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 ?
To make the cells, the researchers first created induced pluripotent stem cells from patients' blood cells or skin cells, then differentiated these into neural progenitor cells and finally Purkinje cells.
The rationale of the present study was to identify the histomorphological changes induced by mobile phones electromagnetic fields on Purkinje cell layer of cerebellum.
Clawson, "Uptake of systemically administered human anticerebellar antibody by rat Purkinje cells following blood-brain barrier disruption," Acta Neuropathologica, vol.
The transition from normal to abnormal cortex is gradual and accompanied by disappearance of purkinje cells and core of the central white matter in the axis of cerebellar folia.
Studies have found that binge ethanol exposure in all three trimesters leads to deficits in fetal cerebellar Purkinje cells (Ramadoss et al.
There was a larger decrease in the Purkinje cell number at days 17 and 25; this concurs with previous results in cerebral cortex, where a significant decrease in the neuronal density was observed at day 25 in mice exposed to a 1/5 [DL.sub.50] of cypermethrin (Jimenez et al., 2008).
In the NE rats the mean volume of Purkinje cell soma was 15% smaller than those of the control rats (table 2).
Sugimori, "Electrophysiological properties of in vitro Purkinje cell dendrites in mammalian cerebellar slices," The Journal of Physiology, vol.
Rudy, "A model of canine purkinje cell electrophysiology and [Ca.sup.2+] cycling: rate dependence, triggered activity, and comparison to ventricular myocytes," Circulation Research, vol.
In healthy cerebellar Purkinje cells, increases in the expression levels of the Na/K pump during postnatal development are associated with the gradual hyperpolarization of the Purkinje cell membrane potential [2, 3].
Only 20% showed nervous signs and brain lesions of neuronal and Purkinje cell necrosis of cerebrum and cerebellum, respectively.