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Biomedical subjects

A Wróbel

Publications and source records attributed to A Wróbel.

53 records · Page 3Linked to original sources
PubMed1981

Interaction of extracerebellar and cerebellar cortical inputs in dentate neurons of the cat.

Interaction of afferent influences from pontine nuclei (NRTP, NPL and NPM) and inferior olive (IO) with influences from the cortex of neocerebellum (Crus I and II of hemisphere) was studied in dentate neurons (ND) in anesthetized and immobilized cats. Interaction of converging influences was tested with regard to response latencies. Activation of pontine nuclei (NP) and IO as well as cerebellar cortex affected all varieties of nuclear neurons regardless of their localization within the nucleus and their type (efferent or intranuclear). Stimulation of precerebellar nuclei (NP and IO) evoked in ND neurons an activity similar in firing patterns, displayed as bursts of excitation (S + S) lasting up to 10 ms. Initial excitation with following inhibition (S+-S), or excitation changed into inhibition with "rebound" [S+ - +(2)S] were also observed. Similar patterns of evoked activity were in neighboring nuclear neurons. Stimulation of lateral parts of Crus I and Crus II was most effective for ND. Influences from different parts of stimulated cortex have points of maximal action onto the given nuclear neuron (discrete action); divergence and convergence of influences were also observed. Cerebellar cortex stimulation depressed background impulse activity of ND neuron with gradual return to an initial level (S-S) or through a "rebound" [S- + (2)S]. Interaction of cortical and precerebellar nuclei influences was determined by algebraic summation of excitatory and inhibitory converging actions and the spontaneous activity. The latter persistently decreased in the course of repeated stimulation of the cerebellar cortex. The data show some peculiarities of that interaction and the role of the nuclear activity proper in forming the signals at the "output" of the cerebellum.

Animals↗
PubMed1981

Light level induced reorganization of cat's lateral geniculate nucleus receptive fields: a spatiotemporal study.

The spatiotemporal organization of receptive fields (RF) of the cat’s lateral geniculate cells was investigated under several scotopic and mesopic light adaptation levels, using stationary and moving light stimuli. A given adaptation level was reached by changing of either the diffuse background or the adapting central spot intensity. Both methods gave the same qualitative results. The RFs were prominently reorganized after dark adaptation. Under such conditions, the central response area was enlarged and the classic excitatory and inhibitory surrounds were hardly visible in most cases. A minimum light level was needed for developing classic surrounds. Both inhibitory and excitatory surrounds changed their spatial positions simultaneously at higher light adaptation levels. ON- and OFF-center cells changed their spatiotemporal organization similarly, thus indicating similar underlying mechanisms.

Action Potentials↗
PubMed1981

Two-unit recordings from the lateral geniculate nucleus of the cat. Some inhibitory interactions.

Pairs of units were recorded by single electrodes from cat’s LGN. Three types of pairs were distinguished. Two of them were classified as retinogeniculate pairs with positive cross-correlograms (ON center – ON center, and OFF center – OFF center); the third type consisted of negatively correlated pairs of LGN neurones. In each case the spatiotemporal organizations of both receptive fields (RFs) were analyzed at several levels of background luminance. An increase of background illumination induced more pronounced compression of the retinal than of the related geniculate ON-center RFs; a strong, central stimulation evoked oscillatory responses only in the LGN cells. The LGN neuron pairs showed a significant overlap of their RFs antagonistic areas. Potentiation of inhibition at the LGN level is discussed in relation to a proposed functional model.

Action Potentials↗
PubMed1975

The effect of background illumination on the responses of the neurons of the cat's superior colliculus to moving stimuli.

The influence of background illumination on unitary neuronal responses of cat's superior colliculus to moving stimuli were investigated. Diverse types of neurons responding to background illumination were observed: Neurons which did not change their activity during background illumination; neurons in which the response to moving stimuli during background light was facilitated; cells in which the spatiotemporal dispersion of the peak of evoked response was narrowed with light adaptation; cells in which activity was suppressed during background illumination; and neurons in which the specific response was changed to an unspecific one (and vice versa) during background illumination. The background illumination itself did not evoke any response in the cell, and the suggestion was put forward that subthreshold influences could modulate the evoked activity of the neuron.

