As the decriminalization of marijuana use becomes more widespread, it is of rapidly increasing importance to understand potential adverse health effects of active use and secondhand exposure. Much of what is known from prospective studies of marijuana use is based on DEA-approved research marijuana from the University of Mississippi, administered by the National Institute on Drug Abuse (NIDA). For example, the applicants have shown that brief exposure of rats to marijuana smoke impairs vascular endothelial function. However, differences in cannabinoid content between the NIDA-supplied marijuana and the material used in real-world practice, such as THC levels that are much lower than those in modern typical marijuana, have raised questions about the applicability of such results to human health. The cannabinoids are not required to impair vascular function, but the presence of endocannabinoid receptors on endothelial cells opens the possibility that the effect may be moderated in one direction or another by THC and CBD at high enough levels. Furthermore, to prevent mold, the NIDA material is dried under more extreme conditions before storage than typical consumer product, and then rehumidified at the user end before experiments. While there is consensus that this should not fundamentally change the smoke, the more aggressive drying may alter volatile terpene content, which may alter the smoke?s pharmacological effects. More importantly, there is a perception problem in which anyone looking for a reason to discount the relevance of such findings can conjure up an objection based on this perceived issue. Therefore, a major service to the public and to other researchers who might study effects of NIDA research marijuana will be to determine how cannabinoid profile and storage conditions influence cardiovascular effects of exposure to smoke or vaporizer aerosol, both in terms of endothelial functional response and cannabinoid receptor-mediated vascular inflammation. For this project, the NIDA Drug Supply Program will provide specially produced small batches of marijuana dried both in their normal fashion and in the less aggressive manner used by commercial growers, and other small batches of marijuana with varying THC/CDB ratios to better represent the range of modern cannabis. The project will accomplish the following goals: (1) Chemically analyze the cannabinoids in these varieties (in plant material, smoke, and vaporizer aerosol) to carefully characterize the products, and determine if chemical composition is changed by the drying regimen. (2) Determine if the drying regimens and/or the cannabinoid profiles influence the known impairment of vascular function in exposed rats, and examine the effect on blood pressure and platelet aggregation. (3) Examine serum from the exposed rats to determine functional and pro- inflammatory effects, and potential changes in serum that impair function of cultured endothelial cells that it contacts. The impact of these results will be to validate (or identify caveats for) the use of NIDA research marijuana in the study of cardiovascular and other physiological effects of cannabis.
As the decriminalization of marijuana use becomes more widespread around the US and the world, it is of rapidly increasing importance to understand potential adverse health effects of active use and secondhand exposure. Much of what we know from prospective studies of marijuana use is based on DEA-approved research marijuana from the University of Mississippi, administered by the National Institute on Drug Abuse (NIDA); however, differences in cannabinoid content and drying regimens between the NIDA marijuana and the material used in real-world practice have raised questions about the applicability of these results to human health. To clarify the validity of results obtained with this material, we will determine how differences in drying regimens and cannabinoid content affect chemical profiles, endothelial functional response to smoke, and cannabinoid receptor-mediated vascular inflammation.
