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 ?
In a 2012 mouse study, Sahin and colleagues knocked out a TSC gene (Tsc1) in Purkinje cells and found social deficits and repetitive behaviors in the mice, together with abnormalities in the cells.
The cortex further has three layers-molecular, Purkinje cell layer and granule cell layer.
The presence and absence of 3 splicing acceptors are correlated with ectopic expression of Doppel (Dpl) and development of late-onset ataxia induced by loss of Purkinje cells.
Multiple exposures of monkey fetuses to alcohol during specific developmental periods cause a reduced number of Purkinje cells in the cerebellum (Bonthius et al.
Finally, the Purkinje cell axons synapse on neurons in deep cerebellar and vestibular nuclei that are constantly modulated by inhibition from the Purkinje cells, which are exclusively GABAergic (Sarna and Hawkes, 2003).
7%) showed brain lesions of neuronal and Purkinje cell necrosis of cerebrum and cerebellum, respectively.
Zinc supplementation does not attenuate alcohol-induced cerebellar Purkinje cell loss during the brain growth spurt period.
In the cerebellar folia, degenerative and necrotic Purkinje cells with their associated necrotic dentritic spheroids in the molecular layer were positive for BoAstV-NeuroS1 (Figure 7).
Palkovits et al (1971) stated the Purkinje cell count in man to be 1.
Thyroid hormone induces cerebellar Purkinje cell dendritic development via the thyroid hormone receptor alpha1.
Roman (2007) hypothesized that even transient intrauterine deficits in thyroid hormones (as little as 3 days) at critical points in gestation could alter the cortical architecture, interfering with neuronal migration and Purkinje cell growth, indications of both of which have been observed in autopsy studies of autism (Fatemi et al.