Terpenes in Cannabis sativa inhibit capsaicin responses in rat DRG neurons via Na+/K+ ATPase activation
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Published version
Author(s)
Anand, Uma
Anand, Praveen
Sodergren, Mikael Hans
Type
Journal Article
Abstract
Terpenes in Cannabis sativa exert analgesic effects, but the mechanisms are uncertain. We exam-ined the effects of 10 terpenes on capsaicin responses in an established model of neuronal hyper-sensitivity. Adult rat DRG neurons cultured with neurotrophic factors NGF and GDNF, were loaded with Fura2AM for calcium imaging, and treated with individual terpenes or vehicle for 5 minutes, followed by 1 µMol capsaicin. In vehicle treated control experiments, capsaicin elicited immediate and sustained calcium influx. Most neurons treated with terpenes responded to capsaicin after 6-8 minutes. Few neurons showed immediate capsaicin responses that were transient or normal. The delayed responses were found to be due to calcium released from the endoplasmic reticulum, as they were maintained in calcium/magnesium free media, but not after thapsigargin pre-treatment. Terpene inhibition of calcium influx was reversed after washout of medium, in the absence of terpenes, and in the presence of the Na+/K+ ATPase inhibitor ouabain, but not CB1 or CB2 receptor antagonists. Thus terpenes inhibit capsaicin evoked calcium influx by Na+/K+ ATPase activation. Immunofluorescence showed TRPV1 co-expression with α1β1 Na+/K+ ATPase in most neurons while others were either TRPV1 or α1β1 Na+/K+ ATPase positive.
Editor(s)
Battino, Maurizio
Date Issued
2023-11-15
Date Acceptance
2023-11-10
Citation
International Journal of Molecular Sciences, 2023, 24 (22)
ISSN
1422-0067
Publisher
MDPI AG
Journal / Book Title
International Journal of Molecular Sciences
Volume
24
Issue
22
Copyright Statement
© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
License URL
Identifier
https://www.mdpi.com/journal/ijms
Subjects
Chronic pain; terpenes; membrane potential; hyperpolarization; sensory neurons
Publication Status
Published
Article Number
ARTN 16340