Abstract

Background

Preclinical and clinical evidence suggests that cannabis has potential analgesic properties. However, cannabinoid receptor expression and localization within spinal cord pain processing circuits remain to be characterized across sex and species.

Aims

We aimed to investigate the differential expression of the cannabinoid type 1 (CB1) receptor across dorsal horn laminae and cell populations in male and female adult rats and humans.

Methods

To investigate and quantify CB1 receptor expression in the spinal dorsal horn across species, we refined immunohistochemical procedures for successful rat and human fixed tissue staining and confocal imaging. Immunohistochemical results were complemented with analysis of CB1 gene (CNR1) expression within rodent and human dorsal horn using single-cell/nuclei RNA sequencing data sets.

Results

We found that CB1 was preferentially localized to the neuropil within the superficial dorsal horn of both rats and humans, with CB1 somatic staining across dorsal horn laminae. CB1 receptor immunoreactivity was significantly higher in the superficial dorsal horn compared to the deeper dorsal horn laminae for both rats and humans, which was conserved across sex. Interestingly, we found that CB1 immunoreactivity was not primarily localized to peptidergic afferents in rats and humans and that CNR1 (CB1) but not CNR2 (CB2) was robustly expressed in dorsal horn neuron subpopulations of both rodents and humans.

Conclusions

The conserved preferential expression of CB1 receptors in the superficial dorsal horn in male and female rodents and humans has significant implications for understanding the roles of this cannabinoid receptor in spinal mechanisms of nociception and analgesia.

Details

Title
Cannabinoid CB1 Receptor Expression and Localization in the Dorsal Horn of Male and Female Rat and Human Spinal Cord
Author
Parnell, Jessica 1   VIAFID ORCID Logo  ; Newton, Martin 2   VIAFID ORCID Logo  ; Dedek, Annemarie 1   VIAFID ORCID Logo  ; Rudyk, Christopher 2 ; Landrigan, Jeffrey 2   VIAFID ORCID Logo  ; Bellavance, Justin 2   VIAFID ORCID Logo  ; VanDerLoo, Simon 2 ; Tsai, Eve C 3   VIAFID ORCID Logo  ; Hildebrand, Michael E 1   VIAFID ORCID Logo 

1  Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada; Neuroscience Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada 
2  Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada 
3  Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada; Neuroscience Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada; Brain and Mind Research Institute, University of Ottawa, Ottawa, Ontario, Canada; Division of Neurosurgery, Department of Surgery, The Ottawa Hospital, Ottawa, Ontario, Canada 
Publication year
2023
Publication date
Jul 2023
Publisher
Taylor & Francis Ltd.
e-ISSN
2474-0527
Source type
Scholarly Journal
Language of publication
English
DOI
https://doi.org/10.1080/24740527.2023.2264895
ProQuest document ID
2915813788
Copyright
© 2023 The Author(s). Published with license by Taylor & Francis Group, LLC. This work is licensed under the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.