Siegel’s team on narcoleptic dogs showed that an unusual activity of the medulla oblongata was responsible for the cataplexy, while the University of Lyon demonstrated that damage in the upper regions of the brainstem that connect to the medulla oblongata affects the disease, as does another area of the brainstem called the locus coeruleus, whose cells become inactive before and during cataplexy and sleep.Īccording to these studies, there are two concomitant causes for the development of the disease: the lack of excitation of motor neurons caused by the suspension of noradrenal cells and the activation, instead, of the parallel system in the medulla that inhibits motor neurons.Īt the same time, at Stanford University, Emmanuel Mignot’s research staff discovered that suffering dogs would be victims of a genetic mutation of the neurotransmitter orexin.Ī third hypothesis was proposed by researchers at the Seiwa Hospital in Tokyo, who verified the link between cataplexy and certain as yet unknown environmental factors that trigger an autoimmune reaction, capable of damaging the neurons that regulate awakening and muscle tone. The causes of this disorder are unknown, although it is thought to be caused by a dysfunction of the sleep-wake functions: in fact, when this disorder occurs, the body feels as if it is sleeping while the mind is in a waking state.Ĭlinical experiments carried out in the 1990s by Jerome M. In the most severe cases, fortunately rare, severe bradycardia (slowing of the heart rate) combined with bradypnoea (slowing of the respiratory rate) and arterial hypotension (lowering of the blood pressure) may occur during the attack, so much so that to the untrained eye the subject may even appear to be dead. Generally, the patient finds himself as if paralysed and risks falling if he is standing at the time.Ĭataplexy can last from a few seconds to about thirty minutes, during which time the patient remains fully conscious of what is happening. These disturbances are sudden, unpredictable and not anticipated by any premonitory signs and can therefore be dangerous if they occur while driving a motor vehicle or when performing dangerous work.
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