{"history":[],"article":{"id":"c58d33c0-195d-4971-b8a8-44234a2e0938","title":"Purkinje cell","slug":"purkinje-cell","content":":::summary\n![Drawing of pigeon Purkinje cells (A) by Santiago Ramon y Cajal](https://upload.wikimedia.org/wikipedia/commons/1/15/PurkinjeCell.jpg)\n**Name:** Purkinje cell \n**Location:** [Cerebellum](https://bliptext.com/articles/cerebellum) \n**Function:** Inhibitory projection neuron \n**Neurotransmitter:** [GABA](https://bliptext.com/articles/gaba) \n**Morphology:** Flat dendritic arbor \n**Afferents:** [Parallel fibers](https://bliptext.com/articles/parallel-fiber) and [climbing fibers](https://bliptext.com/articles/climbing-fiber) \n**Efferents:** Cerebellar deep nuclei \n**Pronunciation:** Often pronounced as ; but Czech pronunciation is ( cells \n:::\n\n# \n**Purkinje cells** or **Purkinje [neurons](https://bliptext.com/articles/neuron)**, named for Czech physiologist [Jan Evangelista Purkyně](https://bliptext.com/articles/jan-evangelista-purkyn) who identified them in 1837, are a unique type of prominent large [neurons](https://bliptext.com/articles/neuron) located in the [cerebellar](https://bliptext.com/articles/cerebellum) [cortex](https://bliptext.com/articles/cortex-anatomy) of the [brain](https://bliptext.com/articles/brain).\nWith their flask-shaped cell bodies, many branching [dendrites](https://bliptext.com/articles/dendrite), and a single long [axon](https://bliptext.com/articles/axon), these cells are essential for controlling motor activity.\nPurkinje cells mainly release GABA ([gamma-aminobutyric acid](https://bliptext.com/articles/gamma-aminobutyric-acid)) neurotransmitter, which inhibits some neurons to reduce nerve impulse transmission.\nPurkinje cells efficiently control and coordinate the body's motor motions through these inhibitory actions.\n\n# Structure\nThese [cells](https://bliptext.com/articles/cell-biology) are some of the largest [neurons](https://bliptext.com/articles/neuron) in the human [brain](https://bliptext.com/articles/brain) (Betz [cells](https://bliptext.com/articles/cell-biology) being the largest), with an intricately elaborate [dendritic](https://bliptext.com/articles/dendrite) arbor, characterized by a large number of [dendritic](https://bliptext.com/articles/dendrite) spines.\nPurkinje cells are found within the [Purkinje layer](https://bliptext.com/articles/purkinje-layer) in the [cerebellum](https://bliptext.com/articles/cerebellum).\nPurkinje cells are aligned like [dominos](https://bliptext.com/articles/domino) stacked one in front of the other.\nTheir large dendritic arbors form nearly [two-dimensional](https://bliptext.com/articles/two-dimensional) layers through which [parallel fibers](https://bliptext.com/articles/parallel-fiber) from the deeper-layers pass.\nThese parallel fibers make relatively weaker [excitatory](https://bliptext.com/articles/excitatory-synapse) ([glutamatergic](https://bliptext.com/articles/glutamatergic)) synapses to spines in the Purkinje cell dendrite, whereas [climbing fibers](https://bliptext.com/articles/climbing-fibers) originating from the [inferior olivary nucleus](https://bliptext.com/articles/inferior-olivary-nucleus) in the [medulla](https://bliptext.com/articles/medulla-oblongata) provide very powerful [excitatory](https://bliptext.com/articles/excitatory-synapse) input to the proximal dendrites and cell soma.\nParallel fibers pass [orthogonally](https://bliptext.com/articles/orthogonal) through the Purkinje neuron's dendritic arbor, with up to 200,000 parallel fibers forming a [Granule-cell-Purkinje-cell synapse](https://bliptext.com/articles/granule-cell-purkinje-cell-synapse) with a single Purkinje cell.\nCanonically, each adult Purkinje cell receives approximately 500 climbing fiber synapses, all originating from a single climbing fiber from the inferior olive.\nThis has led to the notion that a \"highly conserved one-to-one relationship renders Purkinje dendrites into a single computational compartment\".