Animals↗
PubMed1974

Distribution of latencies in the receptive fields of superior colliculus neurons in cats.

Visual receptive fields of superior colliculus neurons were investigated. The latencies of "on" and "off" responses were measured and their distribution all over the field was mapped. In 36 percent of the receptive fields the latency of the "off" response was shorter than the latency of the "on" response; 19 percent of the receptive fields had almost equal latencies; in 13 percent the latency of the "on" response was shorter than that of the "off" response in the majority of explored points; 32 percent were mixed receptive fields with different types of latency distribution. The hypothetical considerations of possible mechanisms of organization of receptive fields in cat midbrain are presented.

Animals↗
PubMed1974

Analysis of visual information in midbrain centers.

The role of pretectum and colliculus superior in the analysis of visual information was studied. Single unit responses to visual stimuli were recorded. Several types of responses were observed, including "suppressed by contrast", "direction non-sensitive" and "direction sensitive" responses. An attempt was made to define the place and mechanism of direction-sensitivity of the cell. The conclusion is put forward that horizontal cells in the first layers of retina are not responsible for direction-sensitivity. Detailed analysis of receptive field structure revealed "homogeneous" and "heterogeneous" types of receptive fields as shown by response patterns of the neuron to a flashing light spot positioned in different parts of the receptive field. Study of latency distributions also revealed both complex "heterolatent" and more simple "homolatent" organizations of receptive fields The effect of the intensity of background illumination was investigated. Results show that changing of the background illumination can influence the response pattern of a cell, and sometimes can influence the direction-sensitivity.

Animals↗
PubMedDate not supplied

Monitoring of MRP-like activity in human erythrocytes: inhibitory effect of isoflavones.

A method to fluorometrically monitor efflux of 2',7'-bis-(carboxypropyl)-5(6)-carboxyfluorescein (BCPCF) from human erythrocytes was developed. Genistein, daidzein, sophoraisoflavone A, and licoisoflavone A induced 50% inhibition (IC(50)) of BCPCF efflux at 15-70 microM. The IC(50) value of the most efficient isoflavone, licoisoflavone A (15-25 microM), was comparable to that of indomethacin (approximately 10 microM) and markedly lower than for probenecid (100-200 microM), both known MRP1 inhibitors. Our results indicate that the human erythrocyte is a useful cell model in screening potential MRP inhibitors, that BCPCF is a good substrate for MRP, and that some isoflavones at low concentrations inhibit MRP-mediated efflux.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMedDate not supplied

[Children and parental depression. An investigation on adult offspring of depressed patients].

The aim of our study was to assess the perception of parental depression by their adult offspring. Twenty nine offsprings aged 22.5 +/- 3.9 years were examined with the use of Parental Bonding Instrument, Beck Depression Inventory, Resenberg Scale, Hopelessness Scale, Automatic Thoughts Questionnaire and our own semistructured inventory. The offsprings of depressed patients reported negative impact of the illness on various aspects of life, especially when mother was ill. Surprisingly, the offsprings did not reveal disturbances in their thinking style, neither did they have depressive symptoms.

Adolescent↗
PubMedDate not supplied

[Religiosity and intensity of endogenous depression symptoms. A follow-up study].

The aim of our study was to determine if the quality of remission in unipolar affective disorder correlates with patient's religiosity. We have investigated 63 patients who were hospitalised in the Department of Psychiatry CMUJ between 1991 and 1997. The quality of remission has been assessed by Beck Depression Inventory (BDI), Rosenberg Self-esteem Scale (RS), Automatic Thoughts Questionnaire (ATQ), Hopelessness Scale (HS). Religiosity has been tested by the Scale of Individual Religiosity, and Religious Life Inventory. Patients were also assessed with the use of our own questionnaire, answering the following questions: 1. Do you believe?, 2. Does the disease influence the faith?, 3. Does your faith help in the disease?. Religiosity did not correlate with the quality of remission in depression in a statistically significant manner. There is only one statistically significant correlation: patients who answered positively the question number 3 (41 patients), have better remission. It is impossible to describe simple correlation between religiosity and remission in unipolar affective disorder. Patients who found their faith helpful have better remission.

