FIGURE 2. Neural systems of addiction.

From the following article:

Drug addiction: bad habits add up

Trevor W. Robbins and Barry J. Everitt

Nature 398, 567-570(15 April 1999)



A dopamine-releasing neuron from the ventral tegmental area (VTA) is shown innervating a medium spiny neuron dendritic spine in the nucleus accumbens (NA). The dopamine transporter (DAT) is a main site for cocaine and amphetamine action. These drugs inhibit the re-uptake of dopamine by the VTA neuron, where it is initially produced from the amino acid tyrosine. Dopamine is shown acting at the two main families of dopamine receptor (D1 and D2). These are coupled to guanine-nucleotide-binding proteins (Gsand Gi), components of the intracellular cyclic AMP system, which also includes adenylyl cyclase (AC) and cAMP-dependent protein kinase (PKA). Possible substrates for this kinase include ion channels and the nuclear transcription factors CREB, Fos and Jun. A, amygdala; HC, hippocampus; PFC, prefrontal cortex; EAAR, excitatory amino-acid receptor; Glu, glutamate. (Adapted from ref. 16.)