\nHowever, multi-innervation has now been found that \"occurs\" in mice among the subset of Purkinje cells with multiple primary dendrites, a dendritic motif that is uncommon in rodents but \"predominant\" in humans.\nBoth basket and stellate cells (found in the cerebellar [molecular layer](https://bliptext.com/articles/cerebellum)) provide [inhibitory](https://bliptext.com/articles/inhibitory) (GABAergic) input to the Purkinje cell, with basket cells synapsing on the Purkinje cell axon initial segment and stellate cells onto the dendrites.\nPurkinje cells send inhibitory projections to the deep cerebellar nuclei, and constitute the sole output of all [motor coordination](https://bliptext.com/articles/motor-coordination) in the cerebellar cortex.\n# [Neurons (Purkinje cells) located in the cerebellum | upload.wikimedia.org/wikipedia/commons/2/28/Neurons///%28Purkinje///cells%29.jpg]\n# [Transverse section of a cerebellar folium (Purkinje cell labeled at center top) | upload.wikimedia.org/wikipedia/commons/7/7c/Gray706.png]\n# [Silver stain of cerebellum showing Purkinje cells | upload.wikimedia.org/wikipedia/commons/8/82/Cerebellum///silver///stain.jpg]\n# [Purkinje cells. Bielschowsky stain. | upload.wikimedia.org/wikipedia/commons/6/6c/Cerebellum///-///biel///-///very///high///mag.jpg]\n# [Confocal microscope image of cerebellar Purkinje cells expressing tdTomato | upload.wikimedia.org/wikipedia/commons/6/6e/All///that///glitters///in///the///brain.jpg]\n\n## Molecular\nThe [Purkinje layer](https://bliptext.com/articles/purkinje-layer) of the cerebellum, which contains the cell bodies of the Purkinje cells and [Bergmann glia](https://bliptext.com/articles/radial-glial-cell), express a large number of unique genes.\nPurkinje-specific gene markers were also proposed by comparing the transcriptome of Purkinje-deficient mice with that of wild-type mice.\nOne illustrative example is the Purkinje cell protein 4 ([PCP4](https://bliptext.com/articles/pcp4)) in [knockout mice](https://bliptext.com/articles/knockout-mice), which exhibit impaired locomotor learning and markedly altered [synaptic plasticity](https://bliptext.com/articles/synaptic-plasticity) in Purkinje neurons.\nPCP4 accelerates both the association and dissociation of [calcium](https://bliptext.com/articles/calcium-in-biology) (Ca2+) with [calmodulin](https://bliptext.com/articles/calmodulin) (CaM) in the cytoplasm of Purkinje cells, and its absence impairs the physiology of these neurons.\n\n## Development\nMammalian embryonic research has detailed the neurogenic origins of Purkinje cells.\nDuring early development Purkinje cells arise in the ventricular zone in the neural tube, the nervous system´s precursor in the embryo.\nAll cerebellar neurons derive from germinal neuroepithelia from the ventricular zone.\nPurkinje cells are specifically generated from progenitors in the ventricular neuroepithelium of the embryonic cerebellar primordium.\nThe first cells generated from the cerebellar primordium form a cap over a diamond-shaped cavity of the developing brain called the fourth ventricle forming the two cerebellar hemispheres.\nThe Purkinje cells that develop later are those of the cerebellum's center-lying section called the vermis.\nThey develop in the cerebellar primordium that covers the fourth ventricle and below a fissure-like region called the isthmus of the developing brain.\nPurkinje cells migrate toward the outer surface of the cerebellar cortex and form the Purkinje cell layer.\nPurkinje cells are born during the earliest stages of cerebellar neurogenesis.\nNeurogenin2, together with neurogenin1, are transiently expressed in restricted domains of the ventricular neuroepithelium during the time-window of Purkinje cell genesis.\nThis spatio-temporal distribution pattern suggests that neurogenins are involved in the specification of phenotypically heterogeneous Purkinje cell subsets, ultimately responsible for constructing the framework of the cerebellar topography.