Cannabinoid and Marijuana Neurobiology

The convergence of political, financial, medical, and basic science interests is transforming the field of marijuana science. The past decade has seen a 140-fold increase in the scientific literature compared with 1960, catalyzed by changes in our perception of marijuana and by the discovery of an entirely new signaling system, the endocannabinoid system in living organisms. Shortly after this discovery, revelations appeared on how plant-based cannabinoids (phytocannabinoids) and de novo synthetically produced cannabinoids target and modulate this system in the brain and in other organs. The past decade has also witnessed a steep rise in marijuana use in the United States. The principal target of marijuana is the multifunctional endocannabinoid signaling system, which modulates a vast range of functions – behavioral, cognitive, endocrine, immune, and motor – in the brain and has an equally central role in shaping the function of many organ systems and metabolism in peripheral tissues. With the potency of marijuana and number of users rising, the impact of marijuana on physiology, pathophysiology, cognitive function, and psychiatric conditions is likely to rise. We have embarked on a vast human experiment without informed consent. This chapter provides an overview of the endocannabinoid signaling system, how THC affects the neurobiology of cannabinoids, and implications of this newly found knowledge for public health and public policy.