The pharmacology of the endocannabinoid system: functional and structural interactions with other neurotransmitter systems and their repercussions in behavioral addiction

Addict Biol. 2008 Jun;13(2):160-87. doi: 10.1111/j.1369-1600.2008.00105.x. Epub 2008 Apr 16.

Abstract

Addiction is a chronic, recurring and complex disorder. It is characterized by anomalous behaviors that are linked to permanent or long-lasting neurobiological alterations. Furthermore, the endocannabinoid system has a crucial role in mediating neurotransmitter release as one of the main neuromodulators of the mammalian central nervous system. The purpose of the present review is to instruct readers about the functional and structural interactions between the endocannabinoid system and the main neurotransmitter systems of the central nervous system in the context of drug addiction. With this aim, we have systematically reviewed the main findings of most of the existing literature that explores cross-talk in the five brain areas that are most traditionally implicated in addiction: amygdala, prefrontal cortex, nucleus accumbens, hippocampus and ventral tegmental area (VTA). The neurotransmission systems influenced by the pharmacology of the endocannabinoid system in these brain areas, which are reviewed here, are gamma-aminobutyric acid (GABA), glutamate, the main biogenic amines (dopamine, noradrenaline and serotonin), acetylcholine and opioids. We show that all of these neurotransmitter systems can be modulated differentially in each brain area by the activation or deactivation of cannabinoid CB1 brain receptors. Specifically, most of the studies relate to the hippocampus and nucleus accumbens. Moreover, the neurotransmitter with the fewest number of related studies is acetylcholine (excepting in the hippocampus), whereas there is a large number that evaluates GABA, glutamate and dopamine. Finally, we propose a possible interpretation of the role of the endocannabinoid system in the phenomenon of addiction.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Amygdala / drug effects
  • Amygdala / physiopathology
  • Animals
  • Brain / drug effects*
  • Brain / physiopathology*
  • Cannabinoid Receptor Modulators / pharmacology*
  • Cannabinoid Receptor Modulators / physiology*
  • Cannabinoids / pharmacology*
  • Endocannabinoids*
  • Hippocampus / drug effects
  • Hippocampus / physiopathology
  • Humans
  • Marijuana Abuse / physiopathology*
  • Neurotransmitter Agents / physiology*
  • Nucleus Accumbens / drug effects
  • Nucleus Accumbens / physiopathology
  • Prefrontal Cortex / drug effects
  • Prefrontal Cortex / physiopathology
  • Receptor, Cannabinoid, CB1 / drug effects
  • Receptor, Cannabinoid, CB1 / physiology
  • Substance-Related Disorders / physiopathology*
  • Ventral Tegmental Area / drug effects
  • Ventral Tegmental Area / physiopathology

Substances

  • Cannabinoid Receptor Modulators
  • Cannabinoids
  • Endocannabinoids
  • Neurotransmitter Agents
  • Receptor, Cannabinoid, CB1