\nThere is evidence in mice and humans that [bone marrow](https://bliptext.com/articles/bone-marrow) cells either fuse with or generate cerebellar Purkinje cells, and it is possible that [bone marrow](https://bliptext.com/articles/bone-marrow) cells, either by direct generation or by cell fusion, could play a role in repair of central nervous system damage.\nFurther evidence points yet towards the possibility of a common [stem cell](https://bliptext.com/articles/stem-cell) ancestor among Purkinje neurons, [B-lymphocytes](https://bliptext.com/articles/b-cell) and [aldosterone](https://bliptext.com/articles/aldosterone)-producing [cells](https://bliptext.com/articles/zona-glomerulosa) of the human [adrenal cortex](https://bliptext.com/articles/adrenal-cortex).\n\n# Function\nPurkinje cells show two distinct forms of electrophysiological activity:\nPurkinje cells show spontaneous electrophysiological activity in the form of trains of spikes both sodium-dependent and calcium-dependent.\nThis was initially shown by [Rodolfo Llinas](https://bliptext.com/articles/rodolfo-llinas) (Llinas and Hess (1977) and Llinas and Sugimori (1980)).\nP-type calcium channels were named after Purkinje cells, where they were initially encountered (Llinas et al. 1989), which are crucial in cerebellar function.\nActivation of the Purkinje cell by climbing fibers can shift its activity from a quiet state to a spontaneously active state and vice versa, serving as a kind of toggle switch.\nThese findings have been challenged by a study suggesting that such toggling by climbing-fiber inputs occurs predominantly in anaesthetized animals and that Purkinje cells in awake behaving animals, in general, operate almost continuously in the upstate.\nBut this latter study has itself been challenged and Purkinje cell toggling has since been observed in awake cats.\nA computational model of the Purkinje cell has shown intracellular calcium computations to be responsible for toggling.\nFindings have suggested that Purkinje cell dendrites release [endocannabinoids](https://bliptext.com/articles/endocannabinoid) that can transiently downregulate both excitatory and inhibitory synapses.\nThe intrinsic activity mode of Purkinje cells is set and controlled by the [sodium-potassium pump](https://bliptext.com/articles/sodium-potassium-pump).\nThis suggests that the pump might not be simply a [homeostatic](https://bliptext.com/articles/homeostatic), \"housekeeping\" molecule for ionic gradients.\nInstead, it could be a [computation](https://bliptext.com/articles/computation) element in the cerebellum and the brain.\nIndeed, a [mutation](https://bliptext.com/articles/mutation) in the - pump causes rapid onset dystonia parkinsonism; its symptoms indicate that it is a pathology of cerebellar computation.\nFurthermore, using the poison [ouabain](https://bliptext.com/articles/ouabain) to block - pumps in the cerebellum of a live mouse induces [ataxia](https://bliptext.com/articles/ataxia) and [dystonia](https://bliptext.com/articles/dystonia).\nNumerical modeling of experimental data suggests that, in vivo, the - pump produces long quiescent punctuations (>> 1 s) to Purkinje neuron firing; these may have a computational role.\n[Alcohol](https://bliptext.com/articles/alcohol-chemistry) inhibits - pumps in the cerebellum and this is likely how it corrupts cerebellar computation and body co-ordination.\n# [The Purkinje cell protein 4 (PCP4) is markedly immunoreactive in the Purkinje cells of the human cerebellum. From top to bottom 40X, 100X and 200X microscopic magnifications. The immunohistochemistry was performed based on published methods. | upload.wikimedia.org/wikipedia/commons/8/8b/PCP4///immunohistochemistry///in///human///cerebellum.jpg]\n# [Microcircuitry of the cerebellum. Excitatory synapses are denoted by (+) and inhibitory synapses by (-).
