The neurons of the dopaminergic pathways have axons that run the entire length of the pathway. The neurons' somata produce the enzymes that synthesize dopamine, and they are then transmitted via the projecting axons to their synaptic destinations, where most of the dopamine is produced. Dopaminergic nerve cell bodies in such areas as the substantia nigra tend to be pigmented due to the presence of the black pigment melanin.
There are eight dopaminergic pathways. The four major ones are:
|Pathway name||Description||Associated disorders|
|The mesolimbic pathway transmits dopamine from the ventral tegmental area (VTA) to the limbic system via the nucleus accumbens. The VTA is located in the midbrain, and the nucleus accumbens is in the ventral striatum. The "meso" prefix in the word "mesolimbic" refers to the midbrain, or "middle brain", since "meso" means "middle" in Greek. This pathway is part of the mesocorticolimbic projection.||schizophrenia, ADHD, addiction|
|The mesocortical pathway transmits dopamine from the VTA to the frontal cortex. The "meso" prefix in "mesocortical" refers to the VTA, which is located in the midbrain, and "cortical" refers to the cortex. This pathway is part of the mesocorticolimbic projection.||schizophrenia, ADHD, addiction|
||The nigrostriatal pathway transmits dopamine from the substantia nigra pars compacta (SNc) to the dorsal striatum (specifically, the caudate nucleus and putamen). This pathway is associated with motor control.||Parkinson's disease, chorea|
||The tuberoinfundibular pathway transmits dopamine from the hypothalamus (arcuate nucleus aka "infundibular nucleus") to the pituitary gland. This pathway influences the secretion of certain hormones, including prolactin. "Infundibular" in the word "tuberoinfundibular" refers to the cup or infundibulum, out of which the pituitary gland develops.||hyperprolactinaemia|
- "Beyond the Reward Pathway". Retrieved 2009-10-23.
- Le Moal, Michel. "Mesocorticolimbic Dopaminergic Neurons". Neuropsychopharmacology: The Fifth Generation of Progress. Retrieved 4 November 2013.
- Malenka RC, Nestler EJ, Hyman SE (2009). "Chapter 10: Neural and Neuroendocrine Control of the Internal Milieu". In Sydor A, Brown RY. Molecular Neuropharmacology: A Foundation for Clinical Neuroscience (2nd ed.). New York: McGraw-Hill Medical. p. 249. ISBN 9780071481274.
Relationship of the hypothalamus and the pituitary gland. The anterior pituitary, or adenohypophysis, receives rich blood flow from the capillaries of the portal hypophyseal system. This system delivers factors released by hypothalamic neurons into portal capillaries at the median eminence. The figure shows one such projection, from the tuberal (arcuate) nuclei via the tuberoinfundibular tract to the median eminence.
- Malenka RC, Nestler EJ, Hyman SE (2009). "Chapter 6: Widely Projecting Systems: Monoamines, Acetylcholine, and Orexin". In Sydor A, Brown RY. Molecular Neuropharmacology: A Foundation for Clinical Neuroscience (2nd ed.). New York: McGraw-Hill Medical. pp. 147–148, 154–157. ISBN 9780071481274.
Neurons from the SNc densely innervate the dorsal striatum where they play a critical role in the learning and execution of motor programs. Neurons from the VTA innervate the ventral striatum (nucleus accumbens), olfactory bulb, amygdala, hippocampus, orbital and medial prefrontal cortex, and cingulate cortex. VTA DA neurons play a critical role in motivation, reward-related behavior, attention, and multiple forms of memory. ... Thus, acting in diverse terminal fields, dopamine confers motivational salience ("wanting") on the reward itself or associated cues (nucleus accumbens shell region), updates the value placed on different goals in light of this new experience (orbital prefrontal cortex), helps consolidate multiple forms of memory (amygdala and hippocampus), and encodes new motor programs that will facilitate obtaining this reward in the future (nucleus accumbens core region and dorsal striatum). ... DA has multiple actions in the prefrontal cortex. It promotes the "cognitive control" of behavior: the selection and successful monitoring of behavior to facilitate attainment of chosen goals. Aspects of cognitive control in which DA plays a role include working memory, the ability to hold information "on line" in order to guide actions, suppression of prepotent behaviors that compete with goal-directed actions, and control of attention and thus the ability to overcome distractions. ... Noradrenergic projections from the LC thus interact with dopaminergic projections from the VTA to regulate cognitive control. ...
- Doyon WM, Thomas AM, Ostroumov A, Dong Y, Dani JA (October 2013). "Potential substrates for nicotine and alcohol interactions: a focus on the mesocorticolimbic dopamine system". Biochem. Pharmacol. 86 (8): 1181–93. doi:10.1016/j.bcp.2013.07.007. PMID 23876345.