Atonía muscular en sueño REM: acciones mediadas por receptores GABAA y GABAB en el peRilocus coeruleus -alfa* / Rem sleep muscular anatonia: actions mediated by Gabaa and Gabab receptors in the perilocus coeruleus alpha

Experimentos con lesiones y registro de unidades han demostrado la importancia del tegmento pontino, concretamente la región del peri-locus coeruleus alfa (pLCa), en la generación de atonía durante el sueño REM. En el pLCa hay terminales y neuronas GABAérgicos. Hemos estudiado si existen a nivel del pLCa influencias GABAérgicas en la atonía muscular del sueño REM, así como el subtipo de receptores (GABAA y/o GABAB) implicados en este efecto. Se implantaron seis gatos con electrodos para registro crónico de sueño y una cánula dirigida estereotáxicamente al pLCa. A intervalos semanales, se microinyectaron en el pLCa 20 nl de Muscimol 50, 100 y 250 mM (agonista de los receptores GABAA) y de Baclofen 34, 77 and 154 mM (agonista de receptores GABAB). La estimulación GABAérgica del pLCa produjo cambios llamativos en la supresión del tono muscular durante el sueño REM. El Muscimol determinó que no se presentara la atonía característica, ya que hubo tono muscular durante todos los episodios de sueño REM. Tras las microinyecciones de Baclofen en el pLCa, los episodios de sueño REM comenzaron con atonía, pero a medida que progresaba el episodio aparecieron fragmentos intermitentes con tono muscular. Estos resultados indican que la neurotransmisión GABAérgica en el pLCa tiene una acción moduladora sobre los mecanismos de atonía del sueño REM. La supresión de la acción inhibitoria del GABA en el pLCa (a través de receptores GABAA y GABAB ) es necesaria para la aparición de atonía durante el sueño REM (AU)

[Behavior disorders during REM sleep. Two clinical cases]. / Trastorno de conducta durante el sueño MOR. Dos casos clínicos.

INTRODUCTION: The behavior disorder occurring during REM (Rapid Eye Movement) sleep is a parasomnia characterized by absence of atonia typical of this phase of sleep, although the other characteristics are maintained, namely rapid eye movements and desynchronization of cortical electrical activity. Clinically it is accompanied by abrupt, often violent movements, which may involve a limb or the trunk in relation to dreams typical of this phase of sleep, and which may interrupt sleep. Many pathological processes have been described, including: the Shy-Dragger syndrome, Parkinson's disease, olivopontocerebellar atrophy, multisystemic atrophy, in relation to certain antidepressant drugs, and most frequently the idiopathic form. CLINICAL CASES: We present two cases, one diagnosed as olivopontocerebellar atrophy and another in which there were no pathological findings. Both were referred to our department for the study of possible sleep disorders. In both cases neurophysiological studies, basically polysomnography with monitorization of various muscle groups and video, led to the diagnosis. CONCLUSIONS: We discuss the diagnostic and physiological criteria, and physiopathological explanations of each case, with special reference to N-Methyl-D-Aspartate (NMDA) and non-N-Methyl-D-Aspartate (non-NMDA) receptors. Finally we consider the pharmacological treatment of this disorder.

[Response to high dose corticosteroids in a girl with bilateral optic neuritis]. / Respuesta a altas dosis de corticosteroides en una niña con neuritis óptica bilateral.

INTRODUCTION: Optic neuritis is rare in childhood. Frequently (35-52% of all cases depending on the series) they have, during their clinical course, foci of demyelination leading to the clinical picture of multiple sclerosis (MS). Since 1993, the optic neuritis study group has recommended treatment with high doses of corticosteroids, since this seemed to stop progression, improve long-term results and delay the appearance of MS. The course of our patient was better than we expected. CLINICAL CASE: A 10 year old prepubertal girl complained of progressive loss of vision and slight pain in the right eye for 26 days before admission to hospital. On examination there was obvious papillitis of the right ocular fundus with total loss of the pupillary light reflex, together with consensual hyporeflexia of the left eye. Study of the visual evoked potentials (VEP) showed that there was marked delay of the P-100 wave, and a lower amplitude in the right eye. Magnetic resonance imaging did not show any demyelinated focus. Serological testing for neurotropic viruses was negative. CONCLUSIONS: After the initial phase of intravenous treatment (third day) there was subjective recovery of vision and the pupillary light reflex returned. VEP studies showed marked recovery. Thirty days after treatment was started there was almost complete subjective and VEP recovery. This rapid progress, as compared to that of other paediatric cases published, suggests a mechanism involving decompression of the optic nerve.

[Neurophysiological study in Alpers syndrome]. / Estudio neurofisiológico en el síndrome de Alpers.

INTRODUCTION: Infantil progressive polydystrophy was described by Alpers in a child with psychomotor retardation, crises which were resistant to treatment and diffuse loss of cortical neurons. OBJECTIVE: The aim of this study was to review the neurophysiological aspects of Alpers syndrome and their clinical correlation. MATERIAL AND METHODS: We present three children with subacute encephalopathy, progressive psychomotor retardation, myoclonic epilepsy which was resistant to treatment and crises of apnea, who had degeneration of the cerebral grey matter. Serial EEG, polysomnographs, auditory evoked potentials of the brain stem and visual evoked potentials were done. RESULTS: The electroencephalogram findings showed the presence of complex bursts of acute waves, small many-pointed or slow waves of great amplitude which were irregular and arrhythmical, lasting one to five seconds, separated by periods of inactivity on the tracing which lasted from three to ten seconds. The EEG was distinctive, changing over the course of the illness, and with increasing numbers and duration of the bursts of suppression of cerebral bioelectric activity. Polysomnography showed cerebral bioelectric activity which was markedly unstructured and with little difference between the tracings when asleep and when awake, together with a large number of apneas of obstructive and mixed types. The PEAT showed reduced amplitude and altered morphology in all the waves, and even absence of some of them. The visual evoked potentials were asymmetrical and with delay in the latency of the P100 wave. CONCLUSIONS: Although definite diagnosis of progressive neurone degeneration requires post mortem examination of the brain, clinico-pathological studies, including electrophysiological, radiological and biochemical studies are sufficiently characteristic to suggest the diagnosis during life.

[Neurophysiological aspects of Proteus syndrome]. / Aspectos neurofisiológicos en el síndrome de Proteus.

INTRODUCTION: The Proteus Syndrome was defined in 1983 by Wiedeman. However, the first case mentioned in the literature was that of Joseph Merrick, the Elephant Man, presented by Sir Frederick Treves in 1884. It is a rare pathological condition. Its multiple clinical features include; partial gigantism of hands and/or feet, pigmented nevi, hemihypertrophy of the body, tumors, skeletal anomalies, growth disorders and visceral anomalies. Hereditary transmission has not been clearly defined. Diagnosis and treatment require the participation of experts from several medical and surgical specialties. CLINICAL CASE: We present a case sent to our hospital for the surgical correction of cranio-facial malformations. Epileptic crises post-operatively indicated the need for neurological and neuro-physiological study. This was done by means of conventional electro-encephalography: brainstem, somato-sensorial and visual auditory evoked potentials, together with imaging techniques which showed the structural and functional asymmetry of the central nervous system at both cerebral and brainstem levels. CONCLUSIONS: Few neuro-physiological studies are included in the literature we reviewed for this paper. Therefore we do not know whether the functional anomalies of the central nervous system which we describe should be considered to be part of the syndrome.