MF: Mossy fiber.
DCN: Deep cerebellar nuclei.
IO: Inferior olive.
CF: Climbing fiber.
GC: Granule cell.
PF: Parallel fiber.
PC: Purkinje cell.
GgC: Golgi cell.
SC: Stellate cell.
BC: Basket cell. | upload.wikimedia.org/wikipedia/commons/9/94/Diagram///of///the///Microanatomy///of///Human///Cerebellar///Cortex.svg]\n\n# Clinical significance\nIn humans, Purkinje cells can be harmed by a variety of causes: toxic exposure, e.g. to alcohol or lithium; [autoimmune diseases](https://bliptext.com/articles/autoimmune-disease); genetic mutations causing spinocerebellar ataxias, [gluten ataxia](https://bliptext.com/articles/ataxia), [Unverricht-Lundborg disease](https://bliptext.com/articles/unverricht-lundborg-disease), or [autism](https://bliptext.com/articles/autism); and neurodegenerative diseases that are not known to have a genetic basis, such as the cerebellar type of multiple system atrophy or sporadic ataxias.\nGluten ataxia is an autoimmune disease triggered by the ingestion of [gluten](https://bliptext.com/articles/gluten).\nThe death of Purkinje cells as a result of gluten exposure is irreversible.\nEarly diagnosis and treatment with a [gluten-free diet](https://bliptext.com/articles/gluten-free-diet) can improve ataxia and prevent its progression.\nLess than 10% of people with gluten ataxia present any gastrointestinal symptom, yet about 40% have intestinal damage.\nIt accounts for 40% of ataxias of unknown origin and 15% of all ataxias.\nThe [neurodegenerative disease](https://bliptext.com/articles/neurodegeneration) [spinocerebellar ataxia type 1](https://bliptext.com/articles/spinocerebellar-ataxia-type-1) (SCA1) is caused by an unstable [polyglutamine expansion](https://bliptext.com/articles/polyglutamine-tract) within the [Ataxin 1](https://bliptext.com/articles/ataxin-1) protein.\nThis defect in Ataxin 1 protein causes impairment of [mitochondria](https://bliptext.com/articles/mitochondrion) in Purkinje cells, leading to premature degeneration of the Purkinje cells.\nAs a consequence, [motor coordination](https://bliptext.com/articles/motor-coordination) declines and eventually death ensues.\nSome domestic animals can develop a condition where the Purkinje cells begin to atrophy shortly after birth, called [cerebellar abiotrophy](https://bliptext.com/articles/cerebellar-abiotrophy).\nIt can lead to symptoms such as [ataxia](https://bliptext.com/articles/ataxia), intention tremors, hyperreactivity, lack of [menace reflex](https://bliptext.com/articles/menace-reflex), stiff or high-stepping gait, apparent lack of awareness of foot position (sometimes standing or walking with a foot knuckled over), and a general inability to determine space and distance.\nA similar condition known as [cerebellar hypoplasia](https://bliptext.com/articles/cerebellar-hypoplasia) occurs when Purkinje cells fail to develop in utero or die off before birth.\nThe genetic conditions [ataxia telangiectasia](https://bliptext.com/articles/ataxia-telangiectasia) and [Niemann Pick disease](https://bliptext.com/articles/niemann-pick-disease) type C, as well as cerebellar [essential tremor](https://bliptext.com/articles/essential-tremor), involve the progressive loss of Purkinje cells.\nIn Alzheimer's disease, spinal pathology is sometimes seen, as well as loss of dendritic branches of the Purkinje cells.\nPurkinje cells can also be damaged by the [rabies](https://bliptext.com/articles/rabies) virus as it migrates from the site of infection in the periphery to the central nervous system.