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Biomedical subjects

K Mitros

Publications and source records attributed to K Mitros.

6 recordsLinked to original sources
PubMed1992

Effect of flunarizine and nimodipine on the decrease in tryptophan hydroxylase activity induced by methamphetamine and 3,4-methylenedioxymethamphetamine.

The effect of calcium channel blockers on the decrease in central tryptophan hydroxylase (TPH) activity and serotonin (5-HT) concentration induced by repeated large doses of methamphetamine (METH) or 3,4-methylenedioxymethamphetamine (MDMA) was evaluated. Rats received four or five injections of METH (10 or 15 mg/kg) or MDMA (10 mg/kg) at 6-h intervals, and were sacrificed 18 to 20 h or 1 week after the last administration. Flunarizine (30 mg/kg) prevented the decline in cortical and neostriatal TPH activity induced by MDMA, but failed to alter the effect of METH. The effect of flunarizine on the METH- and MDMA-induced changes in cortical 5-HT and 5-hydroxyindoleacetic acid concentrations paralleled the changes in enzyme activity. Nimodipine, diltiazem or TA-3090 failed to prevent the MDMA- and the METH-induced decline in TPH activity or in 5-HT and 5-hydroxyindoleacetic acid content. Because haloperidol failed to mimic the protective action of flunarizine, it is unlikely that flunarizine exerts its action by blocking the dopamine D-2 receptors. This study suggests that calcium influx may participate in the MDMA-induced decline in central TPH activity, and that the mechanism by which MDMA and METH decreases TPH activity differs.

3,4-Methylenedioxyamphetamine↗
PubMed1978

The effect of first visual stimulation on incorporation of labelled leucine into cerebral cortex of binocularly deprived kittens.

One-month old kittens, binocularly deprived with hoods from birth, were used. Before the experiments in which visual stimulation was applied the brainstem of kittens was transected at the pretrigeminal level. Cortical EEG activity and ocular behavior indicated that the isolated cerebrum of preparations was usually awake during experiment. Patterned visual stimulation was directed to one hemisphere, while the other was used as a control. Visual stimulation evoked in some cases (in 8 out of 17) an increase of incorporation of labeled leucine into the proteins of the striate cortex. Electrophoresis on polyacrylamide gel did not reveal any differences in the pattern of insoluble proteins between the stimulated and control visual cortex. It is suggested that first visual stimulation may enhance the protein metabolism of striate cortex in young kittens. Some unknown up to now physiological factors (motivation, attention?) may be critical for these phenomena.

Animals↗
PubMed1976

Activity of some enzymes in the cortex of the cat with pretrigeminal brainstem transection.

The visual and somatic sensory cortex were investigated. The activity of acetylcholinesterase and lactate dehydrogenase was similar in the pretrigeminal and non-operated cats. The activity of these two enzymes, as well as that of choline acetyltransferase, butyrylcholinesterase and acid phosphatase was similar 3 and 8 h after the pretrigeminal transection. Results support the possibility of utilizing the pretrigeminal cat for investigations of biochemical correlates of learning.

Acetylcholinesterase↗
PubMed1976

Electrophoretic patterns of insoluble proteins in the sensory cerebral cortex of visually deprived and normal kittens.

Insoluble proteins were investigated in the visual cortex (area 17) and somatic sensory cortex of one month old kittens. Visual deprivation did not affect the electrophoretic pattern but changed percentage distribution of proteins in both cortices. Some of the alterations seemed to appear only in the visual cortex, which is morphologically and functionally deficient in deprived kittens. Electrophoretic patterns of normal kittens differed from those of normal adult cats.

Age Factors↗
PubMed1975

The variability of innate darkness preference in mice: an evaluation of Ungar's design.

This study attempted to elucidate the controversy surrounding the experiments of Ungar examining the effects of scotophobin on dark preference in mice. The behavior of 45 noninjected mice in the type of maze described by Ungar was examined. Seven subsequent tests were conducted for dark box time (DBT) and motor activity. In general, the results indicated that DBT in all subpopulations of mice selected according to different criteria on the preference test fluctuated during the course of experimentation. Further, on the basis of the present data, the problem of summation effects from combined probabilities in the series of independent comparisons was readily apparent, so that the probability of obtaining significant differences between groups was increased as the results of Ungar's data analysis. A strong relationship between motor activity and DBT was also obtained, suggesting that other, nonspecific factors may influence motor activity and shorten the elevation of DBT.

Animals↗