Nigral dopaminergic cell

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Nigral dopaminergic cell is a neuron found in the midbrain of vertebrates. These neurons comprise most of the substantia nigra and mainly regulate motor and sensorimotor functions within the brain.

Basic information

A substantia nigra dopaminergic neuron filled with Biocytin. (http://garcia.rutgers.edu/tepper.research.html)

Neuronal Type: Principal Neurons

Anatomy

The nerve cells within the substantia nigra of humans are indicated by the dark pigment known as neuromelanin.[2] This pigment has been demonstrated to increase with age. The neurons have thick and long dendrites that receive electrical signals from other neurons.

Projections from Substantia Nigra [1]

Molecular profile

  • Neurotransmitter: Dopamine
  • Unique molecular markers:

Physiology

The dopaminergic cells in the substantia nigra, in vivo, show evidence of three distinctive firing patterns: “a pacemaker-like regular firing pattern, a random pattern, and a burst firing pattern.” [1]

Synaptic Connections

The nigral dopaminergic cells make synaptic connections with the ventral tegmental area, which then travel to the prefrontal cortex. In addition, their axons extend along the nigrostriatal pathway to the striatum where they release dopamine via axoplasmic flow. Within the striatum, it specifically projects into the putamen and the caudate nucleus.

Pathology

The axon projection patterns are within the forebrain and have been known to play a significant role in the regulation of bodily movements controlled by the brain. The malfunction or destruction of this these neurons has been found to have a direct relationship to Parkinson’s disease (PD). In 1817, a physician by the name of James Parkinson (1755-1828) discovered this unfortunate neurodegenerative disease.[3]

The symptoms of PD include involuntary body movements, muscular rigidty, and other motor malfunctions. When an individual is diagnosed with PD, approximately 80% of the nigral dopaminergic neurons have been depleted. Subsequently, since these neurons produce the neurotransmitter dopamine, the PD patient also suffers from a depletion of dopamine. This monoamine neurotransmitter dictates motor control, reward, and motivation in the brain. Other pathological changes to the nigral dopaminergic neurons can lead to other neurological disorders, such as schizophrenia (an illness resulting from an overproduction of dopamine) and psychomotor retardation.

The Effects of Parkinson's Disease in the Substantia Nigra (http://www.nlm.nih.gov/MEDLINEPLUS/ency/imagepages/19515.htm)

References

1. P. Celada, C. A. Paladini, and J. M. Tepper. (1999). Gabaergic control of rat substantia nigra dopaminergic neurons: role of globus pallidus and substantia nigra pars reticulate. Aidekman Research Center, Center for molecular and behavioral neuroscience, program in cellular and molecular biodynamics, Rutgers, The State University of New Jersey Newark, Nj. Neuroscience, Vol. 89, Issue 3. 813-825.

2. C. R. Lee, E. D. Abercrombie and J. M. Tepper. (2004). Pallidal control of substantia nigra dopaminergic neuron firing pattern and its relation to extracellular Neostriatal dopamine levels. Center for molecular and behavioral neuroscience, Rutgers, The State University of New Jersey, 197 University Avenue, Newark, NJ. Neuroscience 129. 481-489.

3. Gazzaniga and Heatherton. Psychological Sciences. W.W. Norton and Company. New York, London. 2003.


Additional information

SenseLab Database - Nigral Dopaminergic cell [2]

See also Dopaminergic neurons