Biomedical subjects

A Bal

Publications and source records attributed to A Bal.

At least 37 records · Page 2Linked to original sources

PubMed1987

Separation of the motivational and motor consequences of 6-hydroxydopamine lesions of the mesolimbic or nigrostriatal system in rats.

The effects of 6-hydroxydopamine (6-OHDA) lesions in the ventral tegmental area (VTA) or substantia nigra, pars compacta (SN/pC) on the behaviour of hungry rats were examined in a Columbia obstruction box test. The lesions of dopaminergic neurones in the VTA as well as in the SN/pC decreased the number of crossings of an electric obstruction for food. After the lesion in the VTA the reaction of rats became independent of the level of hunger--the number of their crossings was similar at different levels of hunger. In contrast, no effect of the lesion was found when the animals were trained and tested in the absence of shock. The 6-OHDA lesion in the SN/pC also decreased the number of crossings, but the animals remained sensitive to motivational hunger stimuli: they were still crossing the obstruction in a hunger-dependent manner. Lesions in neither the VTA nor the SN/pC significantly altered the spontaneous food intake and sensitivity to painful electric stimuli. In the Rotarod test only the SN/pC-lesioned rats showed a substantial motor impairment; lesions in the VTA had no effect in that test. The obtained results are discussed in terms of the role of the dopaminergic mesolimbic and nigrostriatal systems in mediation of the motivational arousal and motor performance of an instrumental food response.

Animals↗

PubMed1987

The influence of some antidepressant drugs on the nuclear volume of rat cingular cortex cells in culture.

The changes in the volume of cell nuclei of the rat cingular cortex were investigated in culture after incubation with some antidepressant drugs. Two-week incubation of the cingular cortex culture with both tricyclic (desipramine, imipramine, amitryptyline) and non-tricyclic (mianserin) antidepressants in concentration of 3 X 10(-6) M resulted in a decrease of the volume of the cell nuclei. Because the size of the nucleus is regarded as a criterion of the cell metabolic activity, our results may point to a diminished activity of metabolic processes of the cells.

Animals↗

PubMed1987

Histofluorescence studies of monoamine neurons in the rat brain after cobaltous acetate intoxication.

The aim was to study changes in brain monoamine neurons in an experimental animal model with an extrapyramidal motor syndrome of the parkinsonian type. The neurological signs were observed in rats after acute cobaltous acetate intoxication under mild ischemic conditions. Histofluorescence studies showed a decrease in catecholamine fluorescence (which signifies a decrease in the amine content) in the hypothalamus and mesencephalic reticular formation, but not in the substantia nigra or basal ganglia. Serotonin fluorescence was increased in nerve cell bodies of the dorsal and median raphe nuclei and in nerve terminals in some thalamic and preoptic regions. Histological staining of sections adjacent to the fluorescent ones showed no neuronal loss and some pathology of myelin. The disturbing effect of cobaltous ions on the neuronal transmission, and/or the imbalance between dopamine and serotonin in the extrapyramidal motor syndrome observed in poisoned rats have been discussed.

Acetates↗

PubMed1986

Motivational versus motor impairment after haloperidol injection or 6-OHDA lesions in the ventral tegmental area or substantia nigra in rats.

The effects of blockade of dopaminergic receptors as well as the lesions of dopaminergic neurons on the behaviour of rats in "motivational" and "motor" tests were examined. Both systemic injection of haloperidol and 6-OHDA lesions in the ventral tegmental area (VTA) or substantia nigra, pars compacta (SN/pC) induced a decrease in the number of wins made by thirsty animals fighting for water in a water competition test. The rats with lesions in the VTA became insensitive to motivational thirst stimuli. The reaction of rats lesioned in the SN/pC was still dependent on the level of thirst. Both groups did not differ from controls in the amount of water intake. In the rotating rod test the animals with destroyed nigrostriatal system showed a substantial motor impairment, while destruction of the mesolimbic system had no effect in that test. The role of dopaminergic systems in terms of their involvement in the control of motivational arousal and motor performance has been discussed.

Animals↗

PubMed1985

Distribution of immunoreactive alpha-neo-endorphin in the rat brain.

The distribution of immunoreactive alpha-neo-endorphin (alpha-Neo) in the rat brain was demonstrated by means of highly specific radioimmunoassay (RIA). The highest concentrations of immunoreactive (ir) alpha-Neo (100 pmol/g tissue) were found in the substantia nigra, the hypothalamic supraoptic nucleus (86 pmol/g) and the preoptic area (63 pmol/g); medium levels were found in the basal ganglia, mesencephalic reticular formation, nucleus accumbens and hippocampus. Other structures contained less alpha-Neo-ir. The possible anatomical interaction between alpha-Neo and monoaminergic nerve terminals or cell bodies in some structures is discussed.

Animals↗

PubMed1985

Monoamine distribution on the ventral surface of the rat medulla oblongata.

The distribution of monoamine transmitters in the area near the ventral surface of the rat medulla oblongata was studied using the Falck-Hillarp histofluorescence method. Histological examination and scanning electron microscopy of these regions were also performed. It was found that there is a wide area dense with catecholamine terminals in the external layer of the ventral medulla oblongata. 5-Hydroxytryptamine-containing terminals and nerve cell bodies on and near the surface were also found. Due to their superficial localization these monoamines may influence the content of cerebrospinal fluid and in this way have effects on cardiovascular and other physiological functions.

Animals↗

PubMed1984

The effect of morphine on 5-hydroxytryptamine and catecholamine neurons in the rat brain. Histofluorescence studies.

The effect of acute morphine injection (4 or 40 mg/kg, i.p.) on serotonergic (5-HT) and catecholaminergic (CA) neurons in several areas of the rat brain was studied using the Falck-Hillarp histofluorescence method. Changes in fluorescence intensity (i.e. the changes in amine content) were only found in a few discrete regions. Biphasic changes occurred; an initial decrease (after 40 min) was followed by an increase (after 90 min) in amine content of 5-HT nerve cell bodies and CA terminals in the dorsal raphe nucleus and in the region of group B3. Increases were also observed after 90 min in 5-HT nerve cell bodies in the median raphe nucleus and terminals in the nucleus linearis caudalis, and in CA nerve cell bodies in the pars compacta of the substantia nigra and the ventral tagmental area. No significant changes in fluorescence were observed after two weeks chronic morphine treatment. The changes in fluorescence after acute morphine treatment occurred in structures involved in analgesic function. The time-course of these changes suggests that morphine increases both the release and synthesis of 5-HT and CA in these structures.

Animals↗

PubMed1983