\n\n# Etymology\nPurkinje cells are named after the Czech scientist Jan Evangelista Purkyně, who discovered them in 1839.","current_revision":null,"created_by":"kACnuQmH5k9Nr5VNVEpVeg7XpvUmMctD","created_at":"2025-01-25T22:00:09.887Z","updated_at":"2025-01-25T22:00:09.887Z","search_vector":"'cell':2 'purkinj':1","search_content":" \n \n**Name:** Purkinje cell \n**Location:** [Cerebellum](https://bliptext.com/articles/cerebellum) \n**Function:** Inhibitory projection neuron \n**Neurotransmitter:** [GABA](https://bliptext.com/articles/gaba) \n**Morphology:** Flat dendritic arbor \n**Afferents:** [Parallel fibers](https://bliptext.com/articles/parallel-fiber) and [climbing fibers](https://bliptext.com/articles/climbing-fiber) \n**Efferents:** Cerebellar deep nuclei \n**Pronunciation:** Often pronounced as ; but Czech pronunciation is ( cells \n \n\n# \n**Purkinje cells** or **Purkinje [neurons](https://bliptext.com/articles/neuron)**, named for Czech physiologist [Jan Evangelista Purkyně](https://bliptext.com/articles/jan-evangelista-purkyn) who identified them in 1837, are a unique type of prominent large [neurons](https://bliptext.com/articles/neuron) located in the [cerebellar](https://bliptext.com/articles/cerebellum) [cortex](https://bliptext.com/articles/cortex-anatomy) of the [brain](https://bliptext.com/articles/brain).\nWith their flask-shaped cell bodies, many branching [dendrites](https://bliptext.com/articles/dendrite), and a single long [axon](https://bliptext.com/articles/axon), these cells are essential for controlling motor activity.\nPurkinje cells mainly release GABA ([gamma-aminobutyric acid](https://bliptext.com/articles/gamma-aminobutyric-acid)) neurotransmitter, which inhibits some neurons to reduce nerve impulse transmission.\nPurkinje cells efficiently control and coordinate the body's motor motions through these inhibitory actions.\n\n# Structure\nThese [cells](https://bliptext.com/articles/cell-biology) are some of the largest [neurons](https://bliptext.com/articles/neuron) in the human [brain](https://bliptext.com/articles/brain) (Betz [cells](https://bliptext.com/articles/cell-biology) being the largest), with an intricately elaborate [dendritic](https://bliptext.com/articles/dendrite) arbor, characterized by a large number of [dendritic](https://bliptext.com/articles/dendrite) spines.\nPurkinje cells are found within the [Purkinje layer](https://bliptext.com/articles/purkinje-layer) in the [cerebellum](https://bliptext.com/articles/cerebellum).\nPurkinje cells are aligned like [dominos](https://bliptext.com/articles/domino) stacked one in front of the other.\nTheir large dendritic arbors form nearly [two-dimensional](https://bliptext.com/articles/two-dimensional) layers through which [parallel fibers](https://bliptext.com/articles/parallel-fiber) from the deeper-layers pass.\nThese parallel fibers make relatively weaker [excitatory](https://bliptext.com/articles/excitatory-synapse) ([glutamatergic](https://bliptext.com/articles/glutamatergic)) synapses to spines in the Purkinje cell dendrite, whereas [climbing fibers](https://bliptext.com/articles/climbing-fibers) originating from the [inferior olivary nucleus](https://bliptext.com/articles/inferior-olivary-nucleus) in the [medulla](https://bliptext.com/articles/medulla-oblongata) provide very powerful [excitatory](https://bliptext.com/articles/excitatory-synapse) input to the proximal dendrites and cell soma.\nParallel fibers pass [orthogonally](https://bliptext.com/articles/orthogonal) through the Purkinje neuron's dendritic arbor, with up to 200,000 parallel fibers forming a [Granule-cell-Purkinje-cell synapse](https://bliptext.com/articles/granule-cell-purkinje-cell-synapse) with a single Purkinje cell.\nCanonically, each adult Purkinje cell receives approximately 500 climbing fiber synapses, all originating from a single climbing fiber from the inferior olive.\nThis has led to the notion that a \"highly conserved one-to-one relationship renders Purkinje dendrites into a single computational compartment\".