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. Author manuscript; available in PMC: 2011 Mar 1.
Published in final edited form as: Future Neurol. 2010 May 1;5(3):393–401. doi: 10.2217/fnl.10.14

Figure 1. Neurotransmitter pathways and receptor systems implicated in the acute reinforcing effects of drugs of abuse.

Figure 1

Sagittal rodent brain section. Cocaine and amphetamines increase dopamine levels in the nucleus accumbens and amygdala via direct actions on dopamine terminals. Opioids activate endogenous opioid receptors in the ventral tegmental area, nucleus accumbens and amygdala. Opioids also facilitate the release of dopamine in the nucleus accumbens via actions either in the ventral tegmental area or nucleus accumbens, but are also hypothesized to activate elements independent of the dopamine system. Alcohol activates GABAA receptors or enhances GABA release in the ventral tegmental area, nucleus accumbens and amygdala. Alcohol is also hypothesized to facilitate the release of opioid peptides in the ventral tegmental area, nucleus accumbens and central nucleus of the amygdala. Alcohol facilitates the release of dopamine in the nucleus accumbens via an action either in the ventral tegmental area or nucleus accumbens. Nicotine activates nicotinic acetylcholine receptors in the ventral tegmental area, nucleus accumbens and amygdala, either directly or indirectly, via actions on interneurons. Cannabinoids activate cannabinoid CB1 receptors in the ventral tegmental area, nucleus accumbens and amygdala. Cannabinoids facilitate the release of dopamine in the nucleus accumbens via an unknown mechanism, either in the ventral tegmental area or nucleus accumbens. The blue arrows represent the interactions within the extended amygdala system hypothesized to play a key role in psychostimulant reinforcement. The medial forebrain bundle represents ascending and descending projections between the ventral forebrain (nucleus accumbens, olfactory tubercle and septal area) and the ventral midbrain (ventral tegmental area; not shown in figure for clarity).

AC: Anterior commissure; AMG: Amygdala; ARC: Arcuate nucleus; BNST: Bed nucleus of the stria terminalis; Cer: Cerebellum; C-P: Caudate-putamen; DMT: Dorsomedial thalamus; FC: Frontal cortex; Hippo: Hippocampus; IF: Inferior colliculus; LC: Locus coeruleus; LH: Lateral hypothalamus; MFB: Medial forebrain bundle; N Acc.: Nucleus accumbens; OT: Olfactory tract; PAG: Periaqueductal gray; RPn: Reticular pontine nucleus; SC: Superior colliculus; SNr: Substantia nigra pars reticulata; VP: Ventral pallidum; VTA: Ventral tegmental area.