Endocannabinoid modulation of homeostatic and non-homeostatic feeding circuits

Endocannabinoid modulation of the mesocorticolimbic and hypothalamic circuits: a highly interconnected circuit of excitatory (glutamatergic) and inhibitory (GABAergic) pathways exist between the ventral tegmental area (VTA), nucleus accumbens (NAc), medial prefrontal cortex (mPFC) and hypothalamus (Hyp). Furthermore, the VTA sends prominent dopamine projections to the NAc and mPFC. A number of synaptic inputs onto principal neurons within the VTA (dopamine neurons), NAc (medium spiny neurons), mPFC (pyramidal neurons) and hypothalamus express CB1 receptors, and are sensitive to endocannabinoid-mediated, short-term plasticity (DSI/DSE) and/or long-term plasticity (LTD/iLTD) in naive animals. Exposure to a palatable/high-fat diet (or omega-3 deficient diet) or the development of diet-induced obesity can alter these forms of synaptic plasticity [Insets: +/− indicates present/absent, while ↑/↓/ = /? indicate increase/decrease/no change/unknown, respectively].234