Dopaminergic neurons

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Dopaminergic Neurons are a class of neurons that produce the neurotransmitter dopamine.

Dopaminergic neurons

The human brain contains approximately 400,000 to 600,000 dopaminergic neurons and thus make up less than 1% of the total number of brain neurons. There are nine dopamine-containing neuronal cell groups in the mammalian brain, each with distinct cellular properties. These neurons are vital to diverse brain functions, including: voluntary movement, reward, addiction and stress. Excessive dopamine in the brain is linked to schizophrenia, whereas progressive loss of dopaminergic neurons is responsible for Parkinson’s Disease.

Anatomy

Dopaminergic neurons are located in the diencephalon, mesencephalon, medulla oblangata, hypothalamus, retina and the olfactory bulb. Greater than 70% of all dopaminergic neurons are located in the substantia nigra (see Nigral dopaminergic Cell). Axons of dopaminergic neurons project to the brain by using one of three pathways: the mesostriatal, mesolimbic and mesocortical.

Molecular profile

There is some evidence that dopaminergic neurons in the hypothalamus and the olfactory bulb may express γ-aminobutyric acid (GABA) in addition to dopamine.

Behavior

In the frontal lobes, dopamine controls the flow of information from other areas of the brain. They are necessary for tasks that including motor behavior, motivation and working memory. Dopaminergic neurons, for example, play a crucial role in the reward system that controls the learning of many specific behaviors. Dopamine is also plays a role in reward/pleasure system of the brain. It is released by naturally rewarding experiences such as food, sex, drugs, and neutral stimuli that become associated with them Dopamine also regulates prolactin secretion. Insufficient dopamine biosynthesis in the dopaminergic neurons can cause Parkinson's disease, in which a person loses the ability to execute smooth, controlled movements.

References

  • Bjorkland A., Dunnett S. (2007) Dopamine neuron systems in the brain: an update, Trends in Neuroscience, Vol. 30 (Issue 5) 194-202.
  • Chinta S., Andersen J.(2005) Dopaminergic Neurons, The International Journal of Biochemistry & Cell Biology, Volume 37 (2005) 942-946.

Additional information

see also: Nigral dopaminergic cell