Implication of the endocannabinoid system in the locomotor hyperactivity associated with congenital hypothyroidism

Alterations in motor functions are well-characterized features observed in humans and experimental animals subjected to thyroid hormone dysfunctions during development. Here we show that congenitally hypothyroid rats display hyperactivity in the adult life. This phenotype was associated with a decreased content of cannabinoid receptor type 1 (CB(1)) mRNA in the striatum and a reduction in the number of binding sites in both striatum and projection areas. These findings suggest that hyperactivity may be the consequence of a thyroid hormone deficiency-induced removal of the endocannabinoid tone, normally acting as a brake for hyperactivity at the basal ganglia. In agreement with the decrease in CB(1) receptor gene expression, a lower cannabinoid response, measured by biochemical, genetic and behavioral parameters, was observed in the hypothyroid animals. Finally, both CB(1) receptor gene expression and the biochemical and behavioral dysfunctions found in the hypothyroid animals were improved after a thyroid hormone replacement treatment. Thus, the present study suggests that impairment in the endocannabinoid system can underlay the hyperactive phenotype associated with hypothyroidism.

Motor overactivity and loss of motor circadian rhythm in fatal familial insomnia: an actigraphic study.

The 24-hour rest-activity pattern and the amount of motor activity was studied in a patient with fatal familial insomnia (FFI) by means of wrist actigraphy. During the study, the patient underwent indirect calorimetry. The 52-day recording showed severe disruption of the 24-hour rest-activity pattern with increased motor activity up to 80%. The 24-hour energy expenditure, assayed in a respiration chamber, was strikingly elevated by 60%. Chronic motor overactivity and loss of circadian rest-activity rhythm may play a role in the progressive metabolic exhaustion leading to death in FFI patients.

Mouvements anormaux et accident vasculaire cérébral [Movement disorders in stroke]

Dyskinesias are infrequent presentations in acute stroke (1%). They can be found more frequently as delayed presentations after a stroke, but the prevalence is not available from the literature. The full spectrum of hyper- and hypo-akinetic syndromes has been described, but three main pictures are rather specific of an acute stroke: limb shaking, hemichorea-hemiballism and unilateral asterixis. Besides limb shaking, that seems to reflect a transient diffuse ischemia of the frontosubcortical motor pathway, lesions are described at all levels of the frontosubcortical motor circuit including the sensorimotor frontoparietal cortex, the striatum, the pallidum, the thalamic nuclei, the subthalamic nucleus, the substantia nigra, the cerebellum, the brainstem and their interconnecting pathways, as ischemic or hemorrhagic strokes. The preferentially late development of dyskinesia could reflect the return to a more ancestral motor control level, the most functional possible with the remaining configuration of structures, elaborated by brain plasticity after stroke.

An educator's perspective of Dr. Feingold's K-P (Kaiser- Permanents) elimination diet for hyperkinetic children and others

Do evaluation of the literature and a regional observational report support Dr. Feingold's claim that the K-P (Kaiser-Permanente) elimination diet improves the behaviours of hyperkinetic children, and others? Dr. Feingold suggests that some hyperkinetic children, and other children as well, are genetically predisposed to intolerance of food additives, particularly food colours and flavours. He claims that the K-P diet, that eliminates salicylates and artificial food colours and flavours, improves the hyperkinetic child's behaviour, muscle co-ordination, and scholastic performance. Public acceptance of the K-P diet has outstripped acceptance in the medical and scientific communities. Evaluation of available data and additional studies are needed to arrive at a conclusion of acceptance or rejection of the K-P diet for hyperkinetic children and others. My interest in the K-P elimination diet for hyperkinetic children is educational. My experience as an elementary school teacher in special education and in the classroom from K-8 has taught me that attentiveness is crucial to learning. Hyperkinesis appears to impair a child's ability to attend. Learning problems appear, followed by behavioural and social problems. l If we accept the possibility of a relationship between diet and attentiveness, and attentiveness and school behaviours, then the diet-behaviour link could be of lay importance. For instance, if a diet such as the K-P diet could do what is claimed, substantial benefits could accrue to the child. One could, for example, improve a child's behaviours. One could identify attending disturbances early in the child's education, possibly minimizing, or eliminating future difficulties in school. Finally, the greatest benefit may be the fulfillment of the basic goal of our Ontario schools, that the eh~ld-,lIla1p.evelop happily and competently within our educational framework. 2 This thesis reports evidence from the literature and from a regional observational investigation to determine the possibility of a link between the behaviours of children and Dr. Feingold's K-P elimination diet. The literature research examines (1) Dr. Feingold's concept of H-LD, (2) his K-P elimination diet, and (3) the response from three sectors, medicine, science, and the public. The regional investigation examines the observed behaviours of nine children in Regional Niagara during a nine-month period on the K-P diet.

