By: Maimoona Afzal, Khizar Ali and Rafia Saleem
Neurodegenerative or degenerative nerve diseases are the continuous deprival of structure and function of neurons evenly it includes the conditions in which neurons are completely loss. It mainly affects the neurons which are present in human brain. Neurons are the monomers of nervous system which consist of brain and spinal cord. These diseases are caused by the malfunctioning of the motor neurons of the nervous system. These types of malfunctions are occurred due to the presence or absence of hormones which are released within a brain when neural cell deterioration is occurred. Neurodegenerative diseases include the Parkinson’s disease and Parkinson’s disease related disorders, like Alzheimer’s disease and Huntington’s disease. Then, the biological troubles are arising between the cellular associations within the brain and cure of such type of conditions, demonstrate that how the brain control the movement and behavior.
Brain is the vital organ of our body. The brain is the communication headquarters of our body. It means it deals with all the communication processes of our body. It obtains diverse information from the different parts of sensory system and processes this information in a proper form. Such type of messages which comes from brain prescribes specific behavioral and muscular patterns. This neural system is extremely relay on a cause and effect system where the slightest offset to the organized way of cellular communication results in main behavioral abnormalities. Additionally, there are two certain areas which are present in the brain that are especially about the motor dysfunctions: One is the substania nigra and the other one is striatum. Both the cells of substania nigra and striatum cells serve as the regulator of motor functions such as walking, planning, control and execution of voluntary movement. The information release from the nigra cells move through the synapses with the help of a specific hormone such as dopamine, which is an important chemical neurotransmitter. The presence of dopamine is essential for the function of a substania nigra, it is also play an important role for several muscular movements controlled by the striatum.
Neurodegenerative diseases such as Parkinson’s disease and Huntington’s disease demonstrate two different behavioral patterns that are consequently caused by two reverse and highly extreme biological abnormalities, where the neural contact of substania nigra and striatum is inhibited. Parkinson’s disease caused due to the depletion in the quantity of dopamine that is produced from the brain. At the beginning of the disease, dopamine-secreting cells are experienced cell death either due to some genetic factors and environmental toxins. Thus, the substania nigra cells are not capable to form synapses through which nigra cells secrete dopamine and relay dopamine on the striatum in the neural circuit within the ganglia that is present in the base called basal ganglia. The striatum is also a coordinator part for chemical messengers. It receives the dopaminergic inputs from several different sources and it serves as a primary input for the remaining basal ganglia system. When the level of the dopamine is reduced, then the striatum undergoes a chemical imbalance. While, the basal ganglia play a major inhibitory role on the motor neurons of the spinal cord, the disabilities of the striatum is due to the dopamine level is reduced cause inhibit the movement of muscles. Therefore, as a result of microscopic malfunctions, macroscopic disabilities arise. For example, the symptoms related to the Parkinson’s disease are firmness, no muscular movement, reduction of balance and other physical disorders which also goes towards the certain psychological conditions such as stress and depression.
Huntington’s disease also has a condition like Parkinson’s disease due to the death of basal ganglia in brain. This disease is caused due to the abnormal gene that code for changed protein known as huntingtin. Huntingtin interfere with proteins which are only present in brain. Huntington’s disease can also explain the reverse condition like Parkinson’s disease involves both biologically and behaviorally. This disease results in the hyper-inhibitory response of the striatum and it is due to the loss of striatum inhibitory cells. A hormone called Gamma-amino butyric acid (GABA) produced by striatum that controls the level of dopamine in brain by an inhibitory process. GABA is also a neurotransmitter that inhibits the activity of nerve cells. In Huntington’s disease, due to the loss of the GABA-producing cells, the production of dopamine is increased. So, the inhibitory control on the motor neurons of body is destabilized and the signs of the Huntington’s disease become apparent. These signs or symptoms involve random movement of muscles, dementia and lack of several psychological functions.
Fetal Neural Transplantation:
Fetal neural transplantation is one of the possible and current treatments for both diseases that are Parkinson’s disease and Huntington’s disease. This surgical treatment is very complicated as the disease. This treatment acquire precursor of basal ganglia cells from fetuses, which are several weeks old cells and then put these cells into the nucleus of caudate and putamen of patients. Putamen is the divisions which are present in striatum. The concept behind this fetal neural transplantation is to permit fetal neurons to substitute the lost striatum cells by the formation of new synapses with already present recipient cells that are used for the formation of new neurotransmitters. There is obvious but gradual improvements in those patients whose having this neural transplantation, the fetal cells require a lot of time to develop, differentiate and form associations with the host neurons which are present in the surrounding, specifically dopamine receiving cells. Therefore, took dopamine producing cells from fetuses and then put into the liquid suspension and then inject into the striatum of a patients of a Huntington disease and Parkinson’s disease has been proved to a most favorable surgical process for the relief of the neurodegenerative diseases.
Fetal neural transplantation is a common theory which is developed regarding the structure and intricacies of the brain, by the reflections of all the information and observations which is discussed above. If the any cellular and chemical dysfunctions occur within the brain then as a result directly behavioral problems occur. The common concept is that there is any physical association between the neurons which are present in the brain and having a physical association from the brain to the other parts of the nervous system that is important for the behavioral patterns. One thing can also seen in this theory is that it demonstrates the brain as a box which is composed of a various smaller boxes which are interconnected each other. For example, in Parkinson’s disease, when the box that is substania nigra fails to attain direct contact with a box that is striatum with the aid of the axon associations then the output comes from the striatum is highly effected.