![]() ![]() ![]() In addition, during the off phenomenon, and as a consequence of pharmacological treatment, neuropsychiatric symptoms such as hallucinations, apathy, or anxiety may appear more frequently. It seems that this phenomenon is associated with variations in the blood levodopa level. The on-off phenomenon is a fluctuation of motor activity, and is characterized by periods in which the patient alternates activity with a state of motor difficulty and even freezing of variable duration (from a few seconds to minutes). Two types of phenomena occur: the on-off phenomenon and the wearing-off phenomenon. Dyskinesias occur as part of a phenomenon characterized by motor fluctuations when the efficacy of levodopa treatment begins to diminish throughout the day. What happens when levodopa treatment has been assimilated?ĭyskinesias: abnormal and exaggerated paradoxical movements such as tics or, again, muscle twitching (dystonia) and jerking. It acts on some dopamine receptors found in the striatum, but eventually these receptors are affected by neurodegeneration, or become hypersensitive. Levodopa does not have a permanent effect. Levodopa is the most effective treatment for the motor symptoms of Parkinson’s, although it is not without side effects. The treatment is complex because levodopa is not dopamine itself, but a precursor, since dopamine cannot cross the blood-brain barrier of the nervous system formed by the meninges – in a graphic way, it could be said that it is a “wall” that protects us from external threats. Pharmacological drugs such as levodopa are administered to treat this symptom (and others). Patients may reach “freezing” of movement in moderate and advanced stages of the disease. The duration of these dystonias can last between thirty minutes and five hours and are highly disabling, considerably reducing patients’ quality of life and increasing pain. These dystonias are associated with fluctuating dopamine levels as a consequence of the destruction of the substantia nigra. One of the symptoms of Parkinson’s disease are dystonias, sustained muscle contractions that cause forced and painful positions for patients. In addition, acetylcholine and the cholinergic system are also affected, producing effects such as tremors and postural rigidity. To this must be added the involvement of noradrenergic neuronal circuits, which are responsible for the “maintenance” functions of the rest of the body (cardiovascular system, respiratory system, wakefulness and sleep, etc.) and whose main transmitter is norepinephrine. Among others, viral, toxic (MPTP), mitochondrial or genetic factors have been proposed. The most important of these nuclei -but not the only one- is the substantia nigra: it is the first to suffer neurodegeneration as a consequence of several factors that have not yet been explained. Parkinson’s disease destroys the neuronal nuclei and circuits that are responsible for distributing and generating dopamine. ![]()
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