Physiological and behavioural effects of dextroamphetamine on Beagle dogs : a placebo controlled study

Plusieurs articles scientifiques et manuels de référence en médecine comportementale distinguent l'hyperactivité ou hyperkinésie de l’activité excessive en évaluant la réponse physiologique et comportementale des chiens suite à l’administration per os de 0.2 à 1.0 mg/kg de dextroamphétamine. Selon ces références, le chien atteint d’un syndrome hyperactif ou hyperkinésie, répondra de façon paradoxale à cette médication par une diminution de l’activité motrice accompagnée d’une réduction minimale de 15% de la fréquence respiratoire et de la fréquence cardiaque. L’objectif de la présente étude était de mesurer la variation de la température corporelle, de la fréquence cardiaque, de l’activité motrice et de différents comportements spécifiques chez un groupe de Beagles ayant reçu de la dextroamphétamine. La fiabilité d'un accéléromètre comme mesure objective d’activité motrice a aussi été évaluée. Dans le cadre de cette étude croisée contrôlée par placebo, douze Beagles de la colonie de recherche âgés entre 13 et 20 mois ont reçu une dose orale de 0.2 mg/kg de dextroamphétamine. Le moniteur cardiaque Polar® et un accéléromètre Actical® ont été utilisés pour enregistrer la fréquence cardiaque et l’activité motrice avant et après l’administration de la médication. La durée de chacun des comportements spécifiques a été compilée à l’aide du logiciel Noldus® et la température corporelle a été prise par thermomètre rectal. Le modèle équilibré de mesures répétées indique que les sujets ayant reçu la dextroamphétamine montrent une réduction significative (p = 0.044) de leur fréquence cardiaque comparativement aux chiens ayant reçu le placebo. Aucune variation significative n'a été observée concernant la température corporelle, l'activité motrice, et les autres comportements (léchage des babines, halètements, et bâillements) suite à l’administration de la dextroamphétamine. Une corrélation significative, linéaire et positive (p < 0,0001) entre les périodes de mouvements observées (vidéo) et les mesures d’activité enregistrées par l’accéléromètre a été observée. Les résultats de cette étude indiquent que les Beagles peuvent afficher des effets paradoxaux dans les 90 minutes suivant l’administration per os de dextroamphétamine à raison de 0.2 mg/kg.

Acquired hepatocerebral degeneration and hepatic encephalopathy: correlations and variety of clinical presentations in overt and subclinical liver disease

A degeneração hepatocerebral adquirida (AHD) e a degeneração hepatolenticular podem ter apresentações clínicas semelhantes, mas quando uma doença hepática crônica e achados motores atípicos coexistem, a distinção entre AHD e encefalopatia hepática (HE) pode ser ainda mais complicada. Descrevemos três casos de AHD (dois tendo HE) com diferentes achados em neuroimagem, doenças hepáticas distintas e apresentações motoras semelhantes, todos com hipertensão arterial e perda de peso antes das manifestações motoras. O diagnóstico e a fisiopatologia são comentados e comparados com relatos prévios. Concluímos que existem muitas correlações entre HE, degeneração hepatolenticular e AHD, mas a sobreposição de HE e AHD pode ser mais comum dependendo do conhecimento clínico e da acurácia dos critérios diagnósticos adotados para cada enfermidade. Como a AHD não é considerada prioridade na lista de transplante hepático, o prognóstico dos pacientes com AHD permanece ruim, e a interrupção do fluxo nos shunts portossistêmicos deve ser sempre considerada.

Acute and chronic methylphenidate dose-response assessment on three adolescent male rat strains.

Methylphenidate (MPD), commonly known as Ritalin, is the most frequently prescribed drug to treat children and adults with attention deficit hyperactivity disorder (ADHD). Adolescence is a period of development involving numerous neuroplasticities throughout the central nervous system (CNS). Exposure to a psychostimulant such as MPD during this crucial period of neurodevelopment may cause transient or permanent changes in the CNS. Genetic variability may also influence these differences. Thus, the objective of the present study was to determine whether acute and chronic administration of MPD (0.6, 2.5, or 10.0mg/kg, i.p.) elicit effects among adolescent WKY, SHR, and SD rats and to compare whether there were strain differences. An automated, computerized, open-field activity monitoring system was used to study the dose-response characteristics of acute and repeated MPD administration throughout the 11-day experimental protocol. Results showed that all three adolescent rat groups exhibited dose-response characteristics following acute and chronic MPD administration, as well as strain differences. These strain differences depended on the MPD dose and locomotor index. Chronic treatment of MPD in these animals did not elicit behavioral sensitization, a phenomenon described in adult rats that is characterized by the progressive augmentation of the locomotor response to repeated administration of the drug. These results suggest that the animal's age at time of drug treatment and strain/genetic variability play a crucial role in the acute and chronic effect of MPD and in the development of behavioral sensitization.