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J Narebski

Publications and source records attributed to J Narebski.

33 records · Page 2Linked to original sources
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[Usefulness of a strain of mice with genetically determined audiogenic epilepsy as a model of experimental epilepsy].

Behavioural and bioelectric characteristics of epileptic seizures caused by acoustic stimulus in mice from the Swiss Albino Rb strain with genetically determined audiogenic epilepsy are presented. The value of this epilepsy model is emphasized stressing that the epileptogenic stimulus acts from a distance, causing no damage to the nervous system and no artifacts. Besides that, seizures can be provoked at a definite frequency and at arbitrarily chosen time. A disadvantage of the model is the necessity of provoking each seizure separately which causes that this model cannot meet one of the conditions of Jasper's definition concerning spontaneity of seizure development. With regard to the course of seizure it is emphasized that it is somewhat similar to human grand mal epilepsy representing the basic phases of seizure. Electrophysiological investigations carried out under conditions of long-term fully reproducible experiment demonstrated presence of very evident and rich electrocorticographic symptomatology of audiogenic epileptic seizure whose behavioural phases show a high correlation with phasic changes in bioelectric brain activity. The investigations carried out in sleep failed to demonstrate differences in the susceptibility to seizure development when the stimulus was applied in waking state or in any of both phases of sleep. This strain is useful to morphological ultrastructural, biochemical and possibly electrophysiological investigations.

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Ambient thermal conditions and thermoregulatory mechanisms in fever in rabbits.

At ambient temperatures 10 degrees C, 20 degrees C, 30 degrees C, and 40 degrees C the influence of heat dissipation on the thermoregulatory mechanisms in rabbits with fever was investigated. Temperature of the brain (TBr-accuracy +/- 0.05 degree C) temperature of the nasal mucosa (TN) and temperature of the ear pinna (TAU-accuracy +/- 0.5 degree C) were measured in freely moving rabbits. Changes of conditions of heat dissipation were produced by: preventing heat dissipation by convection and radiation by putting ear-pads on the ear pinnae, high humidity of air for blocking of heat loss through evaporation, and facilitation of heat dissipation through shearing of the fur. The changes of the ambient thermal conditions as well as of the ability of heat dissipation were followed by changes in the dynamics of functions of the remaining (effective) thermoregulatory mechanisms in the rabbits. Thus despite changed thermal conditions of the environment, the TBr of the rabbits with fever was stabilized at a similar level.

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Absence of selective brain cooling in pyrogen-induced fever in rabbits.

In 9 rabbits the effect of intravenous administration of E. coli pyrogen 0.5 microgram/kg on the reaction of selective brain cooling was studied at ambient temperatures of 20, 30 and 40 degrees C. In the freely moving animals the temperatures of the brain, carotid artery and nuchal muscles were measured with an accuracy down to 0.05 degree C and the temperatures of the ear pinna and nasal mucosa were measured accurate to 0.5 degree C. The respiratory rate was measured as well. It was found that the spontaneous febrile reaction without the component of passive hyperthermia failed to cause selective brain cooling, even if its temperature reached higher values than in case of brain temperature rise caused only by high ambient temperature. On the other hand, when the high ambient temperature caused thermal panting, pyrogen administration at an ambient temperature of 30 degrees C could reduce panting, while at an ambient temperature of 40 degrees C intense panting initiated prior to the appearance of the febrile reaction and was associated with the fever and outlasted it.

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Reversible brain hyperthermia during audiogenic seizures in rats.

Reversible brain hyperthermia during audiogenic seizures in rats. Acta Physiol. Pol., 1979, 30 (2): 273--277. Nine rats having inborn audiogenic susceptibility had chronically implanted Cu-constantan thermocouple and epidural EEG electrodes sewed into the skull. In freely moving animals audiogenic seizures were provoked by the use of common electric bell (approx. 100 dB). The EEG trace and brain temperature (with the accuracy of 0.05 degrees C) were recorded simultaneously during 1--8 hours. Temperature increases found during 23 audiogenic seizures were similar to those noted during intensive locomotor activity of animals without seizures. In thermoneutral environment (23 +/- 2 degrees C and humidity 65% +/- 10%) brain temperature never exceeded 41 degrees C.

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