: This study highlighted the expression of cannabinoid receptors in the sensory neurons and glial cells of the dorsal root ganglia. These findings could be of particular relevance for future functional studies assessing the effects of cannabinoids in horses to manage pain.
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Publication Date: 2020-07-04 PubMed ID: 32524649DOI: 10.1111/evj.13305Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research paper investigates the distribution of cannabinoid and cannabinoid-related receptors in the dorsal root ganglia (DRG) of horses, with the aim of understanding if they could be potential targets for pain management treatments.

Objective and Background

  • This study aims to investigate the cellular distribution of canonical and putative (proposed but not yet confirmed) cannabinoid receptors in the cervical dorsal root ganglia of horses.
  • With the mounting evidence that cannabinoid receptors can be potential targets for pain relief, understanding their distribution in an animal’s nervous system is essential for developing effective agonists.
  • The dorsal root ganglia, clusters of neurons in a vertebrate nervous system, play a key role in transmitting sensory information like pain from peripheral nerves to the spinal cord. Discovering a significant presence of cannabinoid receptors in these structures could lead to breakthroughs in pain management strategies.

Methodology

  • Dorsal root ganglia from the cervical region (C6-C8) of six horses, aged 1.5 years, were collected for this study.
  • The collected tissue samples underwent cryosectioning (a technique that involves freezing and slicing the tissue for microscopic examination).
  • These sections were then tested for the immunoreactivity of five types of receptors: two canonical cannabinoid receptors – CB1R and CB2R – and three proposed cannabinoid-related receptors: PPARα, TRPA1, and 5-HT1aR.

Results

  • The neurons tested displayed immunoreactivity for all five receptor types: 100% for CB1R and PPARα, 80% ± 13% for CB2R, 84% ± 6% for 5-HT1aR, and 74% ± 10% for TRPA1.
  • In addition, the neuronal satellite glial cells – non-neural cells that support and protect neurons – showed immunoreactivity to all but the CB1R receptors.

Conclusions

  • While the authors acknowledge the sample size of six horses was relatively small, they emphasize the study’s groundbreaking achievement: it highlights the significant presence of cannabinoid receptors in both sensory neurons and their supporting glial cells within the dorsal root ganglia of horses.
  • This discovery suggests potential for future research into the effects of cannabinoids in managing pain in horses and possibly other animals. It provides a foundation for further functional studies to validate cannabinoid receptors as targets for new pain relief strategies.

Cite This Article

APA
Chiocchetti R, Rinnovati R, Tagliavia C, Stanzani A, Galiazzo G, Giancola F, Silva M, Capodanno Y, Spadari A. (2020). Localisation of cannabinoid and cannabinoid-related receptors in the equine dorsal root ganglia. Equine Vet J, 53(3), 549-557. https://doi.org/10.1111/evj.13305

Publication

Equine veterinary journal
ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English
Volume: 53
Issue: 3
Pages: 549-557

Researcher Affiliations

Chiocchetti, Roberto
  • Department of Veterinary Medical Sciences (UNI EN ISO), University of Bologna, Ozzano dell'Emilia, Italy.
Rinnovati, Riccardo
  • Department of Veterinary Medical Sciences (UNI EN ISO), University of Bologna, Ozzano dell'Emilia, Italy.
Tagliavia, Claudio
  • Department of Veterinary Medical Sciences (UNI EN ISO), University of Bologna, Ozzano dell'Emilia, Italy.
Stanzani, Agnese
  • Department of Veterinary Medical Sciences (UNI EN ISO), University of Bologna, Ozzano dell'Emilia, Italy.
Galiazzo, Giorgia
  • Department of Veterinary Medical Sciences (UNI EN ISO), University of Bologna, Ozzano dell'Emilia, Italy.
Giancola, Fiorella
  • Department of Veterinary Medical Sciences (UNI EN ISO), University of Bologna, Ozzano dell'Emilia, Italy.
Silva, Margherita De
  • Department of Veterinary Medical Sciences (UNI EN ISO), University of Bologna, Ozzano dell'Emilia, Italy.
Capodanno, Ylenia
  • Department of Veterinary Medical Sciences (UNI EN ISO), University of Bologna, Ozzano dell'Emilia, Italy.
Spadari, Alessandro
  • Department of Veterinary Medical Sciences (UNI EN ISO), University of Bologna, Ozzano dell'Emilia, Italy.

MeSH Terms

  • Animals
  • Cannabinoids
  • Ganglia, Spinal
  • Horses
  • Neurons
  • Pain / veterinary
  • Receptors, Cannabinoid

Grant Funding

  • Formula Swiss AG, Switzerland

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Citations

This article has been cited 14 times.
  1. Zamith Cunha R, Zannoni A, Salamanca G, De Silva M, Rinnovati R, Gramenzi A, Forni M, Chiocchetti R. Expression of cannabinoid (CB1 and CB2) and cannabinoid-related receptors (TRPV1, GPR55, and PPARα) in the synovial membrane of the horse metacarpophalangeal joint. Front Vet Sci 2023;10:1045030.
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