Depressive Disorder↗
PubMedDate not supplied

Reversal of stress-induced deficit in aggression by monoamine oxidase inhibitors.

In the present study we investigated the effect of two monoamine oxidase (MAO) inhibitors: moclobemide (selective, reversible inhibitor of MAO-type A) or selegiline (selective irreversible inhibitor of MAO-type B) on electric footshock-induced fighting behavior in normal (unstressed) and chronically stressed (14 various stressors over 16 days) rats. In rats exposed to chronic stress the number of fighting attacks was reduced by about 75%. Prolonged (once a day, for 14 days) treatment with moclobemide (50 mg/kg/day) or selegiline (2 mg/kg/day) counteracted the deficit in aggression induced by chronic stress. The findings of the present study demonstrate that the selective MAO inhibitors, moclobemide and selegiline, protect against "behavioral depression" induced by the chronic stress similarly to other classes of antidepressant drugs.

Aggression↗
PubMedDate not supplied

Pharmacological profile of reboxetine, a representative of new class of antidepressant drugs, selective noradrenaline reuptake inhibitor (NARI), given acutely.

Pharmacological effects of acute treatment with reboxetine (REB), a clinically active antidepressant (a noradrenaline reuptake inhibitor without any affinity for neurotransmitter receptors), were studied in mice and rats. REB inhibited the reserpine- or apomorphine-induced hypothermia in mice. It reduced the immobility time in Porsolt's test in mice and rats, but it did not change the locomotor activity in mice and rats. REB changed neither the clonidine-induced aggressiveness in mice nor the behavioral syndrome induced by oxotremorine in rats. The obtained results indicate that REB, given acutely, shows a pharmacological profile similar to that of tricyclic or tetracyclic noradrenaline reuptake inhibitors. In contrast to the antidepressants mentioned above, REB does not exhibit an alpha1-adrenolytic or cholinolytic activity (in vivo tests).

Adrenergic Uptake Inhibitors↗
PubMedDate not supplied

[Depressive disturbance and quality of life in patients with coronary artery disease].

The aim the study was to evaluate the impact of mood disturbances on the subjective quality of life in patients with coronary artery disease after an effective angioplasty. The study covered 100 patients with the optimum result of PTCA. Their condition was evaluated one day before and four weeks after angioplasty. Significant differences in the subjective quality of life assessment were detected depending on the occurrence and dynamics of depressive symptoms. The authors postulate evaluation of psychological state and introduction of anti-depressive therapy in patients with coronary artery disease subjected to revascularisation.

Coronary Artery Bypass↗
PubMedDate not supplied

Glucocorticoids modulate behavioral effects induced by dopaminergic agonists in rats.

Studies showing the presence of glucocorticoids, and their binding sites in the central nervous system indicate that these hormones may affect central neurotransmission. Both, dopaminergic brain system and glucocorticoids are considered to be involved in certain psychopathological conditions in humans, including depression, addiction or schizophrenia. The present study aimed to investigate the influence of glucocorticoids on dopamine agonists-induced stereotyped behavior and locomotor hyperactivity in rats. The results of the experiment demonstrate that prior to administration of prednisolone (4, 6, 10 or 20 mg/kg) or dexamethasone (4 or 8 mg/kg) intensified and prolonged the stereotypy induced by apomorphine (1 mg/kg sc) or amphetamine (2 mg/kg ip). The effect of dexamethasone was more potent. Amphetamine (0.4 mg/kg)- or amantadine (50 mg/kg)-induced locomotor hyperactivity was significantly reduced in rats pretreated with dexamethasone at a dose of 8 mg/kg or 4 mg/kg. Our observations suggest that exogenous glucocorticoids may enhance the activity of the dopaminergic agonists in the striatum but reduce it in the mesolimbic system of rats.

Animals↗