Localisation of cannabinoid and cannabinoid-related receptors in the equine dorsal root ganglia.
Authors: Chiocchetti Roberto, Rinnovati Riccardo, Tagliavia Claudio, Stanzani Agnese, Galiazzo Giorgia, Giancola Fiorella, Silva Margherita De, Capodanno Ylenia, Spadari Alessandro
Journal: Equine veterinary journal
Summary
# Editorial Summary Dorsal root ganglia (DRG) are pivotal sensory relay stations where nociceptive information originates, making them an essential anatomical target for understanding pain modulation—yet the distribution of cannabinoid receptors in equine DRG had not been systematically mapped despite growing clinical interest in cannabinoid therapeutics for equine pain management. Using immunohistochemical techniques on lumbar and sacral DRG specimens from adult horses, Chiocchetti and colleagues identified and characterised the localisation of cannabinoid receptor 1 (CB1), cannabinoid receptor 2 (CB2), and related receptors (GPR55 and GPR119) within distinct neuronal populations and supporting tissues. The team found CB1 expression predominantly in small-to-medium sensory neurones and their axons—cell types associated with nociception and thermal sensation—whilst CB2 displayed a more restricted distribution in certain neurone populations and particularly in non-neuronal cells, with GPR55 and GPR119 showing additional receptor diversity within the ganglia. These findings substantiate the biological plausibility of targeting cannabinoid pathways for equine pain relief and provide anatomical rationale for further investigation into the efficacy and optimal dosing of cannabinoid-based treatments, whilst also highlighting that receptor distribution patterns may influence both therapeutic efficacy and potential side-effect profiles depending on which receptor subtypes are activated.
Read the full abstract on PubMed
Practical Takeaways
- •Cannabinoid receptor presence in dorsal root ganglia suggests legitimate therapeutic potential for pain management in horses, supporting investigation of cannabinoid-based treatments
- •Understanding receptor distribution helps explain how cannabinoid agonists may modulate pain signalling at the neurological level
- •This foundational anatomical work should precede clinical trials of cannabinoid therapies in equine pain conditions
Key Findings
- •Cannabinoid receptors are localised in equine dorsal root ganglia, providing anatomical basis for their potential analgesic role
- •Cellular distribution of cannabinoid and cannabinoid-related receptors in equine DRG has been characterised for the first time
- •Receptor localisation data establishes foundation for understanding cannabinoid agonist mechanisms in equine pain management