The Role of the Cannabinoid System in Pain Control: Basic and Clinical Implications

Purpose of Review

The purpose of this review is to provide a comprehensive update of the different known components of the endogenous cannabinoid system and the mechanisms of action, as it applies to analgesia.

Recent Findings

Following the discovery of the endogenous cannabinoid system in the early 1990s and the subsequent characterization of the cannabinoid receptor, there has been a renewed interest in cannabinoid research. Recent work has demonstrated its efficacy as a pharmacologic agent. There is limited evidence in the literature about the understanding of the endocannabinoid system and its role in the treatment and management of acute and chronic pain. Further work may elucidate additional roles for the endocannabinoid system within our nervous system and, moreover, additional subtypes of cannabinoid receptors have yet to be discovered.

Summary

Cannabinoid compounds mediate their biological effects via binding and subsequent activation of cannabinoid receptors. These receptors are located throughout the body and make up the endocannabinoid system. These receptors are best understood and have been cloned, type 1 (CB₁) and type 2 (CB₂) [ (1, 2)] [ (1, 2)] [ (1, 2)] [ (1, 2)] [ (1, 2)] [ (1, 2)] [ (1, 2)] [ (1, 2)] [ (1, 2)] [ (1, 2)] [ (1, 2)] [ (1, 2)] [ (1, 2)] [ (1, 2)] [ (1, 2)] [ (1, 2)] [ (1, 2)] [ (1, 2)] [ (1, 2)] [ (1, 2)] [ (1, 2)] [ (1, 2)] [ (1, 2)]. The CB₂ receptor is located primarily in the immune system. CB₁ receptors are primarily located in the nervous system with the highest concentrations in the brain and lower concentrations in the spine and peripheral nervous tissues. Cannabinoids may be promising treatments for neuropathic pain with limited evidence, whereas, the evidence for other uses is insufficient.