Chronic pain is a substantial public health problem, and the current treatment modalities are insufficient.
Cannabis and cannabis extracts have been used for thousands of years for medicinal purposes, and following
its legalization in a number of states, is increasingly being used to manage neurological, psychological, and
inflammatory conditions. However, research on the efficacy, mechanisms of action, and effects of cannabis
and its components on human and health and disease in the United States has been limited by its DEA
Schedule 1 classification. The principal components of cannabis, THC and CBD, are believed to have pain
reducing effects. THC has been most extensively studied, and although it has analgesic properties, its
psychotropic properties limit its utility for pain management. Notably the minor cannabinoids are emerging as
potential natural compounds with anti-inflammatory and pain reducing effects, but without the unwanted
psychotropic effects of THC. At the same time, anti-inflammatory strategies are being explored for treating
chronic pain. We have found that the endocannabinoids anandamide, N-arachidonoyl dopamine and N-oleoyl
dopamine, and the phytocannabinoid, ¿-9-THC, all have anti-inflammatory effects and improve functional
indices in mice treated with LPS. They each profoundly up-regulate plasma levels of IL-10 in LPS-treated mice.
Using bone marrow chimeras, we determined that NADA mediates its anti-inflammatory effects in LPS-treated
mice via the TRPV1 expressed by non-myeloid cell lineages. In contrast, our preliminary data suggest that ¿-9-
THC exerts its anti-inflammatory effects via cannabinoid receptor 1 (CB1R), rather than TRPV1. In preliminary
studies we have found that Cannabidiol (CBD), Cannabinol (CBN), Cannabigerol (CBG) and
Cannabichromene (CBC) modulate inflammatory activation of human microvascular endothelial cells. Taken
together, we broadly hypothesize that minor cannabinoids reduce inflammatory and neuropathic pain via antiinflammatory
mechanisms mediated through the activation of peripheral TRPV1 and CB1R in sensory neurons.
We will leverage the expertise of the PIs in neurobiology, pain biology, TRPV1, immunology, vascular biology
and injury to study the anti-inflammatory and pain reducing effects of CBD, CBN, CBG, and CBC, and other
minor cannabinoids in vitro and in vivo in models of inflammatory and neuropathic pain. In Aim #1 we will
define the ability of minor cannabinoids to modulate inflammatory activation and function of nociceptors,
leukocytes, endothelial cells and determine their dependence on TRPV1 / CB1R and Gpr149. In Aim #2 we will
determine the role of anti-inflammatory mechanisms in reducing pain behaviors and changes in Gpr149
expression in inflammatory and neuropathic pain models in mice. In Aim #3 we will determine how minor
cannabinoids reduce inflammatory and neuropathic pain behaviors through TRPV1- and CB1R- expressed in
nociceptors. These studies will advance the understanding of the endovanilloid and endocannabinoid systems
in pain and will pave the way for future development of minor cannabinoid-based therapies targeting the
endovanilloid and endocannabinoid systems for pain.