Purkinje Cell


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Purkinje cell

[pər′kin·jē ‚sel]
(histology)
Any of the cells of the cerebral cortex with large, flask-shaped bodies forming a single cell layer between the molecular and granular layers.

Purkinje Cell

 

any one of numerous large neurons of the cerebellar cortex whose axons extend beyond the cortex; first described in 1837 by J. E. Purkinje.

Purkinje cells transmit the commands of the cerebellar cortex to its subordinate motor centers, the cerebellar and vestibular nuclei. In mammals and birds, the bodies of Purkinje cells are arranged in the cerebellar cortex in a single layer, called the gangliar, or Purkinje, layer. The Purkinje layer is located between the molecular layer, into which each Purkinje cell extends a dendrite, and the granular layer, through which the axon of a Purkinje cell passes into the white matter of the cerebellum. The flattened dendrite of a Purkinje cell has smooth branches of the first, second, and third orders and short branches (not more than 20 μ long) that are covered with spines. These branches come in contact with the axon endings of the granular cells of the cerebellar cortex; in a cat, for example, there are about 0.2 million synapses per dendrite. The smooth branches of a dendrite and the body of the Purkinje cell come in contact with a convoluted liana-like fiber (one per Purkinje cell) that enters the cerebellum from the inferior olivas and some other nuclei of the medulla oblongata. Both types of synapses are excitatory.

The inhibitory endings of Purkinje cells are formed by intercellular cortical neurons (basket, stellate, and Golgi cells); gamma-aminobutyric acid seems to be the mediator. The same mediator is probably secreted by the axon endings of Purkinje cells onto the neurons of the cerebellar and vestibular nuclei.

The dendrites of Purkinje cells have become progressively more complex and flattened in the course of vertebrate evolution; the total number of Purkinje cells has also increased, totaling 15–20 million in man.

D. A. SAKHAROV

References in periodicals archive ?
Administration of memantine during ethanol withdrawal in neonatal rats: Effects on long-term ethanol-induced motor incoordination and cerebellar Purkinje cell loss.
Subsequent studies found that perinatal estradiol levels influence the number of Purkinje cells and were regulated by reelin levels (Biamonte et al.
Patterned purkinje cell death in the cerebellum, Prog Neurobiol, 70(6): 473-507.
Acid-sensitive channel inhibition prevents fetal alcohol spectrum disorders cerebellar Purkinje cell loss.
The bone marrow nucleus in the fused cell also acts like a Purkinje cell nucleus, they found.
Heaton and colleagues (2000) showed that vitamin E protects against early postnatal alcohol-induced cerebellar Purkinje cell loss in lobule I, a lobule that is most sensitive to alcohol during development.
Decreases in thyroid hormone levels have been shown to alter the complex treelike branching of Purkinje cell dendrites, which is critical to normal brain development.
Purkinje cell deficits in nonhuman primates following weekly exposure to ethanol during gestation.
This is a particularly important input, explains Bloom's co-worker Steven Henrisken, because it preempts the Purkinje cell, interrupting the cell's other activities.
The change in dendrite arborization of the Purkinje cell in primary culture of newborn rat cerebellum was also examined.
Likewise, Purkinje cell degeneration in the cerebellum became more severe and extensive, and scattered degenerating neurons began to appear in the brain stem.
Alcohol-induced Purkinje cell lots depends on developmental timing of alcohol exposure and correlates with motor performance.