\nHowever, multi-innervation has now been found that \"occurs\" in mice among the subset of Purkinje cells with multiple primary dendrites, a dendritic motif that is uncommon in rodents but \"predominant\" in humans.\nBoth basket and stellate cells (found in the cerebellar [molecular layer](https://bliptext.com/articles/cerebellum)) provide [inhibitory](https://bliptext.com/articles/inhibitory) (GABAergic) input to the Purkinje cell, with basket cells synapsing on the Purkinje cell axon initial segment and stellate cells onto the dendrites.\nPurkinje cells send inhibitory projections to the deep cerebellar nuclei, and constitute the sole output of all [motor coordination](https://bliptext.com/articles/motor-coordination) in the cerebellar cortex.\n# [Neurons (Purkinje cells) located in the cerebellum | upload.wikimedia.org/wikipedia/commons/2/28/Neurons///%28Purkinje///cells%29.jpg]\n# [Transverse section of a cerebellar folium (Purkinje cell labeled at center top) | upload.wikimedia.org/wikipedia/commons/7/7c/Gray706.png]\n# [Silver stain of cerebellum showing Purkinje cells | upload.wikimedia.org/wikipedia/commons/8/82/Cerebellum///silver///stain.jpg]\n# [Purkinje cells. Bielschowsky stain. | upload.wikimedia.org/wikipedia/commons/6/6c/Cerebellum///-///biel///-///very///high///mag.jpg]\n# [Confocal microscope image of cerebellar Purkinje cells expressing tdTomato | upload.wikimedia.org/wikipedia/commons/6/6e/All///that///glitters///in///the///brain.jpg]\n\n## Molecular\nThe [Purkinje layer](https://bliptext.com/articles/purkinje-layer) of the cerebellum, which contains the cell bodies of the Purkinje cells and [Bergmann glia](https://bliptext.com/articles/radial-glial-cell), express a large number of unique genes.\nPurkinje-specific gene markers were also proposed by comparing the transcriptome of Purkinje-deficient mice with that of wild-type mice.\nOne illustrative example is the Purkinje cell protein 4 ([PCP4](https://bliptext.com/articles/pcp4)) in [knockout mice](https://bliptext.com/articles/knockout-mice), which exhibit impaired locomotor learning and markedly altered [synaptic plasticity](https://bliptext.com/articles/synaptic-plasticity) in Purkinje neurons.\nPCP4 accelerates both the association and dissociation of [calcium](https://bliptext.com/articles/calcium-in-biology) (Ca2+) with [calmodulin](https://bliptext.com/articles/calmodulin) (CaM) in the cytoplasm of Purkinje cells, and its absence impairs the physiology of these neurons.\n\n## Development\nMammalian embryonic research has detailed the neurogenic origins of Purkinje cells.\nDuring early development Purkinje cells arise in the ventricular zone in the neural tube, the nervous system´s precursor in the embryo.\nAll cerebellar neurons derive from germinal neuroepithelia from the ventricular zone.\nPurkinje cells are specifically generated from progenitors in the ventricular neuroepithelium of the embryonic cerebellar primordium.\nThe first cells generated from the cerebellar primordium form a cap over a diamond-shaped cavity of the developing brain called the fourth ventricle forming the two cerebellar hemispheres.\nThe Purkinje cells that develop later are those of the cerebellum's center-lying section called the vermis.\nThey develop in the cerebellar primordium that covers the fourth ventricle and below a fissure-like region called the isthmus of the developing brain.\nPurkinje cells migrate toward the outer surface of the cerebellar cortex and form the Purkinje cell layer.\nPurkinje cells are born during the earliest stages of cerebellar neurogenesis.\nNeurogenin2, together with neurogenin1, are transiently expressed in restricted domains of the ventricular neuroepithelium during the time-window of Purkinje cell genesis.\nThis spatio-temporal distribution pattern suggests that neurogenins are involved in the specification of phenotypically heterogeneous Purkinje cell subsets, ultimately responsible for constructing the framework of the cerebellar topography.