摘要:

The effect of increasing serum estradiol levels on platelet [3H]PK 11195 binding was investigated to determine the influence of gonadal steroids on platelet peripheral benzodiapezine binding sites. Serum estradiol and platelet [3H]PK 11195 binding were determined in 10 anovulatory, but otherwise healthy women before and after treatment with human menopausal gonadotropin. Despite a 30-fold increase in posttreatment estradiol, the kinetic parameters of platelet [3H]PK 11195 binding (Kd, Bmax) remained essentially unchanged. These data indicate that peripheral benzodiazepine binding sites on platelets are not influenced by elevated concentrations of estradiol. Thus, it is suggested that variations in circulating levels of this female gonadal steroid are likely not responsible for the modifications in platelet peripheral benzodiazepine binding sites seen in association with various disease states.

ISSN:0302-282X    

DOI:10.1159/000119447

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

We investigated the possible relationship between platelet MAO activity and behavioural characteristics, measured by MMPI, in a group of 19 healthy volunteers. The results showed that high MAO activity tended to be typical of subjects with inhibitory characteristics and that low MAO activity was more typical of uninhibited subjects.

ISSN:0302-282X    

DOI:10.1159/000119448

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

The binding of the selective dopamine uptake inhibitor [3H]GBR-12935 to rat striatum was studied. Competition by mazindol and dopamine against [3H]GBR-12935 binding revealed monophasic binding curves. The addition of 100 μM dopamine to the mazindol competition inhibited only 80% of the binding, indicating more than one [3H]GBR-12935 binding site in rat striatum. When a binding fraction that could be discriminated by 1 μM mazindol or 1 mM dopamine was defined as specific binding, a single site binding model was obtained. The [3H]GBR-12935 binding was of protein nature, since it was abolished after protease treatment. Drug inhibition studies with the addition of low concentrations of mazindol and dopamine resulted in alterations in apparent Kd values only, suggesting competitive inhibition by these compounds against [3H]GBR-12935 binding. It is concluded that the [3H]GBR-12935 binding to rat striatum discriminated by 1 μM mazindol reflects binding to the substrate recognition site for the dopamine upta

ISSN:0302-282X    

DOI:10.1159/000119449

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Using positron emission tomography (PET), measurements of the regional cerebral metabolic rate of glucose (rCMRGlc) are able to delineate cerebral metabolic responses to external or mental stimulation. In order to examine possible changes of brain metabolism due to Yoga meditation PET scans were performed in 8 members of a Yoga meditation group during the normal control state (C) and Yoga meditative relaxation (YMR). Whereas there were intraindividual changes of the total CMRGlc, the alterations were not significant for intergroup comparison; specific focal changes or changes in the interhemispheric differences in metabolism were also not seen; however the ratios of frontal vs. occipital rCMRGlc were significantly elevated (p < 0.05) during YMR. These altered ratios were caused by a slight increase of frontal rCMRGlc and a more pronounced reduction in primary and secondary visual centers. These data indicate a holostic behavior of the brain metabolism during the time of altered state of consciousness during YMR.

ISSN:0302-282X    

DOI:10.1159/000119450

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Platelet MAO activity has been found to have behavioral (psychiatric and personality) correlates. The purpose of the present study was to explore the nature of the connections between platelet MAO activity and behavior by analyzing performance in neuropsychological tasks in relation to platelet MAO activity, measured in 37 male subjects. The following neuropsychological tests were given: a finger tapping and alternation test, a reaction time test, a perceptual maze test, a perspective fluctuation task (the Necker cube), and a lexical decision task. The reaction time tasks comprised a motor disinhibition task, in which auditory stimuli given simultaneously with light stimuli were signals for response inhibition. Significant relationships were obtained between low MAO activity and short response times and small variations in response times to left-sided visual stimuli, suggesting a readiness for higher right hemisphere activation in low MAO subjects, and between low platelet MAO activity and many perspective reversals, in line with expectations. Furthermore, high MAO subjects had equal tapping speed for both hands, which has been found in schizophrenic patients. Of special interest in the present results is the strong negative relationship obtained between platelet MAO activity and number of failed inhibitions in the motor disinhibition task, which in a multiple regression analysis highly significantly contributed to the prediction of platelet MAO activity. This finding is in line with the poor passive avoidance performance associated with serotonergic deficiency and syndromes of disinhibition, and thus supports the assumption that platelet MAO activity may be considered as a genetic marker for some properties of the central serotonergic system.

ISSN:0302-282X    

DOI:10.1159/000119451

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

The characteristics of the power density spectra of the frontal and occipital cortical EEG between 1 and 31 Hz as well as the total power of the neck muscle EMG during an 8-second epoch were used to differentiate 8 vigilance stages in normal rats. The following stages and the time spent within these stages during a 6-hour recording (9.00–15.00) were evaluated: waking with active EMG (about 127 min), waking (7 ± 3 min), theta-waking (25.5 ± 9 min), classical sleep I (dozing; 107 ± 11 min), classical sleep II (41 ± 6 min), paradoxical sleep (PS; 30 ± 9 min), transitional phase (PS spindles; 9.5 ± 4 min) and transitional dozing (13 ± 3 min). Two additional stages were differentiated in rats suffering from petit mal: paroxysmally occurring spikes and waves and an especially marked transitional phase. The absolute power spectra of these vigilance stages (except active waking) were plotted as well as the statistically analyzed deviations from the mean power spectra of all epochs without active EMG. A comparison between the mean power spectra of a control recording and a recording after oral application of 10 mg/kg diazepam indicates that these differences are less marked than between the vigilanc

ISSN:0302-282X    

DOI:10.1159/000119452

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Single, 50- and 100-mg oral doses of phenobarbital and a matching placebo were administered double-blind to 8 young, healthy male subjects. Multilead electroencephalographic (EEG) samples were recorded prior to, and at regular intervals within the 2 h following administration. The EEG signal was processed by power spectral analysis; the drug plasma concentration was assessed concomitantly. Plasma peaks after the 50- and 100-mg dose were, respectively, 3.38 ± 1.29 and 4.09 ± 1.24 μg/ml. Despite the low drug plasma concentration, a systematic power increment of the EEG fast frequency spectral segments occurred at either dose on the anterior scalp areas from the 30- or 60-min postdrug control onward, and was preponderant on central electrodes; a significant correlation (Kendal’s coefficient for ranked data) with the drug plasma concentration was observed limitedly to the anterior scalp areas. No correlation with plasma levels was observed for unsystematic EEG variat

ISSN:0302-282X    

DOI:10.1159/000119453

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Spectral analysis was performed to study the response of various EEG sleep activities to a modification of GABAergic sleep regulation by flunitrazepam. We observed sleep stage- and sleep cycle-dependent differences in the topographic distribution of the reactions. An increase in power density was found in the frontal regions for the alpha 2 and sigma 1 frequency band whereas a decrease in power density was emphasized in the posterior regions for the delta and alpha 1 frequency band. These topographic differences might be related to the regional distribution of benzodiazepine receptor subtypes.

ISSN:0302-282X    

DOI:10.1159/000119454

出版商:S. Karger AG    

年代:1990

数据来源: Karger

ISSN:0302-282X    

DOI:10.1159/000119455

出版商:S. Karger AG    

年代:1990

数据来源: Karger

ISSN:0302-282X    

DOI:10.1159/000119456

出版商:S. Karger AG    

年代:1990

数据来源: Karger