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Papers of the Week

Papers: 25 Nov 2023 - 1 Dec 2023

2023 Nov 15

Int J Mol Sci




Terpenes in Cannabis sativa Inhibit Capsaicin Responses in Rat DRG Neurons via Na/K ATPase Activation.


Anand U, Anand P, Sodergren MH


Terpenes in exert analgesic effects, but the mechanisms are uncertain. We examined the effects of 10 terpenes on capsaicin responses in an established model of neuronal hypersensitivity. 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 min, 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 min. 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 CB or CB 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.