“Studies on the effects of marijuana smoking have evolved into the discovery and description of the endocannabinoid system. To date, this system is composed of two receptors, CB1 and CB2, and endogenous ligands including anandamide, 2-arachidonoyl glycerol, and others. CB1 receptors and ligands are found in the brain as well as immune and other peripheral tissues. Conversely, CB2 receptors and ligands are found primarily in the periphery, especially in immune cells. Cannabinoid receptors are G protein-coupled receptors, and they have been linked to signaling pathways and gene activities in common with this receptor family. In addition, cannabinoids have been shown to modulate a variety of immune cell functions in humans and animals and more recently, have been shown to modulate T helper cell development, chemotaxis, and tumor development. Many of these drug effects occur through cannabinoid receptor signaling mechanisms and the modulation of cytokines and other gene products.
It appears the immunocannabinoid system is involved in regulating the brain-immune axis and might be exploited in future therapies for chronic diseases and immune deficiency.”
“The medicinal uses of marijuana were described centuries ago for diseases such as asthma, migraine, pain, convulsions, and anxiety (reviewed in ref.). More recently, emphasis has been placed on marijuana’s putative, beneficial effects on appetite, glaucoma, spasticity in multiple sclerosis, pain, and inflammation.
Recent experimental evidence supports marijuana’s therapeutic potential in some of these maladies.
The active plant ingredients in marijuana belong to the C21-cannabinoid compounds including the primary psychoactive compound, Δ9-tetrahydrocannabinol (THC). This cannabinoid along with others such as Δ8-THC, cannabidiol, and cannabinol, as well as chemical analogs, have been extensively studied over the years for their biological and therapeutic properties. Some of the properties of these agents have included effects on immunity ranging from suppression of resistance to infection to enhancement of IL-1 production by macrophages. These early studies about the immunomodulating effects of these drugs have been the subject of previous overviews and will not be reviewed here. Instead, we will briefly summarize the general features of the cannabinoid system and review recent findings on the structure and function of the cannabinoid system components in the immune system. For convenience, we will refer to this as the “immunocannabinoid” system.
