When neuroscientists talk about dendrites, the parts of neurons commonly used to receive information from other neurons, they think of Purinier cells.
They form an extensive specialized network that interacts with the minutes of the ventricles to initiate ventricular contraction.
Computational studies show that cellular sources of arrhythmias, such as early post-polarization, may be due to their unique electrophysiological characteristics.
General information
Purkinje cells, also known as Purkinje neurons, are located in the cerebral cortex. They were the first to be identified neuronal cells. Jan Evangelista Purkinje, who worked at the University of Breslau in Prussia (today the University of Wroclaw, Poland), discovered the cells in the middle of the 19th century. In 1932, the scientist became the owner of an achromatic microscope that simultaneously focuses two colors. Thanks to the microscope, the anatomist began to study sheep cells. He described the structures later named after him in an article on histology “Recent Research anatomy of nerves and brain ", presented in September 1837 in Prague, Bohemia (territory of modern Czech Republic).
In the late 19th century, Camillo Golgi of the University of Pavia in Lombardy, Italy, studied cells by staining them with silver nitrate. Silver nitrate stains helped the scientist describe the cell body with its processes. Santiago Ramon y Cajal of the University of Barcelona in Barcelona, Spain, has perfected Golgi technology and found that the cells have dendritic processes, similar to small ball-shaped doorknobs on dendrites. Golgi and Ramon y Cajal jointly won the Nobel Prize in Medicine in 1906 for their research on structure nervous system.
Structure
The cell body is pear-shaped with many filamentous processes (dendrites) that receive impulses from other small cells known as granular cells. Their axons (output elements) transmit impulses to the part of the brain that controls movement (cerebellum). The body of formation is 8 microns in diameter. Cells have a large, branched, two-dimensional (flat) tree-like structure.
Functions
Purkinje cells are inhibitory neurons: they release neurotransmitters that bind to receptors and decrease the activation of other neurons. They:
- participate in the process of motor control and learning;
- the only ones receive signals from the cerebellar cortex (its outer layer), and also receive information from hundreds of others thousands of body cells, suppress the excitatory neurons of the spinal cord and other areas from which they receive information;
- regulate the activation of excitatory neurons through interaction with dendrites;
- secrete gamma-aminobutyric acid (neurotransmitter), which inhibits neurons from transmitted impulses. Their exit is carried out through axons carrying electrical impulses.
- inhibit output centers, deep nuclei and vestibular nuclear neurons in the cerebellum, coordinate the response time to an electrical signal (action potential) on the axons of neuronal nuclei. These, in turn, regulate the output signals of the cerebellum.
- through synchronized signals, control the rate at which signals reach the cerebellum to obtain accurate exit from the nuclei neurons, facilitating coordination of movements, such as arm movements, reaching the highest development by the age of eight person.
This is why young children look awkward and awkward. Research in mammals has shown that cells synthesize the hormones progesterone and estradiol during the formation of cerebellar chains during embryonic development. Progesterone and estradiol contribute to the growth of dendrites, the development synapses (synaptogenesis) and the development of dendritic processes in the developing cell.
Investigation of embryos from mice and chicks demonstrates that by producing proteins called the sonic hedgehog, these cells are essential for the growth and patterning of the cerebellum. They are susceptible to both genetic and environmental influences that can disrupt their regular functions. Embryonic studies of the C65Dn mouse strain (genetic model of Down syndrome) showed cell degeneration. Exposure to alcohol on the fetus during embryonic growth can destroy them and lead to fetal alcohol syndrome (a deviation that affects children whose mothers took alcohol). People with autism syndrome (a disorder that results from a developmental disorder of the brain) have fewer Purkinje cells than healthy people. People with fewer cells are more prone to Niemann-Pick disease (type C), a rare inherited lysosomal storage disease.