\nThere is evidence in mice and humans that [bone marrow](https://bliptext.com/articles/bone-marrow) cells either fuse with or generate cerebellar Purkinje cells, and it is possible that [bone marrow](https://bliptext.com/articles/bone-marrow) cells, either by direct generation or by cell fusion, could play a role in repair of central nervous system damage.\nFurther evidence points yet towards the possibility of a common [stem cell](https://bliptext.com/articles/stem-cell) ancestor among Purkinje neurons, [B-lymphocytes](https://bliptext.com/articles/b-cell) and [aldosterone](https://bliptext.com/articles/aldosterone)-producing [cells](https://bliptext.com/articles/zona-glomerulosa) of the human [adrenal cortex](https://bliptext.com/articles/adrenal-cortex).\n\n# Function\nPurkinje cells show two distinct forms of electrophysiological activity:\nPurkinje cells show spontaneous electrophysiological activity in the form of trains of spikes both sodium-dependent and calcium-dependent.\nThis was initially shown by [Rodolfo Llinas](https://bliptext.com/articles/rodolfo-llinas) (Llinas and Hess (1977) and Llinas and Sugimori (1980)).\nP-type calcium channels were named after Purkinje cells, where they were initially encountered (Llinas et al. 1989), which are crucial in cerebellar function.\nActivation of the Purkinje cell by climbing fibers can shift its activity from a quiet state to a spontaneously active state and vice versa, serving as a kind of toggle switch.\nThese findings have been challenged by a study suggesting that such toggling by climbing-fiber inputs occurs predominantly in anaesthetized animals and that Purkinje cells in awake behaving animals, in general, operate almost continuously in the upstate.\nBut this latter study has itself been challenged and Purkinje cell toggling has since been observed in awake cats.\nA computational model of the Purkinje cell has shown intracellular calcium computations to be responsible for toggling.\nFindings have suggested that Purkinje cell dendrites release [endocannabinoids](https://bliptext.com/articles/endocannabinoid) that can transiently downregulate both excitatory and inhibitory synapses.\nThe intrinsic activity mode of Purkinje cells is set and controlled by the [sodium-potassium pump](https://bliptext.com/articles/sodium-potassium-pump).\nThis suggests that the pump might not be simply a [homeostatic](https://bliptext.com/articles/homeostatic), \"housekeeping\" molecule for ionic gradients.\nInstead, it could be a [computation](https://bliptext.com/articles/computation) element in the cerebellum and the brain.\nIndeed, a [mutation](https://bliptext.com/articles/mutation) in the - pump causes rapid onset dystonia parkinsonism; its symptoms indicate that it is a pathology of cerebellar computation.\nFurthermore, using the poison [ouabain](https://bliptext.com/articles/ouabain) to block - pumps in the cerebellum of a live mouse induces [ataxia](https://bliptext.com/articles/ataxia) and [dystonia](https://bliptext.com/articles/dystonia).\nNumerical modeling of experimental data suggests that, in vivo, the - pump produces long quiescent punctuations (>> 1 s) to Purkinje neuron firing; these may have a computational role.\n[Alcohol](https://bliptext.com/articles/alcohol-chemistry) inhibits - pumps in the cerebellum and this is likely how it corrupts cerebellar computation and body co-ordination.