Article Publish Status: FREE
Abstract Title:

The CannabinoidsΔTHC, CBD, and HU-308 Act via Distinct Receptors to Reduce Corneal Pain and Inflammation.

Abstract Source:

Cannabis Cannabinoid Res. 2018 ;3(1):11-20. Epub 2018 Feb 1. PMID: 29450258

Abstract Author(s):

Dinesh Thapa, Elizabeth A Cairns, Anna-Maria Szczesniak, James T Toguri, Meggie D Caldwell, Melanie E M Kelly

Article Affiliation:

Dinesh Thapa


Corneal injury can result in dysfunction of corneal nociceptive signaling and corneal sensitization. Activation of the endocannabinoid system has been reported to be analgesic and anti-inflammatory. The purpose of this research was to investigate the antinociceptive and anti-inflammatory effects of cannabinoids with reported actions at cannabinoid 1 (CBR) and cannabinoid 2 (CBR) receptors and/or noncannabinoid receptors in an experimental model of corneal hyperalgesia.Corneal hyperalgesia (increased pain response) was generated using chemical cauterization of the corneal epithelium in wild-type (WT) and CBR knockout (CBR) mice. Cauterized eyes were treated topically with the phytocannabinoidsΔ-tetrahydrocannabinol (ΔTHC) or cannabidiol (CBD), or the CBD derivative HU-308, in the presence or absence of the CBR antagonist AM251 (2.0 mg/kg i.p.), or the 5-HTreceptor antagonist WAY100635 (1 mg/kg i.p.). Behavioral pain responses to a topical capsaicin challenge at 6 h postinjury were quantified from video recordings. Mice were euthanized at 6 and 12 h postcorneal injury for immunohistochemical analysis to quantify corneal neutrophil infiltration.Corneal cauterization resulted in hyperalgesia to capsaicin at 6 h postinjury compared to sham control eyes. Neutrophil infiltration, indicative of inflammation, was apparent at 6 and 12 h postinjury in WT mice. Application of ΔTHC, CBD, and HU-308 reduced the pain score and neutrophil infiltration in WT mice. The antinociceptive and anti-inflammatory actions ofΔTHC, but not CBD, were blocked by the CBR antagonist AM251, but were still apparent, for both cannabinoids, in CBRmice. However, the antinociceptive and anti-inflammatory actions of HU-308 were absent in the CBRmice. The antinociceptive and anti-inflammatory effects of CBD were blocked by the 5-HTantagonist WAY100635.Topical cannabinoids reduce corneal hyperalgesia and inflammation. The antinociceptive and anti-inflammatory effects ofΔTHC are mediated primarily via CBR, whereas that of the cannabinoids CBD and HU-308, involve activation of 5-HTreceptors and CBRs, respectively. Cannabinoids could be a novel clinical therapy for corneal pain and inflammation resulting from ocular surface injury.

Study Type : Animal Study

Print Options

Key Research Topics

Sayer Ji
Founder of GreenMedInfo.com

Subscribe to our informative Newsletter & get Nature's Evidence-Based Pharmacy

Our newsletter serves 500,000 with essential news, research & healthy tips, daily.

Download Now

500+ pages of Natural Medicine Alternatives and Information.

This website is for information purposes only. By providing the information contained herein we are not diagnosing, treating, curing, mitigating, or preventing any type of disease or medical condition. Before beginning any type of natural, integrative or conventional treatment regimen, it is advisable to seek the advice of a licensed healthcare professional.

© Copyright 2008-2022 GreenMedInfo.com, Journal Articles copyright of original owners, MeSH copyright NLM.