\n# [The Purkinje cell protein 4 (PCP4) is markedly immunoreactive in the Purkinje cells of the human cerebellum. From top to bottom 40X, 100X and 200X microscopic magnifications. The immunohistochemistry was performed based on published methods. | upload.wikimedia.org/wikipedia/commons/8/8b/PCP4///immunohistochemistry///in///human///cerebellum.jpg]\n# [Microcircuitry of the cerebellum. Excitatory synapses are denoted by (+) and inhibitory synapses by (-). MF: Mossy fiber. DCN: Deep cerebellar nuclei. IO: Inferior olive. CF: Climbing fiber. GC: Granule cell. PF: Parallel fiber. PC: Purkinje cell. GgC: Golgi cell. SC: Stellate cell. BC: Basket cell. | upload.wikimedia.org/wikipedia/commons/9/94/Diagram///of///the///Microanatomy///of///Human///Cerebellar///Cortex.svg]\n\n# Clinical significance\nIn humans, Purkinje cells can be harmed by a variety of causes: toxic exposure, e.g. to alcohol or lithium; [autoimmune diseases](https://bliptext.com/articles/autoimmune-disease); genetic mutations causing spinocerebellar ataxias, [gluten ataxia](https://bliptext.com/articles/ataxia), [Unverricht-Lundborg disease](https://bliptext.com/articles/unverricht-lundborg-disease), or [autism](https://bliptext.com/articles/autism); and neurodegenerative diseases that are not known to have a genetic basis, such as the cerebellar type of multiple system atrophy or sporadic ataxias.\nGluten ataxia is an autoimmune disease triggered by the ingestion of [gluten](https://bliptext.com/articles/gluten).\nThe death of Purkinje cells as a result of gluten exposure is irreversible.\nEarly diagnosis and treatment with a [gluten-free diet](https://bliptext.com/articles/gluten-free-diet) can improve ataxia and prevent its progression.\nLess than 10% of people with gluten ataxia present any gastrointestinal symptom, yet about 40% have intestinal damage.\nIt accounts for 40% of ataxias of unknown origin and 15% of all ataxias.\nThe [neurodegenerative disease](https://bliptext.com/articles/neurodegeneration) [spinocerebellar ataxia type 1](https://bliptext.com/articles/spinocerebellar-ataxia-type-1) (SCA1) is caused by an unstable [polyglutamine expansion](https://bliptext.com/articles/polyglutamine-tract) within the [Ataxin 1](https://bliptext.com/articles/ataxin-1) protein.\nThis defect in Ataxin 1 protein causes impairment of [mitochondria](https://bliptext.com/articles/mitochondrion) in Purkinje cells, leading to premature degeneration of the Purkinje cells.\nAs a consequence, [motor coordination](https://bliptext.com/articles/motor-coordination) declines and eventually death ensues.\nSome domestic animals can develop a condition where the Purkinje cells begin to atrophy shortly after birth, called [cerebellar abiotrophy](https://bliptext.com/articles/cerebellar-abiotrophy).\nIt can lead to symptoms such as [ataxia](https://bliptext.com/articles/ataxia), intention tremors, hyperreactivity, lack of [menace reflex](https://bliptext.com/articles/menace-reflex), stiff or high-stepping gait, apparent lack of awareness of foot position (sometimes standing or walking with a foot knuckled over), and a general inability to determine space and distance.\nA similar condition known as [cerebellar hypoplasia](https://bliptext.com/articles/cerebellar-hypoplasia) occurs when Purkinje cells fail to develop in utero or die off before birth.\nThe genetic conditions [ataxia telangiectasia](https://bliptext.com/articles/ataxia-telangiectasia) and [Niemann Pick disease](https://bliptext.com/articles/niemann-pick-disease) type C, as well as cerebellar [essential tremor](https://bliptext.com/articles/essential-tremor), involve the progressive loss of Purkinje cells.\nIn Alzheimer's disease, spinal pathology is sometimes seen, as well as loss of dendritic branches of the Purkinje cells.\nPurkinje cells can also be damaged by the [rabies](https://bliptext.com/articles/rabies) virus as it migrates from the site of infection in the periphery to the central nervous system.\n\n# Etymology\nPurkinje cells are named after the Czech scientist Jan Evangelista Purkyně, who discovered them in 1839.","revisionCount":0},"hasMore":false,"nextCursor":null}

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